Ofmega 170 crankset BB compatibility

Antti Salonen said:

I mentioned in another thread some two months ago that I bought an early
80's Guerciotti, which was generally in great shape. It's a racing bike
with a mix of Campagnolo Gran Sport and Ofmega components. The crankset
is Ofmega, as is the BB. I had the BB opened and removed by the LBS
at least for now, as it clearly required new grease, although the BB
and the bearings seem to be in fine shape.

If possible, I'd like to replace the BB with a modern Campagnolo
cartridge BB like the AC-H, as I use those on other bikes and have the
tools already. The Ofmega BB has a 115 mm spindle and when I tried the
Ofmega crank on a spare Campagnolo AC-S BB with a 115 mm spindle, which I
have collecting dust, the cranks seemed to fit fine.

So the question is: Are the spindles identical, or just close?

Your Ofmega BB is a good quality component which, with
regular cleaning/fresh grease/new balls will last a good
long while.

That spindle is compatible with the older Campagnolo 1046a
Nuovo Record BB* and as such is asymmetric. If you want a
cartridge unit, get an asymmetric Phil or a longer spindle
version of a modern symmetric one.

*(And New Dura Ace BB7400, Nervar, TA-Tevano, Sugino Mighty,
Superbe and a host of others)
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

Your Ofmega BB is a good quality component which, with
regular cleaning/fresh grease/new balls will last a good
long while.

That's certainly what it looked like. It's in great shape as the bike
hasn't been ridden much, but it had to get it opened because the
20-year-old grease needed to be replaced.

Quoted message said:

That spindle is compatible with the older Campagnolo 1046a
Nuovo Record BB* and as such is asymmetric. If you want a
cartridge unit, get an asymmetric Phil or a longer spindle
version of a modern symmetric one.

I ended up buying the Tacx tools (fixed cup, adjustable cup and lock
ring wrenches) for about 50 Euros. Replacing the BB with a modern
cheap Campagnolo cartridge BB would've been much cheaper, but it indeed
looks like the spindle is clearly asymmetric. I'm unlikely to be putting
any significant mileage on this bike, as I have other bikes for that.
I'm going to ride this thing on selected, beautiful summer days, so the
Ofmega BB should last forever.

-as