BB & chainset and chain compatible: Shimano octalink 8 s

Sares · Post by **Sares** » 29 Mar 2008, 6:00pm

I bought a bike frame & wheels secondhand, which currently has a 5 speed freewheel on the back, and no BB or chainset . I want to get it on the road without changing more than I have to. I have found an 8 speed octalink sora triple FC-3304 because 8-sp chain should work with both the freewheel and the chainrings. However, I do not know what sort of BB would work with this, assuming English threads on the BB.

Can anyone here help by identifying a BB that should fit, or could I use a 9 sp chainset and not have a problem with the chain between thinner front chainrings and 5-sp freewheel?

Thanks!

Steve · Post by **Steve** » 29 Mar 2008, 6:10pm

Ribble Cycles' site says a 118mm octalink BB for the Sora triple - although an old bike might have a slightly different geometry. Choosing bottom brackets lenths isn't always a precise science!

http://www.ribblecycles.co.uk/productde ... HIMCHAR800

Sares · Post by **Sares** » 30 Mar 2008, 11:24am

Thanks, Steve, that was very helpful!

gilesjuk · Post by **gilesjuk** » 30 Mar 2008, 5:15pm

Bear in mind that splined BBs have smaller bearings and dont last as long.

BBs with external bearings are better.

Raceface, Hope and Shimano all do these. You need a crankset compatible with these. You just tap the crank through the bearing cups and tighten up an allen bolt (very tightly).

andwags · Post by **andwags** » 31 Mar 2008, 1:17pm

BB length is a precise science unless you're putting parts together that don't belong together. All chainsets have a recommended bottom bracket to go with it. You can download the service instructions from their respective web-sites. In this case go to:

http://techdocs.shimano.com/techdocs/index.jsp

pigman · Post by **pigman** » 31 Mar 2008, 1:36pm

if you're getting the octalink chainset, cheap, 2nd hand, then go for it. otherwise if its not a bargain, I'd avoid it, as the small BallBs on the Octalink BB wear quickly. Also, Octalink is now superceded and parts are becoming obsolete, so youre consciously buying into obsolesence.

Steve · Post by **Steve** » 31 Mar 2008, 8:44pm

BB length is a precise science unless you're putting parts together that don't belong together.

I would say an 8 speed chainset with a 5 speed freewheel was probably a case in point...