How tight is the hex bolt on crank on 3 pc sq BB?

[horsefarmer]

Trying to work on a Chinese Schwinn mountain bike. I think I may want to change the front sprocket to taller gear.
Not sure but think its a TruVativ cartridge, 113mm spindle (SRAM) square type according to specs I found online.
How ttight are those hex capscrews that fasten the cranks supposed to be I'm afraid I may snap them off trying to remove them.
They are R.H. thread, right?

 

[RustySprockets]

In a word...tight! Typically, crank retaining bolts/nuts are torqued to a minimum of 30-35 foot-pounds. Your assumption is correct, though--the bolts are standard right-hand threads on both sides. The cartridge itself, however, is likely left-hand threaded on the drive side...right-hand threaded on the non-drive.

 

[SILVERKINGPC]

RH thread on both sides....it would be good to see a pic of it. Sometimes the hex cap bolts are self-removing, so when backing them out, the crank arms come off as well. Otherwise, you will need a crank puller after the bolts are removed. With many 3-piece cranks, you can remove/change the sprocket w/o removing the crank arms. Check for this possibility first!

 

[gowjobs]

While the crank bolts are usually tightened up from 35-50 ft-lbs., they are also often treated with thread-lock tape/liquid before installation to help prevent them from backing out. This may cause a little extra muscle to be required during the initial removal.

 

[horsefarmer]

Thanks everyone! I was able to remove the bolt by hand - It did take quite a lot of torque but it came off fine!

 

[g-ratter]

I use to have a boss say "tighten it till you hear it snap then back it off a quarter turn"

 

[Bendix]

I use to have a boss say "tighten it till you hear it snap then back it off a quarter turn"

CAREFUL!


That advice is just for carbon fiber...