8 speed shifter compatibility with vintage dura ace

[cycletothesea]

I have a lovely Pinarello with a 7400 dura ace groupset, however the shifters recently gave up working properly. Rather than buying some more expensive Dura Ace downtube shifters, I tried to fit some more modern SL-R400 shimano 8 speed shifters. Trouble is, I can't get them to index properly with the old Dura Ace derailleur. Should this be a problem? Are they likely to be incompatible?

 

[foz]

Re:

They are incompatible, Dura ace 8 speed only works with dura ACE 8 speed. Or with 9 speed. You can always use them in friction mode...

 

[hamster]

IIRC the trick is to lay about three layers of insulating tape into the groove in the shifters. This brings the cable pull up and they will then work.

 

[legrandefromage]

weirdly the 7spd DA shifters I have index perfectly with a thoroughly modern 105 10spd rear mech.

you could try clamping the cable slightly differently or using a j-tech shift mate.

 

[cycletothesea]

Some different solutions here - insulating tape and j-techs (whatever that is!). The issue I have, in more detail, is when I adjust the pull to index the first two sprockets perfectly the are totally out of sync when the chain rides up the cassette. But if I re-adjust slightly to make the top of the cassette index smoothly, then it skips down the cassette two at a time on the way back. Obviously, I can see now that it's just incompatible, though I don't really understand why - from my amateur point of view it's just a lever pulling a wire a bit at a time.

Might have to bite the bullet and find a DA 8-speed shifter set, although they're retailing at £60 quid !!

 

[cycletothesea]

IIRC the trick is to lay about three layers of insulating tape into the groove in the shifters. This brings the cable pull up and they will then work.

Haha, I've read this 10 times, and I still can't visualise how the heck that would work. It obviously does work, otherwise you wouldn't suggest it, but I don't understand the mechanics. The insulating tape would have to be about 1mm wide to fit in the groove???

 

[legrandefromage]

IIRC the trick is to lay about three layers of insulating tape into the groove in the shifters. This brings the cable pull up and they will then work.

Haha, I've read this 10 times, and I still can't visualise how the heck that would work. It obviously does work, otherwise you wouldn't suggest it, but I don't understand the mechanics. The insulating tape would have to be about 1mm wide to fit in the groove???

Increasing the diameter of the shifter increases the amount of cable pulled for each shifter

Your DA stuff had its own cable pull when compared to the rest of the shimano range

 

[cycletothesea]

I think I'll try and put the old DA shifters back on and just use friction mode. Not sure I want to start wrapping tape around the new ones, and finding an original 8 speed DA shifter set seems to be almost impossible.

 

[tpjm191]

https://www.sheldonbrown.com/drivetrain-mixing.shtml

I think this might help visualise some possible solutions

 

[cycletothesea]

I've read a few forum replies that suggest ANY modern Shimano 9-SPEED downtube shifter will operate an 8-speed 7402 DA Derailleur - is that true?