Yet another BB query.

Chet Spiker

Regular
Location
Wales
Sorry about this - my first post on this forum and it's a BB question which I'm sure you are all fed up with but here goes; I have an Orange Speedwork S, bought almost a year ago and ridden about five or six hours a week mostly on forestry roads/bridleways/towpaths etc. The BB (a RaceFace X-type, shell measures 68mm across) has started creaking when climbing hills and looking around cycling forums it seems they don't have a very good reputation. The dealer has said it's a service issue not a warranty issue. I had the same problem with my last bike (Cannondale CAADX with a BB30). I don't know much about bikes but I have a long background in electronic/light mechanical engineering and am reasonably handy. I would like to buy a good quality replacement (Hope Tech possibly?) and henceforth be independently able to maintain my own BB. It's confusing though, isn't it? Until I bought the Cannondale I had no idea that BB problems were so pervasive and absolutely no idea that there were so many variations in style and dimensions. I don't mind stumping up for a decent BB and whatever tool it needs but obviously I don't want to pfaff around ordering something that doesn't fit. Any advice greatly appreciated.
 

Cycleops

Guru
Location
Accra, Ghana
Youre right, it's quite a widespread problem. With pressfit BBs the frame needs to be manufactured to very exacting tolerances but sometimes things go awry. Hence the problem of creaking.
There are various options and this is for the Rotor conversion.

View: https://youtu.be/H6rsDioMt0Y
 
OP
Chet Spiker

Chet Spiker

Regular
Location
Wales
Thanks, Cycleops that's an interesting video - unfortunately the Cannondale was badly damaged in a crash last year and is no more.
I think the RaceFace on the Orange I have now is an external threaded BB so I went on to the Hope website to see their compatibility chart but it seems I would have to strip it down to find out whether the shaft diameter is 24 or 30mm. Maybe it will be worth getting the tool and seeing if I can save the existing bearings by re-packing them with a good quality grease. Hmmmm... something to think about!
 
Location
Loch side.
Thanks, Cycleops that's an interesting video - unfortunately the Cannondale was badly damaged in a crash last year and is no more.
I think the RaceFace on the Orange I have now is an external threaded BB so I went on to the Hope website to see their compatibility chart but it seems I would have to strip it down to find out whether the shaft diameter is 24 or 30mm. Maybe it will be worth getting the tool and seeing if I can save the existing bearings by re-packing them with a good quality grease. Hmmmm... something to think about!


Take the advice offered to you two replies above and read up on the problem. It isn't the bearing that's creaking, so your plan with grease won't work.
 
Location
Loch side.
It's not a press fit BB though. The threads you listed above don't apply directly in this case - so what's the likely cause of the creak in that case?
It is the interface between BB and BB shell. Dirty water gets into the threads and dry out, but leaves dirt (fine gritty silica) behind. When pedalling hard, the BB cup precesses in the BB shell, causing micro-fretting and hence, noise. This noise is worse on an alu frame and much, much worse if the frame is carbon (even with an alu threaded insert in the BB) because carbon is such a nice conductor of sound and resonates nicely at that frequency.

This doesn't happen with square taper BBs because the BB is one piece and better supported in the frame. Loose cups on the other hand have shallow threads and require very, very good shoulder contact to be reasonably quiet.

In rare cases a very dry bearing will creak but it's usual modus operandi is to hum. This is easy to diagnose. Remove the chain, spin the crank with a good whack of the pedal and put your ear to the top tube. A bad bearing goes RRRRRRRR, a good one goes SSSSSSSSSSH. A very bad bearing doesn't even require an ear to the top tube, it will be really loud when that crank spins.
 
OP
Chet Spiker

Chet Spiker

Regular
Location
Wales
Thanks, Yellow Saddle.
 
OP
Chet Spiker

Chet Spiker

Regular
Location
Wales
Somehow managed to post that after just two words. Perhaps the best thing to try would be to get a tool (Park BBT9 I think) remove the BB then give all threaded surfaces a thorough clean and a liberal application of waterproof grease. Thanks all.
 
Location
London
I may as well eventually ask the question - as have sometimes idly wondered - what are supposed to be the advantages of these "press fit" as I believe they are called BBs?
 

si_c

Veteran
Location
Wirral
It is the interface between BB and BB shell. Dirty water gets into the threads and dry out, but leaves dirt (fine gritty silica) behind. When pedalling hard, the BB cup precesses in the BB shell, causing micro-fretting and hence, noise. This noise is worse on an alu frame and much, much worse if the frame is carbon (even with an alu threaded insert in the BB) because carbon is such a nice conductor of sound and resonates nicely at that frequency.

This doesn't happen with square taper BBs because the BB is one piece and better supported in the frame. Loose cups on the other hand have shallow threads and require very, very good shoulder contact to be reasonably quiet.

In rare cases a very dry bearing will creak but it's usual modus operandi is to hum. This is easy to diagnose. Remove the chain, spin the crank with a good whack of the pedal and put your ear to the top tube. A bad bearing goes RRRRRRRR, a good one goes SSSSSSSSSSH. A very bad bearing doesn't even require an ear to the top tube, it will be really loud when that crank spins.
Thanks, that makes sense. So what is the best way of trying to avoid the noise? Would PTFE tape on the threads of the BB cups be worth trying to avoid the ingress of contaminants?
 

SkipdiverJohn

Über Member
Location
London
I may as well eventually ask the question - as have sometimes idly wondered - what are supposed to be the advantages of these "press fit" as I believe they are called BBs?
All the advantages appear to accrue to the manufacturers, not the owner who buys the thing. Cheaper and easier manufacturing, especially in the case of carbon fibre frames. I'm sticking to threaded cup & cone bearings, and square taper or cottered axles. They can keep all the other inferior rubbish.
 
D

Deleted member 6179

Guest
I may as well eventually ask the question - as have sometimes idly wondered - what are supposed to be the advantages of these "press fit" as I believe they are called BBs?
I have had 20000 miles out of a Shimano Press-fit, never had more than 3000 out of an external HT2 BB or BB30 or 5000 out of a square taper.
The downside is they tend to click after they have been out in the rain or washed too vigorously.
 
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