mickt90

Dumb question I expect:
Looking at the description of "Campagnolo Comp Triple" chainset on velobase, the description says "BB length: 111, 115.5" (can't post the url).
I'm not sure how to read that. Would it mean
(1) it is compatible with either of the two spindle lengths, or
(2) it comes in two sizes, each of which is compatible with only one of the lengths (a bit like crank arm sizing for example)?

Reading the general info, I think it's probably (1) but I'm not 100%.
tia.

Iride01 

This Campy Triple?

https://www.velobase.com/ViewCompone...4077d&Enum=115

It's going to depend on what you are putting it on as to the length of the bb spindle you need.

Welcome to BF

mickt90

Yes that's the one.
Ok, so there would have been only one version of the chainset which was compatible with both lengths of BB spindle? (Well, two versions based on the crank arm length, but not 2x2 = 4 variations).

I have one of these already (on a 111mm spindle). I'm going to have to replace it with something - probably something different but hopefully similar - and I'm trying to understand to what extent spindle length/chainset compatibility will be an issue. Eg I see other sorts of campag triple chainsets available which look similar but say they require a 115mm spindle, so it seems I would need to replace the BB at the same time. Does that sound right?

SpedFast

It appears to me that Iride01 posted the info you need to make that determination based on measuring the bottom (BB) of your frame. Welcome to BF

Andrew R Stewart 

When frames are made with larger diameter tubes and/or are made with MtB rear hub chainline specs the chainrings might need to sit further out. To either clear the fatter frame tubes and/or to have a better chainline with the rear cogs. Andy

Hondo6

One caution, OP.

I'm certainly no Campagnolo expert, but I understand Campagnolo uses ISO taper on their square taper BBs. If you end up using a replacement BB having a JIS taper, that will alter the length of the spindle you need. One of the mismatches moves the cranks inwards, while the other moves them outwards.

Both the Rene Herse and Sheldon Brown websites discuss this issue in some detail. As I recall, the bottom line is that mixing the two is not recommended, but it works - so long as you (1) don't go back and forth between ISO and JIS taper repeatedly with the same crank, (2) don't bottom and/or over-torque the spindle, and (3) account for the difference in chainline due to the taper mismatch.

Might be a good idea to look over those pages carefully if you end up considering a JIS spindle BB out of necessity.

Dave Mayer

Andrew provided the right answer. The Campy crankset should only be matched with a Campy BB (ISO), of which at any time there are dozens of compatible models online.

Going from memory, there are 2 different Campy BBs that will work with this triple, either 111 (symmetrical) or 115.5mm (asymmetrical). The Record/Chorus BBs don't work with this crankset.

Depending on your frame tubes, you might need either the 111 or the 115.5. Skinny steel tubes for the 111. Fat alu tubes: the wider one.

Iride01 

Is that chainset already on your bike? If you remove the BB, the numbers are probably on the cartridge that will tell you what the spindle length is on it currently. Or does your bike not have a cartridge and is still the old separate spindle, bearings and cups? In that case just measure.

I know in your second response you said you were going to replace or put in something else. But it wasn't clear to me what was going to be replaced or put.

Since you said chainset, can we assume you are from UK or somewhere that use that term? Here in the States, most use the term crankset. Some will argue you up and down that it's a crankset. I just think it's interesting like the differences in tire and tyre.

dedhed

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The 111mm BB spindles were for 28.6mm seat tubes while the 115.5mm spindles were for 32 or 35 mm oversize seat tubes.