lobster4u

Hi,

I'm a reasonable experienced mechanic and but I have to research this one as I am new to external BBs. Any help would be appreciated. I've been running an Ultegra Crank on my mtn bike turned high speed commuter for two years now. I bought an external BB (Race face X type) and a Bontrager race light crankset (ISIS type spindle) to go with it. Once installed the crank bolt (non drive side) is tightened the chainrings hit the frame. I looks like I need a longer spindle. Are these integrated cranksets available with different spindle lengths? Or would I need a different BB.I played with the spacers but could not get it to work.

Thanks,
Tim

joejack951

You were likely using a longer-than-spec'd bottom bracket with your Ultegra crank in order to get chainring clearance. Unfortunately, integrated spindle cranks do not allow changes in chainline, as was accomplished by using the longer BB before. Without being able to modify the spindle length, spacers cannot be used. And no, integrated spindles are not available seperately as they are not a user serviceable item, if they are serviceable at all.

52/53 tooth chainrings are available with 110mm BCDs so if you can find a MTB-chainline crank with that BCD, you could convert it to a road crank chainring configuration (not cheap though). Why did you ditch the Ultegra crank anyway?

lobster4u

I thought the prospect of using an integrated road crank was diminished. I love the system though, and perhaps I'll find a mtn crankset with 110 BCD. Since this discovery the Ultegra will remain on my bike.
Thanks for the info, much appreciated.

joejack951

FWIW, if you can get a crank with a 48 tooth big ring (not that uncommon on MTB cranks), paired with an 11T cog you'll have a gear bigger than a 52/12. Granted, the smaller 26" wheels reduce the gear inches so it's not quite the same as a 52/12 on a road bike but it's a big gear nonetheless. On a bike with that gearing (26 x 1.5" tires), I had to get over 35mph before pedaling started to feel useless.