Transmission database - for all your crank / bb / bottom bracket questions

anyone know what BB tool would be needed?

shape seems to be small notch followed by a very large notch, repeated all the way around.

Or can a motorcycle oil filter tool do the job?

Need some help fitting a Sram GX dub crank to a voodoo. Voodoo has a FSA BB-7420 73x113mm shell. Bike is going to 1x 12 speed. Can someone recommend what bottom bracket I should be fitting here to achieve a good chain line?

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External BBs don't have the spindle requirements like BBs of old.

Look for BSA SRAM DUB BB (incidentally, thats what the Prime hub posted above I am trying to figure out the BB tool required) they will be 68/73, with associated spacers.

The cranks will have the spindle attached already, and you want a narrow wide chain ring to keep the thing aligned.

Watch out for boost spaced rear wheels, they need an offset chain ring for the wider rear.

Couple of questions please.

SRAM gxp. On a 68mm BB SRAM say put 2.5mm spacer each side but I have read several accounts on here of people not using them. Do they make any difference?

My second hand crank only has a single bolt holding it together. There are two bolts normally
https://www.sjscycles.co.uk/chainsets/sram-gxp-crank-arm-bolt-m15-m22-alloy-self-extracting-black/
What does the second larger bolt do of anything?
Thanks

https://www.merlincycles.com/icetoolz-12-tooth-external-bottom-bracket-tool-121875.html

I'm looking at this. Maybe for the Prime too.

I'd assemble the bb on the spindle and see what kinda width you get to. I thought GXP didn't need spacers but maybe I'm thinking of the road/track version as it was with Omnoms that I used it so maybe the mtb version needs spacers as per Shimano.

The larger bit is the self extracting cap, screws into the arm after the crank bolt and the crank bolt pushes against it to remove the crank when you undo the bolt.

Ah ok that makes sense thanks.

I also have a GXP question - am I missing a plastic shield on the non drive side here? I’m almost certain I am (ID of the bearing is larger than the spindle), so follow up question: anyone know where I can buy that? Working from the parts bin so no idea what spacers/shields it had new and have not been able to google it

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Yes if you do an image search for gxp shield it's the one with the star cutout to fit over the end of the crank axle

right ok thanks for getting back to me! is this the right one? was thrown off by the "press fit"
https://www.deporvillage.net/replacement-dust-washers-sram-pressfit-gxp

Took my bike to the LBS with a noisy BB. Turns out the carbon sleeve (?) has been damaged and so BB is loose. Spoke to Carbon Repair Place in Leatherhead as recommended and quoted possibly up to £360 + paint and would need new BB and. CHainset.

That makes the repair uneconomical. I bought the frame second hand and it’s been on Zwift duty on a Tacx Neo. Possibly that’s the problem - I’ve heard carbon and static trainers can cause issues.

Anyway - if I don’t want to pay up for a repair is there a bodge that could get the BB wedged tightly again. I accept that this may cause more issues down the line, but the frame would be written off in any case and will only have indoor duties from now on so not worried about high speed frame failure.

Useless photo below - not even sure if it’s the side that is problematic.

Thanks in advance for any thoughts.

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Fairly basic request. Does anyone know of a source for a spare sleeve for T47 Bb (CK, obvs)? I've managed to munch one during installation.

What is the usual torque recommended to install a crankset on a square taper BB?
Came across 35 to 45 Nm from parktool spreadsheet, 35 Nm from Probikeshop recommendation, and some sources also for around 35 Nm.

Contacted the manufacturer directly that handed me a document where it states "left arm (shim) 12 to 15Nm", suspected it was for hollow BB and not square for the mention of left arm only and much lower torque compared to what I came across, but when I raised the interrogation they did not answer back.

So anyone got a usual torque recommendation for these? And please do not describe how you install it by feel, I am after a reference value because I am already doing it by feel but would like to install the next one properly as much as possible.

Anyone with technical advices such as @gbj_tester for example :)?

Does anyone happen to have a gxp bottom bracket non drive side washer knocking about their parts bin that they wouldn't mind posting to me? I've lost mine when my crank fell off (long story) and am loathe to pay £10 for a new one. It's the one with the star like cut out in.

My DA 7410 Cartridge BB is feeling quite rough, anyone know if this can be serviced or will it be easier to just get a replacement?

Easier to replace, but if you’ve got the time and interest you might wanna give it a shot at servicing.

http://www.bikepro.com/products/bottom_brackets/shimda.shtml

According to that article, they were able to remove the side covers on the bearing cartridges, exposing the bearings. If you can do this, then you can service the cartridge like you would a Chris King hub. You might find once you’ve cleaned the gunk out that the bearings/races aren’t worth servicing though.

Déjà vu?

In two minds as there aren't alot of 68x103 bb replacement out there atm and all the BB on ebay around£50 plus...

DA 7410 Cartridge BB

Could try a Tange Seiki for £25?

If you have the tools, it’s a 30-60 minute job (assuming it’s doable). Put on an audiobook or podcast and save £50? No condescension intended, dunno if it comes across that way.

Took apart a UN55 non-drive side for the heck of it (currently job hunting...), pretty easy to do if you have 2 or 3 spoke width picks, or finer.

First pic is a black plastic retainer cap that fits tight over the axle and holds down a rubber dust cap. Note the pick marks from where I pried it off; would recommend using multiple picks and a flat tool like a c Hh sim checker to gently lift it around the circumference of the axle like a tyre off a rim. Note which side goes down because if you reinstall it wrong it’ll create loads of drag.

Second and third pics are inside of the cartridge: the grey/white plastic you see is the bearing retainer, which lifts off easily exposing the bearings. You can clean them out and regrease, but they don’t come out of the BB from non drive side.

Drive side axle has a tough retaining ring, possibly steel, pressed tight onto the axle. Couldn’t pry it out but didn’t force it.

Putting it back together is easier than taking it apart, just be careful with that black cap.

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Praxis 22/24 mm bb question. i have installed one last night with the plastic protective sleve backwards i.e.flange side of the sleve into nds cup, everythings seems smooth, is it ok, or do i need to take it apart ? It was a loose fit either way and didn't bother reading the instructions...

Is there alternatives for SRAM DUB bottom bracket (SRAM NX Eagle 12 Speed Mountain Bike Groupset)?

Rotor track cranks. Are the ROTOR track BB cups slightly narrower than normal (i.e Hollowtech) 24mm road BB's?

Would i need to use the Rotor specific BB to get the right chainline or can i use other cheaper options?

Specialized Langster frame

It just says

Cr-Mo axle, 68mm

Cranks to be used are Miche Primato 49x170

I'm not sure which Bottom Bracket would work? Please help!

what hub you got?