Smorgasbord42

I've seen lots of threads on converting from a triple to compact double, and even vice-versa, but I couldn't find anything on the best way to convert a regular double to a compact double. One bike I'm looking at getting comes stock in a double (53/39 and 11/23), but that's too tall for me and my terrain. What's the best way to get some lower gears in?

My first thought was to change the rear cassette to a 13/29, but then I have to change the rear derailleur (looking at Campy components). The other way is the change the crankset, and then change the front derailleur. If I did the latter, I suppose I could just change to a triple - right?

Is one method preferable to the other, and if so why?

Mose

To go from classic double to compact double -> new crankset, possibly remove a few chain links, adjust FD.

To go from classic double to triple -> new crankset, new FD, new F brifter, readjust everything.

I'd just try a 12-27 first and see how you like it. That's what I ride with a 53/39 on the hills around here, and I'm not a very good rider, and it suits me just fine.

Wil Davis

My Bianchi Veloce came with a Campagnolo Veloce 52/42/30 Triple, on a 111mm spindle and a 13-26 cassette. I've since tried 53/39 and 50/34 crank sets using the same spindle. I changed the FD to compact, although the conventional double FD worked OK, and the triple FD might have worked also. I also changed the RD to a short-cage as I wanted to used all the triple h/w for another project, but the long-cage RD worked perfectly OK with both doubles and the triple. The Campy Veloce front brifter works OK with doubles or triples as there aren't specific positions for the shifter, just a series of clicks, so its behaviour is more like that of a friction shifter.

- Wil

rschulze

I shifted my Colnago double to a compact double. Same BB, same Front Drllr (needed to tweak the adjustment), Had to put a very thin spacer (think drivers license thin) behind the front drllr where it bolted onto the frame. Swapped cranks, kept rear cassette 11-23. This worked pretty good.

I kept the spacer in (the frame didn't like doubles) and swapped record road to record compact front drllr, rode it ever since. Love it

BlastRadius

You don't need a new rear derailer to use a 13/29 cassette.
You may need to lengthen the chain, but if it's a new bike, the chain is likely too long anyway.
I haven't seen many shops that take the time to make sure a chain is the correct length on a newly built bike.

*see correction in post #7

Smorgasbord42

OK, so I've seen a couple of posts where people claimed that Campy's derailileur specs are too conservative (Campy says 26 is max # teeth, with a 27 chain wrap total. For the latter I'd be at 53-39+29-13=30. So, I'd be out of spec on both counts. I suppose I could try it and if it doesn't work out, a new rear derailleur, even a Chorus, seems to run around $200, so maybe swapping isn't such a big deal.

I do wonder who the target market for the non-compact double bikes is - maybe people who are weight weanies without steep hills? Is that a large target market?

BlastRadius

Oops... I take my previous note back... from the Campy website for the Centaur group.

Mhendricks

FYI. I'm running a compact double with a 13-28 cassette, Centaur CT FD, and a Campy 9-speed Long cage derailleur. Works great for me.