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Old 10-21-10, 06:06 AM   #1
bijan
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crankarm/chainring bolts too long

Hi I have a Bianchi San Jose. It has Sugino cranks with a single chainring in the front (it was originally a single speed). I removed the smooth black chainring guard disc in order to install an actual chainguard.

The problem is now that the 2mm thick disc is gone, the chainring/crankarm bolts are 2mm too long. I went to the hardware store and got some 2mm washers and used those to fit the bolts, but two of them came loose last night (after about a week and a half).

My question is should I try to get thicker washers, or are there shorter bolts available?

For reference I believe my bolts are 10.5 mm long. I can post a picture if that helps...
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Old 10-21-10, 06:34 AM   #2
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After doing some more research it seems that my options are to get 8.5mm bolts or to get a 2mm or 2.2 mm spacer...

My next question is will going with one rather than the other affect the chainline?
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Old 10-21-10, 06:52 AM   #3
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I think the washers (and the chainguard disc before that) weren't between the crankarms and the chainring, so I guess it wouldn't make a difference to the chainline...

I hope I've answered my own question correctly...
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Old 10-21-10, 09:18 AM   #4
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Go to your LBS and pick up a set of BMX stack bolts. They're designed for single chainrings and are much cheaper than "Pista" stack bolts.
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Old 10-21-10, 09:35 AM   #5
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If the chain ring has not been relocated on the crank arm spider, the chainline has not changed.

the use of a shorter nut and bolt would be cleaner than the spacer added to existing bolt set,
but I suspect you didn't tighten the bolts adequately is why the 1st setup didn't work..

As you say, ''but two of them came loose last night (after about a week and a half).''
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Old 10-21-10, 10:17 AM   #6
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Thanks John and Fietsbob. I will stop by a shop and get some proper sized bolts.

I tightened them pretty well. But the reason I say the washer is a problem, is that now they are still too long even with the washer (bolt/nut spins in the hole, even when tightened as much as possible). I guess the washer must have been some soft material or barely wide enough and compressed somehow?
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Old 10-21-10, 10:29 AM   #7
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You say: "(bolt/nut spins in the hole, even when tightened as much as possible)."

NB, There is a pin spanner wrench, pretty cheap, sheet metal, tempered for strength,

while you tighten the bolt with the allen wrench .. that will hold the sleeve nut from rotating ..

There are slots in those nuts to engage the pin spanner tool.

also, LBS can supply a machined aluminum spacer set to retain the same chain ring bolts ..

Last edited by fietsbob; 10-21-10 at 12:05 PM.
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Old 10-21-10, 10:31 AM   #8
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As said above, get some short stack (single chainring bolts). Origin 8 makes a nice chromed steel (and also black) set. They're also available in colors in aluminum (but why would someone use aluminum bolts?). Some folks put a drop of lock tight on the bolts. I use grease!
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Old 10-21-10, 10:36 AM   #9
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You can also grind your bolts and nuts shorter. I use a bench disc sander.
I wanted to keep the T.A. bolts.


Last edited by Grand Bois; 10-21-10 at 10:44 AM.
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Old 10-21-10, 10:39 AM   #10
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^ I'm thinking that had proper bolts been available for your application, you'd have spent $6 on new ones.
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Old 10-21-10, 11:42 AM   #11
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Originally Posted by ColonelJLloyd View Post
^ I'm thinking that had proper bolts been available for your application, you'd have spent $6 on new ones.
You're wrong. Proper bolts would be T.A. Pista bolts, and they don't sell for $6. I don't mind the extra work. I spent a week of free time grinding the gouges out of that crank and repolishing it. I find it therapeutic.

On this one, I kept the Campy bolts, but used bmx nuts. Nuts made for a double will bottom out on a single.


Last edited by Grand Bois; 10-21-10 at 11:47 AM.
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Old 10-21-10, 12:04 PM   #12
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Quote:
Originally Posted by fietsbob View Post
There is a pin spanner wrench, pretty cheap, sheet metal, tempered for strength,

while you tighten the bolt with the allen wrench .. that will hold the sleeve nut from rotating ..

There are slots in those nuts to engage the pin spanner tool.

also, LBS can supply a machined aluminum spacer set to retain the same chain ring bolts ..
No the problem is not that, I mean even when tightened fully using that tool the bolt/nut is loose and the chainring wobbles sideways.

Edit: not loose as in not tightened, loose as in too big/wide to grip the chainring to the crankarms.

Last edited by bijan; 10-21-10 at 12:08 PM.
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Old 10-21-10, 12:06 PM   #13
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Originally Posted by Grand Bois View Post
You can also grind your bolts and nuts shorter. I use a bench disc sander.
I wanted to keep the T.A. bolts.
Well after going to the shop and finding out that they didn't have such bolts in stock, and not wanting to have them special ordered, the mechanic offered to shorten my bolts for me... So I'll be taking my bike in tomorrow.

I'll keep you all posted on how it goes tomorrow.
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Old 10-21-10, 12:19 PM   #14
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Originally Posted by Grand Bois View Post
You're wrong. Proper bolts would be T.A. Pista bolts, and they don't sell for $6. I don't mind the extra work. I spent a week of free time grinding the gouges out of that crank and repolishing it. I find it therapeutic.
Read my post again, GB. I'm not wrong. I knew the TA Pista bolts weren't available (at least at a reasonable price) and that's why you chose to grind the originals. My point was that if TA Pista bolts (the proper bolt for your application) were available for $6 you'd probably have gone that route. The OP just needs a set of $6 bolts to do it right. To me, I don't see the point in grinding down bolts when you can pop into any LBS, lay down $6 and be done with it.

Edit: I see the OP's LBS didn't have them. Shame. Is there not an LBS in your town that caters to the 20" crowd?

It'd be worth ordering from a website if you're in need of other bike stuff.
http://store.velo-orange.com/index.p...ngle-ring.html

Last edited by ColonelJLloyd; 10-21-10 at 02:02 PM.
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Old 10-21-10, 01:15 PM   #15
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You're still wrong. You have not correctly predicted what I would do.

Shortening the bolts is easier for me than making a trip to a bike shop that probably won't have them or waiting a week for my online order. Shipping will cost more than the bolts. Bmx and fixed gears aren't popular here, so I'd probably have to make a trip to Berkeley to get the bolts from a shop. Parking in Berkeley is a nightmare. I'm not fond of the look of cheap generic bolts, anyway.

The hard part is finding something to hold the bolts while you grind them. I have a bunch of tapered carbon fiber tubes left over from my kite flying days. I just have to cut the tube to the length that makes it a jam fit in the bolts and nuts.

Last edited by Grand Bois; 10-21-10 at 01:27 PM.
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Old 10-21-10, 02:04 PM   #16
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I thought I was a hard a$$. You don't give an inch!
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Old 10-23-10, 06:31 AM   #17
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In the end the shop shortened the bolts for me, and the problem is solved.

Thanks again for the help!
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