Forum menu
Contemplating making the switch back, but realise I haven't a clue about sizing. One bike has 68mm shell (Ti456), the other 73mm (Turner), so that's the first number sorted out.
What's the second number (mid-point to chainline, maybe)? And how do I know what length I need?
Cheers
What's the second number (mid-point to chainline, maybe)?
Not as complex as that - it's just spindle length.
And how do I know what length I need?
Uh oh, more complex! Depends on frame and chainset variables. You want to get a chainline of circa 50mm - technically there's a more accurate number than that to aim at which is specific to the frame, but in reality, on an MTB, it makes no odds.
Basically... go with a 113mm! No, ideally you should really find the size info from the frame manufacturer. But in these days of external BBs it might be hard to find. 113mm is the best bet in that case.
Loads of info [url= http://www.sheldonbrown.com/bbsize.html ]here![/url]
Cheers Chela. I'll see what I can find out from On One & Turner.
It's more related to your cranks, check with their manufacturer.
Go with a 118,
Nothing to do with frame, all to do with chainset.
Farticus,
I run the Ti 456 with a Royce 110 axel and Middleburn cranks. There is approx 2mm between the inner face of the arm and the BB cup ( which is proud of the frame by approx 3mm, this is a Royce design that spreads the bearing load). If the cups were flush with the frame then there would be approx 5mm.
There is approx 6-7mm between the inner face (@ the pedal) and the frame.
I have it set up with close clearence.... you could run a 113-115 for that exra bit.