Vintage Dura Ace question

[RonW87]

Will an 8 speed dura ace rear derailleur (first gen. STI, I think) work with a shimano index-shifting 7 speed downtube shifter?

[likebikes]

nope

[oldpotatoe]

Will an 8 speed dura ace rear derailleur (first gen. STI, I think) work with a shimano index-shifting 7 speed downtube shifter?

If it's a 2 bolt one(7400) yes. If the next gen, 7402(?)...then with DA8s DT shifters only.

[bluemax]

What is meant by a "2 bolt one"? If you mean the exposed head of the cage pivot bolt, that was common to 7400 and 7401. 7402 was the 8 speed model and lacked the exposed bolt head.

I didn't realize the cable pull varied between 7402 and the other two. If that's correct you can replace a 1050 or 6208 rear derailleur with a 7400 or 7401. Good to know.

[oldpotatoe]

What is meant by a "2 bolt one"? If you mean the exposed head of the cage pivot bolt, that was common to 7400 and 7401. 7402 was the 8 speed model and lacked the exposed bolt head.

I didn't realize the cable pull varied between 7402 and the other two. If that's correct you can replace a 1050 or 6208 rear derailleur with a 7400 or 7401. Good to know.

Here..same geometry as ultegra..That's what I mean.

[Black Dog]

If it's a 2 bolt one(7400) yes. If the next gen, 7402(?)...then with DA8s DT shifters only.

I used, for many moons, the 1 bolt (7402) with 7 speed dura-ace downtube shifters. It works perfectly; in fact, on the bottom of the deraillure there is a setting screw for 7 or 8 speed.