New Departure rear hub discs

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Miq

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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. :p

1574396078509.png
 
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pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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

Cruisin' on my Bluebird
Jun 27, 2008
3,127
United States
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.
 

Miq

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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.
1574440747001.png


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

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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.
D2F48831-A61E-4940-AAEF-5A5D1589F50B.jpeg

5CDE8095-BEEC-40C3-978E-1AD4C10E3321.jpeg


Interestingly, despite the pics showing 17 discs in the set, my box came with 19 discs! o_O
FF4A26A0-2806-4107-972B-F7AFC1704A37.jpeg

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.
89A36DEA-F9DD-40DD-837A-43DAF602F303.jpeg


Here’s the correct 17 disc stack. 0.75”. That’s better!!
3B2EFF44-71DA-410A-BC97-B18E19413187.jpeg


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. :p
 

pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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

I live for the CABE
Dec 27, 2015
1,661
59
Sanger, TX
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.
 

pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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?
 

Tim the Skid

I live for the CABE
Jan 3, 2013
1,521
Tacoma, United States
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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pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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?
 

pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
@pedalpower17 See the bottom of post #9.

1575870940565.png


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1575871476566.png
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?
 

Tim the Skid

I live for the CABE
Jan 3, 2013
1,521
Tacoma, United States
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.
 

Miq

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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. :p
 

Miq

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
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. :p
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??? :p
 
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Miq

Wore out three sets of tires already!
Jan 12, 2019
799
49
Arizona
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. :)
 

pedalpower17

Finally riding a big boys bike
Oct 20, 2010
312
Michigan
.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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