BB new one. or ditch whole crankset?

Moonbiker

Hi I have ridley x-bow that came with a truvativ elita crank & gxp BB. Its my first cx bike & my first modern bike with STI, not downtube shifter, 10 speed chain etc & not a square taper BB. :shock:


After one season of just using it only for races so probably less than 50 miles, the BB bearing have completely gone. (Crank was wobbling so opened up & they were all gunked & rusted up.) I never used a pressure washer on it either always cleaned it with bucket of water.


So was thinking just buy a new £20 quid BB gxp?

But after doing abit of googling seems gxp BB & cyclcross or even cycling in the rain is a very bad idea. Seems theese BB need maintenance after every cx ride it the wet?

http://velonews.competitor.com/2012/12/ ... eet_269323

Better off just buying a new square taper or other more durable crankset do you reckon?

Only other option is expensive new upgraded bearing races but seems can only get them from USA & you need special tools. Theese bearings are supposedly alot more durable though...

http://www.enduroforkseals.com/id193.html

EDIT: Just found another solution hope BB with a converter:

http://singletrackworld.com/forum/topic ... brackets-1

woolwich

Realistically having the bearings external is just a plain daft idea from a durability perspective. You can get through a lot of GXP bearings very quickly.

I wouldn't expect any greater durability from the Hope BB and converter. I have one and it still requires the bearings to be replaced annually if ridden in wet weather even on a road bike
.
It might be possible with care to pop just the bearings out of a cheap GXP unit and just replace those, although I have never done it and the ali case may be too soft.

I gave up with GXP and raced last year with a cheap Stronglight Crankset, 36/46 and JIS BB. This year I got hold of a slightly posher but functionally identical Middleburn crankset with JIS. Neither bearings have given up the ghost yet and I do pressure wash.
There is a minor weight penalty to pay with JIS but you would never notice. If I was seriously competitive it would be a problem but otherwise who cares?

Chris James

I don't know about GXP bottom brackets, but the Shimano HT2 ones are fine for actual cross racing / mud fests in my experience, so not all external BBs are crap.

Moonbiker

I tried putting an old miche (campy bcd) crankset on it I had spare, but the chainrings spacing is slightly wider so the 10 speed chain kept falling down between the chainrings.

Not many 10 speed square taper options, can only find stronglight impact.


Supose I could go HT2

VamP

HT2 at £10 a pop.

Easy to fit, cheap, and last the whole season without any maintenance. I replace mine when I rebuild the bikes in the summer, but you could probably get two seasons out of them.

My season is 30+ races plus training rides, so more like 300+ miles per bike.

tgotb

The only fundamental difference between HT and GXP bottom brackets is the internal diameter of the non drive side bearing. Obviously the crank attachment is slightly different, but the bearings themselves are built the same way, so a *decent* GXP BB should be no worse than a decent HT BB (unlike BB30 etc, which are inherently less well sealed).

I was under the impression that it was specifically the SRAM GXP BBs that had a poor reputation; I'd be inclined to stick with the crankset you have for the time being, and try a different manufacturer's BB. There's almost certainly one out there that's as good as VamP's HT BBs.

As an aside, I managed to get my (terribly sealed) BB30s to last a whole season by overloading the bearings with grease, and then prising off the seals after every race and injecting more. If there are no voids, it's harder for the water to get in because it has to displace grease to do so.

Moonbiker

Thanks all this modern bike bits stuff if new to me. 8)

As an aside, I managed to get my (terribly sealed) BB30s to last a whole season by overloading the bearings with grease, and then prising off the seals after every race and injecting more. If there are no voids, it's harder for the water to get in because it has to displace grease to do so.

Lennard Zinn says he does this also after every cross race with the gxp bb :roll:

BB seals have being taken off & cleaned out on the the current team gxp BB, & ball races repacked with marine grease, Ball bearings actually were ok under all the rust from the other BB parts. Will see how it lasts.


Seemed to run ok when I tested it today for 20 miles.

As for gxp BB's with better durability reputations, there token & hope with adapters or the expensive £120 SRAM one, and the enduro bearing kits from USA to retrofit the current BB.

woolwich

Honestly don't waste your money on high end GXP equivalents, you are essentially buying the same design from another manufacturer.

As mentioned by the others the Shimano version does have a slightly better reputation, which is strange, as TGOTB says it is more or less the same thing.
I have just spent a while looking at them all on my bikes and figure that the crank design must afford just a little extra protection on Shimano.
Whilst it doesn't matter so much on a race bike, regular fettling and stripping and cleaning is just part and parcel of it. It is a complete ball ache to be wrecking BB's every few hundred miles otherwise.

I thought I would have a play. This took no money, ten minutes all in and might provide a solution of sorts.

Take two Domestic Aerosol Caps, Drill a 24 or 25mm hole in them and cut to around 15mm or so deep and mount on the cranks, just remember your wave washer.

Admittedly it would have looked nicer with black caps but it is basically unobstrusive. Here it is on my TT bike just for testing.

Doesn't foul on anything and seems to have a more or less ideal amount of clearance, around a mm or so. So hopefully it should prevent most water entry but not be a trap. Weighs nothing. I'll try it and see how it goes, for commuters, training and utility bikes it has potential.

Moonbiker

I like the home made covers.

Just ordered some "aire bearings" £10 on ebay hope they will fit/do the job, as cranks still all wobbly

http://www.ebay.co.uk/itm/TRUVATIV-BOTT ... D100275%26

Dunno why gxp are worse maybe the quality of bearing seals?

Looked at ht2 cranks but they would cost about £80 with a BB. Was looking at cx50 tigara 105 etc

Also found this BB:

http://www.freeborn.co.uk/wheels-manufa ... compatible

Moonbiker

The Aire 2pcs bearing races came today, the ones linked above, the 22m one fitted perfectly the other one, the 24mm side one,the internal diameter of the bearing race is smaller so the nylon plastic shim won't fit between race & axle and it is 1mm fatter so the circlip to hold bearing race in place would not fit either.

Just had to leave both thoose 2 bits out, & without the plastic shim = very slight play on the cranks.



Second pic should be 7mm not 8m I think and the 24mm seems more like 23.8mm :evil:

Will see how it does anyway might be ok i dunno need to ride bike a few miles to test it.

Pic of bit I left out:



http://en.hollandbikeshop.com/sram/truv ... 10-pieces/