chainring question

[HimynameisMike]

I've got a 40t ring on my commuter/am/enduro/awesome hardtail bike. I was riding to work this morning and noticed that the chainring looks buckled. Is this a common thing to happen? I cannot recall ever striking it on anything (no bashguard, so I'd definitely know if I did.) What could be the cause of it?

 

[The Duckmeister]

Any movement in the bottom bracket? Munted bearings will allow the crank to rock with each pedal stroke, giving the appearance of a buckled ring.

Either that or you have actually hit it on something.

 

[HimynameisMike]

Just replaced the bottom bracket last week, I've checked the crankbolts properly tightened.

 

[T-Rex]

A bent spider. Although you usually achieve that with a really big hit, so you would know about it. Unless you got the cranks second hand?

I can't think how you would bend a chain ring without it taking a big hit. Maybe pull it off and check it on a flat surface to make sure it's really bent.

If it is, and the chain stays on, I wouldn't get to worried about it.

EDIT: it's not unheard of to bend a chain ring in a crash, if the bike gets wrapped around a tree or similar.

 

[silentbutdeadly]

Some singlespeeders and power riders can warp bigger chainrings (especially those with 104 BCD) simply through their delivery or a minor loosening of chainbolts. This is why it is increasingly common to see 5 bolt chainsets from cross bikes on these bikes.

 

[HimynameisMike]

I have been using the 40t on some pretty steep hills..... though I doubt I'd have the power in my chubby legs to put enough pressure on the pedals to warp anything. Thanks for the input people, will make further investigations to see if I can fix it.