Bottom Bracket compatability?

[.:ROBBO:.]

I need to replace the bottom Bracket in my demo 9. Its currently running a Truvativ ISIS Gigapipe 4-bearing DH, 73mm shell, 128mm spindle. Is there a way I can run an external Bottom Bracket on this? And whats involved in the conversion?

Im running Truvativ Holzfeller 7050, ISIS spline, 7050 alloy, 170mm Cranks.

I can buy a replacement Gigapipe BB but would prefere to upgrade it if I can.

 

[dj3]

not much help to you with the length of your spindle fitting in an external bb, but i do know that a external bb will fit on your demo 9, i upgraded mine from internal to external without a hitch.

 

[.:ROBBO:.]

Thanks. Ive seen it done with other cranks but I really dont want to buy other cranks at the moment. Was hopeing I could find an ISIS type external BB that would fit.

 

[Stacks!]

The truvativ Howitzer bb may be what you're looking for. External bearing bb with isis drive, i'm not sure what the spindle length is tho.

Easiest way still is to just buy new cranks.

 

[rone]

The Demo9 is one of only a few bikes (the only?) to run the 73mm bb shell/150mm axle combo. As a result the BB axle needs to be super wide so the cranks clear the swingarm.

I wanted Saints on mine, but had to get the 83mm axle M815 cranks to clear. With this I found that the Saint BB bearings, even when spaced out with the 2.5mm spacers didn't mate up with the raised bearing surfaces on the BB axle. To get around this I fitted the FSA BB-9550 MTB double row bearings as they were the only ones wide enough to mate properly with the axle.

Back to your axle - I suspect that as long as the OD is 24mm it SHOULD work and would allow you to upgrade to an 83mm crankset at a later date.

Clear as mud? Good

 

[.:ROBBO:.]

Thanks Rone. I had looked at your thread for info and noticed your set up. I think im just going to buy a replacement gigapipe for now. As the plan is to go to Saint cranks in the long term. I was hopeing I could have maybe upgraded the BB now and got away with also using it when I buy new cranks.