who can help me. I got a tandem with Shimano ST6510 shifters 2 x 9. I want to change this tandem into a 3 x 9. The shifters I can use for 3 x 9 as well but I need a new rearderailleur long cage and front derailleur triple.
The front derailleur should be a FD 6503 triple, the rear a RD6500 but of course those are older models and not for sale anymoe. What's should I use instead, what's compatitble with the old 6500 series?