# New Departure rear hub discs



## jd56 (Apr 23, 2014)

On a model D, how many steel disc's and how many brass discs should there be?


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## jd56 (Apr 23, 2014)

I posted this earlier in another thread that had this ND mod D diagram.






As it states in this diagram, there a 23 count on the disc   pack. 
I have a mod D that had 26 discs. One extra steel disc's from what can guess. 
Removed the extra and then started reassembly.  The brake clutch with the spring won't fit onto the shaft. I never took this section apart in fact I greased that ends bearing with it all assembled as I don't have the spanner wrench to remove the hub sprocket.









So I took out 6 more discs and now it fits onto the spline.




So can this work?
I'm guessing someone must have serviced this hub and added the extra disc by accident but I can't see how or why an additional 6 would be added.

Let me also mention this hub was never tested before it's breakdown. It was very tight though (not free spinning as one would expect).

I am stuck at this point with this rear wheel resto....help me guys and gals!!


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## dougfisk (Apr 23, 2014)

There are a couple different versions.  The most common (in my experience) has 17 discs.  These discs would be noticably thicker than the version with 23.  Measure the height of the stack and compare to others in your posession... or I can measure some later this evening.  What is the approximate vintage of the hub you are working on?


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## jd56 (Apr 23, 2014)

Don't have another that ai can breakdown to measure. The discs seem to be the seem thickness as all the other D's I've done in the past.
The bike is a 1938 Hawthorne. Have no idea if it is the correct rear hub. The brake arm as pictured above appears to be from th eff prewar 30s era. With the model D stamping on the arm with 2 hash marks
Doug if you can measure what your stacks are, maybe that will help.
I guess my concern is if it all fits together with the removed discs, will it work?


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## dougfisk (Apr 23, 2014)

I counted and measured the discs in 4 older ND hubs.  I found: 20 at .690, 20 at .714, 23 at .723, 21 at .79 and 21 at .751.  I have seen hubs with different thicknesses mixed together.  My (2) 20's would not be original as OEM would always have been an odd number.

I ran out of time tonight, but tomorrow I can open some boxes and measure the height of new replacement sets.  I think I remember doing that before, and I think .750 is it.  If you need to wrap it up now, I would start with whatever odd number stacks up to .750.  If you do not like the action, you can add or subtract as needed.


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## jd56 (Apr 24, 2014)

*3/4" high*

Thanks Doug.
Obi Wan mentioned he thought it was 3/4" high as well in my other thread about the discs number.
I agree that it should be an odd number so 19 to 21 will be the number I go with. 
Not sure if I have the thick discs vs the thinner discs on this setup.
but do recall that it should start with steel and end with steel discs.

I also brass brushed the discs to try to remove the glazing that accumulates after years of used. Hopefully that it the correct proceedure to do.
Brushed 30 weight motor oil on the discs to lubricate as well.

Just don't understand why so many extra discs were in the hub when I disassembled. They just don't all fit on the spline (#22 in the pictured diagram above) as to allow the clutch (#6) with the spring (#12) to fit on the squared splined end.


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## dougfisk (Apr 24, 2014)

My new-in-the-box replacement sets have 17 discs and measure .750 inch.  So, again, I would use whatever odd number it takes of yours to equal three quarters of an inch.


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## jd56 (Apr 26, 2014)

My discs seem to be thicker than I've seen before.
But, I did install 19 on this application. And the stack was about 3/4". We'll see how it works.


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## Miq (Nov 17, 2019)

I was looking at this today.  My 1941 Schwinn's ND Model D came with 23 discs.  Similar to what's called out in this dwg:





But clearly this changed over time. Dropping to 21 discs called out in step 4 of this dwg:





And down to the now default number of 17 discs per set (D278).





The Schwinn Repair Manual that @rustjunkie provided here has a great section on coaster brakes.  This page has some info on the disc sets, and the note at the bottom in Step 7 pretty much sums it all up:







Having a higher number of thinner discs would give the brake slightly more braking surface area rubbing together but I doubt it makes much of a difference if you can lock the brakes up with 17 thicker discs.




I also thought this note at the bottom of step 4 on assembling the disc sets was interesting and have never heard this before.  I thought you HAD TO start and end with Steel discs:






The other thing that I've been following, is the many methods of lubricating the ND coaster brake.  I hadn't noticed that the recommendations from ND changed over time.  It has always been grease on the bearings and oil on the discs, but I imagine as people realized that light motor oil was too thin and could work its way out through the grease, they started to increase the weight of the oil.  Thicker oil sticks to the discs better and doesn't mix with the bearing grease and work its way out as easy.

Old 20 weight oil call out:




Here they are calling out Hypoid (gear) Oil:




And the Schwinn Repair Manual says Hypoid or Castor Oil:




I hope this post can help others unravel the differences in number of discs seen in these hubs and how to lubricate them correctly.   Fast forwarding to the Schwinn Repair Manual advice is probably the best IMHO.

3/4" total disc stack height and thick gear oil on the discs


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## pedalpower17 (Nov 21, 2019)

A related question.... I'm overhauling my second ND Model D hub.  Unlike the first one, on this one, some of the flanges on each copper disc have taken some serious force that has slightly damaged the ends of some of the flanges.  See pic.  The result are little spurs that stick up slightly, perpendicular to the plane of the disc.  I'm thinking of taking the time to gently sand these down so that the disc is again smooth.  I did not test the function of the hub before disassembly, so don't know if this damage had any effect on the function of the brake.  Anyone have any experience to share?


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## Andrew Gorman (Nov 21, 2019)

I always clean up any little burrs.  The faces of the washers are the braking surface.


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## gkeep (Nov 21, 2019)

Those burrs may cause brake "snap" when you stop pedaling. No expert but my guess is it causes the ears to bind when they slide in the keyway of the hub. There are some great threads about this topic with comments by much more qualified people than me.


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## pedalpower17 (Nov 21, 2019)

gkeep said:


> There are some great threads about this topic with comments by much more qualified people than me.



thanks, I'll do a search for those threads


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## piercer_99 (Nov 21, 2019)

pedalpower17 said:


> A related question.... I'm overhauling my second ND Model D hub.  Unlike the first one, on this one, some of the flanges on each copper disc have taken some serious force that has slightly damaged the ends of some of the flanges.  See pic.  The result are little spurs that stick up slightly, perpendicular to the plane of the disc.  I'm thinking of taking the time to gently sand these down so that the disc is again smooth.  I did not test the function of the hub before disassembly, so don't know if this damage had any effect on the function of the brake.  Anyone have any experience to share?
> 
> View attachment 1099176




I would replace the discs, they are available.


Also Scott sells them, @sm2501

It is worth it.  The flanges are the key to solid braking,  they will start to wear with the chink like that, the it shears off and scores the hub.

I have had that happen to a hub and the results are not pretty.

Although, depending on how much you ride, and how hard, sanding the discs down will work for a while.


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## pedalpower17 (Nov 21, 2019)

piercer_99 said:


> I would replace the discs, they are available.
> 
> 
> Also Scott sells them, @sm2501
> ...



Piercer, sounds like a solid idea. I wasn't looking forward to the tedium of sanding down 30+ burrs of soft copper without wearing too much into the surrounding disc.  I've reached out to Scott.  Thanks


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## piercer_99 (Nov 21, 2019)

the nos disc sets are sweet.


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## Miq (Nov 21, 2019)

I ordered this set from eBay recently.  I contacted @rustjunkie a few days ago and he does not have any replacement sets in stock at the moment but thought the NK set on eBay was worthy and priced correctly under $20


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## pedalpower17 (Nov 21, 2019)

Miq said:


> I ordered this set from eBay recently. I contacted @rustjunkie a few days ago and he does not have any replacement sets in stock at the moment but thought the NK set on eBay was worthy and priced correctly under $20



Miq, thanks for the suggestion.  I just saw them on ebay, but notice that this is a 17 disc set, 8 flanged and 9 regular.  My hub has a 23-disc set.  Did you use your NK set to replace an ND 23-disc set?  If so, I'm guessing that these discs must be thicker, but that the total stack height is the same.


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## Rivnut (Nov 21, 2019)

I think you'll be okay as long as the stack is .750" tall and you have a steel disk on each end.  I've rebuilt a couple of these and I lay a piece of 400 grit wet/dry paper on the work bench with a little water on it which has a dab of Dawn detergent on it.  Slide each side of each disk around in a circular motion.  Just enough to smooth the up. Doesn't take all that long. Rinse. Reassemble putting grease on each side of each disk.


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## Andrew Gorman (Nov 21, 2019)

Nankai and Mattatuck discs work fine in the ND, along with SOME other parts.  Definitely not the retarder spring. Mattatucks were used a lot on little kids bikes.


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## Miq (Nov 21, 2019)

I think the NK75 set will be approx 0.75” so it should fit ok.  I am still waiting for them to arrive.  

There will be less braking surface area than the current 23 disc set in my 41 ND hub, but I can easily lock up the wheel.  I doubt it will make any difference.

17/23 = 0.74 = 74% of the surface area of 23 discs.


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## pedalpower17 (Nov 22, 2019)

Miq said:


> think the NK75 set will be approx 0.75” so it should fit ok. I am still waiting for them to arrive.
> 
> There will be less braking surface area than the current 23 disc set in my 41 ND hub, but I can easily lock up the wheel. I doubt it will make any difference.



Miq, while it's really cool to get the tech analysis of the braking capacity (truly appreciate, I love that stuff!), this is a 1940 Westfield Davega that will not be bombed down any big hills, but occasionally ridden around the flat neighborhood by my wife.  I want it to brake decently so that she's comfortable and secure, with no risk of the hub seizing up or failing due to old worn discs.  I suspect that the NK discs would meet the criteria really well, but will wait and see if Scott has an original 23-disc set from ND.  In any case, once you receive your NK set, could you confirm for me the .75" stack height?


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## SirMike1983 (Nov 22, 2019)

The most important dimension is the overall height of the disc stack, within certain tolerances. This dimension helps set up the proper engagement of other parts in the hub. Second you have the number of alternating clutch discs and brake discs. This does not have a bearing so much on the overall stack height as it does on braking surface area (if you had all one-type of disc, you could still produce the appropriately sized stack, but you'd have minimal braking power). The brake converts kinetic energy to heat through friction over this surface area.

With the disc sets you see the thin discs and the thicker discs. The thinner discs produce a higher braking friction area. In theory this should be a better option, but in reality, the thinner discs are more prone to shearing and cracking. I've fixed several sets of the thin discs where at least some of the discs have cracked or sheared. In fact, this appears to have been quite common. The thicker discs, while giving less braking surface area within the stack, are generally more durable.

If you are dealing with any kind of real hills, I suggest the addition of a front brake as well. A drum might be sufficient in that regard, but I prefer a good caliper brake in front. If you're in a flat area and riding casually, you might get by on just the coaster.

I like the New Departure brakes, but my experience is the later Bendix, when adjusted properly, blows them away.


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## Miq (Nov 22, 2019)

Good stuff @SirMike1983 .  New Departure clearly saw the issues that @pedalpower17 is seeing in his 1940 D hub with the thinner discs being more prone to folding and nicking on the thin tabs.




They changed to 21 and then 17 discs for a reason, and were happy to trade the slight decrease in braking surface area for increased reliability and life.  You don't need all 23 discs to lock up your back wheel, but you do need it to work every time...


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## Miq (Nov 22, 2019)

So I received the discs today in the mail from Dennis in Chico.  The Hansing’s have been in business since 1955! 

The discs came well packaged and the box is not beat up or dirty.  The discs themselves are very clean.  Wish they had a little more oil on them as some of the steel discs have light corrosion.  Nothing bad or unusable.  






Interestingly, despite the pics showing 17 discs in the set, my box came with 19 discs! 



There is an extra steel and an extra bronze disc in the set I received.

Here’s all 19 stacked up.  0.839”!  That’s not right.




Here’s the correct 17 disc stack.  0.75”. That’s better!!




I tried them on a ND Model D disc holder (D-22) and they fit nicely.  

I’ll take the extra 2 discs and store them when I use this set.  I'm ok getting more than I needed.


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## pedalpower17 (Nov 22, 2019)

Miq said:


> Here’s the correct 17 disc stack. 0.75”. That’s better!!



Thanks, Miq.  Very cool backstory on those discs and Hansings.  Today I bought a set of 23 ND from Scott.  I don't think my wife is going to be too abusive on those thin, vulnerable flanges!   I appreciate all your detailed comments on this question.  All the best with your project!  - Mike


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## piercer_99 (Nov 23, 2019)

pedalpower17 said:


> Miq, thanks for the suggestion.  I just saw them on ebay, but notice that this is a 17 disc set, 8 flanged and 9 regular.  My hub has a 23-disc set.  Did you use your NK set to replace an ND 23-disc set?  If so, I'm guessing that these discs must be thicker, but that the total stack height is the same.





the NK are a direct replacement in the New Departure D and C.

NK made an identical hub, the 17 disc set is similar to the early ND 17 disc, steel/bronze disc sets, a little thicker and in my experience, better braking.

I prefer the steel/bronze sets over the late ND steel/steel sets.  I have some NOS early steel/bronze sets that I save for a couple of my bikes, just in case what is in them fails.


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## pedalpower17 (Dec 8, 2019)

I just finished  rebuilding mine with a NOS set of discs, and liberal amounts of Phil's bike grease.  There is still a lot of resistance to the hub's spinning, even when a good amount of "play" left in the adjustment.  The great condition of the bearings and the races, as well as the "feel" of the resistance, tells me the resistance is likely coming from the discs.  Specifically, the silver no-tab ones spinning against the bronze tabbed ones....despite the abundant lubrication.  Does anyone know if these discs require a few miles of riding...a "break in" period?


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## Tim the Skid (Dec 8, 2019)

pedalpower17 said:


> I just finished  rebuilding mine with a NOS set of discs, and liberal amounts of Phil's bike grease.  There is still a lot of resistance to the hub's spinning, even when a good amount of "play" left in the adjustment.  The great condition of the bearings and the races, as well as the "feel" of the resistance, tells me the resistance is likely coming from the discs.  Specifically, the silver no-tab ones spinning against the bronze tabbed ones....despite the abundant lubrication.  Does anyone know if these discs require a few miles of riding...a "break in" period?



you mention using liberal amounts of grease. I only use a lightweight motor oil on the discs. no grease. If you greased the discs that would be your source of resistance. grease on the bearings is fine, try lubricating the discs in a coating of oil only.


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## Miq (Dec 8, 2019)

@pedalpower17 See the bottom of post #9.


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## pedalpower17 (Dec 9, 2019)

Tim the Skid said:


> ou mention using liberal amounts of grease. I only use a lightweight motor oil on the discs. no grease. If you greased the discs that would be your source of resistance. grease on the bearings is fine, try lubricating the discs in a coating of oil only.



Thanks, Tim.  Could grease really cause such resistance?  Anyway, I also suspect you're right.  I initially used Phil's Tenacious Bicycle lube, which is pretty viscous.  It caused resistance.  So, I took it back apart, cleaned and tried grease.  No difference.  I'll do it again with a lightweight oil or teflon-based lube.  By the way, did you put a light coat of grease on spline on which the discs are placed, or the light oil, or just dry?


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## pedalpower17 (Dec 9, 2019)

Miq said:


> @pedalpower17 See the bottom of post #9.
> 
> View attachment 1107793
> 
> ...



Thanks, Miq.  I had actually read the instructions indicating lighweight oil, but also saw a YouTube video and the guy used grease, so I just went with that.   Do you use the same Gear Oil on the spline onto which the discs are placed?  Or just let the excess oil from the discs lubricate the shaft as well?


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## Tim the Skid (Dec 9, 2019)

put some grease on the spline, but oil only on the discs. I put a small amount of oil (30 wt or 10/40 will work) in a sandwich bag, drop the discs in and coat them that way. also make sure your bearing cones are not too tight.


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## Miq (Dec 9, 2019)

The heavier weight oil (hypoid gear) is much more lubricating than grease but sticks to the discs better than lighter weight oils like 10W.  The problem with the lighter weight oils is that they tend to work their way through the grease in the bearings over time and make a mess on the outside of the hub.  This is especially true here in AZ when it’s 110F outside.


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## Tim the Skid (Dec 9, 2019)

Good point Miq. I'm in Washington State. If it's 110 here we're not riding our bikes.


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## Miq (Dec 9, 2019)

Tim when it's 110 in WA you need to stay inside.    

The other good thing about the gear oil is that it's designed for high stress applications like getting squeezed at high pressure between a bunch of spinning and stationary discs.  But I'd guess ALL modern motor oils are made to endure much more stressful applications than a coaster brake will typically cause...


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## pedalpower17 (Dec 10, 2019)

Tim the Skid said:


> put some grease on the spline, but oil only on the discs. I put a small amount of oil (30 wt or 10/40 will work) in a sandwich bag, drop the discs in and coat them that way. also make sure your bearing cones are not too tight.



Thanks, Tim.  I'm gonna pull it out again, clean the discs and use some lightweight oil/lube.  The bearing cone adjustment will be done correctly.....and with these old bikes, that means leaving quite a bit of play, most of which is then eliminated when the wheel is mounted tightly in the frame!


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## pedalpower17 (Dec 10, 2019)

Miq said:


> The heavier weight oil (hypoid gear) is much more lubricating than grease but sticks to the discs better than lighter weight oils like 10W. The problem with the lighter weight oils is that they tend to work their way through the grease in the bearings over time and make a mess on the outside of the hub. This is especially true here in AZ when it’s 110F outside.



Miq, here in MI we don't have much concern about performance at 110°...but your point is well taken.  Whatever oil I use, I don't plan on have a lot of excess on the discs, but just enough to coat them....kind like the strategy for chain lube.  Just one thing...how will in work on a -20° day here in MI???


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## Miq (Dec 10, 2019)

I don’t know, it’s not just the temp if you ask me. I drip oil into the oiler port every so often, so it’s more than just an extra thin coating.  It‘s made to be regularly lubricated with oil.  The drag you are feeling with the grease is exactly why the generous coating of oil is necessary. There are sets of discs constantly rubbing against each other, even when you are not braking. A little more oil is better, unless it gets so much that it leaks out...which is why you want to use the heavier oil.


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## pedalpower17 (Dec 11, 2019)

Miq said:


> .which is why you want to use the heavier oil.



Miq, that comment about -20° was just a joke...I love to ride the vintage bikes, but not on those days!   Anyway, I apologize if paying too much attention to a subject that doesn't warrant it, but you seem to know your oils/lubes.  So, another question.  Have you ever heard of Phil's Tenacious Oil, sold in bike shops?  It's a viscous oil used by some mechanics for chains subjected to lots of wet conditions or to minimal maintenance (i.e. kids bikes).  Before putting grease on my current discs, I tried the hub assembly with this Tenacious Oil.  It also produced resistance that I wasn't expecting.  In any case, before the weekend I'm going to pick up a bottle of Master Pro Gear Oil you recommend.  Thanks for all the info!


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## Rivnut (Dec 11, 2019)

I've been using Lucas Red-n-tacky in a couple of ND hubs and so far everything is working fine.  Used it for the entire hub - disks and bearings.


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## Miq (Dec 11, 2019)

pedalpower17 said:


> Have you ever heard of Phil's Tenacious Oil, sold in bike shops?  It's a viscous oil used by some mechanics for chains subjected to lots of wet conditions or to minimal maintenance (i.e. kids bikes).  Before putting grease on my current discs, I tried the hub assembly with this Tenacious Oil.  It also produced resistance that I wasn't expecting.  In any case, before the weekend I'm going to pick up a bottle of Master Pro Gear Oil you recommend.  Thanks for all the info!




I‘ve never used Phil’s Tenacious Oil but all the Phil Wood products are quality lubricants. I’d imagine it’s a lot like hypoid gear oil.  

After reading that you tried just tenacious oil in the hub with no grease and it still produced resistance, I’m worried there may be something else going on. There will always be some drag since it’s a system that relies on friction to work and that friction can’t be completely eliminated, even while coasting but it shouldn’t be tons. Without spinning the wheel myself, it’s hard to tell if what you are experiencing is a normal amount of friction or not.  

When I lift my rear tire and gently spin the wheel, it spins smoothly, but only for a single rotation or maybe two.  It does not feel rough or sticky, but it doesn’t spin for hours like a super low friction bearing set, or even as long as my 1941 front WL hub.


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## pedalpower17 (Dec 11, 2019)

Miq said:


> After reading that you tried just tenacious oil in the hub with no grease and it still produced resistance, I’m worried there may be something else going on.



I didn't explain well.  I used bicycle grease on bearings, races, cones etc, and only used the Tenacious Oil on the rings.  I understand about some drag always being present, but with the current ND hub (using either Tenacious Oil or grease on the discs, and with noticeable play in the adjustment), I can't even hold the axle in my fingers and spin the wheel.  I might be able to hold for a second or two, but the axle always winds up spinning in my fingers.   Pretty strong resistance.  The bearings/races are in good condition, installed properly and well greased. As mentioned, the discs are a NOS set from New Departure.  Let's see what happens with the Gear Oil.


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## pedalpower17 (Dec 14, 2019)

LUBE CONCLUSION:  I tried three different strategies for lubricating the discs of my ND Model D hub, using a set of NOS ND discs....Park bicycle grease, Phil's Tenacious Oil and the MasterPro 85W-140 Gear Oil recommended by Miq above.  The Gear Oil is lighter than Tenacious Oil and resulted in noticeably less resistance, as well as a lot less resistance than grease.  Good to know.  Thanks, Miq!


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## J-wagon (Mar 9, 2022)

Hi all, just noticed my ND only has 16 discs (8 brass, 8 steel), about 0.7" stack. Recently acquired wheel, spins and brakes normally on the stand. Based on this thread info, sounds like I might have less braking power. Would there be other issues? 
Thx!


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## bloo (Mar 9, 2022)

No, and in fact that is probably close enough.

1) New Departure changed the thickness and number of the discs at some point
2) They changed from bronze to steel at some point too.
3) Aftermarket companies made disc packs.
4) Discs from clones fit (Mattatuck, etc).
5) Clone packs are too thick so you don't put all of it in.
6) New Departure wanted you to change whole packs no matter what.
7) You could ignore their advice and add a disc if the pack is too thin.

You won't be able to make any sense of disc packs In my opinion. The stack should be about 0.75". Thickness mainly affects how far you have to pedal back before it starts braking. You can tune it with the pack thickness if you like within reason, especially since they made discs in different thicknesses at different times. You could add an extra no-tab disc of whatever thickness to get where you want to be. 0.75" pack thickness is default, but I don't think it is quite the hard limit. The only limit is if you put too much in it could drag or not release at all.


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## coasterbrakejunkie1969 (Mar 9, 2022)

bloo said:


> The stack should be about 0.75".



Yes sir that is it number of discs does not matter. start with spacer end with spacer.


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## coasterbrakejunkie1969 (Mar 9, 2022)

J-wagon said:


> Hi all, just noticed my ND only has 16 discs (8 brass, 8 steel), about 0.7" stack. Recently acquired wheel, spins and brakes normally on the stand. Based on this thread info, sounds like I might have less braking power. Would there be other issues?
> Thx!
> 
> View attachment 1585761
> ...



Your missing a spacer


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## J-wagon (Mar 9, 2022)

If I decide to add a disc, can I just use a thin machine washer. Since it's nonflanged disc missing, not really engaging the hub so all I need is space filler right?


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## Miq (Mar 9, 2022)

@J-wagon I bet a steel washer of the right dimensions would work fine.  The ND advertising makes it sound exotic. 🤩




I'm guessing if a single disc, (2 friction surfaces) out of all the other ones, is slightly different (creates less friction), it's probably not going to be noticeable as far as stopping power.  Maybe it will wear a little faster??  The center of it does engage the axle though as Bloo mentions.

I bet you can lock up the back wheel when you test it.   😎


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## bloo (Mar 9, 2022)

coasterbrakejunkie1969 said:


> Your missing a spacer




Oh crap, I see it now. There is a missing disc in the middle of the pack.



J-wagon said:


> If I decide to add a disc, can I just use a thin machine washer. Since it's nonflanged disc missing, not really engaging the hub so all I need is space filler right?




It is engaging the hub. Take them off and look.


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## Miq (Mar 9, 2022)

Here's how the center hole looks:




If it doesn't engage the axle it wont create any friction and will spin with the surrounding copper discs (that are engaged with the hub with their teeth).

Its going to be a lot simpler to buy a replacement washer or set of them.


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## J-wagon (Mar 9, 2022)

Interesting, steel ones have squared of circular hole and the brass flanged have circle hole


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## Miq (Mar 9, 2022)




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## J-wagon (Mar 9, 2022)

Well, I'll reassemble, ride, experiment. See how it goes. Seems like a shake down ride won't fubar anything.


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## Miq (Mar 9, 2022)

Yes you can totally see how the keying works.  The black discs only engage with the axle since they have the flat center hole edges and no outside edge teeth,  The copper discs only engage with the hub since they have a toothed outside edge and a fully round center hole.  When you rotate the pedals backward, the hub starts to push these two sets of disks together.  Since the axle is fastened to the frame of the bike with nuts, it and the black discs do not spin when the wheel is rotating, but the copper hub discs are always following the rotation of the hub.  When you rub those two sets of discs together (rotating and fixed) the friction slows the rotation of the wheel down.  The harder you push the more friction it makes.


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## Miq (Mar 9, 2022)

J-wagon said:


> Well, I'll reassemble, ride, experiment. See how it goes. Seems like a shake down ride won't fubar anything.



For sure.  Does the short stack (by one disc) affect the amount of backward pedal rotation at all??  Does it even matter?


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## bloo (Mar 9, 2022)

Yep. The steel ones are keyed to the hub, the bronze ones to the shell. Squeeze them together, you stop.


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## bloo (Mar 9, 2022)

I think the backward pedal rotation is the ONLY thing stack thickness affects. That's how you can set it if you want it a certain way. Well.. as long as it is not too much too thick, then it couldn't release properly.


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## J-wagon (Mar 10, 2022)

Miq said:


> For sure. Does the short stack (by one disc) affect the amount of backward pedal rotation at all?? Does it even matter?



Test ride 10 miles with the 16 disc and seems ok. Brake engagement fine with ¼ backwards pedal. Seems ok 👍. 

I applied 3-in-1 motor oil 20 SAE to each disc and then topped off the hub via oil port (about 5 ml). The oil promptly leaked out during the ride, mostly from driveside. I guess the hub isn't designed to hold oil like a sealed chamber. My impression is that these hubs require frequent oiling via oil port, just enough to keep disc wet.


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## Andrew Gorman (Mar 10, 2022)

The grease in the bearings acts as an oil seal.  They will leak, but it shouldn't be excessive.


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## J-wagon (Mar 10, 2022)

Actually just took a peek and leaking from both sides. Here's nondrive. On first ride after repack I usually get grease ooze. But guess with oil plus grease it runny, down spokes etc


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## bloo (Mar 10, 2022)

.


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## J-wagon (Mar 10, 2022)

I just noticed my bendix 2-speed kickback has 10 discs, much less than ND. If disc count correlates with braking power via braking surface area, is bendix kickback substantively less powerful brake than ND? 

Bendix redband 2-speed coaster here:




New departure model D here:


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## Boris (Mar 10, 2022)

Bottom photo is missing a non-toothed disk. Looks like this should be a 17 disk cluster.
Quiz: Can you guess where the missing disk goes?


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## J-wagon (Mar 10, 2022)

J-wagon said:


> Hi all, just noticed my ND only has 16 discs (8 brass, 8 steel), about 0.7" stack. Recently acquired wheel, spins and brakes normally on the stand. Based on this thread info, sounds like I might have less braking power. Would there be other issues?
> Thx!




Yup, back in post #45


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## bloo (Mar 10, 2022)

J-wagon said:


> I just noticed my bendix 2-speed kickback has 10 discs, much less than ND. If disc count correlates with braking power via braking surface area, is bendix kickback substantively less powerful brake than ND?




They're bigger discs though. Also, I think the 3-band hub brakes through the planetary gears making more force. Later 3-banders have shoes instead of the discs.

New Departure used to advertise they had more swept area than anyone else, so yeah that's probably more. Also at some point New Departure made the discs thicker, so that would have made the discs stronger, but it would have been less swept area than before because there were less discs in a 3/4" pack.



J-wagon said:


> Actually just took a peek and leaking from both sides. Here's nondrive. On first ride after repack I usually get grease ooze. But guess with oil plus grease it runny, down spokes etc




They do leak like a sieve, but that is ridiculous. I've never seen that. How far did you ride? There are no seals, so it all runs out eventually. I used to run Marvel Mystery Oil in the 70s and it all ran out, so I had to service it way too much, but the area was infested with goatheads so I was probably patching the tire twice a week anyway. On the ones I did recently I used Redline synthetic grease in the bearings and 0w16 (super light) synthetic motor oil on the discs. They don't even look messy. admittedly I haven't been riding much because its winter, snowy, etc. If you have just oiled the discs on assembly there's no need to add more until later. Yes, you are just oiling the discs to keep them spinning freely, not trying to fill it up. Hope this helps.


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## J-wagon (Mar 11, 2022)

bloo said:


> They're bigger discs though. Also, I think the 3-band hub brakes through the planetary gears making more force



Good point! No doubt the engineers made sure similar braking. 



bloo said:


> Yes, you are just oiling the discs to keep them spinning freely, not trying to fill it up. Hope this helps.



Thx! I tend to be heavy on lube repack, ride klunkers in hilly area, steep downhill grades, squished out the excess. Next time when discs become squeaking, I know top off unnecessary. 👍


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## dirtman (Mar 11, 2022)

After reading through all 7 pages here I figured I'd snap a few pics of an old cut away hub I've had for decades here.
Its likely prewar and came from an old bike shop I worked at as a kid. The owner had one on his desk, set up as a trophy for the number of bikes sold one year in the mid 50's. The other was a loose hub that floated around the shop for years. It was dirty, dusty and a bit rusty when I found it 50 some years ago when they were cleaning out the place after the owner retired. 

The hub has 23 discs, from 'drive' to braking' the sprocket turns 90°. (The same as various new old stock hubs I still have here). 
The cut away hub is assembled dry, the stack when compressed measures .675". 

Back when I was working in that shop, we got regular visits from various factory reps that would often hand out display pieces and training aids so to speak. 
The story I got was that this hub was to demonstrate what a hub with the maximum amount of wear looked like. I think to show that even at this point the hub still is able to function normally. 

If you look close, the tabs of the bronze discs are hammered a bit but they do not touch. The hub has what is considered an acceptable amount of back pedal and it the drive clutch engages firmly. Functionally it feels the same in hand as a new hub right out of the box. 
The new hubs I have are likely a bit newer than this cut away, I seem to recall being told the bulk box of hubs was dated 1953. 
I took a few of the new hubs apart back when I built them into wheels and they too had 23 discs.

From experience, a Model D will continue to work until either one of the bronze discs is worn completely away or its tabs shear off.
I remember taking apart a few of these years ago where all the discs had spun in the shell. The most common failure though is a broken reaction spring. 

The drive clutch face can take a lot of wear, it sort of wears into the hub and will continue to 'grab' and move forward until the cone wears to the point where it runs out of conical seating area due to its reduced size. The spring wears out and fails long before that ever happens.
Over the years, my junk parts box for ND has mostly broken springs, a few sets of drive clutches with stripped teeth, and a few pounds of burnt, worn, and sheared discs.  I've likely had a few thousand of these apart over the years. At one point they were the most common hub, with Bendix being the next most common. 



One really important thing with any coaster brake hub is to have the bearings properly adjusted. This affects both load capacity, braking, and axle strength. 
If the bearing are loose, weight is applied to the disks, both preventing free movement and causing all sort of wear and damage. Most commonly is wear on the round disc center flats and left bearing cone assembly can become grooved by the discs prematurely. 
These ride on a 3/8" mild steel axle, if the bearings are loose, the axle can flex both causing misalignment of the discs and the drive clutch. 
Bearings need to be at zero play, no wiggle should be felt, but no roughness either. 
Oil must be present in the hub and the grease for the bearings should not 'spill' over into the hub. We were taught to pack the bearings, wipe some grease over the races and that's it. The hub gets two good shots of straight weight 30 wt oil and no more. It only needs enough to lubricate the discs. 
The drive side is not a slip clutch, its an on/off action so other than keeping the driver threads lubed and moving freely, it doesn't need a ton of lube. 

One of the comments made way back in the day that stuck in my mind was that the hub shell of the Model D was designed to act as a heat sink, the discs need to transmit the heat from braking to the hub shell, which dissipates the heat as it moves through the air. We were told that too much lube actually could interfere with the transfer of heat. We were told that oil acts as a coolant as its circulated with movement, while as grease can act as an insulator. (A grease covered hub shell can prevent the oil from transferring its heat to the shell). While all of this is only tech talk and likely only a concern in extreme instances it does explain a bit about how the engineers were thinking when they designed this hub. 
As you can see by the cut away model, there's not a lot of free space inside the hub, it don't take a lot of oil to be well lubricated. I've read a few posts on the web elsewhere where it stated to put 1.5 oz of oil in the oil port or to fill it till it comes out the dust caps. That is not so. Grease the bearings 'sufficiently' and give the hub a squirt or two of a typical oil can in the oil port and your done. a light squirt of oil from time to time won't hurt but if you don't see it dripping out, its likely still lubed just fine unless its been sitting for years. These hubs can survive on just oil too, if you notice there's no stop for the oil at the bearings, so oil that reaches the clutches will make its way to the bearings too. You just don't want them so wet that they drip oil out the dust covers. A little oil goes a long way. Too much oil will dilute and wash out any grease you put on the bearings.
Also, keep in mind that New Departure was part of General Motors, it was primarily a bearing manufacturer and were involved in the automotive, aviation, and railroad industries as well as building bicycle hubs. 
Bicycle bearings are not under extreme loads very often in normal use. Oil is a sufficient lubricant for ball bearings, maybe even better than grease but it doesn't stay put and since we don't ride our bikes 24/7, grease is the better choice for the bearings since most of us don't ad oil every ride and likely don't care to have to. Things were looked at differently 80 years ago, we had engines that 'used' oil by design and a little mess on the back wheel was acceptable. There was no brake caliper to worry about and men wore pants and bikes had fenders. If the rear wheel occasionally slung of a bit of oil it was no big deal. Now that these are more collectible rides that we try to keep presentable and we don't care to have a greasy spot on the floor where we park our bikes, we grease the bearings and don't 'fill' the rear hub with oil. 
In reality, since we grease the bearings, the hub needs only a few drops of oil every so often. Just enough to keep things moving freely.
If you look at the cut away hub, think about where a table spoon of oil would go if poured into the oil port. then think about the hub leaning to the left side on a kickstand. There is no means to retain the oil. Its not an oil reservoir, it just needs to be 'oiled' occasionally and kept 'wet' with oil.  Dumping in oil will only wash out the bearings you greased. If you put in so much oil it runs freely to the bearings, you likely over oiled the hub.

Oil doesn't 'dry' up very fast, put a few drops in a bottle cap and sit it on the shelf, see how long it takes to 'dry up'. Dust build up and bugs will accumulate in it over time but it won't likely dry up and go away. When it oil congeals, its a two fold process between it mixing with dirt and solids and the solvents evaporating over time. With modern oil the latter happens far slower than it did 80 years ago.


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## J-wagon (Mar 11, 2022)

Very informative! Sounds like my 16 disc with 0.7" stack and ¼ reverse pedal (90 degrees) will be fline. The missing 17th disc is the smooth steel, I can only wonder why it missing, perhaps someone was customizing pedal play brake action or just no reason.


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## J-wagon (Jun 21, 2022)

Hi all, I'm cleaning another new departure model D rear hub, it's a 23 disc version. I noticed one of the flanged discs is tweaked,see pics. One tab is bent deformed and other two tabs sheared/worn off. My impression is if tab shears off, metal debris can damage other hub components, internal surface, etc. My plan is to grind off the deformity (with dremel), in essence it will become a spacer (non flanged) disc. 
Thoughts? Thx!


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## Freqman1 (Jun 21, 2022)

J-wagon said:


> Hi all, I'm cleaning another new departure model D rear hub, it's a 23 disc version. I noticed one of the flanged discs is tweaked,see pics. One tab is bent deformed and other two tabs sheared/worn off. My impression is if tab shears off, metal debris can damage other hub components, internal surface, etc. My plan is to grind off the deformity (with dremel), in essence it will become a spacer (non flanged) disc.
> Thoughts? Thx!
> View attachment 1649684
> View attachment 1649683



I'd definitely check that hub shell before re-using. I believe the spacers are thinner than the clutch discs. That said it may not make a whole lot of difference. I accidently put one together, rode it, and came back to the garage to see one of the discs laying on the bench! V/r Shawn


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## ricobike (Jun 21, 2022)

J-wagon said:


> Hi all, I'm cleaning another new departure model D rear hub, it's a 23 disc version. I noticed one of the flanged discs is tweaked,see pics. One tab is bent deformed and other two tabs sheared/worn off. My impression is if tab shears off, metal debris can damage other hub components, internal surface, etc. My plan is to grind off the deformity (with dremel), in essence it will become a spacer (non flanged) disc.
> Thoughts? Thx!
> View attachment 1649684
> View attachment 1649683




I'd try to replace that one, or really the whole pack.  The way that it works is, the disks with the flanges around them attach to the hub shell, the other disks basically attach to a driver which attaches to the axle.  When they compress it's the friction of the flanged against the non-flanged that causes the braking.  If you just remove the flanges from a flanged disk, they will just spin with the non-flanged and you'll have reduced braking.  Hope that makes sense.


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## J-wagon (Jun 21, 2022)

Hi all, I just reviewed my notes and thread, I am going to experiment, deburr it and ride, see how braking feels. Instead of 11 flanged discs, it will have 10. My math is bad but maybe 1/11 less braking performance or 1/23 less, I don't know. Hopefully the ND hub engineers designed redundancy safety margin. 👍🤞👌


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## BF2485 (Jun 21, 2022)

J-wagon said:


> Hi all, I'm cleaning another new departure model D rear hub, it's a 23 disc version. I noticed one of the flanged discs is tweaked,see pics. One tab is bent deformed and other two tabs sheared/worn off. My impression is if tab shears off, metal debris can damage other hub components, internal surface, etc. My plan is to grind off the deformity (with dremel), in essence it will become a spacer (non flanged) disc.
> Thoughts? Thx!
> View attachment 1649684
> View attachment 1649683



https://www.ebay.com/itm/255430883638?campid=5335809022


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## J-wagon (Jun 21, 2022)

Thx @BF2485, hopefully my experiment results in coaster with acceptable braking.  Note: I also have 17 disc version of ND Model D hub, discs around 0.04375". My 23 discs thinner, each around 0.03“ 👍


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## srfndoc (Jun 21, 2022)

Doesn't matter which disc pack you use, just that the total thickness ends up being .75" with a spacer on each end.


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## bloo (Jun 21, 2022)

This^^

You are SUPPOSED to replace the whole pack if there's trouble, but I rarely if ever do. I would say the damage on that disc is not from shearing off from load or abuse. *It was not engaged in the 3 slots! *In my opinion, the question you need to be asking yourself is "why"?

As for the disc itself, probably nothing bad will happen, but these are common parts, especially if you take one disc from some other old mangled pack. Why on earth not? It couldn't be very expensive.

The elephant in the room though is why was it not engaged in the slots? The thing is, within reason, you can add or reduce total thickness of the pack to adjust how much backpedal it takes to engage the brakes. There is a limit though, and you run into it right away. There has to be enough space in there to disengage the drive clutch.

Schwinn says in their manual that if the disc support sleeve is imperfectly machined, and the first steel disc does not sit perfectly flat against the side of the support sleeve, that you can run a bronze disc right against the support sleeve, using the sleeve itself as a steel disc. You still need 0.75" pack thickness. I'm not advocating that, but the implication is that even if the outer steel disc is completely missing all the bronze discs should still engage the slots.

What happened here? Was there any explanation? A completely disintegrated or missing bearing? A bearing cone way loose and a back wheel flopping around? Broken axle?


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## Miq (Jun 21, 2022)

@bloo is right about starting and ending with each kind of disc.  It is important to alternate types to allow the most friction making surfaces to interact with each other, but you can start with either type.

@J-wagon you're also right that you could hardly notice that kind of difference (one disc).  I always ask, "Can you lock up the rear wheel?"  If yes, it's probably enough braking power.  😀


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## Miq (Jun 21, 2022)




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## Miq (Jun 21, 2022)




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## J-wagon (Jun 21, 2022)

Here are pics of before :  damaged disc at nondrive end, several discs minor tab wear, other parts look ok. Not sure how disc got damaged, 2 tabs gone and third bent mangled. 












Well, I ended up grind disc. Dry mock assembly seems working, nothing out of ordinary. But will need to bomb down hill for real test 👍🤞.


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## Freqman1 (Jun 22, 2022)

J-wagon said:


> Here are pics of before :  damaged disc at nondrive end, several discs minor tab wear, other parts look ok. Not sure how disc got damaged, 2 tabs gone and third bent mangled.
> View attachment 1649842
> 
> View attachment 1649843
> ...



The inside of that hub doesn't look good. I'd probably swap it out if I planned on riding this much. V/r Shawn


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## Miq (Nov 4, 2022)

Carlisle "Fun with Your Bike" - Maintenance Page  😀


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## piercer_99 (Nov 5, 2022)

J-wagon said:


> Here are pics of before :  damaged disc at nondrive end, several discs minor tab wear, other parts look ok. Not sure how disc got damaged, 2 tabs gone and third bent mangled.
> View attachment 1649842
> 
> View attachment 1649843
> ...



seen this before, the last tabbed disc spun a little on installation the last time it was serviced, then it got torqued down and eventually spun the tabs, scarring the hub shell.


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