will a 7 speed shifter and cassette work with an 8 speed derailleur?

i think it could work never heard of sti except on the brake shifters i will guess its shimano sis and would be able to adjust to go on 7 speed by limit screws on the derailleur and the spacing controled by the shifters,would work as spacing correct

but i have a little saying going round in my brain says campy goes with campy but could mean shifter to cassette,....................... i say it will work........

Shimano 7 Speed Shifter

Probably. The derailleur really doesn't make a difference in the whole equation (in spite of what Shimano and Campy may try to tell you). As long as the chain travels through the derailleur without any trouble and the derailleur travels the entire width of the cassette, you should be fine. I currently use a 20-year-old Shimano Exage derailleur originally esigned for a 6-speed freewheel with a 10-speed SRAM cassette without any problems. The only hitch you may have is if you have a 30 tooth low gear on your cassette as some derailleurs are limited as to how large of a rear gear they can shift into.

If it is a Shimano 7 speed shifter and cassette, it will not work with a campagnolo derailleur. You will have to find a derailleur made by the same company as the shifter

is it all campy?

if so it might work

shimano 7 speed shifters would work on 8 speed cassette

7 and 8 are compatible

9 and 10 can be made to work with spacers in the cassette

9/10 shifters won;t shift 7/8 speed cassettes though

not sure about shimano campy mix

wle

As long as the derailleur is index compatible, and as long as the derailleur is not an 8-sp Dura Ace, it will work. Not all derailleurs in the past were index compatible. Shimano noted its index compatible system with the SIS designation when it appeared.