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Help! I'm trying to replace my splined, square-taper BB from my STP 400. Ive changed a few on different bikes before, so I know how this job should go. Both crankbolts are removed and neither crank will budge. I'm ashamed to say this is the original BB on a 2001 bike that is ridden hard. Anyway - anyone know anyway to loosen these up? Aside from spraying something on them because like i said they're REALLY stuck. thanks
 

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HammerHead
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Use Crank pullers or mount selfextracting bolts

Are you using crank pullers like this one?
http://www.performancebike.com/shop/Profile.cfm?SKU=703&item=70-1440&slitrk=search&slisearch=true
Or you can install self extracting bolts like one shown below,
Similar to this one http://www.chainreactioncycles.com/Models.aspx?ModelID=132
You first install the bolt not to tight, then using the needle nose pliers you install the locking washer, then you undo the bolt and bolt will push against the locking washer and will pull the crank. Though I prefer to use crank puller.
 

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A wheelist
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C4Byke said:
I tried the self-extracting bolts off of my road bike, no good- loosening the crankbolts backs them out too.
Ditch the self-extracting bolts and get a real crank puller.

Remove crank bolts and make damn sure there is no bolt washer still left in there! Screw extractor tool in fully and snug it down with a wrench. Make sure the center extractor bolt is not touching the spindle as this will prevent the body from screwing in fully. If you don't have all the threads engaged you will pull the threads out of the crank and you won't be the first one to do this.

Now the cranks will come off.
 

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take it to a shop. if they rip the threads out, they'll replace the cranks (hopefully). if you rip out the threads, you're screwed.

hopefully the shop with have something like Campy's crank puller (Shimano and Pedro's make a similar one...they just don't feel as good as Campy's).
 

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HammerHead
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If crank puller fails, use axle puller

As said by many my preference will be to use the crank puller. Here are the instructions on how to do it from Park Tool website and Utah MTB
http://www.parktool.com/repair/readhowto.asp?id=103
http://www.utahmountainbiking.com/fix/crank.htm
But if threads are stripped on the inside hole of the crank you can try automotive axle or bearing pullers shown below. You can rent/buy it from your local automotive Kragen/Autozone store, just make sure you get the right size, that will grip around the crank, and inner screw of of the puller is narrow enough to fit inside the crank hole and push against the BB spindle. If you are planning on reusing the BB protect the threads on the spindle by loosly mounting the BB bolt, so puller inner screw will push against the bolt.
Of course you can also try to drive a wedge between the BB and the crank but that approach will almost cretain to damage the frame/BB/crank
 

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C4Byke said:
Help! I'm trying to replace my splined, square-taper BB from my STP 400. Ive changed a few on different bikes before, so I know how this job should go. Both crankbolts are removed and neither crank will budge. I'm ashamed to say this is the original BB on a 2001 bike that is ridden hard. Anyway - anyone know anyway to loosen these up? Aside from spraying something on them because like i said they're REALLY stuck. thanks
......
 

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take the bolts and washers all the way out and go ride. not on the trails, just around the block. Same thing happened to me about 6 months ago....rode it for a while and it just fell off. Fun to get home lol.
 

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I had one really stuck - I ripped the extractor threads out and ended up having to cut a slot in the crank arm parallel to the spindle with a dremel and banging a chisel in to free it. Needless to say both the crank and BB where shot afterwards - even when I got enough of the arm off to remove the BB, there where still pieces of aluminum stuck to the square taper.

Just saying, if it's really stuck, you might need more than a crank puller, or even axle puller. If that's the case, good luck - you'll need it.
 

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Former Bike Wrench
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As an ex bicycle mechanic, there was one trick that worked frequently on really stuck cranks (when crank pullers failed and threads were stripped). HEAT...a heat gun is best but a cheap propane torch worked in a pinch. Get things nice and hot then use the axle pullers.

Also, I saw many a crank striped by a cheap crank puller, that when a Park crank puller was installed, could be removed. The cheap tools are not as precise and were just a hair undersized, whereas the Park fit perfect and could still grip the remnants of the treads enough to pull the crank.
 

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mtnbiker72 said:
As an ex bicycle mechanic, there was one trick that worked frequently on really stuck cranks (when crank pullers failed and threads were stripped). HEAT...a heat gun is best but a cheap propane torch worked in a pinch. Get things nice and hot then use the axle pullers.
Nothing is more fun than using a propane torch on your bike, but remember that he has a carbon frame.:nono:

I suppose with the torch you could just cut the tubing and take the entire bb shell out. :eekster:
 

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If the cranks are junk then pull out the bolts and washers. Take off the wheels and clamp one arm in a very solid bench vise. grasp the rear dropout in one hand and the head tube in the other. flex the frame back and forth and you will walk the taper off the spindle. Clamp the other arm in and repeat.

The Campy sparkplug style puller has never let me down personaly. I had to pull the vise trick when away from home (with someone else's bike).
 

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thanks einstein

Baulz said:
Nothing is more fun than using a propane torch on your bike, but remember that he has a carbon frame.:nono:

I suppose with the torch you could just cut the tubing and take the entire bb shell out. :eekster:
Did I say anything about using a torch on his frame??? NO

He is trying to remove his cranks smartass...I've remove thousands of crankarms on steel, aluminum, carbon, and Ti frames, how many have you done?

:skep:
 

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mtnbiker72 said:
Did I say anything about using a torch on his frame??? NO

He is trying to remove his cranks smartass...I've remove thousands of crankarms on steel, aluminum, carbon, and Ti frames, how many have you done?

:skep:
Woah, relax man, just trying to help out. I know you didn't say to torch the frame, but the cranks are very close to the frame, right? And if you don't aim the torch properly, there is a chance of doing a lot of damage to the frame.

I obviously don't have your crank removal resume, but I do have the ability to help someone without having to throw around some insults. :rolleyes:
 

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Baulz said:
Woah, relax man, just trying to help out. I know you didn't say to torch the frame, but the cranks are very close to the frame, right? And if you don't aim the torch properly, there is a chance of doing a lot of damage to the frame.

I obviously don't have your crank removal resume, but I do have the ability to help someone without having to throw around some insults. :rolleyes:
He recommended a heat gun, which should be safe and easy. In a pinch, it's not hard to point and aim a torch, the flame that the "disposable" ones put out isn't big enough that you are likely to overshoot and melt a frame or anything. If you start using a torch or heat gun (think oversized hair dryer), and you don't get anywhere, try alternating them with liberal applications of PB blaster or another penetrating oil. If you mix heat and lubrication, you can make almost anything come loose.
 

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Danke said:
If the cranks are junk then pull out the bolts and washers. Take off the wheels and clamp one arm in a very solid bench vise. grasp the rear dropout in one hand and the head tube in the other. flex the frame back and forth and you will walk the taper off the spindle. Clamp the other arm in and repeat. (with someone else's bike).
Using this method is much more likely to cause frame damage than a little heat. You can develope some big leverage at the end of the dropout. Assuming that a proper crank puller is being used a little heat could be just the right tool. ALuminum grows and srhinks much more than steel with changes in temp. Lightly heating the cranks will cause the tapered hole to grow while there will be very little change in the size of the steel BB. I would install the puller and put tension on it then heat the crank. The crank will likely pop free before it gets hot enough to burn you. It is not necessary to heat the crank very hot at the outset. A small propane torch ( that you get at the hardware store) should do a good job. I have used heat to help losen a bb that was stuck in the frame due to corrosion. It was a painted AL frame and very little heat was needed to break the bond between the BB and frame threads. I didn't even discolor the paint with the torch.
 

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The Flexo (tm) method pressumes that the puller threads were stripped out by a thoughtless goon, the somewhat unusual shape of the crank precludes a gear puller, and the person in charge doesn't have the hands of a ditch digger. Something about the location preculdes the use of a power saw to split them off and a torch to heat them and you can add a 24 style countdown clock to increase the sense of urgency. Living by your wits instead of your credit card.
 
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