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

very tight clearance on a 7vrn frame with a 111mm Campag Record crankset and BB.
115mm ISO seem to be available... is 2mm a side enough!? looks super close and some small marks from the previous owner on the chainstays.
But going over 117 seems a lot on a track bike!

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Hi, I’ve bought a rockhopper from the forum few months ago but need to fit a BB and a I wanted to install a single chainring. Originally had a triple. I’ve measure the length of the bb and it seems to be 70mm. I’ve used a laser to check where the new chainring would be in the middle of the cassette, and that is 10mm from the BB. Not sure what thread the BB is? I assume English? How can you tell? I’ve got no experience with BB and would like to know where to start. Also, which chainring would be best to ensure chain doesn’t pop out? Thanks in advance!

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Hey,

Looking for options in Europe for a square taper bottom bracket, with BSC threads and 68mm shell, an ISO square staper and width around 120-122mm.

So far, I seem to find only this option from Specialites TA which seems nice, but rather spendy. Would anyone have a different option in mind?

Which BB spindle length and taper type (JIS/ISO) do I need for these cheap Campagnolo cranks? Currently the bike has a comedy long BB spindle, so that's not gonna help us.

Ok I've managed to answer my own question - The chainset is likely 8 speed Avanti, requiring a 111mm ISO bottom bracket.

Frustratingly, it's a French threaded BB shell so I'm just going to have to get a 110mm JIS threadless BB (i.e. YST) and just figure it out.

if I remember correctly, an ISO crank on a JIS BB will sit further out. I think the chainline difference is something like 2mm?

Yeah you're right. And there's a few different estimates online for how many mm difference it makes ~ 1-4mm outboard offset per crank.

What's the easiest way to install a hollowtech crankset to a PFBB30a (for power meter reasons solely)? And what's the best?

No tools for PF but would ideally like to DIY with a cheap converter unless the results will be horrible... That way I could eventually look into pedal power meters / selling my current and replacing with something more useful!

this is the best especially in a carbon shell
this is cheaper and worth a go if you have bb30 bearings already in place
this is essentially the same as above, not sure if the higher price changes anything

Cheers, I found a few of these but as far as I understand it BB30A is asymmetrical, just to make life harder. So was struggling to find an insert.

Only one that I think would work is the first?

true yes, but they come up second hand

Ok, will keep an eye out cheers. There seems to be differing standards of megaexo - some have said this may work?

https://www.tredz.co.uk/.FSA-BB30A-Reducer-Kit_106427.htm

these should work, i had those megaexo ones in bb30 fashion with a 6800 crankset, so this should be the right assymetrical version

I have never understood how BB/crank/hub compatibility worked until today and just assumed the LBS would have fitted the correctly-sized one for my cranks when I last got the BB replaced. They have not done so, and when I recently replaced the BB I used the measurements they did rather than going by the crank manufacturer's recommendations, so now I have a 113mm BB instead of the recommended 107 and I am having chainline issues - drivetrain is fairly noisy (particularly after a rainy day when I forget to reapply lube) and I think my chain has been worn having only changed it three months ago.

Am pretty keen to keep the BB because I had to search high and low for the UN55 I've now got in there and paid a pretty penny for it, and am thinking of shifting the chainring inside of the spider rather than outside. Are there safety concerns with doing that if there are no indents on the spider (i.e. the ring was designed to go on the outside)? Am riding a fixed gear conversion and so rear spacing is 130mm but rear wheel is 120mm with spacers; I am alternatively considering shifting the spacers to the NDS then dishing the wheel towards the NDS to re-centre - which would be the better solution? Would far prefer not to have to dish the wheel as I have never built a wheel before and would have no idea what I'm doing, but I presume just loosening the DS and tightening NDS will achieve the necessary effect, then I can centre the wheel in the frame using the brakes as a guide.

How much did you pay for a UN55?? I would just buy and fit a UN300 in the correct size you need rather than messing around re-dishing a whole wheel just to accommodate your current BB. They're only £15

I’ve got a Dolan DF3 with a Rotor Track BB. I bought this 7vrn crankset (https://www.brookscycles.co.uk/product/7vrn-track-chainset/) but there is loads of play so that the chain set can move along the axel by 5-10 mm through the BB.

The crankset came with its own BB, but there’s a lot of resistance when I try and install it, feels like I’m cutting extra thread (it’s wayy tight and harder than the Rotor BB). Not sure if it’s been manufactured poorly, or if this normal for installing a new BB?

Does anyone know if I should just use more spacers between the BB and cranks, or if not, what cranksets they would recommend that work with the rotor bb (obviously rotor will work, but a bit spenny)?

I can’t find a PF DUB Road 86.5, anyone bought one recently or have a spare?

I have a T47 DUB BB, the plastic sleeve/ cup/ interface has been damaged, it's a first components BB. Am I likely to be able to find just this part?

Here's a picture of the sorry thing

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Got a bike with a BB86 shell. Saw the "cheap" Easton crank arms for an upgrade and they're a 30mm spindle. So. I was looking around on google for info on BB86 with 30mm and there's a longish blogpost on a certain toxic vlogger's website about how bb86 and 30mm spindles shouldn't be combined.

Is there any truth in that?

Are the standard options for a 73mm BB shell just mtb cranksets or a deore triple? I want to run a 2x gravel style gearing with say a max 46t chainring , are there any 2x cranksets that fit a 73mm bb - I am getting myself very confused.

Run a triple as a double loosing the outer ring (ugly), get TA Chinook chainrings for mtb crankset or square table double providing I can get the right width BB for the chainline?

Is a SRAM Rival AXS 12s likely to be compatible with 11s ultegra chain/cassette?

Hello,
I run ck ceramic bb + omniums for the last 10 years. I've cleaned and regreased the set up recently and noticed small play. Wondering what could be wrong? Driveside two white spacers + disc spring, Left side steel spacer.

No, not likely

Thx... saved me 120 euros :)

The chain is a maybe, I used a 12 speed SRAM chain ok on an 11 speed set up but I think the outer plates are a little narrower on the 12 so I'm not sure it would work well the other way around assuming a 12 speed cassette, which would definitely be a must.
12s ultegra I'm sure would work perfectly with 12s rival, but not 11