bottom brackets - pressfit 92mm

J

justinb

Likes Bikes
hi,

Building up a Duelly and currently trying to track down a BB.

I'm struggling to find anything OTHER then the shimano (whatever the model is) press-fit BB for a 92mm MTB. the thing is, the design is getting some bad reviews (according to some sites I'm looking at) that they crap-out after around 1000km... which isn't a lot when you think about it.

So - I want to run Shimano XT dyna-sys 2 chainring, 10 cassette.. what are my options for BB? from what I can see, Chris King doesn't do anything, and I assume the SRAM one doesn't work with Shimano crankset...

help from the guru's pls
Justin
 
0

0psi

Eats Squid
Raceface make one, not sure how good they are as I've never actually used one, but they make one.
 
T

tomli123001

Likes Dirt
The stock oem grade press fit bottom brackets by Shimano are known as SM-BB71 and they are not offered in aftermarket. All Giant and other OEM bikes all come with this model, disregarding if the crankset installed on bikes were XT or SLX or XTR (check on Giant's website across its range, take Trance X0 for example here, http://www.giant-bicycles.com/en-au/bikes/model/trance.x/9718/50946/)

Most bad reviews were done on them. However, you can get the upgraded BB91 version in aftermarket and they are advertised as XTR grade bearing, http://tbsm.com.au/index.php?main_page=product_info&cPath=149_153_232_279&products_id=10469

I think these are much better quality and not reviewed on by much, as it does not come with original bikes.

I personally own a 2011 Giant trance X2 with BB71 press fit. I have done about 1000km now on road and in manly dam. Took it apart last week and it was feeling very smooth.
 
T

tomli123001

Likes Dirt
By the way, do not go with SRAM or Raceface. Both brands' bottom bearings are famous for short lifespan, as reviewed by many including Bikeradar.com and countless bike shop mechanics I talked to.
 
J

justinb

Likes Bikes
tomli123001 said:
By the way, do not go with SRAM or Raceface. Both brands' bottom bearings are famous for short lifespan, as reviewed by many including Bikeradar.com and countless bike shop mechanics I talked to.
Click to expand...
Thanks for the information... Especially about the xtr bb information ... Even shimano website does not have any of that information. I've been looking for ages

Tbsm order placed later today

Thanks for the help
 
top_oz_bloke

top_oz_bloke

Likes Dirt
My BB71 gave up after I'm guessing around 2000km, although it dealt with some pretty bad abuse. Dirt Works, Husky, numerous local wet/mudddy rides and then Bottlebutt finished it off.

I keep one as a spare now - very easy to change out with the right tools.
 
Pebble

Pebble

Likes Bikes and Dirt
I'm watching this thread out of curiosity because if I was to buy a bike again some time in the future it would no doubt be a Giant and no doubt with press fit BB.

What I was curious about was weather some of the BMX BBs (namely the MID bb) which are press fit would be the same as the ones that Giant uses???
 
T

tomli123001

Likes Dirt
Pebble said:
I'm watching this thread out of curiosity because if I was to buy a bike again some time in the future it would no doubt be a Giant and no doubt with press fit BB.

What I was curious about was weather some of the BMX BBs (namely the MID bb) which are press fit would be the same as the ones that Giant uses???
Click to expand...
Nope.

Mid or Spanish BB used in BMX are totally different from Shimano press fit. The BMX BB has naked bearings sitting right inside the frame. Whereas the Shimano ones have a pressed in type polymer housing around the bearing.

You can think of them as the difference between integrated and internal (knowns as zero stack or semi-integrated) headsets. The first has no internal cup, and the later has a cup between the bearing and the headtube.

See pictures below:

Notice the BMX mid BB has naked bearing with no housing.
Odyssey_MidBB.jpg

The Shimano ones do:
shimano_pressfit_bb_42mm.jpg
 
G

Glen2

Likes Dirt
Wish i found this thread earlier. I accidently ordered the wrong PF Adaptor for my frame.

I have a Shimano SM-BB91-41A bottom bracket going very cheap if anyone can make use of it.
 
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