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grinding cranks


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My cranks have a distinct grinding noise when I pedal, i can even feel it in my feet.

 

 

 

I am imagining bearings, but I'm not a tech type, so a little unsure.

 

 

 

If it is wearing out, how soon does it normally happen? I have hardly ridden my bike at all. Everything on the bike is stock, and brand new. Bike has roughly 200km on it, if that much. It's been in the LBS since just after sabie classic, where it has been for just below 2 months. since i got it back I have only managed 4 rides on it.

 

 

 

I did clean it properly, lubed everything and still that noise?

 

 

 

should i take it back to LBS to sort out? Since I purchased the bike in January, it has been constantly going back for suspension trouble, perhaps they just forgot to grease the cranks when they put it back together?

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Just take the cranks off, maybe some dirt is just trapped between the crank arm and bearings.

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You don't say what type of bottom bracket it is, but I assume Shimano Hollowtech? A grinding noise indicates a kaput bracket. Buy new ones for R500 or more or fix the existing ones by replacing the bearings.

 

To test, remove the chain. Spin the cranks and put your ear against one of the bigger tubes on the frame. You'll hear a rumbling, grinding noise. These are the bearings speaking to you, telling you they want out.  Be careful how you position your face, a spinning crank in the teeth is not nice.
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Thanks Johan, that's exactly it. Sorry, didn't know the different cranks etc will become required.

 

 

 

thing is, so soon? I mean, so soon? My previous bikes I rode thousands of km's and nothing like this happened. meh.

 

 

 

Thanks, will take it into the shop to fix. again.

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I have a hope bb with the ceramic bearing which supposedly should be well sealed.  I dont really ride in mucky conditions nor jetwash it, but it makes a rumbly (not really grindy) noise when pedalling/spinning the cranks. 

 

Seems to almost amplify the sound of the movement of the bearings through the frame and then makes that noise.  It does not feel rough or stiff though, any help as to what this is or how to remedy it  ?
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The BB on my wife's Silverback also gave out within 500Km. Replaced it (with the same model number), did a few thousand so far, no problem. I had a GT a few years ago and its bb also went feet up within the first 1000Km. Others last forever.  I think those ones were assembled on a friday.

 

 

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I have a hope bb with the ceramic bearing which supposedly should be well sealed.  I dont really ride in mucky conditions nor jetwash it' date=' but it makes a rumbly (not really grindy) noise when pedalling/spinning the cranks. 

 

Seems to almost amplify the sound of the movement of the bearings through the frame and then makes that noise.  It does not feel rough or stiff though, any help as to what this is or how to remedy it  ?
[/quote']

 

Say goodbye to your fancy-pantsy ceramic bearings. They ate the steel races and now the beautiful smooth bearings are running offroad over pitted and rusted races.

 

A bearing seal is just a thin blade of rubber that runs against a steel or aluminium cup. It is forseeable that grit will grind the seal away and water will penetrate the bearing. With the water comes dirt. With the dirt comes trouble.

 

Grease inside cartridge bearings is a consumable, since the seals are designed to let out a little bit if grease so that they don't run dry. With experience, you can judge whether the bearing is just dry or buggered.

 

You may be able to pry off the seal and clean the bearings and put fresh grease in there, but it is a mission, especially with hollowtech BBs since getting the plastic cup off is difficult.

 

Buy cheaper BBs and replace the bearings with Enduro bearings when they wear out.

 

 
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Thanks, sal loer Johan. 

 

Erks me if the thing is now stuffed, really haven't had it for a very long time and the reviews were positive in really muddy british conditions.  

 

Oh well, so you learn not to buy expensive consumables.

Wonder what funny story the LBS is gonna spin, get the popcorn and I'll post it some time ;)
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Do the test Johan describes to make sure. Other this that I have found to make funny noises when you pedal and that you can feel are the chain and pedals. You will be amazed at the grinding noise a dirty chain can make but it eventually subsides. Here I'm not talking oil but sand. If you did a ride with lots of sand/mud and only wiped the chain before lubing it again some of that sand remains and if you take the chain between your fingers and twist it you will hear the grind. This happens very easily with a new bike because of the lube they put on the chain. That stuff is a sand magnet. If you do not hear the noise when doing Johan's test then remove the chain and wash in a solvent, re-install and lube and try again.

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Thanks will try, brand new chain and cassette, done 1 ride with them, degreased and then the race.  Pedals are oldish though.

 

But you can hear the noise coming from hte bb when you rotate the crank by hand so should be that.

 

Beats me why these things are so badly sealed in a bike thats made to take on such conditions daily ? Obviously to make money...
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