Best & narrowest ISIS Crank/BB combo?

[Pastashop]

OK, I've been spending too much idle time contemplating nearly useless bike-related things, and here's one of them:

I'm interested in the ISIS crank / BB standard, with the intent to install in a normal steel frame with a threaded BB. I'm partial to Q factors of ~145mm or narrower, doubles. What's out there these days?.. Did Ritchey make a Logic crank that used the ISIS standard, or was there only the Octalink version?..

Thanks in advance!

[bicycletricycle]

ritchey used octalink only, FSA made some ISIS stuff

the ISIS bottom brackets tend to use pretty fragile bearings with short service life in my experience.

[gdw]

+1 ISIS bottom brackets have a well earned bad reputation.

[Pastashop]

OK, Sheldon's site:

http://www.sheldonbrown.com/bbsize.html

... turns out that Stronglight Speedlight cranks come / came in ISIS. I have one that's an ISO square taper – pretty crank. Using a 102mm Chorus BB I wind up with ~145mm Q factor...

Still, for some (hair-splitting) reason I'm intrigued by the ISIS option.... but not if all the bearings in the ISIS BBs are crap (?). Why are they necessarily worse than Octalink BBs?..

[fiamme red]

ritchey used octalink only, FSA made some ISIS stuff

the ISIS bottom brackets tend to use pretty fragile bearings with short service life in my experience.These have a 10-year warranty: https://www.compasscycle.com/shop/components/bottom-brackets/skf-bottom-bracket-isis/.

[bicycletricycle]

the large spindle size leaves little room for ball bearings. The shimano octalink bottom brackets have the bearing races ground directly into the spindle and threaded cup, allowing for bigger bearings. The ISIS bottom brackets attempted to use off the shelf cartridge style bearings which required room for separate associated bearing races and thus even less room for the balls.

the proper solution would have probably been needle/roller bearings and ball bearings (original octalink style) but those are difficult to manufacture and maintain.


OK, Sheldon's site:

http://www.sheldonbrown.com/bbsize.html

... turns out that Stronglight Speedlight cranks come / came in ISIS. I have one that's an ISO square taper – pretty crank. Using a 102mm Chorus BB I wind up with ~145mm Q factor...

Still, for some (hair-splitting) reason I'm intrigued by the ISIS option.... but not if all the bearings in the ISIS BBs are crap (?). Why are they necessarily worse than Octalink BBs?..

[Pastashop]

Yep, the SKS version of ISIS has the race ground directly into the spindle... ITA is a "cheap" $90 on sale from Compass, whereas the BSA version is $150 and out of stock. :-/

hmm...

[Vinci]

A few months back, I went down the ISIS road to put together a weight weenie crankset. I ended up finding some super-light bottom brackets, but the sealed bearings are pretty small.

The plus side is that they are easy and cheap to replace. The negative side is that they are going to need it a lot more often than other BB standards.

FWIW, the narrowest ISIS BB is a 109mm, which is what you want for a road double. An FSA SL-K carbon ISIS crank with a Omni carbon/Ti bottom bracket ended up being slightly lighter (~10g) than a Sram Red22 crank of the same size. I was impressed.

[dustyrider]

The only part I recall liking about isis bb is when they went away. I used to get less than a single season of mtb riding on them....compared to square taper bb that I've used for years and years.