Viewing 40 posts - 1 through 40 (of 44 total)
  • pressfit BBs, I am sooo out of my depth….
  • Stoner
    Free Member

    I’m unfortunately being dragged kicking etc into the world of pressfit BBs.

    It’s a long way from UN72/54 which are in the rest of my bikes and I havent a clue.

    A quick look around and it seems Mr Hope wants to charge me £100 for a PF41 / BB92 unit. That. Is. A. Lot. Of. Money.

    That’s like 8x UN54s.
    And I go through one of those every 4 years or so.

    Can I assume the Hope one lasts forever then? It says it’s serviceable – can I do that with a hammer/vice/drift and other carefully calibrated tools from the landrover tool box?

    Are there other serviceable ones out there? How are they installed – can I use a workshop pneumatic press?

    benji
    Free Member

    Really wouldn’t use a workshop press, it’s only a light pressing action they need, two washers and some studding would do it.

    The Hope needs their tool for installation, and I believe it does the servicing as well.

    Suggsey
    Free Member

    Conversion cups and run your favoured UN units?

    Fresh Goods Friday 696: The Middling Edition

    Fresh Goods Friday 696: The Middlin...
    Latest Singletrack Videos
    Stoner
    Free Member

    Conversion cups and run your favoured UN units?

    talk to me honey

    Stoner
    Free Member

    The Hope needs their tool for installation, and I believe it does the servicing as well.

    christ that’s another £40!

    Suggsey
    Free Member

    Was thinking praxis type affair but I’m sure I had seen another type of conversion kit to retro fit. I’m googling away….

    pete68
    Free Member

    “Only” £80 unless you’re going for the ceramic bearing get version. If you’re comparing like for like then the shimano pf91 any be had for £24.99

    Garry_Lager
    Full Member

    They’re the best for servicing – bearings wise it’s knock em out, press em in, done.
    The problem is that this servicing needs to be easy, as you may find yourself doing it rather more often than you are used to. Most people report pretty bad bearing life – they seem to be poorly protected. I’ve not had too bad results myself, but it’s still a different story to older style bbs.

    djflexure
    Full Member

    I put a praxis on the wife’s salsa, running shimano cranks. Fitted with headset press no problem and been trouble free for a year or more. Seems quality. Either that or Hope I would have thought, although praxis is cheaper.

    Get over to the Cevennes thread

    Stoner
    Free Member

    quick trip back to basics

    what does the 41 mean in PF41

    and what does the 92 mean in BB92?

    and are these different to PF46, PF30, BB30 etc?

    irvb
    Full Member

    Watching this thread with interest as my 2011 Trek Paragon needs a new BB – apparently a SM-BB91-41A.

    http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/bb-2011-trek-paragon-655788.html

    Stoner
    Free Member

    cheers djf.

    will look out praxis ones.
    and have posted in cevennes.

    andytherocketeer
    Full Member

    yes, all different.
    all the numbers approx 80+ are the bb shell width?
    and all the ones ca. 40 are shell diameter
    and 24, 30 is axle diameter.

    I is sticking with BSA until it’s impossible to get BSA bikes.
    Even half the cranksets come with a BSA 68/73 BB, and then you’re expected to get the pressfit bit as well. Sod that.

    Hope have several vids showing simple tapping out of bearings. What they don’t show is that when you do it, there’s a whole blimmin bike or wheel attached to that bearing shell.

    djflexure
    Full Member

    http://www.velo-direct.ch/44_pdf/047251.pdf

    Comprehensive guide by Hope that I found useful

    singlespeedstu
    Full Member

    Praxis will not fit a BB92 BB.
    The 92 in BB92 is the width of the BB shell.
    The 41 in PF41 is the diameter of the BB shell.

    Stoner
    Free Member

    cheers guys.
    anyone know what the shimano part number is for 41 x 92 shell then?
    on eBay it seems to be 42mm stuff?

    molgrips
    Free Member

    This was me with headsets before Christmas. Welcome to the modern world Stoner 🙂

    singlespeedstu
    Full Member

    I get around 12 months out of these.

    http://www.chainreactioncycles.com/shimano-bb91-mtb-press-fit-bottom-bracket/rp-prod44225

    Not bothered with a Hope PF41 as replacement bearings for it cost almost as much as the Shimano BB.

    Dead easy to change with a sleeve anchor for removal and threaded bar to re fit.

    Stoner
    Free Member

    cheers Stu.

    Now this:

    Shimano BB91

    …is annoying though.

    Im guessing it’s interchangeable with BB92, but why are there two names? It makes searching for stuff much harder 🙁

    grips, aye, I dread the day, I really do….

    nickc
    Full Member

    I’ve used the same Shimano one that SSS uses. You have to use a spacer for the different shell widths, either 91 or 89.5 (supplied with the BB)

    Pressing them in is almost finger pressure, no need for anything fancy, a soft faced mallet will tap them in place pretty happily without walloping them. removal after 18 months of Chiltern slop was a blunt screwdriver, and again just knock them out. I’ve refitted with some metal shelled versions rather than the soft polymer shimano offerings just to see if they last a bit longer.

    EDIT: BB91 and BB92 are exactly the same thing (no, I’ve no idea either)

    singlespeedstu
    Full Member

    The BB91 is confusingly just the Shimano model No.
    They also do a lower priced BB71.
    Both are the same size and both fit a 92 x 41 shell.

    They also do road versions with the same codes which are narrower. 😆

    Suggsey
    Free Member

    Blowed if I can google it…maybe it was in a recent magazine, maybe it was for a fat bike but I recall seeing a device that was two semi press fit cups that had two steel shafts basically with external heads running through the step down in the BB she’ll cups that you tighten up to lock the step down cups in. These cups were threaded for standard BB applications. If I find it I will post up some sort of link.

    Stoner
    Free Member

    The BB91 is confusingly just the Shimano model No.

    *loads shotgun. FFS*

    cheers lads, I think I know what Im going to have a go at then.

    nickc
    Full Member

    this was me with headsets before Christmas. Welcome to the modern world Stoner

    My new bike has an tapered internal campy … Please!

    Suggsey
    Free Member

    My apologia for getting your hopes up, excuse the pun I was thinking of one of these I had seen I think which of course will be the wrong size.
    http://www.wrenchscience.com/DBImages/BTI/pictures/400h/TV2650.jpg

    perthmtb
    Free Member

    Like most people I didn’t particularly want to go Pressfit, but it seems to be the way the major brands are going so I’ve now got three bikes with PF, so my advice is to embrace it!

    I do only run XTR level BBs which are better sealed than the rest of the Shimano line, and which I get from Germany for 15 quid each here, and at that price I just treat them as a consumable and replace at annual service along with brake pads, tyres, chain etc.

    Also worth investing in the proper tools to remove and fit – makes it a piece of cake, and although you can get away with a hammer/screwdriver/bits of wood it’s not worth the risk to bu@@er up your BB shell IMHO. My tools are a combination of the Park remover and fitting cups together with some threaded rod and nuts & washers from the hardware store – all up cost about 50 quid.

    tthew
    Full Member

    * narrows eyes* Perthmtb, have you been rooting through my toolbox?

    Think I’ve realised that the width isn’t really that important as long as you stick with the same brand. Just reuse the centre spacer.

    Happy to be corrected, before I make a purchasing mistake!

    eemy
    Free Member

    I have this Token BB from Planet X and it seems alright. Especially for the money (£14.99)

    qwerty
    Free Member

    I have a brand new, unfitted Race Face PF92 waiting to go in the classifieds for less than whatever CRC sell em for. Email in profile.

    sillyoldman
    Full Member

    Wheels Manufacturing make a nice one (specific models for Shimano and for Sram) with Enduro Angular Contact bearings at £69.99, or standard radial Enduro bearings at £49.99.

    jmatlock
    Free Member

    So, If I was looking to replace my BB30 on my 2013 Specialized Camber with something less likey to click and creak (and I wanted to keep the current chainset) what would you guys reccomend.

    This is truly a minefield.

    Stoner
    Free Member

    suggsey – thanks. I had seen something similar but only for BB30 – a stainless steel sleeve that press fit in and left you with BSA threads but given the 92mm ish hub shell width compared to 68/73mm UN54 that’s never going to work for the larger type I realise now.

    perth – thanks for the link, they look the same as the ones SSStu linked to but a fair bit cheaper. I will fabricate my own tools in the workshop if all they entail is a press with correct diameter faces and an extraction drift.

    eemy – how long has that token lasted for you? Pricing seems good, but I wouldnt want to have to keep changing it out.

    sillyoldman – too spendy!

    andytherocketeer
    Full Member

    so my advice is to embrace it!

    I don’t particularly intend to embrace the creak, and yet another tool, nor the use of a hammer as the replacement tool, and is worse from an engineering point of view.

    I do actually have a headset press (why spend 20 on bits when you can spend 30 on the real thing), which I guess can be slightly modified to press in a PF BB.

    May reluctantly admit defeat and let the mfrs save on the cost of machining a thread, but I won’t embrace it.

    But I do get the XT/XTR screw in BBs for 15, and use them as disposable items. So long as they last more than 20% of the duration of Hope etc. then I’m winning.

    BB30 is out though, or any where the actual bearing is pressed directly. At least plastic may deform before the BB shell.

    perthmtb
    Free Member

    I will fabricate my own tools in the workshop if all they entail is a press with correct diameter faces and an extraction drift.

    If you’re good at that sort of thing (I’m not) then yes it should be reasonably easy. Only thing to watch out for is that the Park cup presses have a raised ridge around the outside (see below) so they press on the housing, rather than the bearing race itself. The inner bearing race is slightly raised, so if you used a flat cup press that’s what would take all the force – not a good idea, and also why it’s not so good to use a hammer and a piece of wood. So, if you can replicate this feature on your home made one all the better!

    frogstomp
    Full Member

    The Shimano ones have a plastic shell which makes them easy to push in / out. As mentioned above you can also just knock out the bearings to service / replace.

    PSA: If you already have the correct length sleeve, the road version of the Shimano BB91 is only £16.99 on CRC (as opposed to £24.99 for the MTB version). As far as I can see the cups / bearings are identical…

    Stoner
    Free Member

    why cant I find an SLX chainset anywhere that comes with a pushfit BB rather than the standard hollowtech 68/73 unit. I would have thought since it’s their standard they might sell crank & BB92 sets 🙁

    Perth, yep I have access to enough bits of junk that I can make a proper dimensioned press.

    nickc
    Full Member

    more importantly…what new bike have you bought that needs a new BB anyway?

    Stoner
    Free Member

    Some damn fule thinks that there’s more to cycling than SS rigid hairshirt. YGM

    perthmtb
    Free Member

    Should probably mention that the BB91 both I and SSStu linked to earlier in this thread are now the old model. The latest incarnation is the BB94 here

    No idea if it’s an improvement, although the marketing blurb says “18.5 g lighter than previous SM BB91-41A. Smooth-rotation. Developed specifically for MTB use: improved seal for long life”

    Stoner
    Free Member

    Should probably mention that the BB91 both I and SSStu linked to earlier in this thread are now the old model. The latest incarnation is the BB94 here

    stop doing that, or I shall come round there and beat you to death with a pair of middleburns. GahhhHH!!

Viewing 40 posts - 1 through 40 (of 44 total)

The topic ‘pressfit BBs, I am sooo out of my depth….’ is closed to new replies.

New deal added to Members Discounts