Viewing 39 posts - 1 through 39 (of 39 total)
  • How freely does your DUB BB rotate without a chain ?
  • Premier Icon weeksy
    Full Member

    Fiddling with the new bike and removed the cranks to check the BB, it’s fine… but not convinced i like the DUB BB.

    Tiny amount on the preload ring takes it from spinning freely but a tiny bit of play into 1 rotation of the cranks only. My Shimano cranks on the Pressfit stuff rotate fairly freely even when a chain fitted, with no chain they spin effortlessly.

    So i’m wondering if i’m missing something with the DUB ? It’s got the 3.5mm spacer fitted, if i fit a smaller one i cannot dial out the freeplay/wiggle in the cranks. Cranks are a set of descendant.

    Sadly i don’t have a DUB removal tool yet as i need to order from CRC/Wiggle. I could then fit another set of cranks, but they’re GXP so not a million times better lol. But i think i’d prefer GXP over the DUB at the moment.

    It’s possible it’s down to the fact the previous owner has broken the preload ring slightly by over tightening it i’m guessing, so 1 side of the protruding bits the screw goes into isn’t fully attached as cracked on one side.. i’ve ordered a new ring but do i wanna go nuts and fit the GXPs instead ? lol

    Thoughts and derision appreciated.

    Premier Icon weeksy
    Full Member

    just in case we still need to.

    Premier Icon JefWachowchow
    Free Member

    My boy has a DUB BB on his Ripcord. It spins freely enough (maybe 4 or 5 rotations with chain off).
    It came on the bike and I’ve not yet had cause to do any servicing yet to see how it installs or if there are any spacers.
    Never had or used DUB before so no previous. I only noticed this one was at the weekend to be honest, but the cranks always get a spin when its cleaned.

    Premier Icon Yak
    Full Member

    There is a little bit of resistance, but not much. It’s no UN71 though (spin for days…)

    But as you’ve already seen, dub is pants. Tiny plastic preload collar, 2mm bolt, tiny bearings…almost as if it has been designed not to last and certainly not go anywhere near the muck.

    I prefer GXP tbh.

    Anyway, watch the bearings. Once they start to bind, you better be rapid on the replacement or your crank spindle will be toast before you realise. I recommend removing the crank once a month for a check. If you find you are nipping up the preload collar, then you are definitely well on the way to a new bb. Mrs Yak goes through 4 per year, but we have now just toasted a spindle so it’s new crank time.

    Premier Icon weeksy
    Full Member

    Yeah i think i’ll be going GXP by the weekend. I assume there’s no reason not to and no reason a manufacturer would use DUB that i can’t see ? It’s a standard BSA type, not pressfit, so i’m guessing my GXPs will go straight on once i’ve got the DUB removal tool to whip it off.

    Only minor downside is that the DUB cranks i have is 175mm whereas i’ve generally been running 170mm.
    (stealth swap ad there maybe)

    Premier Icon Yak
    Full Member

    GXP would be fine. Manufacturers just buy in groupsets and sram ones will be dub nowadays I imagine.
    I prefer HT2 over GXP though, but if you have GXP just run it.

    Premier Icon joebristol
    Full Member

    DUB is the newer Sram standard than gxp. They aren’t cross compatible as the spindle diameter is different.

    If you have a 73mm bb shell and bsa screw in you should have no spacer between the bb cups and the frame – and then one x plastic 4.5mm spacer between the driveside cup and the crank. It kind of clips into the bb cup. You tighten it up to the 40-50nm of torque (I remember it’s high) then just dial out any slight play with the preload ring on the non driveside. It doesn’t need to be tight – just take out the play.

    I don’t think how far a crank spins with no chain is really a big thing either way – any slight drag is just the seals doing their thing. So say DUB has better sealing than gxp. I’ve got both – 1 on each bike – I’d say they’re both about the same in terms of longevity.

    I wouldn’t bother changing them out – where’s the benefit in that?

    Premier Icon weeksy
    Full Member

    I’ve got a HTII setup as well but it’s currently on a double and i don’t have a decent sized NW to throw on it, so don’t wanna mess about too much. So throwing a GXP on seems to be the obvious solution for now at least. I’ve got 2 GXP BBs in the spares box, one used and one new, so covers spares on that side as well.

    Premier Icon weeksy
    Full Member

    I wouldn’t bother changing them out – where’s the benefit in that?

    my perception is that if the cranks don’t spin freely then it’s using more effort to propel me ? or is that complete rubbish ?

    Premier Icon richardthird
    Full Member

    Got BSA Dub on my Norco, been lasting well, easily as good as XT. Remember to tap the driveside with rubber mallet after torquing up and before winding in the pre-load.

    About 3:00 here https://www.youtube.com/watch?v=E0CDaxwbd5c

    Premier Icon Yak
    Full Member

    It won’t slow you down by a noticeable amount.

    My downer on dub is based on the short lifespan of the bb compared to ht2, and then if you miss a binding bearing, the very rapid spindle damage as it’s soft alu v HT2’s steel. Ie no window to spot an issue – damage can occur v quickly. I also think 2mm bolts have no place on the muckiest part of a bike along with the cheesy preload collar. There was nothing wrong with the wave washer on gxp as far as I could tell either.

    Premier Icon Scienceofficer
    Free Member

    My downer on dub is based on the short lifespan of the bb compared to ht2, and then if you miss a binding bearing, the very rapid spindle damage as it’s soft alu v HT2’s steel. Ie no window to spot an issue – damage can occur v quickly.

    This.

    I’m running dub because shimano wasn’t doing 12 speed at the time.

    Turns out SRAM x-sync 2 is brilliant, but the BB and crank axles kill themselves in rapid order when it starts to wear.

    I’m wearing out what I’ve got then moving back to shimano HT2 for the bigger bearings and steel axle. Bearing durability certainly won’t be worse, but I wont have to replace my cranks just because I missed my bearings getting a bit stiff.

    Premier Icon kelvin
    Full Member

    Second hand BB that’s knackered enough to either have no play or run freely, but not both at the same time? Needs a new BB by the sounds of it, whatever the type.

    Premier Icon weeksy
    Full Member

    I’m feeling the gxp will be on by tomorrow.

    Cheers all.

    Premier Icon joebristol
    Full Member

    my perception is that if the cranks don’t spin freely then it’s using more effort to propel me ? or is that complete rubbish ?

    Talking very marginal gains there. I went dub descendant carbon cranks on my most recent hardtail build and have X1 carbon gxp cranks on my Bird. Really can’t tell any difference at all.

    Premier Icon weeksy
    Full Member

    Talking very marginal gains there. I went dub descendant carbon cranks on my most recent hardtail build and have X1 carbon gxp cranks on my Bird. Really can’t tell any difference at all.

    I’m struggling with how… if it’s not spinning freely then it’s dragging surely ? Dragging must = more effort to propel a rider… I dunno though, i’m happy to be wrong here, but i still think i’ll be using my own logic and going to GXP once the bits arrive.

    Premier Icon joebristol
    Full Member

    Knock yourself out – you’ll do the change anyway because that’s what you do! I’d wager that very slight drag is barely even measurable in watts. I’m pretty sure that slight drag actually goes away as the bb wears in anyway.

    Gxp isn’t the best standard as it is – I find my gxp bbs do ok but can go rattle after a while. They aren’t bad but I don’t find they’re outlasting dub.

    Ht2 is probably the best standard for bsa screw in – but Shimano don’t do carbon cranks and I like the look of the carbon ones plus the bit of weight saving. I mean I’ve ruined that weight saving with Lyriks and a coil in the Bird and the heavy steel frame on the Marino but hey how!

    Premier Icon ofked
    Free Member

    Of course drag means lost watts and therefore more effort. It reads like this isn’t seal drag since it spins freely when the preload is backed off.
    If you can’t find a preload where it spins freely with no play, you’ve got a problem (which could be the broken ring).
    FWIW I canned my dub BB as it just didn’t last. First one did only 500 summer miles, the replacement lasted only two wet rides! I had a sense of humour failure and replaced it with hope BB and xt cranks! Probably an over reaction but it’s been faultless for thousands of miles

    Premier Icon weeksy
    Full Member

    If you can’t find a preload where it spins freely with no play, you’ve got a problem (which could be the broken ring).

    If the new one arrives today i’ll certainly test with preload ring

    Premier Icon fitnessischeating
    Free Member

    The drag on the system when spun unweighted doesn’t necessarily bear much resemblance to the drag in the system when 60-100kg of weight is standing on it whilst turning it…

    A loose/poor bearing may spin very freely, but bind when loaded.

    Not saying it is what is going on here but crank spinning isn’t a good test for how good a bb is

    Premier Icon weeksy
    Full Member

    A loose/poor bearing may spin very freely, but bind when loaded.

    Indeedy, that’s completely possible. But i don’t want to fit the new BB in case i end up binning the DUB setup later this week and if i do that, i’ll be selling it, so better selling the cranks/setup with a spare brand new BB too.

    Premier Icon desperatebicycle
    Free Member

    Makes you wonder if WC DH racers, or their mechanics, check their cranks are spinning freely. “I could’ve won at Maribor but my DUB crank’s friction cost me 100th of a second!”

    Premier Icon Yak
    Full Member

    Makes you wonder if WC DH racers, or their mechanics, check their cranks are spinning freely. “I could’ve won at Maribor but my DUB crank’s friction cost me 100th of a second!”

    Well some do – i recall Peaty’s mechanic had stripped the grease* out and ran oil for the race run for his world champs win by 5/100th of a second in Canberra in 2009 . Obviously we are into 1 run stuff now with no rain. Really though for us punters it makes no difference.

    *might have been hubs? Not sure. Anyway – marginal one run gains. Not for us lot

    Premier Icon desperatebicycle
    Free Member

    Really though for us punters it makes no difference.

    Pretty much what I was saying.

    Premier Icon fossy
    Full Member

    Praxis do a replacement BB for GXP – and you can easily replace the bearings (just done my drive side). Must say they still don’t last. Mine spins fine, but not half as well as the UN91 and UN71’s on my road bikes – they just go on and on and on.

    Premier Icon mos
    Full Member

    The dub cranks on my cx bike don’t spin very well, maybe one rev. Although i doubt its why i don’t win races, i’m pretty sure that’s because i don’t shave my legs.
    TBH most things from HT2 onwards seem noticeably less spinny than a good old sq taper. I think its down to the number of bearings in contact with the grease in the bearing.

    Premier Icon singlespeedstu
    Full Member

    If you want a fast spinning BB install a King and run it with thin oil in there instead of grease.
    It’ll make no difference to how fast you are/aren’t though.

    Premier Icon ballsofcottonwool
    Free Member

    the drag is from the bearings being out of alignment it is an inherent flaw in external bearing BBs. Crap for bearing life, good for bearing sales.

    Premier Icon weeksy
    Full Member

    If you want a fast spinning BB install a King and run it with thin oil in there instead of grease.
    It’ll make no difference to how fast you are/aren’t though.

    I wasn’t questioning my speed, more the fact as to whether it’s right or wrong for it to only do 1 rotation. Either way, i won’t be troubling the leaders at Southern Enduro.

    Premier Icon crazyjenkins01
    Full Member

    Weeksy, have you tried an after market DUB from someone non-SRAM?

    I’ve got a DUB BB from Uberbike (in green!) on my Triple B and its been spot on. Good sealing from the elements, looks nice, haven’t noticed any play at all and (pretty sure…) replaceable cartridge bearing.

    My Mate has a Nukeproof DUB one on his Sentry

    Edit: remove formatting

    Premier Icon weeksy
    Full Member

    Weeksy, have you tried an after market DUB from someone non-SRAM?

    No mate, i only picked up the bike this week, this is the first time i’ve ever even seen a DUB setup, let alone used one. The fact that i’ve got spare cranks and BBs i can use means i don’t actually need to worry about it too much or spend any more money as i can fit them, so buying a new BB when i already have 5 in total in spares box, some new, some used, seems a little crazy.

    If i were going to stick with DUB, then sure, it’d be an option. But i’m not convinced i will.

    Premier Icon singlespeedstu
    Full Member

    Sound from your description as others have pointed out the bearings are shot.
    Whether that’s right or wrong is entirely up to you.
    It’ll make minimal difference either way until it gets worse/ the bearings seize/collapse.
    The bottom bracket on one of our hardtails was gritty and slow spinning for a couple of months. Despite having a new one ready to go in it stayed that way until it started knocking then I changed it. Made bugger all difference to the speed of the bike.

    Premier Icon weeksy
    Full Member

    I can’t swap them out for either the GXP or the other DUB as i’m waiting for the BB removal tool which i ordered on next day from CRC 🙂

    Premier Icon drinfinity
    Free Member

    Removal tool – a regular plumber’s adjustable wrench will do just fine for a threaded external BB, and is a universal fit. Can also be used carefully to install an obscure BB too.

    pressfit – Mallet and a drift will usually do the job.

    Premier Icon weeksy
    Full Member

    Removal tool – a regular plumber’s adjustable wrench will do just fine for a threaded external BB, and is a universal fit. Can also be used carefully to install an obscure BB too.

    No thanks. That’s not how I do things.

    Premier Icon crazyjenkins01
    Full Member

    No mate….

    Thats fair enough. I used an Uberbike one on my last bike (Bossnut V1) and it was still going when I sold the bike, so got one of their DUB ones cos I wanted a pretty colour!! Plus I can change just the bearing without shelling out for a whole new BB

    Premier Icon weeksy
    Full Member

    Cranks swapped, no wiggle or play and smooth spinning with the gxp setup. Sweet.

    The Dub crankset is up in the classifieds

    Premier Icon joebristol
    Full Member

    You’re definitely going to finish a few places higher at your enduro races now 🤣

    Premier Icon weeksy
    Full Member

    You’re definitely going to finish a few places higher at your enduro races now

    IT’d be hard to finish any lower 😀

Viewing 39 posts - 1 through 39 (of 39 total)

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