upup

Far from knowledgeable when it come to bike mechanics but the above setup seems to working great. In a foreign country and somehow the fact I wanted a 10 speed cassette was lost in translation. I didn't notice until days later because it shifted great and it has the standard cable routing.

The cable lost some tension and it stopped shifting into the small cog but after tightening it again shifted almost flawlessly. I think the xt cogs are slightly thicker than the road bikes. Maybe this reduces the variance???

Even though I'm more than satisfied with the shifting, is there something I should be aware of? For example, are the pulleys not aligned perfectly after shifting which creates friction. They sure look to be aligned perfectly.

I have a race in a few weeks with a 7,500 climb at the end - hence the new 11-34 cassette. Would hate to be losing power because of pulley alignment issues if that is even possible

cyccommute 

It should shift perfectly. If it isn't, you should try tuning it again. There should be no issues.

Shimano road and mountain bike rear derailers used to share the same amount of cable pull which made them cross compatible. A 10, 9, 8, 7, or 6 speed STI will shift any 9, 8, 7, or 6 speed mountain bike rear derailer on any cassette as long as the cassette matches the shifter. 6, 7 and maybe 8 speed STI shifters are even cross compatible on their respective cassettes. In other words, a 7 speed shifter will shift a 6 speed cassette with an extra click left over. (You could even shift a 7 speed cassette with a 6 speed shifter but you'd have an extra useless cog.) An 8 speed shifter might do a 6 but it can be dicey.

Shimano, in an effort to keep us from using their equipment in a way that they don't like, has decided to make Dynasys incompatible with their road line, however. That means that the 10 speed mountain equipment can't be used with 10 speed road equipment. They'll probably do something go the road line soon. That leaves people who what wide range gears on road bikes in the lurch.

shelbyfv

Apparently OP is using a 10 speed shifter with a 9 speed cassette. Interesting that it works!

bradtx

upup, I have the same thoughts as above in post 2. The major friction in the system will be the chain's angle of engagement between the front and rear. This is visable at the tension pulley and top of the rear cog. Excessive friction can sometimes be heard and felt when the bike is on a repair stand (or upside down on the ground) and the crank is used to turn the rear wheel with a bit of load applied from the brake.

From your description, you're fine.

Brad

bradtx

I took it for granted the this had been rectified, perhaps I shouldn't have.

Brad

shelbyfv

Yes, I think that is his point. It shouldn't work but apparently it is.....

upup

It hasn't been rectified It even gets worse. I liked the new setup during my big climbs the following three days and decided to get 11 34 put on another wheel before realizing they were 9 speed. Now I have 2 wheels with 11 34 XT MTB 9 speed cassettes with 10 speed dura ace shifters. I don't get it but it seems to work great.

Dave Mayer

This part makes me nervous. I seem to have become the 'bike guy' at work. Folks bring me their bikes on a regular basis with issues. I always check their shifting and even if they say it is no problem, I am regularly amazed and appalled with what I find.

Last bike I checked out was a high-end Wilier road bike. Owner thought he had a flat spot in the rear wheel, but I checked the shifting anyway.

There was so much cable slack in the rear shifter that the owner could not shift into the top 3 cassette cogs. Owner never noticed . He made some vague comments about finding it hard to climb, but never made the connection. Further, the cable tension was so far off that the derailleur was constantly randomly clattering over the cassette. If it settled into a gear is was just by chance. To most folks, continuous clattering, grinding and skipping coming from the back of the bike is just unavoidable business as usual. To most of my 'clients', the barrel adjuster on the derailleur is as mysterious a device as the circuit board on their computers.

OK. To the point. Shimano 10-speed road shifters and non-Dyna-sys derailleurs will NOT index properly with a 9-speed cassette. A properly configured indexing drivetrain will shift perfectly every time. No hesitation. No overshifting. No undershifting. No clattering or noise coming from the cassette while running. It will be dead quiet except the 1/10th of a second during shifting.

Do you have 10-speed road shifters with a Dyna-sys rear derailleur and 9-speed cassette? Perhaps this is some weird configuration that just works by chance. I don't know, or I haven't run the numbers. But I recommend you do some more research.

upup

Dave - Thanks for the comment. I'm nothing like the customer you mentioned. Don't take this as bragging but just want t give you some perspective. I'm an excellent climber that knows how to utilize gears. I'm not a perfectionist, prob should be, and almost perfect shifting doesn't bother me.

With your knowledge, you can definitely help me out. If it is shifting through all the gears and the pulleys look to be aligned visually, there isn't any power loss in the drive train?

The Dura ace 10 speed shifters are 5 years old and the rear dr is long gage 9 speed XT ( assume it isn't dyna-sys because it is 9 speed), and the 9 speed casette is MTB XT 11 32.

Thanks for your input! I'm racing today and will see how it all works with higher power output.

Kimmo

No it shouldn't.

Shimano's 7s spacing is 5mm, same as Campy's 7s and 8s spacing.
Shimano 8s is 4.8mm.
Shimano 9s is 4.34mm.
Shimano 10s is 3.95mm. So you're getting a 0.39mm overshift per cog, which could be hard to see over one shift, but even if you've adjusted it as well as possible, you're still out by over a mm at each end, which should make for sluggish shifting on the edges towards the centre of the cassette, not to mention creating wear on the jockey wheel and contributing drag.

Shimano was finally forced to make a long-overdue revision to their derailer geometry to increase cable pull because their stupidly short 10s cable pull as seen on road gear is completely unworkable with full-length gear housing like you find on many dual-suspension rigs.

This would definitely be a good thing, as long as they apply it across the board, which they haven't - I gather road derailers were revised with the 2nd-gen 10s (aero cables) ad it's probably shared with 11s, but this was in the worst way possible: not compatible with Dynasis, not meaningfully increasing the cable pull, but breaking compatibility with the old stuff anyway.

Boo, Shimano. You're losing your way.