Scooter123

Hi Folks,

I have a 1993 Basso Gap made of Columbus SL tubing. It's in fairly good shape, but the crankset is scratched up and the rings are wearing out. It's an old Dura Ace 42/52 that had a lot of miles on it when the frame was new.

The bottom bracket is a square taper Campy Chorus, all chrome-moly. Having just gotten over a knee injury, I want to switch to a triple crankset for this bike. I'd like it to be lighter but I'm not sure I want to pony up for carbon fiber.

I'd consider switching to a nicer bottom bracket as well, but I'm not sure I can find one that would fit. The bottom bracket shell measures 2.75" or 70mm wide.

In case someone recommends going to a freewheel with larger sprockets instead, I'd rather avoid it. I'd have to swap out the derailleur for one with a longer cage, and the current derailleur is fairly new. And then I'd still have a worn out looking crankset.

Thanks for your advice,

Scott C.

Torchy McFlux

Well, if you want to go to a triple crankset, you're going to need more than just the crank. A different bottom bracket (longer spindle for the extra chainring), front derailleur (to shift between 3 rings instead of just 2), and probably front shifter will be needed too. You might be able to get away with keeping the short-cage rear derailleur, but excessive chain slack while in the granny ring is something you'll have to watch out for.
Also, I'm a little surprised the Shimano crank is matched with a Campy BB - they don't tend to work well with each other since the square tapers are slightly different.
A 70mm wide BB shell takes an Italian BB. Still fairly common and widely available.
If you're changing your mind now, most short-cage rear derailleurs can handle cogs up to about 28t. You can always match that with a 39t chainring up front and have a decently wide range.

bigbossman 

If your BB spindle is 111mm, you can drop a triple crank on it without changing out the BB. You'd probably still need to change the FD, but they are cheap. If your friction shifting, the front shifter is good to go for a triple FD, and if you have Campy ergo they are set for triple operation, as well.

Might be a little more painless to try a compact crank up front if your BB is 102mm. Any modern Campy BB/crankset combo will fit your BB shell, so no worries there.

dit

If your seat tube dia is up towards 31mm you will need a 115mm spindle, depending which triple crankset you go to. I doubt that you will be able to retain your current rd with a triple. Chain wrap issues will be the probable problem.

https://www.lickbike.com/ Has the info that you need for spindle length.

bigbossman 

32mm does spec a 115mm spindle, but I had success using a standard 111mm Veloce bb and Centaur triple on my 32mm tubed Pinarello. As an aside, I'd be very surprised if a 1993 Basso had a 32mm seat tube - especially Columbus SL.

As another aside - 111mm Veloce/Centaur bb does not equal 111mm Chorus/Record bb. If the op's bb is a 111mm Chorus, he'll likely need a Chorus or Record triple crank or it won't shift right. at least with the newer (mid-2000's and up) stuff.

Scooter123

bigbossman, dit:

Thanks for the info. Yeah, I forgot that there would need to be extra chain wrap with the granny gear, so off comes the rear derailleur and I'll need one with a longer cage.

I'll take a look at a compact setup. I'm not sure it will provide the range & selection I want.

The shifter is Ultegra bar-ends, with indexing optional for the rear. I'm certain it has the cable takeup to handle a triple. As you say, the front derailleur is another matter. It's a Campy chorus as well, and it came with the frame. I'm doubt it can handle it, but it's not hard to upgrade.

I need to take the cranks off and measure to determine the width of the BB spindle. I suspect it's not long enough. There's not much gap between the current double crank and the bearing cup on the drive side, and the front derailleur does not have to extend at all to put the chain on the small ring (on the double).

Looks like the first step will be to see if it's worth the expense to do all this...

Thanks again,

Scott C.

Scooter123

FWIW, I wound up with an FSA compact crank, dura-ace external bearing BB, 8 speed mtb cassette, used/resurrected Shimano STS rear derailleur, and dura ace 9 speed chain. The crank was one the store had salvaged so I got a decent deal on it all. Not cheap overall, but much less than a new bike... Especially one I'd like as much. A few more weeks of PT and I'll be riding in style.

Thanks for all of the good pointers.

Scott C.

bigbossman 

No probllem. I have a 1992 Pogliaghi that I hung a 10 speed Campy triple group on. It has turned into my favorite bike.