Converting triple chainset with compact rings?

Discuss light weight issues concerning road bikes & parts.
Posts: 361
Joined: Sun Mar 23, 2008 7:31 pm

by Camilo

sigismond0 wrote:... If you just want to put a standard 53/39 on your 130mm BCD, you can absolutely do that. You'll need to put a double derailleur and shifter. I'd say just leave your old shifter/derailleur/smallest ring, put 53/39 on the big rings, and just don't use the littlest ring.

The only other option is to just switch your BB, crankset, shifter, and front derailleur.

Triple FD's are generally different than doubles, but they often (usually? almost always?) work fine with a double. I'd try it before buying a new one.

As for the shifter - again, my experience - the triples can be used for doubles. Setting the stop limits on the derailleur itself to a double configuration will simply eliminate the triple "clicks" from the shifter and it will work fine for the double.

Interestingly, I can't see mention of the teeth on the current crank's rings - usually road triples are simply a road double (~52-39 or 52-42) with an inner ring. If so, (in my opinion), the OP has two straight forward options for converting his 130BCD triple crank to a double:

1. Simply remove the inner ring, set the derailleur stop limit to stop on the middle ring, voila, it's a double. This is a good solution for simplicity and if the OP doesn't have any problems with his triple's Q factor (width of the crank). Also depends on how the chain line is using the smaller (formerly middle, now inner) ring with the inner rear sprockets. Depending on the bottom bracket, he might be able to take this one step further and replacing the BB with a compatible one for a double, thus reducing the q factor to that of a normal double and making the chain line better if it's a problem. BB's really aren't too expensive unless you get crazy about things like ceramic bearings.

2. Replace the BB and the crank with a normal double. Sell the triple and bb on ebay - there's a good market for them. Net cost will be fairly low. Try the FD and see if it works satisfactorily. If not, sell it and buy a "real" double FD. Again, shouldn't be much of a net cost - FDs, even high end ones, are one of the cheaper issues here. The shifters should be fine.

Posts: 236
Joined: Tue Feb 05, 2013 8:29 pm

by sigismond0

Or get something like this to replace the big ring: ... 232b5f2857

by Weenie

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