DA7700 Rear Derailleur with 10spd DA TT shifters?

[BRad704]

So I've got this old Trek 2100 that I put TT bars and shifters on... I've replaced the RD with an Ultegra 6700 just because I had it laying around. NOW I'm thinking about swapping that 6700 RD for a DuraAce 7700 RD that's also laying around. No real point to it, and i don't expect any more than 40-50 watts extra on my FTP from this change...

But, is this more of a downgrade for the sake of some bling-silver-DuraAce? Or is the 7700 going to be just fine to replace the 6700? (I'm talking ONLY about RD's here.)

[jtbadge]

Those RDs are totally interchangeable assuming your cassette doesn't exceed the capacity of the DA.

[Black Dog]

7700 rd's work perfectly with 10 speed. Besides, it is the best looking RD that Shimano ever made.

[BRad704]

Ok awesome! Thanks guys.

Ya can't just leave THIS sitting in the parts bin.

https://uploads.tapatalk-cdn.com/20200331/d7ff7a47af16d7db3905d25e4c55fd93.jpg


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[robt57]

Use the one with the lowest previous use. Or if the 6700 is a GS and you want to use 32-6t cassette that is a gimme.

The RD-7700/7800 and RD-6700-GS are two of my favorite shimano RDs. And 9s MTN stuff.

The 6700 is also a bit more modern looking than the 7799/7800.
If you have a lot of black going on on the bike...

[jtbadge]

Nice, the GS cage, even! Those are pretty desirable for their greater chainwrap capacity.

[robt57]

Ok awesome! Thanks guys.

Ya can't just leave THIS sitting in the parts bin.

https://uploads.tapatalk-cdn.com/20200331/d7ff7a47af16d7db3905d25e4c55fd93.jpg


That looks like the rare RD for DA triple to me...

Should do a 32t

[BRad704]

That looks like the rare RD for DA triple to me...



Should do a 32t



It is. :D but I didn't know they were rare. this one came off my wife's 2005 Trek Pilot 5.0. Originally 3x9


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[robt57]

It is. :D but I didn't know they were rare. this one came off my wife's 2005 Trek Pilot 5.0. Originally 3x9

Perfect RD for a 10s 11-32 [maybe 34] with 30/46 chainrings.

Trick BTW; I you used an 11s chain on your 10s system, you can use the 11-34 [R800-11-34] cassette that fits on a 10s freehub, adjust out the 11t cog and you will have a 30/34 low gear. 7700/7800 top pulley floats nice and will play with the 11s cassette fine with 11s chain.

This will work with the Sunrace cassettes, maybe even the 40t.
36t cassette probably if your DR hanger isn't hyper short.

I have a bike with a 35mm long RD hanger with a RD-6700-GS that can handle a 40t top...

Just watch pushing capacity too far, or stick with front chain rings like 36/46, or 34/46 to open capacity to get more RD/cassette range. YADA.

[cmbicycles]

The larger pulleys on the DA will have less drivetrain friction... yuuge watts savings... at least that's what other companies say about their oversized pulleys. ;)

[BRad704]

Oh baby

https://uploads.tapatalk-cdn.com/20200331/e0417dfa94de35f3b06da56c34b97984.jpg

https://uploads.tapatalk-cdn.com/20200331/acbe3be6322e5c0dfd46c0c8feba693c.jpg

The whole bike for reference. Wheels are about to be sold though.
https://uploads.tapatalk-cdn.com/20200331/4612bfb91c698b62aff849b555d4af34.jpg


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[JAGI410]

Perfect RD for a 10s 11-32 [maybe 34] with 30/46 chainrings.

Trick BTW; I you used an 11s chain on your 10s system, you can use the 11-34 [R800-11-34] cassette that fits on a 10s freehub, adjust out the 11t cog and you will have a 30/34 low gear. 7700/7800 top pulley floats nice and will play with the 11s cassette fine with 11s chain.

This will work with the Sunrace cassettes, maybe even the 40t.
36t cassette probably if your DR hanger isn't hyper short.

I have a bike with a 35mm long RD hanger with a RD-6700-GS that can handle a 40t top...

Just watch pushing capacity too far, or stick with front chain rings like 36/46, or 34/46 to open capacity to get more RD/cassette range. YADA.

Oh man. I have one of these rear D's (7800 long) on my 3x9 Cross Check and was debating upgrading the drivetrain. Now these tidbits have me rethinking my strategy! Hmmm....

[JPS123]

Perfect RD for a 10s 11-32 [maybe 34] with 30/46 chainrings.

Trick BTW; I you used an 11s chain on your 10s system, you can use the 11-34 [R800-11-34] cassette that fits on a 10s freehub, adjust out the 11t cog and you will have a 30/34 low gear. 7700/7800 top pulley floats nice and will play with the 11s cassette fine with 11s chain.

This will work with the Sunrace cassettes, maybe even the 40t.
36t cassette probably if your DR hanger isn't hyper short.

I have a bike with a 35mm long RD hanger with a RD-6700-GS that can handle a 40t top...

Just watch pushing capacity too far, or stick with front chain rings like 36/46, or 34/46 to open capacity to get more RD/cassette range. YADA.

Will this 10 speed Dura Ace Index Shifter work on a Mid Cage 5800 105 Rear Der? 10 Speed Cassette, 11 speed Chain, 1x up front?

[zzy]

I've never had luck getting a long cage 9sp road derailleur to work with a 32t.. Even if it clears, the jockey is grinding the chain against the cog. The official max was 27t, even for the long.

[Black Dog]

I've never had luck getting a long cage 9sp road derailleur to work with a 32t.. Even if it clears, the jockey is grinding the chain against the cog. The official max was 27t, even for the long.

Reversing the B-screw helps with this.

[robt57]

Will this 10 speed Dura Ace Index Shifter work on a Mid Cage 5800 105 Rear Der? 10 Speed Cassette, 11 speed Chain, 1x up front?


No go on that shifter and RD-5800, 99% sure. Any 8-9 speed MTN or 8-10s road Shimano RD yes. Although 8 speed DA not, and one of the newer lower end 10s Shimano [claris/sora?] not. forget which on the later stuff.

[robt57]

I've never had luck getting a long cage 9sp road derailleur to work with a 32t.. Even if it clears, the jockey is grinding the chain against the cog. The official max was 27t, even for the long.

Length of RD hanger I have found is the determining factor. When you reverse the B-screw and mess about with a shorter chain to have it sit back further in the bigger cogs, it never really shifts that nice, and I quit trying years ago.

Important to look up the actual spec and not push the capacity spec especially too far. When the RD hanger is longer the fudging of the spec is less objectionable in use I have found.

[Mike Bryant]

I used one of those RD-7700GS to run a 12-30 10 speed cassette with a 30/50 White Industries crankset.
RD handled 30t fine with b-screw all the way in. Double FD-7800 even handles 20t difference even though max recommended is 16t.
Gear inch for 50-12 high end combo is very close to 46-11. Benefit was closer jumps in the cassette mid range. Downside is changing chainrings takes three cog clicks on the cassette (versus the usual two) for progression. Oh, and the big-big combo won’t bust anything, but the chain rub on the top of the FD cage will remind you not to be there.


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