Mtb bottom bracket
Discussion
Hi
Bought a cube mtb last November and have done approx 700 miles on it, and the bottom bearing is now getting rough and has play in it.
Took it to local bike store retailer and they have said it's got wet (!) and as I hadn't cleaned it and regreased after every ride it's not covered by warranty. It's a press fit bearing for starters so it's unlikely to be a good idea to remove it frequently.
They said bottom brackets these days are basically hit and miss some can last many miles others fail early as mine has. That suggests a manufacturing defect frankly.
What do others think? Suck it up buttercup and move on, or kick up a fuss for a replacement. It's a raceface if those are any good i don't know.
In terms of replacements, what are good makes ?
Thanks
Mike
Bought a cube mtb last November and have done approx 700 miles on it, and the bottom bearing is now getting rough and has play in it.
Took it to local bike store retailer and they have said it's got wet (!) and as I hadn't cleaned it and regreased after every ride it's not covered by warranty. It's a press fit bearing for starters so it's unlikely to be a good idea to remove it frequently.
They said bottom brackets these days are basically hit and miss some can last many miles others fail early as mine has. That suggests a manufacturing defect frankly.
What do others think? Suck it up buttercup and move on, or kick up a fuss for a replacement. It's a raceface if those are any good i don't know.
In terms of replacements, what are good makes ?
Thanks
Mike
Bottom Brackets are like a consumable item! They are basically a sealed for life unit which you cannot strip apart to clean etc. and as stated the quality can be a bit hit or miss.
I've had good life out of the higher-end Shimano press-fit bearings, but Hope do a Press-Fit unit with replaceable bearings, not cheap though.
They are pretty easy to remove and re-fit, a DIY job. When fitting a new one put plenty of extra grease around the bearings to keep the water at bay, Thick silicone grease is good for this of you can find some.
I've had good life out of the higher-end Shimano press-fit bearings, but Hope do a Press-Fit unit with replaceable bearings, not cheap though.
They are pretty easy to remove and re-fit, a DIY job. When fitting a new one put plenty of extra grease around the bearings to keep the water at bay, Thick silicone grease is good for this of you can find some.
Yeah to be fair the conversation was quite funny in hindsight. When I first got into the shop a tech was wiggling the pedals and said it's only a tiny bit of play. So I turned the bike over and took the chain off, and showed him how to inspect the BB. So then he says it's not covered because it's got wet. As the bike was bone dry at the time I asked him how he knew the bike had got wet. Well, it's a.. ummm. Mountain bike? Yes.
If raceface are crap I'll see if they can do me a deal on a Hope.
Thanks everyone. Sounds like it's 75:25 to suck-it-up-buttercup
If raceface are crap I'll see if they can do me a deal on a Hope.
Thanks everyone. Sounds like it's 75:25 to suck-it-up-buttercup
The cheap no-name one on my Marin was graunchy and making creaking noises after less miles than that. A new Shimano one was £9 and took a couple of minutes to fit.
You can do some preventative maintenance on them by whipping the cranks off and making sure you've got some thick grease between the outer plastic part and the bearing itself which will limit how much can get in. It's not like an old loose bearing unit though where you can open it up and regrease properly.
Overtightening when putting the cranks on - ie too much side-to-side tension on the BB bearings - can also shorten BB life. Tighten enough to remove play but no more.
You can do some preventative maintenance on them by whipping the cranks off and making sure you've got some thick grease between the outer plastic part and the bearing itself which will limit how much can get in. It's not like an old loose bearing unit though where you can open it up and regrease properly.
Overtightening when putting the cranks on - ie too much side-to-side tension on the BB bearings - can also shorten BB life. Tighten enough to remove play but no more.
IT might be a problem with the cranks rather than the ball bearings.
If it is a Cinch crank, then first try checking the plasic preload ring on the non-drive side.
If it's not that, then unbolting each crank 8mm and 16mm Allen Keys @50Nm and cleaning and regreasing could solve the problem.
At least, if you remove the cranks you can identify if the issue is with the bearings or the crank assembly.
If it is a Cinch crank, then first try checking the plasic preload ring on the non-drive side.
If it's not that, then unbolting each crank 8mm and 16mm Allen Keys @50Nm and cleaning and regreasing could solve the problem.
At least, if you remove the cranks you can identify if the issue is with the bearings or the crank assembly.
Former bike mechanic here, and these are my thoughts on the matter:
t.
t idea and never should have caught on (probably cheaper to make though so a good money saver for the manufacturer)
My advice would be use one of the cheaper models of a decent brand (Shimano are always my go to, however this might be dictated by which crankset and BB type you have) and treat it as a consumable.
RF used to be good but I fear that they are a bit st now that the original brand went bust and got bought out by someone else.
bmwmike said:
Hi
Bought a cube mtb last November and have done approx 700 miles on it
what kind of miles? depending on riding style and what kind of terrain you ride it on, distance can be almost irrelevantBought a cube mtb last November and have done approx 700 miles on it
bmwmike said:
Took it to local bike store retailer and they have said it's got wet (!)
water in the bearings would wash the grease out, wash various kinds of crud in and generally accelerate wear, so this is probably true.bmwmike said:
as I hadn't cleaned it and regreased after every ride it's not covered by warranty.
This is horse st.bmwmike said:
It's a press fit bearing for starters so it's unlikely to be a good idea to remove it frequently.
this is true. Press fit BB is a st idea and never should have caught on (probably cheaper to make though so a good money saver for the manufacturer)bmwmike said:
They said bottom brackets these days are basically hit and miss some can last many miles others fail early as mine has. That suggests a manufacturing defect frankly.
The first point is true, the second is probably not quite true, it's more the fact that it is a part that is highly stressed and in just about the worst position possible for adverse operating conditions to occur, so to make a properly weather proof and endlessly durable BB would be expensive, heavy and complex.bmwmike said:
What do others think? Suck it up buttercup and move on, or kick up a fuss for a replacement. It's a raceface if those are any good i don't know.
In terms of replacements, what are good makes ?
I think you are well within your rights to ask them to replace it as it has failed within warranty period, however you will come to learn that when it comes to BBs, you just have to suck it up and accept that they are consumables. In terms of replacements, what are good makes ?
My advice would be use one of the cheaper models of a decent brand (Shimano are always my go to, however this might be dictated by which crankset and BB type you have) and treat it as a consumable.
RF used to be good but I fear that they are a bit s
t now that the original brand went bust and got bought out by someone else.Edited by deadtom on Wednesday 5th June 16:07
Thanks,all good advice.
The bike Web page says the crankset is a "Race Face Ride Cinch, 32T, 170mm".
Measuring it with a ruler, it seems to be 95mm wide and I think around 25mm diameter. There are numbers stamped onto the bearing itself but couldn't quite see them properly. Do I need those numbers to know what replacement to buy?
This is the bike: https://www.cube.eu/en/2019/bikes/mountainbike/har...
The bike Web page says the crankset is a "Race Face Ride Cinch, 32T, 170mm".
Measuring it with a ruler, it seems to be 95mm wide and I think around 25mm diameter. There are numbers stamped onto the bearing itself but couldn't quite see them properly. Do I need those numbers to know what replacement to buy?
This is the bike: https://www.cube.eu/en/2019/bikes/mountainbike/har...
AndrewEH1 said:
If it was me and after that initial first conversation I'd be looking for another LBS!!
This. See if "they" can do you a deal on a Hope BB by all means, but first make sure the "they" you are dealing with are not the original shower that told you that you need to strip down a BB after each and every wet ride. This is one of the biggest loads of cobblers I've ever heard regarding bicycles. Typically, in any owners manual or maintenance instruction, that is the kind of job that the bike manufacturer or component company would be recommending you to "consult a qualified bike mechanic" for!ps: I don't go through all that many BBs comparative to most riders I've talked to. Perhaps because I don't ford streams and rivers, aim to go round puddles where at all possible, rather than straight through the middle, and I seldom wash my bike. I just leave it in the garage and brush the mud off when it dries. I think both my MTB and my road bike have press fit BBs too, although I would prefer a nice threaded Shimano BB with outboard bearing cups if I had the choice...
I’ve got a Cube GTC which is a carbon frame with pushfit bb it’s a crap idea for the home mechanic as you can easily damage the fram unless everything is perfectly aligned, you need a press and tools to change them over.
I ride mine in all conditions and ,touch wood, the bb is ok after 18 months however my front wheel bearings needed changing whereas the rear is fine.
I think that with sealed bearings it’s hit and miss some let in water some are really well sealed.
My advice would be to find a mechanic who knows what they are talking about , pressfit bb are not normally a serviceable item
and just replace the bearings like for like, if they fail then consider the more expensive options
Replacing the bearings should be less than £30
I ride mine in all conditions and ,touch wood, the bb is ok after 18 months however my front wheel bearings needed changing whereas the rear is fine.
I think that with sealed bearings it’s hit and miss some let in water some are really well sealed.
My advice would be to find a mechanic who knows what they are talking about , pressfit bb are not normally a serviceable item
and just replace the bearings like for like, if they fail then consider the more expensive options
Replacing the bearings should be less than £30
BOR said:
IT might be a problem with the cranks rather than the ball bearings.
If it is a Cinch crank, then first try checking the plasic preload ring on the non-drive side.
If it's not that, then unbolting each crank 8mm and 16mm Allen Keys @50Nm and cleaning and regreasing could solve the problem.
At least, if you remove the cranks you can identify if the issue is with the bearings or the crank assembly.
It is a cinch crank but all I have is an 8mm bolt which wasn't particularly tight. If I remove that I thought the pedal crank would come off but it's stuck fast. Do I need a puller to get it off? If it is a Cinch crank, then first try checking the plasic preload ring on the non-drive side.
If it's not that, then unbolting each crank 8mm and 16mm Allen Keys @50Nm and cleaning and regreasing could solve the problem.
At least, if you remove the cranks you can identify if the issue is with the bearings or the crank assembly.
Thanks
My Cinch crank had a plastic screw (16mm ) above the 8mm screw.
You are meant to leave the 16mm screw in place, and the 8mm screw pushes against the cap screw to lift the crank off the axle.
(Non drive side has a single 16mm screw, but once removed, you can use the 8mm/16mm from the drive side to extract)
Torque value on my cranks are quite high - 50Nm for the main screws (2Nm for the plastic cap screw).
If your bolt seemed loose, that could be the source of your problem.
You are meant to leave the 16mm screw in place, and the 8mm screw pushes against the cap screw to lift the crank off the axle.
(Non drive side has a single 16mm screw, but once removed, you can use the 8mm/16mm from the drive side to extract)
Torque value on my cranks are quite high - 50Nm for the main screws (2Nm for the plastic cap screw).
If your bolt seemed loose, that could be the source of your problem.
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