# Chain Tensioner for Balloon Tire Bike?



## RadRacer203 (Jun 11, 2018)

I'm working on my '52 Murray today, taking off the crappy Chinese chain tensioner I had on there as a temporary fix. I shortened the chain a couple links and it looks a lot better, but the oversize 26x2.35 tires I had in it rub the frame. Is there any way I can get the back wheel to move back an extra 1/8"? I was thinking of either putting on a stretched out old chain or a tensioner, but none of the new tensioners look good on this thing. I'm going for a sort of 60's custom theme on this thing with no new parts, and it's looking really good but it just doesn't look right without the oversize tires. 

I'll try and post some pictures soon, I'm pretty proud of this thing. Once I can get the oversize tires on, it's pretty much exactly the bike I've always wanted- Bendix 2 speed hub, Schwinn crank with smaller sprocket, rat trap pedals, period headlight, reupholstered Troxel seat, and an NOS Cat Eye reflector on the rear. I even managed to save the original white rims with the red pinstripe that none of the local shops said were salvageable


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## Autocycleplane (Jun 11, 2018)

KMC and others make half links for various width 1/2" pitch chains, that might help.


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## RadRacer203 (Jun 11, 2018)

Here are a few pictures, I built this thing last year. In the pics it has the crappy Chinese tensioner on it along with the oversize tires. I polished, buffed, and wiped a coat of Val Oil over the entire bike before assembly. All original paint.


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## RadRacer203 (Jun 11, 2018)

Autocycleplane said:


> KMC and others make half links for various width 1/2" pitch chains, that might help.




I was thinking about that, but I can't figure out what size chain I have. It's made by KMC but there's no markings indicating the size. I ordered one after measuring it but it was too big for my chain


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## Jay81 (Jun 11, 2018)

If your axle is all the way back in the dropout, then no, there is no way to move it back farther. Try this:

1.Get rid of the tensioner.

2.Try loosening the axle nuts and see if you can move the wheel back farther. If this fixes the problem, proceed to #3.
If it doesn't fix the problem, see #4 after completing #3.

3. Shorten the chain to the proper length and you won't need to use the tensioner.

4. Is the tire rubbing the frame all the time, or only rubbing in certain spots? If it's only rubbing in certain spots, try truing the wheel and that may solve the rubbing issue.


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## RadRacer203 (Jun 11, 2018)

The wheel is actually almost all the way forward in the dropout now that I deleted the tensioner. Even with a set of 26x2.10 tires it still just barely rubs. The chain is as tight as I dare make it, but I need the wheel to move back about a quarter inch or so. The wheel is pretty true and when it's not rubbing it's 1/16" away from the frame


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## Jay81 (Jun 11, 2018)

Also, your chainring is backwards. While I don't think it's contributing to the issue you're having, it may cause premature chain wear. 
I have seen them mounted backwards on 5 speed bikes, but on single and two speed bikes it is supposed to be flipped around.


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## RadRacer203 (Jun 11, 2018)

Jay81 said:


> Also, your chainring is backwards. While I don't think it's contributing to the issue you're having, it may cause premature chain wear.
> I have seen them mounted backwards on 5 speed bikes, but on single and two speed bikes it is supposed to be flipped around.




Yeah, I flipped it because it's not the stock crank, rear hub, or crank sprocket. With all those changes it seemed to line up better that way


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## Jay81 (Jun 11, 2018)

RadRacer203 said:


> The wheel is actually almost all the way forward in the dropout now that I deleted the tensioner. Even with a set of 26x2.10 tires it still just barely rubs. The chain is as tight as I dare make it, but I need the wheel to move back about a quarter inch or so. The wheel is pretty true and when it's not rubbing it's 1/16" away from the frame




That doesn't make any sense. The only purpose of the tensioner is to take up the slack from the chain being too long. It looks like with the tensioner off, you should have pleanty of chain to move the axle all the way back in the dropout.


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## RadRacer203 (Jun 11, 2018)

Without the tensioner, and with the previous chain length the chain was too long, I took out 1 link and it's too short now. If I have that extra link and push the wheel back, the tire rubs the fender, if I remove it and tension it, it rubs the frame


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## Jay81 (Jun 11, 2018)

RadRacer203 said:


> Without the tensioner, and with the previous chain length the chain was too long, I took out 1 link and it's too short now. If I have that extra link and push the wheel back, the tire rubs the fender, if I remove it and tension it, it rubs the frame




Maybe move the wheel all the way back, and see if you can attach the rear fender brace to the axle, rather than the frame? Looks like it may give you a little more fender clearance? Just "thinking out loud"


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## bairdco (Jun 12, 2018)

"Extreme" measures, you could dimple the frame where the tire hits.

Less extreme measure, change the sprocket or the cog on the hub, meaning add a tooth or lose one, to put the wheel where you need it.


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## RadRacer203 (Jun 12, 2018)

bairdco said:


> Less extreme measure, change the sprocket or the cog on the hub, meaning add a tooth or lose one, to put the wheel where you need it.




Now that's not a bad idea, but where would I get a new sprocket for the bendix hub? I'd probably either go 1 larger on that or 1 smaller on the crank sprocket. It currently has a 46t on the crank and an 18t on the hub


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## GTV (Jun 12, 2018)

RadRacer203 said:


> Now that's not a bad idea, but where would I get a new sprocket for the bendix hub? I'd probably either go 1 larger on that or 1 smaller on the crank sprocket. It currently has a 46t on the crank and an 18t on the hub




Good luck finding a kickback cog in anything other than 18t.
A 44t chain ring would be easy to find, a 48t probably wouldn't be too bad either. 



RadRacer203 said:


> I was thinking about that, but I can't figure out what size chain I have. It's made by KMC but there's no markings indicating the size. I ordered one after measuring it but it was too big for my chain




You must be using a narrow chain then. Normal chains for use without a derailer is 1/8" wide by 1/2" pitch.


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## RadRacer203 (Jun 12, 2018)

I would definitely want a smaller 44t sprocket rather than the 48t. Lots of hills in my area. But with that smaller sprocket, I think I might have the same issue with it being too far back and rubbing on the fender in back.


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## RadRacer203 (Jun 12, 2018)

Can anyone tell me what size chain I have? All it says on the side is KMC and 6K-2. I did some measuring and I think just a half link should do it. If anyone has a spare 44t sprocket I wouldn't mind one of those either. Always better to have more options


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## GTV (Jun 12, 2018)

RadRacer203 said:


> I would definitely want a smaller 44t sprocket rather than the 48t. Lots of hills in my area. But with that smaller sprocket, I think I might have the same issue with it being too far back and rubbing on the fender in back.




Then you take a link out of the chain.

There is a happy place where it will all work, you just have to play around and find it.


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## Gordon (Jun 14, 2018)

Pretty sure your chain is 1/2 x 3/32.


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## Archie Sturmer (Jun 14, 2018)

I just re-did the math. 
An added half link (1/2") results in about 1/4" move of the axle in the drop-outs. 
A 1-tooth change, (in either front or rear), results in a 1/8" move in the drop-outs.


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## bike (Jun 14, 2018)

Is it possible that your bike is a middleweight? That would explain tight clearance....


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## bairdco (Jun 14, 2018)

If you want to over-think this some more, with your drop-outs, you're moving your wheel up or down on an angle, not straight back, which complicates all your calculations.


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## RadRacer203 (Jun 15, 2018)

Got it! I decided to put on a worn out chain I had laying around, and that pushed the wheel back almost perfectly, but it still rubbed just a hair, so I decided to put a very small dimple in either side of the frame, so now it fits perfectly with about 1/16" of space on either side of the tire. I'm really glad I could get these tires on without the chain tensioner. They really make the bike. They just fill up the fenders so well. While the wheels were off I decided to fix the rattling too by putting silicone between the fenders and brackets and then a couple shims to take up the slack where the rivets had loosened up.


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