So i got this very nice 125mm Ofmega crankset for my daugher's 450A Motobecane



What size spindle do I need to get? I imagine I will need to find that proprietary Ofmega taper. I can find 115's without too much trouble. Too long for a kids bike?

I suspect that crank, which seems to be an older Ofmega model, does use the thinner tapered end spindle. You'll have to find an Ofmega BB to match up to the crank the, otherwise, other brand ISO tapered spindles might not fit far in enough into the square tapered holes on the crankset. Not sure if the Ofmega/Avocet connection means that some Avocet spindles might work. Avocet spindles are easier to find than Ofmegas at eBay.

Chombi

That's what I figured, but what length? I do need to match it up to the shell width yes? That's short (60mm) too.

I've never mounted an Ofmega crank on my bikes. I have not seen any charts showing recommended lengths for spindles either (IIRC, even Sheldon Brown does not provide specs and numbers for Ofmega BBs). I suspect that they might be similar to what is used on other Italian cranksets. Something like 113mm to 116mm for 68mm BB shell widths. Maybe someone else with more Ofmega experience can chime in to confirm.

Chombi

Hope so, I'm already 8mm short of the standard 68mm shell.

great to se you got those cranks-now where is the thread you promised on that bike!!


talk with andycapp,he has the same pair and can check the measurements
a track axle come to mind as a maybe
he would love to drillium that for you!
my last set of Ofmega junior cranks left the building last week,
I do remember flipping the axle around to get the chainline closer inboard

But I do recall the square end being standard sizing.

Thread's coming, I'm still collecting parts! If that's a standard ISO taper that would solve a world of problems.

No drillium for this, it already doesn't weigh anything!

I know your pain as I have an Ofmega Mistral crankset coming in soon in the mail for one of my projects. I'm already stressing about not really knowing what BB/spindle to use on it. I did see in some internet threads that some later Ofmega cranks might have standard spindle tapers and its most likely just the older Ofmega cranks (early 80's and earlier) that required the Ofmega tapered spindles.
I just hope it will be OK when I test fit it on one of my ISO tapered spindles on my other bikes.

Chombi

I'll have to take the Olmo's BB apart to get some measurements for you... The weather really sucks here so I'll be confined to the indoors tonight. Stay tuned... When are we going to see some pics of this bike?

-Andy

My ofmega spindle seemed to have the same taper (attempted to measure with calipers) as a late Campagnolo centaur bottom bracket. English bottom brackets seem impossible to find, but the Italian spindle, the correct English campy cups, and a modern bb spacer work nicely. Let me know if you need more info.

Soon. I'm almost done "shopping" for this one.