Bicycle Mechanics - Crank Bolts

Are crank bolts interchangeable? I have Shimano XTR cranks (not new 2003), and they use the self extracting bolts.Out of curiosity could I put standard bolts in? I think the dust cap threads are stripped, can I retap them?
Thanks

Also I'm afraid that I didnt line up the splines correctly. Any tips to doing it? Should I remove the dust cap and then line them up, put the bolt on tight, then put the dust cap back on? I got the drive side crank on tight but I cant get the non drive side on really.

Also I'm afraid that I didnt line up the splines correctly. Any tips to doing it? Should I remove the dust cap and then line them up, put the bolt on tight, then put the dust cap back on? I got the drive side crank on tight but I cant get the non drive side on really.


There really isnt a way to not put a splined crank on correctly. Octalink is just crappy anyway.

Unfortunately Klein, it is possible to mis-assemble the octalink, though intuitively it would appear to be a no brainer like taper square assembly.
I, ahem, have done it and there have been prior threads attestling to others
who have managed the feat. Attention needs to be paid to the length of the
splines and a calibrated eyeball used when the crank is assembled. The crank should slid on at least the length of the splines. When tightening/torquing the crank bolts, attention to the movement of the crank onto the shaft should be paid. If any wobble is left in the crank when torquing is complete, the splines are not seated, unfortunately this is sometimes only apparent under riding level torque. The result is the axle splines chewup part of the crank splines. This is
where the calibrated hand, eye and brain come into play: ie experience in the art of bicycle mechanics. Steve

The bolts are not interchangable. Also, it's easy to mess up the new XTR. It isn't the normal Octalink. hence why it was new for 03.

If the threads are stripped make sure the threads aren't sure in the cranks.

You should be able to get the bolts in any shop.. they should order them.

Unfortunately Klein, it is possible to mis-assemble the octalink


Really? Wow I didnt even know. I have never actually installed octalink. I dont see how you could mess them up if they are all the same size. You did mention there can be some play if you dont put them on right though. Weird. When I didnt know **** about bike stuff I had a shop install octalink on my klein, and they messed it up big time (like you mentioned the bb spindle chewed up the splines).

Yea octalink is annoying, you dont feel the splines engage until you tighten it, its not like isis or square taper where you just slid it on. i dont like it at all, but my boss has been doing it for so many years its become second nature to him, so ill get him to do it

Octalink cranks need to be mounted by HAND! Do NOT put the crank arm on there and tighten them down with the bolts. You MUST push the crank arms on by hand and then snug down the bolts to torque spec.

Also I'm afraid that I didnt line up the splines correctly. Any tips to doing it? Should I remove the dust cap and then line them up, put the bolt on tight, then put the dust cap back on? I got the drive side crank on tight but I cant get the non drive side on really.


There is a trick. Take a sharpie marker and draw a line straight from the top of the spline down the spindle toward the BB Shell a half an inch or so. Then draw a line on the crank arm even with the gap for the spline. Match up the two lines and tighten.

If the crank arm is mis-aligned when tightened, it will damage the splines and not be fully engaged and possibly dangerous.

Definately talk with someone at your LBS about getting the proper bolts.

Ride On,
Brian

and they use the self extracting bolts.Out of curiosity could I put standard bolts in?

You can swap out the self extracting bolts for standard bolts as long as the thread pattern is the same. Every one I ride with including my self toss out the self extracting bolts. Go to your LBS and get some bolts from them.

:beer:

whats wrong with self-extracting bolts?

Depends on how well they are made.

Let's look at the design. The way the self extracting bolt works is as follows: A bolt with a flange is used to torque down the crank. Then a ring is threaded into the crank which surounds the flange (there is a thrust washer to reduce friction <if it moves freely against one of the surfaces>). To remove the crank the bolt must press against this ring.

A) The ring must be screwed in tight enough to not come loose or the system fails
B) The ring must be strong enough to take the pressure.

Notes:
* The ring is fairly thin and thus only has a certain level of stength or ridigity (resistance to flexing).
* All of the pressure is placed on the inside of this ring during the extraction. This pressure causes the ring to bevel from the center... This reduces the surface area or contact area of the threads between where this ring screws into the crank. Thus there are actually less threads in the crank doing the work of holding in the ring.

I've seen these rings POP out of the crank SHEARING off the aluminum threads in the crank. Now there is no (easy) way to remove the crank because there is no threads to hold the ring and witnout the ring there is nothing for the bolt's flange to press against.

Now for doing things the old school way:
1) Pull off the ring.
2) Extract the bolt
3) Thread in a crank extractor.
4) tighten extractor to pull off crank.

The extrator has a LARGE barrel with plenty of UMPH. No worry about flex (not if it is a good tool).

It don't have to be light. It is designed for maximum strength as it is a tool not a part.

Safest way to protect the threads in the crank arm that were intended for a crank puller to thread into.

Best reason to use the extrator ring/bolt combo? Never if possible. However I still use the bolts as if I am in the field and have a problem with the BB or like I saw one time a bad case of chain suck (on a triple crank actually) where the chain got stuck between the tiny ring and the frame... To the point where if we pulled harder we were going to twist the chan or bend the frame....

Well that is when I pull out my CRANK BROS's tool and pray I got enough strength to twist off the crank arm!

In the shop use the tool.
In the field use what you have to!