Sprocket bolts
 

My sprocket bolts have stripped the threads getting an old sprocket off and are covered in loctite. I have got them all out and cleaned up the sprocket carrier, but need new bolts.

Can I just replace them with a standard steel bolt or do I need to find hi-tensile bolts with a suitable length non-threaded shoulder?

Thanks

http://i227.photobucket.com/albums/d.../SNC000261.jpg

I'd just pic something up at the hardware store.

You really want hi-ten steel on load bearing items. There's A LOT of different forces and pretty high stresses on your sprocket.

If you want to hold your transmission together with chocolate soft cheap bolts, then you're asking for trouble.

They just maybe ok for the life of the bike but is it really worth the risk for a few extra quid.

+1 .... use Hi-ten

Are the standard bolts Hi Ten ?
 

I think the standard bolts are mild steel (what does it say on the bolt head ?) due the cush drive taking alot of the sharp, sudden forces during hard gear changes and similar behaviour.

But the others are correct Hi tensile would be better and last longer, well longer than the sprocket anyway.

Yah, look at the head of the bolts and replace with whatever was originally used. FWIW, I've got twice as many bolts on my KLR, and that might mean something (like, for example, that there's more stress on that attachment than you might suspect), which in itself suggests erring on the side of more thorough rather than less.

I'd answer differently if you were somewhere in the middle of nowhere in the Developing World....but you're not, right? Do you really want to ride that bike around all over the back of beyond wondering whether the strange new vibration you're feeling is related to using junk bolts on your rear sprocket? I didn't think so.

Mark

(from somewhere in the middle of noplace in particular, Bahia, Brazil)

There's a big tip in what you said - the original bolts threads are stripped and covered in Loctite - seems to me the manufacturer was worried about them failing in some way.

For future reference - if a bolt has been heavily loctited use a little heat to break the seal, then they come off easier and can probably be reused, unless the manufacturer specifically says no. On an average trailbike, that's unlikely, on the latest crotch rocket you'd be surprised how many bolts are use once.

I tend to buy factory bolts if they're in any way special, or if they're standard looking but there is a question of strength involved, I just buy the very best I can find and don't worry about it. A cheap junk bolt may be 20 cents, a good one 30 and the best 40 cents. Easy choice for me.

On my own bike the only "ordinary" bolts hold on the licence plate, everything else is the best I can get.

Edit: Correction - I just checked - they're Grade 8's on the plate.

Thanks for all the replies folks. There is no marking on the head as it's not a bolt. It's a threaded stud and a nut.

Somebody has since explained to me why they use studs not bolts though

"Because a bolt moves with respect to the thread as you apply torque increasing risk of tearing metal.

Stud, threads are stationary, you apply torque to nut so apply direct tensile force to metal of threads rather than combined tensile/surface traction (or frictional shear or whatever you want to call it)"

That makes sense to me so I'm going to stick with the OEM studs and order some from a Yamaha dealer.

Thanks again everybody.

Thats what I would have done. OEM as much as possible.

When I start thinking of replacing hardware with something thats stronger. I always ask myself...whats the next part that could fail in the assembly if the stronger bolts don't break. Sometimes those soft bolts act kinda like a fuse in an electrical system. Sure bolts shear off at the least convenient times...but I rather have them shear than break the bosses that they tread into on the bikes frame.

daryl

Good thinking !!! That's something I try and work into the pannier frames I make..

I've built weaknesses into the frames to save the aluminium frame bosses if they take a whack in a crash or fall.

Of course I get people saying "Jeez, you need thick box section this and that" but id rather replace an M6 bolt than my subframe ;)

Looking at that picture again, it's pretty clear it's a stud and the non threaded section sits inline with the sprocket....

:oops2: Sorry..