I'm referring to a late model 105. I know that with older triple STI shifters, like RSX and 105, you can set up the triple shifter to work perfectly with a double crank. I've done it several times. However, a freind recently toasted a late model Tiagra triple when using it with a double compact crank. It was a Trek and it came that way from the factory. The bike shop that repaired it said this shifter was not made to work with that crank and they had seen this several times before. BTW, this happened within one year of purchase, still under warranty.
I've got a 06 Giant OCR-C3 with 105 triple left (10 speed). I'm seriously thinking of going from a triple to a compact double. The question is, will this shifter also have problems working with a double or is the problem limited to Tiagra 9 speed left?
Thanks for all replies.