I just bought old Shimano RSX STI shifters for my 90s road bike, which had a Shimano 600 Tricolor Group (2x7) with downtube shifters. While the rear shifter I bought is correctly a 7 speed one, the front one is a 3 speed one. Is there any way to adapt it so it works on the 2 speed crankset and derailleur?


  • 2
    I’d just try if it works. 2 chainring front derailleurs are pretty easy to get adjusted. Most 2 chainring shifters do have an intermediate middle (“trim”) position to avoid the chain rubbing on the derailleur in small sprockets.
    – Michael
    Mar 12, 2021 at 19:04
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    I +1'd mikes' answer, but there is one important trick to this kind of setup: you need to adjust it so that the STI can't get into "shift locked" position. This happens when in the high ring, the force needed on the release paddle is too high and damage to the internal parts will result sooner or later. It can be tricky to adjust 3x STIs on doubles without having this happen. Usually you do it by allowing the cable to be slacker than normal in the low position. Why the cable pull amounts don't line up the same I'm not sure, but this is the thing to watch out for. Mar 13, 2021 at 0:09
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    @Nathan Knutson Since the actuating arm moves in a curved path, the amount of vertical movement it undergoes per unit of cable pull is not consistent throughout its stroke.
    – MaplePanda
    Mar 13, 2021 at 3:06
  • Thanks everyone. As long as it's feasible I'm fine, I'll just have someone more knowledgeable set them up for me
    – Davide ND
    Mar 13, 2021 at 14:27

1 Answer 1


Just set it up and adjust it as you would a two speed shifter. Make your initial adjustments using the first and second shift positions. The "HIGH LIMIT" screw on the front derailleur will prevent you from reaching the third shift point.

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