What size bottom bracket axle ?

[Mike Muz]

Hi folks ,

Hoping to pick some brains :roll:

I have just got hold of a Shimano M730 chainset for my Scott project , but am unsure what size bottom bracket to use with it . The shell size is 68mm , but I'm not sure what length axle it needs . I know that road axles vary in length , is it the same for mtb axles ?
Also , in your opinion , would a cup and cone b/b be more authentic in a '93 frame , or a cartridge job be more appropriate ?

Any help will be gratefully received , thank you kindly , Mike .

 

[bodrobert]

Around 120-122 mm, I think. I used 120 mm in my Scott Comp Racing.
It might depend a bit on the square of the arms. Two size exists, according to the JIS and the ISO standards. The JIS axles has bigger size ends if I remember well.
You have to match the axle with the arms...

 

[xxnick1975]

unless you are trying for best in show, i would get a new cartridge from CRC from about a £10

s/be 122.5 i think - but google Sheldon Brown Bottom Bracket size and you will get to a data base that list out most of the shimano chainsets

 

[FluffyChicken]

122.5 was the standard length for the cranks and a cartridge bottom bracket is well and truly correct for 1993.

You would move to 127.5 if you only really needed to.

A year or two earlier and you'd be in Cup/Cone territory.

 

[skolioza]

All Scotts I know takes 122,5 for M730

 

[stumpjumper1990]

http://sheldonbrown.com/bbsize.html

Need I say more??

M730 always 122.5!

 

[shinobi]

Hi mate
i have a spare 68x122.5 your welcome to try if it helps
Cheers Paul

 

[FluffyChicken]

http://sheldonbrown.com/bbsize.html

Need I say more??

M730 always 122.5!

Sheldon, bah.
I give you the horses mouth


http://www.retrobike.co.uk/gallery2/v/M ... 0.JPG.html

http://www.retrobike.co.uk/gallery2/v/M ... ewsIndex=1
etc...

 

[Mike Muz]

Thanks for all your help , men of mountain bike mayhem

 

[wookiee]

another 122.5mm here...