dgsca

As I understand it, you can use DA 9 speed brifters with an otherwise DA 8 speed drive train.

I would like to change from DT shifters to a brake/shifter combo.

First choice would be to find 8 speed DA brifters (good ones are rare), second (?) is to locate DA 9 speed brifters (expensive but more available) and the last option it to try the 9 speed Microshift brifters.

The Misroshift brifters are available and pretty cheap by comparison. The reviews are generally positive.

So, will the Microshift 9 speed work with an otherwise DA (7400) 8 speed drive train?

Are there any options I've missed?

Thanks to all. dgsca

nwbikeman

Spacing is different on the 9 speed shimano. I would keep it 8 speed so the rest of the drive train doesn.t have to be replaced as well, deraileurs, cassette,chain and crankset. You can get bar end shifters for about $100, but there are Shimano RSX, RX100 105,600, and dura ace shifters in 8 speed. I have been told many times that Dura-Ace only works with DA because of a different throw ratio but it seems to work with other Shimano shifters just fine.

desertdork

If you're using a 74XX rd, then (according to Sheldon) you can use any Shimano or Shimano-compatible 9-sp shifters with your 8-sp cassette. I haven't tried it, nor do I now anyone who has.

https://www.sheldonbrown.com/dura-ace.html

Steev

If that's right about using 9 speed shifters, you can use new Sora or Tiagra shifters.

cappuccino911

you can use any 9speed shifters with the alternate cable routing. I did it with 9 speed microshift shifters for a few weeks and it worked fine. Eventually I swapped casettes and went to 9speed. if you look around enough, you may find some 8 speed microshift brifters.

Al1943

Actually you can use any 9-speed Shimano shifters with your D-A 8-speed as long as you are also using the D-A 8-speed rear derailleur. Shimano 9-speed shifters have the same cable pull as 8-speed D-A. The D-A rear derailleur actuation ratio is unique.
Do not use the alternate cable routing with this setup.

It's all explained on this chart: https://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946 Scroll down to Shimano mechs.

I don't know about the microshifter cable pull, but I do not believe you would want Shimano 8-speed microshifters. If the Shimano 9-speed Microshifter has the same cable pull as the STI 9-speed shifter it should work with your D-A 8-speed rear derailleur.

dgsca

To recap all the good information thus far: It appears I can use either a DA 8 speed brifter with the 7400 RD Or any Shimano 9 speed brifter. Following said, it would be logical the 7400 RD would operate with either of the "new" 9 speed "compatible" brifters currently on the market.

An added factor: The current rear hub is a Shimano 105 cassette that can be used as an 8 or 9, maybe even a 10. I assume thekey to how many speeds is dictated by the spacers used between the cogs.

On one of the charts from https://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946 it gives the pitch, or center to center dimension for various speeds. The 8 speed pitch is 4.8 mm while the 9 speed is noted as 4.35 mm. Again, I assume the pitchis dictated by the spacer thickness between the cogs.

As recall from the original stacking (its been a few yeas) there is a spacer between each cog except the bottom two. The bottom cog has a built in spacer that adds threads for the final assembly.

So, I believe it will necessary to change to a thinner spacer and/or bottom cog to bring the cassette pitch in spec with a traditional 9 speed. Will the new cassette pitch require a narrower 9 speed chain?

I'm getting close to having my head wrapped around this issue, but I'd like some conformation before I make any purchases. Thanks to all for your input.

dgsca

cappuccino911

I already told you, I used a microshift 9speed shifter with a shimano 2200 RD and an ultegra RD and it shifted fine for me. go for it, or just upgrade to 9 speed.

Al1943

I don't think you quite understand. If you use a D-A 8-speed shifter or any Shimano 9-speed shifter with your D-A 8-speed rear derailleur the pitch will be correct to match the spacing on any Shimano 8-speed cassette. In either case you will be able to use only an 8-speed cassette. With the 9-speed shifter you will have one extra unusable click stop.

If you want a 9-speed cassette you will also need 9-speed shifters, rear derailleur, and chain. With 10-speeds you will need 10-speed shifters, cassette, and chain and either 9-speed or 10-speed rear derailleur.

Re-spacing an 8-speed cassette to a 9 or 10-speed cassette is not practical and would probably cost more than a new cassette if it is even possible. Further, most cassettes have the larger cogs pinned together on a common carrier and cannot be re-spaced or used as individuals. And Shimano does not sell individual cogs.

Al1943

He has an 8-speed D-A rear derailleur. With it a 9-speed Shimano shifter will work perfectly with the normal cable routing.

DannoXYZ 

Did you read the OP's post? He's using a Dura-Ace RD, NOT Shimano 2200 RD. The Dura-Ace 6/7/8-spd shifters pull less cable per click than other Shimano 6/7/8-spd shifters.

Do you understand the purpose behind Sheldon's alternate cable routing? What the alternate cable-routing does is moves the non Dura-Ace derailleur more than the Dura-Ace 6/7/8spd-shifter allows with the shorter cable-pull. So there are only TWO instances where you can use the alternate cable-routing:The OP doesn't have any of these two conditions. He's got Dura-Ace 8-spd RD. As it turns out, the shorter cable-pull of 9-spd shifters matches the cable-pull of Dura-Ace 8-spd shifters. So... this 3rd condition will work:All he needs to do is get a 9-spd brifter and it'll shift his Dura-Ace RD across 8-spd cluster just fine. The 9th-gear position will just be locked out by the inner limit-screw.