Stiff press fit BB on new bike

warrior4life

I have a 2010 cube agree gtc race and it came with a triple, we've changed it to a double and left the original BB in.
The trouble is the chainset doesn't spin that freely, I've taken it out and span the BB with my fingers and its very smooth just stiff, The bike's done about 2500 miles.

I've just checked 2 of my other bikes and the chainsets (Both cartridge BB's) spin far more easily.
It almost feels like the grease is to thick in the BB.

I've had it into a bike shop and they say its normal, I'm not really sure what to do, Should i buy a new BB?
Does it make that much difference?
Any help much appreciated.

MrChuck

I think it's normal- I've got two external-BB equpped bikes and neither of them seem to spin as freely as cartridge ones.

maddog 2

some external bearings (pressfit or cups) are sluggish some are better. You can't tell when you're pedalling so unless your TTing and want every nanosecond I wouldn't worry about it.

Having said.... my Endura ceramics (BB90) are very spinny and I love them 8)

warrior4life

I think im going to change the BB.

If its a cube with BB90 does that mean that im pretty restricted with the BB's i can choose from?

The bottom bracket shell isnt threaded, can i use any press fit bb?

I've been searching google to find more info but its hard to find and my computer is very slow.

HadronCyclist

To be honest, it sounds like you don't need to change the BB at all. Smoothness is what is important, however, I too have been annoyed by a lack of "spininess" and so:

If its a cube with BB90 does that mean that im pretty restricted with the BB's i can choose from?

Luckily, BB90 is compatible with every set of cranks, therefore there are a large range of BB options to choose form to suit you budget and requirements

The bottom bracket shell isnt threaded, can i use any press fit bb?

Ideally you want to get a workshop to measure the diameter of your BB shell and go for a new BB ~0.1mm bigger to ensure a decent press fit. You need to do this accurately as the press-fit nature of the sealed bearings means they put a considerable force on your frame, and can damage it irreparable if not fitted properly. i.e. Don't use a hammer to smack it in, use a proper Press-fit tool such as the Park Tool HHP-2 in conjunction with a BBT-90.3 set of bushings.

If you want to do the job yourself check out the fantastic Hayes Manual equivalent for bikes, the Barnett's Manual of Bicycle Repair which will give you some very nice info... available to browse here:
http://www.scribd.com/doc/16958306/The-Barnetts-Manual-of-Bicycle-Repair

Hope that has been helpful.
D

maddog 2

Shimano do BB90 pressfit cups (see CRC)

Enduro do some fancier ones, see http://www.enduroforkseals.com/id258.html

(I run a ceramic version on my fancy roadie)

Just remember that Shimano and SRAM are different though, just like with regular external cups.

warrior4life

Many thanks for the help, Will probably end up with some ceramic enduro bearings as long as they work with the Ultegra chainset.

I usually do all bike repairs myself but i think this one will have to go to the shop.

desweller

Modern BBs are equipped with seals, but these come with the penalty of a little friction as the interface necessarily involves sliding surfaces.

However, the friction is low and is not an indicator of how the bearing will perform under load. If you cannot feel any rumble in the bearing then you do not need to replace it.

maddog 2

the bearings are very easy to fit

just whack them out and fit new ones with a headset press.