QUESTION: Can I Use 9-Speed Derailleurs with 10-Speed Shifters?

You CAN however, use SRAM 9 speed derailleurs with Dynasys shifters. The pull ratio is the same strangely enough. Been doing it for a while no problems to speak of.

I do, on a road bike though 😀

If you have Shimano Mega 9 why would you want to switch to Shimano DynaSys 10? Oddly enough the nine cog system has a wider gear range then the newer ten speed system because Shimano had to compromise and drop the 44 tooth large chain ring to a smaller 42 tooth gear system in order to give the rear derailleur enough chain take up to shift to the larger 36 tooth rear cog.

So really Shimano’s new DynaSys 10 is a compromise system that is trying to accommodate both the 26er and the 29er crowd. The 26er crowd lost top end speed with the loss of the big 44 tooth chain ring and while with the larger 36 tooth cog the 29er crowd gained a little but it is still not a low enough gear ratio to replicate the low gearing of 24/34 geared 26er.

I think the only winners with Shimano’s DynaSys 10 are riders that run a twin chain ring set up who never break 40 kph. But really, who wants a mountain bike that can’t break 40 kph going down a hill? Going fast down the hills is one of the greatest pleasures of mountain biking and Shimano killed it!

@alloycowboy

you do get 42T instead of 44T in the crankset, but you also get 36T instead of 34T in the cassette. 42/36 gives actually gives you a lower ratio than 44/34. Moreover, the differences in ratios between gears are smaller which is perfect if you care about cadence. So IMHO it does make sense.

@DasBike – 9-speed and 10-speed chains (Shimano/SRAM, not sure about Campy) both have the same width between the inner plates, thus chainring thickness can be the same for both 9&10-speed. Plate thickness is where the 10-speed chains become a bit thinner.

going from a 44 to a 42 chainring you only lose 4 gear inches.

I personally like dyna-sys. The 11-36 cogset gives me enough range to run a single 36 or 38 ring and still make it home in one piece. By the way, the Shadow Plus XTR derailleur is probably the best mechanical derailleur to come out of any of the three companies in a long time.

Also honestly, nothing is stopping you from swapping the 42 to a 44 if you really need that extra gear or you can spin your legs a bit faster

Ryan – 10/19/11 – 10:46am

You CAN however, use SRAM 9 speed derailleurs with Dynasys shifters. The pull ratio is the same strangely enough. Been doing it for a while no problems to speak of.

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Hold the phone? Really, this works? Awesome if true!

dynasys shifter + sram 9v rd = ok
sram 9v shifter + dynasys rd = ok
yes,it really works…you can mix shimano x sram and use the best of both worlds…

Here’s a question: are there any cassettes that don’t gouge the F out of my freehub bodies? XX cassette I imagine is one, since i hear it drives off the big 36T cog, considering it’s usually the smallest 3-4 that gouge.

So if I have a SRAM X0 9spd RD, I can upgrade to 10 spd by simply getting a dynasys rear shifter, 10 spd cassette, and 10 spd chain?

@ Rommel Timonera,

I know it’s a little bit of grave digging…but,

This was discussed on various forums including PB which I was in.. Long story short, YES
a 9-Speed X-Series (x5+) or X.0, will work with a Zee 10spd Derailer. There’s a video on Youtube too showing it works fine and appears to shift very decently. It was recommended that a 6mm Spacer be put between on the attaching hanger screw (to space out further)to really fine tune it but seems to work good regardless.

Also, I haven’t seen anyone try it with the M820 Derailer, but gonna be getting one soon and will try it out to a X9 Shifter.

All I can say is Shimano made it impossible to run 10 speed mountain mech with 10 speed road STI levers by changing cable pull rates (which they didn’t need to do). Cross platform compatibility was always Shimano’s strong suit. Then they messed with it for no good reason. Now it’s a science project. We expect that from Campy.