Loose chainring bolts
 

My chainring bolts keep coming loose... I have to tighten them every other day and I'm just riding my bike to and from class every day. What can I do to stop them from coming loose all the time?

The bike is a Motobecane Track with the stock chainring and cranks.

The cycling team here is having a bike repair fundraiser, so maybe I'll stop in see if they can fix it. My bottom bracket also needs a good lubing, anyways.

The nuts at the back of the chainring are probably just turning, so you aren't getting them tight enough. When you go to fundraiser, see if they have a tool that allows you to keep the nuts from turning while you tighten the bolts like this >>> http://www.parktool.com/products/det...=26&item=CNW-2

Yup. That's exactly what's happening. I've been using a makeshift flat piece of metal to hold the back still while I tighten, but I guess it's not tightening enough.

you can always use a little loctite. the stuff that's not permanent though (i think the blue is what you want)

The problem with doing that, though, is that while the bolts won't loosen up and fall off, they won't get tight enough to keep the chainring from creaking as you pedal forward and reverse on a fixed gear.

Ah, yeah, that's absolutely the issue, then. You have to securely hold the nut when you tighten the bolt.

If he tightens them enough before the locktite dries, then this won't be an issue. It sounds like they're self-loosening from not being tightened enough. OP, try using the correct tool, chainring bolt screwdriver, and hex wrench, before going with locktite. This happend to me in the past, I was not tightening them with enough torque.

If you tighten them properly, they won't get loose and don't need loctite. The reason they were getting loose was that they were not being tightened properly due to the nuts turning w/o being restrained by a nut tool as I showed here >>> http://www.parktool.com/products/det...=26&item=CNW-2 When you tighten a bolt and nut sufficiently to attain proper preload tension, the connection will not loosen. Loctite is primarily beneficial when high torque cannot be used, such as when threading a steel bolt into an aluminum part.

+1

if you use the loctite on the lip of the nut side, that might give enough friction for the nut to stay put while tightening the bolts.

but as a temporary measure.

That's what I just said

@kringle - You said it needed loctite and I said it didn't need loctite - that's where we disagree.

re-read it, i said try tightening it down properly before using locktite. I'm sure I could have worded it better.

Campagnolo used to make knurled chainring bolts for pista use for this reason; they had a patent on it at the time but I suspect it has long expired:
http://www.worldclasscycles.com/camp...g_bolts400.jpg

They still do and so does Sugino >>>> http://www.worldclasscycles.com/sugi...ring_bolts.htm

However, they only work with high end true track cranks, which have a recess in the back of the spiders (arms) to accept the nuts. I have them on my old Campy Record Pista and Sugino 75 cranks. Not only don't they turn, but they don't fall out when you remove the bolts to make a gearing change, which is very convenient at the track.