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

Thanks @nohwolf
Ended up going for the shimano as I figured that would be the case.

BB required to get DA 7400 cranks to 42mm chainline on the outer ring?

Doesn't @Borek have those?

Possibly on the hill climb bike.

Scored some real cheap for my beater.

For a double 7400 chainset a 112mm BB is required am I right. So if a 42mm chainline on the outer ring is need a 104mm BB should do it. However as that is not made you will have to make do with a 103mm BB like the tange seiki LN3922 or LN7922 amongst others.

Has anyone used a Doval rings? Are they any good? They have a new lighter version which seem pretty good value http://www.bikeradar.com/road/news/article/doval-chainrings-just-in-42951/

Q
lateral movement on the chainring. square taper bottom bracket. old.
when the drive-side arm is at 9, the chain rubs the inside of the front derailleur.
when at 3, a few mm away from the outside.
is this a bottom bracket issue?

Maybe, maybe not, take cranks off and have a look at tapers, if they're good have a look at the bottom bracket for any slight play. I doubt it's either of these.

So either bent cranks, or bent chainrings, probably the latter, you producing massiv wattz?

cheers.
new cranks and rings. tapers great nick.
play likely then.

Currently got SG75s (170mm) fitted with a Campy centaur bb but the crank arm clips on the driveside (when riding). Can anyone suggest / is there a wider bb that will fix this?

Omniums not spinning freely after install (without a hammer) and tightening ?

i've never dealt with these GXP/integrated Cranks, i think i remember reading somewhere on here recently that the hammer is the solution?

Hi, speaking of omniums: which bottom brackets are compatible? Any GXP or it must be the truvativ one?
Thanks for your help!

My roadbike needs a little TLC on the drivetrain.
Wheels, cassette and chain are all reletively new, but i need a new F mech and want to upgrade to a semi compact (52/36) crankset.

Cranks nearly all seem to be 11 speed specific, but i am running a 9 block out back.
Don't want to upgrade the full GS, will a 11sp cranks work fine with my existing chain/ cassette?

Similar issues with front mechs, they seem to be 10 or 11, guess a 10 would be better suited to a 9 speed setup.

Should I switch to 10sp chain too?

Thanks fixed gear and single speed forumites!

Needing a bit of help here, Fitted my GXP bottom bracket to my 2015 leader 725, 68mm bb, fitted and torqued the sram omnium crankset and there is still around 2-3mm of side-side play.. Spacers required?

If you mean that they're quite stiff and don't just rotate to top and bottom then that's normal with a new BB, ride and they'll begin to spin more freely.

Any GXP that fits your frame will work fine.

Make sure the cranks are tight and that you're installed all bits of the BB.

I find that omniums bolts can tighten up before they done up all the way, within 1/2 a turn it may get looser again.

Thanks IR! Will order one, any advise (except Chris King, I don't really want to spend £110 in a BB...)

I'm using one of these.
http://www.ebay.co.uk/itm/UNITi-External-GXP-Ceramic-Bottom-Bracket-MTB-SRAM-Truvativ-BB24-English-/221433380212?pt=UK_sportsleisure_cycling_bikeparts_SR&var=&hash=item338e753d74

Hi there, got a problem with a fixed BB cup on the driveside of a lovely Lapierre 531 frame I was given. Its a French, R hand thread. It hasn't shifted one iota with the proper cup extractor tool and a 10 foot scaffold pole being used on it, even after a 2 week soak in rusteater. Vaz offered to whack a new ISO BB shell in there for a very good price but I want to keep the paint and patina intact.

So its got to be cut out.

My question is: does anybody know of an engineering shop in south London who is friendly enough to take this on? Needs either a horizontal mill or a drill press. I have seen that Ryan at oak cycles has done this before but I also understand he's not mad about taking on small jobs like this.

I have a 30mm starrett HSS hole cutter. My idea is to drill from the non drive side and take out the middle of the cup, leaving approx 2.5mm each side - hoping that the clockwise cutting motion also loosens the fucker (optomist). Then I was hoping to take the rest out by running a 32tpi hacksaw through....though some thread damage is inevitable its the way that would give me finest control.

All of this feels a bit like escaping from Shawshank with a rock hammer, can anyone whose been in this position offer guidance or a good metal basher who can help?

thanks

Dave

Have you tried to use a vise? You will have a better lever arm like this.

I bought the same BB as @IR, but now I'm confused: I don't have any piece like the "star spacer" in this picture:

Is it annoying? Does it work without this piece?
Thanks for your help!

Mine didn't come with one either, it's not caused a problem for me with Omniums or with my stylos currently on the 29er.

Have you tried to fit it to see if it's fine?

Not yet, not yet :) I'm trying to understand how it works to avoid any "bad experimentation".
Do you remember if you used the spacers provided?

Not for the MTB but perhaps I used one for omniums, if I did it would have been for chainline and not general fit.

Can't really remember, sorry.

Thanks for your help IR! This was a stupid question anyway, because it completely depends of the frame. I will try without it and see how it goes.