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BB Spacing - how much is too much?

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BB Spacing - how much is too much?

Old 06-23-09, 11:12 AM
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arcellus
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BB Spacing - how much is too much?

Hey all - I'm building up a 'cross bike and have hit a couple of snags. I was originally trying to use a compact road double crankset I had laying around, and soon realized that the width of the chainstays required a much wider chainline. So I've swapped that for a nice Ritchey WCS crankset and Octalink BB that I found for a great price. However, the spindle is still a bit short (109.5, and this is OL V1 by the way).

I've added a 2mm BB spacer to the drive side and with that I've got 2-3 mm of clearance between the crankarms and chainstays. I'm worried about rubbing with my heel and would like to space it out maybe another 2mm. So, my question is - is 4mm too much? With the 2mm spacer the BB threads in and torques down solidly which leads me to believe that I've got some room to work with. Ideally, I'd like to have the same spacing on both sides - 2x2mm drive side, 2x2mm on non-drive side. Way too much? Is 2mm enough clearance between crank and stay? The build isn't finished yet, so I haven't checked it out, but I'm worried.

Thanks for any help.
-A
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Old 06-24-09, 10:22 PM
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Hello what size BB does the Ritchey crankset require? in the 7 or 8 years I worked in bike shops and all the years I have been around bikes I do not think I ever heard of anyone spacing a BB. there is a reason for all those threads. the less threads you have contacting each other the less strength. also you are the cranks to the right and might affect your knees.
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Old 06-24-09, 10:51 PM
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4mm on both sides won't work since octalink is cartridge. you move the drive side 4mm out, then the nds sinks in 4mm. try a triple 118.5mm BB.

what BB style is your road compact double? outboard BB? square taper?
for compact double, square taper with 36T small ring, a 110mm axle should work for bowed chainstays
outboard BB compact double, 34T should barely clear a bowed chainstay, you should be able to add a 2mm spacer to one side.
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