Tell me about them please.

Do you have one?

Is it a PITA?

Would it put you off buying a frame with one?

What BB/crank do you use?

You can get hope now….

Will have one at the end of the week 🙂 Kinda of guessing it will eventually creak like my BB30 in the road bike.

I’ve got a shimano press fit in my new bike, didnt give it a second thought to be honest. They’re basically disposable items anyway

I have a BB71 (XT version) in my Pivot atm as that was what the bike shop had for what i had left from my budget. Seem to be running ok but I have only had the frame just over a month, so not sure of the longevity as of yet.
It certainly wouldn’t put me off buying a frame with a pressfit bb esp with hope now producing one. The only annoyance is the lack of iscg mounts on my bike.
Currently running it with 10speed XT cranks.

I’ve got one on my 2010 Stumpjumper FSR. It’s the weird Specialized specific size. Something like BB92 41A, but am not entirely sure.

I use it with an XT crankset; M770 I think.

It’s fine apart from when it’s been really wet or I’ve washed it a bit enthusiastically. Then it goes a bit stiff until the pedals get a few revolutions under them; then it suddenly frees up – almost like it siezes slightly.

My main issues with it are that:
– it doesn’t appear that easy for a home mechanic to change. It probably is, but it just doesn’t appear to be, whereas HTII is just unscrew, re-screw as long as you have the right tool. It probably is OK once you’ve done it once, but it doesn’t look as simple.
– I am not entirely sure what I need to order when I replace it, but I am not sure if this is just because the Specialized one is slightly different.

I am very tempted to get the Hope pressfit BB when it comes out so long as it fits.
Or get one of the adaptors that allow it to run with a HTII although I am not sure if that is only available with BB30…..?

For BB92 you need

Press fit tool
Remover

Rorschach – Member

You can get hope now….

You fitted any yet?

Press fit bb are basically a headset design with plastic cups into which bearings are pressed so to remove them you have to tap carefully on the inner face of the cups as you look through a BB shell, if you manage to do this without breaking the cups then the entire assembly will pop out of the frame – throw the shite assembly in the nearest bin and fit a Hope unit which is a doddle, you don’t necessarily need the specialist hope press-fit tool but if you can afford it then all well and good. If you have carefully tapped in a headset or used a big muckle vice or a length of threaded rod to fit a headset then it’s basically the same idea but pay attention to the use of BB spacers if needed dependant on the width of your BB shell.

It is actually easier to change a press fitt BB than the old UN72 square taper or HT11 or Octalink etc as all you need is a big hammer and a punch, and a small amount of mechanical sympathy.

Would it put me off a bike if it came with one?……… not really as they are a doddle to change or press new enduro bearings into existing cups but i doubt any bike frame i will own in the future will have a press fit BB just coz i is so niche 😉

Remover
Press fit tool

Aye.Straight forward enough,not too sure about an ali shell pressed into ali frame but plenty of anti corrosion paste and she’ll be reet.
Can’t figure out a way of fitting the centre sleeve without the tool though (ie diy) 🙁
At least you only have to pay to do it once.

Can’t figure out a way of fitting the centre sleeve without the tool though

All you need is a corresponding sized nut that fits into the hex in the centre sleeve and lock two of the nuts together on a bit of threaded bar and use a socket on one of them and swing from a breaker bar on the other, i forget what the size of the nut is but from memory it may be 19mm, i can check on thursday when i’m in the shop.

Or I can just use my hope fitting tool 8)

I’m more worried about creakage between the bb shell and the outer part of the cups than anything.

It’s a stainless steel bb shell so should be relativley tough.

Nice to know I’d be able to fit it myself.

I pressume the Hope adaptor/converter thing stays in the bb shell and you just change the bearings when they’re ****?

Kenny.
If you could let me know what size nut i need to turn the inner sleeve that’d be great.

You can get hope now….

Where? Nowhere I can see.

I can use my hope fitting tool as well 😉 , but to be honest you’d be just as quick to use a flat lump of hardwood across the BB press cup face and whack (tap) it in gently as long as you make sure it goes in square to the face of the BB shell, or use a punch or suitable sized socket with a threaded bar etc…etc…, if i had bought every “special” tool i’ve needed over the course of 20+ years being a mechanic (engines/gearboxes/cars/motorbikes other engineery stuff) then i’d have wasted a £ucking fortune and have a massive stock of useless or one use only tools that only gets used a few times in a lifetime.

I’ll let you know stu 🙂

Cheers mate.

Where? Nowhere I can see.

We’ve got them in stock – with free fitting too. If you’re not local, come for a ride at the same time! 😉

With much of the point of this BB (with the threaded centre piece) being to get better alignment of the cups, why the hell would you pay that much for a BB and then smack it in with a bit of wood?!

18bikes – I could well be up for that at some point. Not local though so it would be a good excuse for a ride too. Probably wait for it to dry out though!

Can you confirm whether it would fit a 2010 Stumpjumper FSR? I think it’s a BB91-42A…..

I guess some folk may be not be mechanically sympathetic to whacking in bearings or bearing cups wi bits of wood and punches and that’s fine, but personally i feel quite competent in doing so, been doing it to very expensive bits of car exotica for years and recently used a vice and bit of wood followed by a few taps of a punch and hammer to press and seat a wheel bearing on an old but fully restored Aston Martin DB5 belonging to a fisherman up here, also done various scooby/mitsubishi wheel bearings for the rally crowd and suchlike on stages. You press it in so far with the vice or tap it in wi the wood/hammer method making sure the bearings cups go in absolutely square then you tap round the edge of the cups and listen for the particular percussion noise of bearing seat against flange and then you know the cup is seated correctly.

A bike frame is no different, in fact it’s a damn site easier as you can spin it round and check for alignment.

Give me good quality set of punches and a suitably weighted hammer and i’ll attempt anything with confidence 😉

stumpy – I think that’s the one that’s different – some Specialized bikes around that time used a 42mm version of that bottom bracket (not the 41mm ones that the Hope one replaces)

If you can email me with more details/a frame number then I can double check with Specialized for you.

Si

“custom Shimano integrated” – so it would seem!

Stu, its a 25mm sized nut or allen key you need to tighten the inner sleeve

I have a Zesty which uses that standard. Zesty’s are known to go through BB like a dose of salt, due to the seat tube not draining. I drain my seat tube every ride now and am getting loads more life out the standrad Shimano BB71 or BB91.
I made a tool for fitting which works well. Using an old cut down cup from a knacked BB71 so it only pushes on the outer face of the cup and not the bearing. and then a threaded bar washer stack etc. And due to the fact they are plastic cups they push in nicely. No big deal. Getting old ones out is the real challenge though. In the end I just knock the bearings out of the cups whilst in situ in the frame, leaving only the cups in place, then very carefully with a very sharp blade like a stanley, cut through the length of the cup, stopping just before going through the cup completely and scratching the BB shell, then one tap from the other side and it usually breaks and pops out. Its a bit of PITA and no where near as easy as fitting an outboard cup but it works

With two bikes with press-fit BBs, and an average life expectancy of around nine months per unit, I decided it was worth investing in the proper tools…

Changing a BB is now a ten minute job, and the tools cost about 40 quid IIRC, so a no brainer really…

Edit: Yes I realise Hope ones need an additional tool, but I’ll probably stick to the disposable Shimano ones – I just treat BBs as a consumable now, like tyres and brake pads 😀

18 bikes – mine isn’t the alloy frame. Sorry, I should have said that.

Mine is the carbon version….like this (but different colour)…

http://www.specialized.com/gb/gb/bikes/archive/2010/stumpjumperfsr/stumpjumperfsrexpertcarbon#specs

Which reckons the BB is this:

BOTTOM BRACKET Custom Shimano BB-91, OS, press-in bearing.

I think the ‘custom’ bit refers to the width of the shell and that it needs a spacer.

See the bottom diagram of this shimano tech doc…

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/BB/EV-SM-BB91-2987A_v1_m56577569830726016.pdf

thanks for the info Kenny.

If it’s the BB91-41, then we’re ok. If it’s the BB91-42 then I think that’s a no.

There are various widths of BB91-41, which do make use of spacers in a similar way to the HT2 cups.

Si