GXP bottom brackets

d3matt

I've got some complete beginners questions here as well as buying advice...

My 2010 Boardman FS Team needs a new bottom bracket. The original is a Truvativ GXP.
1. I see these come in either English or Italian threads. Would mine be English? Mine says "BSA" on it - is that the thread?
2. Do these come in different sizes or are they all one standard size? I've taken the non-drive side of my bottom bracket off and the the bearing cup is printed "47-09" and on the plastic tube is "49-09". Yet all online pictures I see of these, they show different numbers.
3. Do I have any choice of manufacturers (I have a Truvativ Firex 3.2 GXP 44/32/22T chainset)? So far I've only seen the SRAM/Truvativ ones and the Superstar Angletech one. Is the Superstar one a straight swap? Is it any good or better than the SRAM Team at the same price? It has angular contact bearings, which doesn't mean anything to me. Superstar stuff is good value so I assume it must be better than the SRAM.
4. Ceramic or not? While the SRAM ceramic bearing version is out the question at £150, the Superstar ceramic one is £50 and I'd stretch to that. From my experience of ceramic bearings in my KCNC jockey wheels, I'd very happily spend a little bit more.

Thanks for any help. I want to order one tonight online but I'm a BB virgin.

bigpee

I can help with some of these - I have the same chainset (originally from a Boardman HT).
1 - English thread.
2 - As long as it's a GXP bottom bracket it will fit.
3 - Think there are various different manufacturers although I just put in a new Truvativ one for £20. Just make sure whatever you buy it is GXP.
4 - No experience on ceramic but if it costs £50 for ceramic ones and £20 for normal it needs to last 2.5 times as long. Quite happy with my non-ceramic one.

bigpee

PS - forgot to mention. What tightening up the extracting bolt don't over-tighten. I did, and it cost £15 to replace and was near on impossible to source.

cooldad

I'm a big superstar fan, but read the Angletech reviews - not good. I went for XTR after reading them. Obviously that's no good for you.

Anonymous

With that crank, you're fixed to GXP brackets. That's SRAM/Truvativ then or something compatible. A number of alternate BBs have adapters available to convert them to GXP. I believe Raceface do an adapter and I know you can get one for Hope.

Easy option is a Truvativ Team GXP BB. Dead cheap, dead simple to fit. There are others in the GXP range, like push fit, BB30, etc. These all refer to how they fit onto the frame, they all work with GXP cranks. For a mountain bike it's usually a threaded shell so a standard GXP BB will do and usually that's what people sell.

Note with the threading, that even though it's 'English' the threading is different on each cup, one cup threads clockwise, the other anticlockwise. Make sure you get it right! Mainly a problem when removing though, as I found out when I forgot and overtightened the thing!

When fitting, you'll need to know the BB shell size to work out if you need to fit the spacers it comes with, though should be same as the existing BB you have.

Also I found the newer GXP BBs leave a small gap sometimes on the drive side between BB and crank face. This is normal apparently.

Tightening the crank - needs a lot of force for GXP due to the design, but yes don't over tighten (torque wrench can help), make sure you only tighten the inner 8mm nut. Getting them off I end up using a breaker bar even though they're torqued to spec.

Ceramic - don't know. The cheap one that came with the old bike lasted a couple of years fine. Some complain about GXPs and say they wear out in a few months, but I suspect this may be the older BBs and/or they've been fitted incorrectly or the frame is badly faced (though GXP is supposed to reduce the issues with poor facing). Also wonder if they're just complaining about noises due to poor or excessive cleaning.

d3matt

Thank you everyone for your replies. Tonight has been yet another lesson and with this and Youtube videos, I've now know more about bottom brackets.
Have now got a SuperStar Angletech BB coming. I know the reviews aren't that good, but for £15 from another forum member, I thought I'd give it a go. But then the Truvativ Team gets bad reviews too.
Mine has lasted 13 months with riding on average just once a week, all off road.

PXR5

Posted this a while ago in case its any help,

viewtopic.php?f=10004&t=12798848

the download Supersonic talks about is

http://www.sram.com/sites/default/files ... nksets.pdf

I had considered buying a replacement, but after last rebuild/regrease it seems pretty much OK.