Discussion
Bought my daughter an Islabike Beinn 20 for her birthday and she is very chuffed with it. Adjusting teh gears at the weekend, I noticed that the when turning the pedals the cranks feel a a bit stiff and hard to turn. On my bike, if i take the chain off the cranks fall under their own weight, but on her bike they just stay in place.
Is it easy to remove the bottom bracket and re-grease it? or is it a replacement needed? If I need to replace it, how do I work out which type/shape/size I need to get?
Is it easy to remove the bottom bracket and re-grease it? or is it a replacement needed? If I need to replace it, how do I work out which type/shape/size I need to get?
what do you mean the cranks fall under their own weight? You mean if you remove the chain and one crank arm the other will move under its own weight?
BB is a cartridge type so if it is knackered then you will need to replace the lot.
Odd that the cranks are stiff to turn though, its very rare for that to be the case unless the bearings are overloaded, but on the type of BB that your daughters bike will have, that is near enough impossible to do. Could be a manufacturing defect in the BB i suppose.
BB is a cartridge type so if it is knackered then you will need to replace the lot.
Odd that the cranks are stiff to turn though, its very rare for that to be the case unless the bearings are overloaded, but on the type of BB that your daughters bike will have, that is near enough impossible to do. Could be a manufacturing defect in the BB i suppose.
deadtom said:
what do you mean the cranks fall under their own weight? You mean if you remove the chain and one crank arm the other will move under its own weight?
BB is a cartridge type so if it is knackered then you will need to replace the lot.
Odd that the cranks are stiff to turn though, its very rare for that to be the case unless the bearings are overloaded, but on the type of BB that your daughters bike will have, that is near enough impossible to do. Could be a manufacturing defect in the BB i suppose.
Yeah, on my bike if I remove a pedal, the other crank drops down due to the weight of the other pedal. it is very easy to move, offering almost no resistance to rotation. On my daughter's bike it feels like the bearings are full of treacle - the movement is smooth but there is constant resistance. It's not notchy, there is no odd noises from the crank and there is no "wobble" if i pull and push on the crank arm.BB is a cartridge type so if it is knackered then you will need to replace the lot.
Odd that the cranks are stiff to turn though, its very rare for that to be the case unless the bearings are overloaded, but on the type of BB that your daughters bike will have, that is near enough impossible to do. Could be a manufacturing defect in the BB i suppose.
when you say replace the lot, does that mean the whole bearing and cranks, or do you mean the bearing itself is a sealed unit?
hmm, how bad is it?
new parts often take a bit of use to bed in before they work properly, and the bearings inside a bottom bracket (BB) are pretty heavy duty things so may well just need a bit of time and use to free up
by replacing the lot i mean the entire bottom bracket, rather than just the bearings inside the BB. certain types of BB do have replaceable bearings, but they tend to be higher spec units than you will get on an islabike
new parts often take a bit of use to bed in before they work properly, and the bearings inside a bottom bracket (BB) are pretty heavy duty things so may well just need a bit of time and use to free up
by replacing the lot i mean the entire bottom bracket, rather than just the bearings inside the BB. certain types of BB do have replaceable bearings, but they tend to be higher spec units than you will get on an islabike
deadtom said:
hmm, how bad is it?
new parts often take a bit of use to bed in before they work properly, and the bearings inside a bottom bracket (BB) are pretty heavy duty things so may well just need a bit of time and use to free up
by replacing the lot i mean the entire bottom bracket, rather than just the bearings inside the BB. certain types of BB do have replaceable bearings, but they tend to be higher spec units than you will get on an islabike
It's not terrible, she can still ride it but I imagine it requires a fair bit more effort to keep going which is tiring for a small six year old.new parts often take a bit of use to bed in before they work properly, and the bearings inside a bottom bracket (BB) are pretty heavy duty things so may well just need a bit of time and use to free up
by replacing the lot i mean the entire bottom bracket, rather than just the bearings inside the BB. certain types of BB do have replaceable bearings, but they tend to be higher spec units than you will get on an islabike
It's a second-hand bike, so i would have thought it would have worn-in (and possibly worn-out) by now
ah right, fair enough
though that doesn't make it any less odd, because as they start to wear out they tend to get looser until they start to knock and rattle.
Maybe it just had a lot of use in gritty sandy places, and all the crud has worked it's way into the BB and is causing it to bind a bit.
I'd say just replace the BB, it's an easy job for a bike shop to do and the part is relatively cheap. I'd be surprised if your local shop wanted more than about £30 all in to replace it
though that doesn't make it any less odd, because as they start to wear out they tend to get looser until they start to knock and rattle.
Maybe it just had a lot of use in gritty sandy places, and all the crud has worked it's way into the BB and is causing it to bind a bit.
I'd say just replace the BB, it's an easy job for a bike shop to do and the part is relatively cheap. I'd be surprised if your local shop wanted more than about £30 all in to replace it
Iv suffered with this in the past, the issue I had was a tolerance issue on the bearing itself, when fitted into the housing the bearings were crimped up, the outer race was slightly oversize, swapped for another outer race and it was all good, this was on a brand new sram blackbox ceramic bottom bracket.
An old post - but we had a second hand Islabikes Beinn with the same problem. When removed the BB was fine, a replacement had the same problem.
After chasing the threads the problem had gone on both of the bottom brackets. I suspect there was a worn tool used during manufacture of some frames
After chasing the threads the problem had gone on both of the bottom brackets. I suspect there was a worn tool used during manufacture of some frames
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