Cracking/snapping sound from BB area

[Twilkes]

If I put my front wheel against a wall so the bike won't move, and put pressure on either pedal I get a thin metallic snap or crack sound. This often happens while riding, usually on the left side only, but the harder I push the more it happens on both sides and the more cracks/snaps there are per revolution of the pedals.

It's a pushfit BB30, does this sound like symptoms of Cannondale creak, i.e. the BB isn't sitting 100% tight in the frame? If so, is there potential for damage/breakage, or is it just an annoying superficial noise?

LBS isn't taking service bookings for a month and I've got some bigger rides coming up, just want to assess the risk of the BB or cranks leaving me stranded.

edit - also, is there any cleaning/maintenance I can do on such a bottom bracket without actually taking anything apart?

 

[Milkfloat]

Before you blame the BB check your headset, seat post and saddle are torqued up properly. Then check your quick release. Only after ruling out these easy to fix problems would I go for the BB. However, having said that, the symptoms would match the BB with various ways to solve it. If you don't have the tools to take out and refit the BB you can at least take the crank off and check to see if the bearings are smooth and if the spindle has worn in contact with the bearing.

 

[Twilkes]

Before you blame the BB check your headset, seat post and saddle are torqued up properly. Then check your quick release. Only after ruling out these easy to fix problems would I go for the BB. However, having said that, the symptoms would match the BB with various ways to solve it. If you don't have the tools to take out and refit the BB you can at least take the crank off and check to see if the bearings are smooth and if the spindle has worn in contact with the bearing.

Don't think I have the tools to take the cranks off either, and I wouldn't really want to get my bike into an unrideable state in case I couldn't make it rideable again. Will check the other things and then probably just wait for a service slot at the LBS.

 

[cyberknight]

get it checked i had a HT2 BB that was making those noises and the axle snapped and the left crank fell off .

 

[RoubaixCube]

axle snapped and the left crank fell off .

This sounds like one of them limericks about people coughing and legs falling off and floating down rivers.

 

[fossyant]

BB30 - oh no.

 

[Twilkes]

get it checked i had a HT2 BB that was making those noises and the axle snapped and the left crank fell off .

It's a 9 month old SRAM two-piece crankset, so I'd be unlucky for that to snap after a few thousand miles, I'd hope. Trying it again it seems to be when the frame flexes so hopefully it's a cosmetic noise that will last another month, it still comes and goes anyway.

Yeah I wouldn't get BB30 again. Or anything with FSA cranks. Or mechanical discs.

 

[Cycleops]

You don't need anything apart from an Allen Key to remove the cranks. It would be worthwhile to check the spindle on the two piece crank, you might spot any signs of impending failure.

 

[Twilkes]

You don't need anything apart from an Allen Key to remove the cranks. It would be worthwhile to check the spindle on the two piece crank, you might spot any signs of impending failure.

The guides I've seen keep mentioning a bottom bracket tool, is that not necessary? One side has an 8mm Allen key bolt, the other side looks like it is sealed or has a cover on it.

 

[Twilkes]

You don't need anything apart from an Allen Key to remove the cranks. It would be worthwhile to check the spindle on the two piece crank, you might spot any signs of impending failure.

Okay yes, looks like an 8mm Allen key would get it off. Any tips for refitting it again?

 

[Cycleops]

Not sure but bound to be straightforward. Usually when the non drive side is released the drive side with the spindle will slide out.
I have a Hollowtech which is similar but varies from yours I think. Check out YouTube there is sure to be a vid.
Be sure to carefully inspect the area where the spindle joins the chain wheel.

 

[Twilkes]

All seemed okay, plumbed it back in and noise was still there. Noticed that once it's 'cracked' on one side it won't make any more noise until the other side is pushed down, so thinking it's the BB moving ever so slightly when pressure is applied or when the frame bends. Annoying but should last until I can get it looked at.

 

[Cycleops]

In that case I'm sure it'll be safe to ride, just be annoying. The BB inner shell has to be machined to very fine tolerances which aren't always reached.