Want to know what bottom bracket length you need?

[FluffyChicken]

in retroland the 50mm is (mainly) for fatter seat tubes.

since nowadays almost everything has a fatter seat tube, 50mm has become the standard

Is that because of fatter tubes or because Shimano wanted to make things cheaper (by making just one version, I don't blame them)
So bottom brackets would be 73mm (and shimmed to fit for smaller sizes and meaning the wider chainline is often preferred for cup clearance)
Same for the front mech use the wider one and shim it down (meaning the 50mm chainline is again prefered for shifting alignment)

Also the move to 9 speed probably means the 50mm is slightly better (never actually looked to see if it is ?)

All in all a much better business production model and customer model.

 

[Antfox]

I have no idea at all now when it comes to this , just wish there was a chart to show what's what based on the bike and the kit you are running .

 

[FluffyChicken]

I have no idea at all now when it comes to this , just wish there was a chart to show what's what based on the bike and the kit you are running .

Cheaper (well much easier) just to have a 107 and 122 bottom bracket in (with a few in the middle if you want, like 11. Get them from old bike or next to nowt on CRC in the sale.
Fit and try, then work it out.

 

[Antfox]

That's a good idea matey , I have not yet decided on a set of cranks so that's going to be a major factor on the seize

 

[elPedro666]

Sheldon wasn't always right either.....

Burn the blasphemer! :evil:

 

[Dick Scruttock]

And you have all been trumped by this:
http://www.bikepro.com/products/bottom_ ... able.shtml

 

[secret_squirrel]

And you have all been trumped by this:
http://www.bikepro.com/products/bottom_ ... able.shtml

Unless you have Middleburn cranks for example.....

(ps 107mm for RS3's and 122 for RS2's)

 

[Dick Scruttock]

And you have all been trumped by this:
http://www.bikepro.com/products/bottom_ ... able.shtml

Unless you have Middleburn cranks for example.....

(ps 107mm for RS3's and 122 for RS2's)

Middleburn smiddleburn