ISIS bb compatability.

[mrowkoob]

I´m investing in a new crankset I´ve been looking at several brands (FSA,Stronglight,Stella Azurra,Gass,Race Face) who all are ISIS compatible. However some people tell me that even If you have a standard isis bottom bracket (there are many availiable) there migh be compatability problems with for example a fsa bb and a Stronglight crankset (the exactness of the isis might hae salldifferences between brands). Anyone with any experience in this field? Is it true you have to buy same brand bb or can you safely combine different brands?

 

[boudreaux]

Originally posted by mrowkoob
I´m investing in a new crankset I´ve been looking at several brands (FSA,Stronglight,Stella Azurra,Gass,Race Face) who all are ISIS compatible. However some people tell me that even If you have a standard isis bottom bracket (there are many availiable) there migh be compatability problems with for example a fsa bb and a Stronglight crankset (the exactness of the isis might hae salldifferences between brands). Anyone with any experience in this field? Is it true you have to buy same brand bb or can you safely combine different brands?

It's suppose to be a standard.I't's no standard if there is incomaptibility. There are always manufacturing +/- tolerances that in themselves do not create incompatibility.The crank does have to be matched to the correct spindle length.

 

[mrowkoob]

Well I agree but fsa dealers for example (some of them) claim that their isis cranks might not be compatible with other isis bb´s of the same lenght (108mm)... SO whats that about?

 

[boudreaux]

Originally posted by mrowkoob
Well I agree but fsa dealers for example (some of them) claim that their isis cranks might not be compatible with other isis bb´s of the same lenght (108mm)... SO whats that about?

They want to sell you their ****, or they are just morons. Note, that it is just 'some' of them. www.fullspeedahead.com ask them.

 

[dhk]

Yes, ISIS is an "open standard" which specifies both the spindle and crank dimensions and tolerances. It's available free to manufacturers.

I got an FSA ISIS OS BB and crankset on my new bike. Believe it's a great way to go, since ISIS allows manufacturers (like FSA, etc) to compete with Shimano and Campagnolo, without having to paid them royalities for their proprietary designs.

You can download the ISIS standard with drawings from:

http://www.chrisking.com/pdfs/ISIS Drive Complete Rev D.pdf