Strange noise

arctine · 28 Jan 2012 at 17:47

Just got back from a short ride in the sun.

Was riding down a country lane and it was slightly muddy, I guess. Anyway, all of a sudden, upon descending a hill, there was a strange noise coming from the back wheel. It was quite loud and sounded like the wheel had picked up a twig or some stones and they hit the mudguard or something. The sound stopped. I carried on riding for a bit and it came back so I pulled over.

I rocked the bike back and forth and narrowed the noise down to definitely being around the back wheel. It sounded like a creaking noise, as if metal was being stretched, so I checked the chain wasn't too tight and it was fine. I then realised it only happened when the bike was moving forwards. I looked at the back brake and couldn't see anything wrong. I checked all around the wheel and there was nothing that stuck out or looked suspicious.

I got back on the bike and rode slowly a few yards listening carefully. I then started applying the back brake stiffly to check it was working properly. As far as I could tell, it was. Anyway this got rid of the noise so I presumed it must have been some muck between the brake pads and the discs so I rode home.

When I got home I rocked the bike back and forwards again and there was a different noise that I've never noticed before. It sounds like rubber catching on something and it happens which ever way the back wheel is turning. There is nothing catching the tyre and the wheel spins freely as far as I can tell. I checked the chain wasn't just rubbing on something and couldn't find anything.

I'm lost, any ideas please? Thanks in advance.

Dureth · 28 Jan 2012 at 18:40

My first thought is whip the rear brake pads out and double check they haven't got a bit of something embedded in them.

arctine · 28 Jan 2012 at 19:06

Yeah I'll go have a look now.

My other thought is that when tightening the chain the other day, I may have tightened the axel bolt too much? Is that possible.

Ghosteh · 28 Jan 2012 at 19:09

arctine said:
Yeah I'll go have a look now.

My other thought is that when tightening the chain the other day, I may have tightened the axel bolt too much? Is that possible.

It is possible I suppose, have you got a torque wrench to tighten it with, along with the torque rating?

arctine · 28 Jan 2012 at 19:13

Ghosteh said:
It is possible I suppose, have you got a torque wrench to tighten it with, along with the torque rating?

Nah. I tightened it by hand so I'm skeptical as to how possible it is that it could be too tight.

I just hope this isn't something serious like bearings

Dureth · 28 Jan 2012 at 19:17

Unlikely to be the axle too tight, the race bike gets it done up by hand and you can be sure its as tight as a nuns **** before I go out on it!

PS. wheel bearings aren't too bad, just a 30 minute job for someone with a press and they only cost a couple of quid each.

arctine · 28 Jan 2012 at 21:04

Just looked at the brake and found out what the loud noise was when riding. Though I'm not sure why the noise stopped :confused:

One of the pads is worn completely down on one half and so it's now metal against the disc

Why would the pads wear unevenly? The one pad is fine and like I said, only half the other pad is worn.

I did notice when putting the pads back in, there's like a spring at the bottom of the calliper which pushes the pads back against the piston when they're moved. The spring on the worn pad's side doesn't push it back. I'm can't see why either.

My guess would be this is the reason the pad has worn unevenly and quicker than the other one, because it's being pushed back into place when the brake is released.

I'm no mechanic though, anyone with a bit more knowledge got any ideas?

Oh and the squeeking noise is still there when the brake calliper is removed. I think this might just be a natural noise the bike makes that I haven't noticed before now though.

partypooper · 29 Jan 2012 at 16:18

could be a wheel bearing on its way out,lift back wheel off ground and hold the wheel in the 12 and 6 o clock position and pull and push it towards you,if any movement chances are its a wheel bearing

for your brake caliper use some wd40 on the piston and push back in and pump the piston in and out a few times to loosen it up abit,could be sticking slightly hence the uneven wear

could also be the rubber cush drives in/under the sprocket carrier

arctine · 29 Jan 2012 at 16:34

partypooper said:
could be a wheel bearing on its way out,lift back wheel off ground and hold the wheel in the 12 and 6 o clock position and pull and push it towards you,if any movement chances are its a wheel bearing

for your brake caliper use some wd40 on the piston and push back in and pump the piston in and out a few times to loosen it up abit,could be sticking slightly hence the uneven wear

could also be the rubber cush drives in/under the sprocket carrier

Cheers for the info.

I'm gonna take all three callipers off and get my brother to rebuild them with new pistons and seals. Obviously I'll bleed the system and change the pads while I'm at it. I'm guessing it hasn't ever been done because the bikes only traveled 13k. I've only done 1k of that.

I'll take a look at the cush drives as well. I need to change the chain anyway so I may as change the sprockets and cush rubbers as well.

May as well do the radiator coolant and oil/filter while she's off the road.

Turning into a full service now

Dureth · 29 Jan 2012 at 20:16

arctine said:
I'll take a look at the cush drives as well. I need to change the chain anyway so I may as change the sprockets and cush rubbers as well.

May as well do the radiator coolant and oil/filter while she's off the road.

Turning into a full service now

Always change chains and sprockets together, part worn sprockets will destroy a new chain so quickly. Well looked after a new set should last 20K miles at least.