Dura Ace 8spd-9spd Compatibility

[cachagua]

My question basically is, is Dura Ace 9-speed just Dura-Ace 8-speed plus one more cog?

Practically, I want to know if I can use a 7700 rear derailleur with 7700 shifters and get correct indexing/spacing on 8-speed cassettes, simply by excluding the lowest gear position with the limit screw. In other words, does 9-8-7-6-5-4-3-2 equal 8-7-6-5-4-3-2-1? Or not?

Or, is there another combination of any shifter with a 7700 r. drlr. that will allow me to use my 8-speed wheels with this derailleur?

Thanks in advance.

[PacNW2Ford]

Any non-Dura-Ace 8-speed shifter will shift a 7700 rear derailleur over an 8-speed cassette.

[cachagua]

Any non-Dura-Ace 8-speed shifter will shift a 7700 rear derailleur over an 8-speed cassette.


??? Not a competing brand, you mean another Shimano? For example, I could use an Ultegra 8-spd downtube shifter and a 7700 rear drlr and get correct indexing?

And do you mean, a 7700 downtube shifter would not work?

[Tandem Rider]

No, 7700 has 9 cogs in the same space as 74xx has 8 cogs. Therefore the cogs are spaced differently on 8 speed and 9 speed cassettes and the shifters pull less cable per click on 9 speed.

If you want to use your existing wheels with your 7700 der, any other 8 speed Shimano shifter will do it, OR, replace the 8 speed cassette with a 9 speed which will let you keep using 7700 shifters. This may be cheapest and easiest solution.

[oldpotatoe]

My question basically is, is Dura Ace 9-speed just Dura-Ace 8-speed plus one more cog?

Practically, I want to know if I can use a 7700 rear derailleur with 7700 shifters and get correct indexing/spacing on 8-speed cassettes, simply by excluding the lowest gear position with the limit screw. In other words, does 9-8-7-6-5-4-3-2 equal 8-7-6-5-4-3-2-1? Or not?

Or, is there another combination of any shifter with a 7700 r. drlr. that will allow me to use my 8-speed wheels with this derailleur?

Thanks in advance.

Not. 8s spacing and 9s cogset spacing different.

Any 8s shifter including DA, with DA mounting the der cable above, rather than below, the fixing bolt or any other shimano 8s shifter, like 6400.

[Grant McLean]

Or, is there another combination of any shifter with a 7700 r. drlr. that will allow me to use my 8-speed wheels with this derailleur?


If the hub is shimano HG compatible it's the same body dimensions for 8-9-10.
The overall width is the same, cogs are just closer spaced.

You can tell if the hub has a lockring holding the cassette, it will be HG (hyper glide)
If the first cog of the 8 is threaded onto the freehub body, it's UG uniglide8
and HG cogs won't fit. You can also tell HG from UG by tooth profile,
Just google it.

As was suggested, swap the cassette for a 9 speed and you're good to go
with 7700 shifters and derailleurs.

-g

[cachagua]

I pretend to have moral objections to 9-speed, but they're just a thin disguise for my inability to count higher than 8. So I'm going to try the "7400 shifter/7700 derailleur w/ relocated cable" arrangement. Thanks, all, for your suggestions!

[PacNW2Ford]

??? Not a competing brand, you mean another Shimano? For example, I could use an Ultegra 8-spd downtube shifter and a 7700 rear drlr and get correct indexing?

And do you mean, a 7700 downtube shifter would not work?

Yes, an Ultegra, or any other non-Dura-Ace 8-speed shifter will work and as others have pointed out, a DA 7400 will work with the cable reroute.

[eak12]

The late Sheldon Brown has an excellent page explaining Dura Ace compatibility: http://www.sheldonbrown.com/dura-ace.html

Another option for you is a Shimergo with:
Campagnolo 10 shifters + DA 7700 rear derailleur + Shimano 8 sp cassette
*** Use regular cable routing for this particular setup ***

Best of luck with your project :)

[cachagua]

Sheldon! I poked around a little in his site but didn't find that page.

Most Shimano rear derailers index the same, and are equally compatible with different shifters that match the cassette to be used.

Thanks once again to all of you who've responded, I'm really psyched about putting this bike together -- it's the pearl-white Kirk formerly owned by yngpunk, some of you are probably familiar with it. And based on this information I'll be able to a) exchange all my wheels same as i do with my other bikes, and b) go solid, uninterrupted silver over the whole bike, derailleurs, brakes, post, stem, headset et cetera et cetera, which is the only look I think I could accept for this thing. So I am a very happy guy now.

All I've got to do is shop for a pair of 7700 derailleurs, but -- nothing so unhappy about that!

[cachagua]

Alright, I got a pair of derailleurs, but the plot thickens:

What I took away from our earlier conversation was that Dura Ace 8-speed and 9-speed are basically derailleur-invariant: just match the shifters to the cassette, and you're golden. This makes perfect sense -- the two derailleurs look a little different but operate essentially the same, and the brains of the system are in the shifters and the cogs.

Only, what about the bar-end shifters that claim to work with either 8-speed *or* 9-speed DA? There's a pair on eBay right now, item # 400953034755 .

Maybe it's more or less academic, but I'd like to understand this. Seems like the derailleur-invariance above, and the cross-compatibility Shimano claims for these bar-ends, can't both be true.

Or if so -- then am I back to where I started, and I can treat my 8-speed cassettes as 9-speeds minus one cog? That'll be hard to believe, but if it's true, then I'll happily ride it.

[cmbicycles]

If you switch the shifters to friction mode they would work for both 8 and 9 speed, can't see them working as indexed for both... I'm too lazy to look up the link but me thinks they are blowing smoke from somewhere below the belt.

[oldpotatoe]

If you switch the shifters to friction mode they would work for both 8 and 9 speed, can't see them working as indexed for both... I'm too lazy to look up the link but me thinks they are blowing smoke from somewhere below the belt.

What they were saying is first gen DA 9s barends, when you used a DA 8s rear der, it would shift 8s spacing. Use a 7700/6500 rear der, and it would shift 9s spacing..I think..it was 15 years ago.

[oliver1850]

The SL-BS77 9 speed shifters will shift any Shimano 9 speed RD over 9 cogs or a 740X (only) RD over 8 cogs.

There was a dedicated 8 speed DA bar end shifter. The model was SL-BS50-8. The -8 is key as these will only work with 740X RDs.

http://www.ebay.com/itm/Shimano-SL-BS50-8-8-Speed-Bar-End-Shifters-/121790533620?hash=item1c5b480ff4%3Ag%3ABwsAAOSwI-BWIrNI&nma=true&si=1S%252FDW7zq78tU35Ayr7v5Qz5WRoY%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

The BS50-8 would though shift a 9 speed RD on a 9 speed cassette, but only over 8 cogs.

The SL-BS50 shifters were 7 speed, meant to be used with all 7 speed RDs except 7400. They also came with a little plastic insert that fit into the cable groove and could then be used for six speed.

http://www.ebay.com/itm/NOS-New-Vintage-Shimano-Ultegra-Bar-end-Shifters-SL-BS50-7-Speed-SIS-Bar-con-/281811808090?hash=item419d4aef5a%3Ag%3AMs8AAOSwKIp WCK1l&nma=true&si=1S%252FDW7zq78tU35Ayr7v5Qz5WRoY%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

The SL-BS64 shifters were for 8 speed RDs other than 7403. You can also use a 9 speed RD with them for 8 speed setups.

[cachagua]

How do you guys KNOW these things? That's awesome.

Thank you, I'll be looking for some BS64s. Or some plain old 7402 downtube levers.

It's winter now, according to my ride thermometer, and just to make things more interesting I'm moving. So it may be some time before I get this new bike on the road. But thanks to all who've offered guidance.

[oliver1850]

If you want to run DT shifters with the 7700 RD on an 8 speed cassette, you want SL-6401 or SL-1056, not 7402s. I think 105 and Ultegra were the only other 8 speed shifters, RSX and RX100 stayed 7 speed.

PS, I shoveled snow for several hours yesterday. The off-season is here.

[sjbraun]

'The SL-BS77 9 speed shifters will shift any Shimano 9 speed RD over 9 cogs"

Will the SL-BS77 shifters shift 9 cogs with an XT (M-737) 8 speed RD?

Thanks

[oliver1850]

I'm pretty sure I have BS77s and an M735 on a gravel bike, and it works fine. M737 should be fine as well.