30T cassette with Dura Ace rear der?

[BoulderGeek]

On another thread I started here, I was advised to get a Sheldon Brown custom 12-30 cassette for my Shimano 9-speed travel bike for the Alps.

I just installed it, with a new SRAM 9-speed chain.

In the 30T big sprocket, the top jockey pulley makes noise as it sandwiches the chain. I have fiddled with the dérailleur's set screw to let the body slide forward a bit. Still, it feels rough and unhappy in the 30T.

Can a standard DA rear der take a 30 tooth sprocket, or is 29 the max?

[davep]

Don't know about a DA, but it works fine with an Ultegra.

[BdaGhisallo]

I always thought that 27 was the max for the DA rear derr. Looking in my Shimano catalog I see that they now have two DA rear derrailleurs, a short and a mid cage. The max for both is quoted as 27T. I am sure that the max is derived from the angle of the parallelogram that describes the movement of the rear derr as it shifts up the cassette. As it shifts in toward the larger cogs, it also moves down, so I guess it only moves down enough to allow for the vertical height of a 27 cog. I think you are out of luck with the setup you are looking at.

Reinforcing this is the fact that shimano doesn't make any road cassettes with a top cog bigger than 27T.

[BoulderGeek]

Thanks for the input.

I wrote to Sheldon. We'll see what he says.

Guess I could go XTR and up to a 34. That's not a very "roadie" look.

[Johny]

Guess I could go XTR and up to a 34. That's not a very "roadie" look.

It's very MRB looking.

http://forums.thepaceline.net/attachment.php?attachmentid=11737&stc=1

[BarryG]

I always thought that 27 was the max for the DA rear derr. I am sure that the max is derived from the angle of the parallelogram . . .I think the max is derived from Shimano only offering 27T max size road cog. I've got a beater bike with 105 RD (spec'd "27 max") and works fine with 12-32 cassette.

[rdparadise]

on my Litespeed triple too! It works great, no problems in the rear at all with the XTR.

Bob

[eddief]

da 9 with 30 tooth cog. i finally got it adjusted to where it worked ok, but never perfect. been on mt rear derailleurs and big cogs sets ever since.

you could stick with roady look and invest in compact crank. ritchey splined compacts can be had for a song and a half.

[Too Tall]

I am not looking at the spec. however I recall that the rear cage needs to be in the 89mm range...maybe I'm wrong. However what need is Ultegra. Your rig will be perfect with that.

[dirtdigger88]

It's very MRB looking.

http://forums.thepaceline.net/attachment.php?attachmentid=11737&stc=1

yes very MRB indeed-

I took my ques from Johny . . .

http://forums.thepaceline.net/attachment.php?attachmentid=23858&stc=1

jason

[Serotta PETE]

Think this bike flew past me in AUGUST at the RAMBLE :D :D

It's very MRB looking.

http://forums.thepaceline.net/attachment.php?attachmentid=11737&stc=1

[BoulderGeek]

OK, good info, thanks.

Sheldon said to amp up the "B-Tension" set screw to move the pulleys away from the largest cog. That did help a bit.

I went for a ride with lots of climbing last night. While riding, I couldn't tell that there was tension between the upper jockey pulley and the 30T cog.

On the stand, there is only a slight clicking when in the 30T cog and the 39T small ring. Surprisingly, in the big ring, the pulley cage is at a 50 degree angle and there is no pressure.

So, it is only in one gear that I have issues. Since I just paid $80(!) for the cassette, and used it, I guess it will be fine.

So, a derivative question for you XT rear der folks: can I use a newer Rapid Rise XT der with Dura Ace 9 brifters? Does the spring tension pull direction make any difference?

Update: I do hope the XT der that I have will work. I just bought a 9-speed 11-32 cassette. We'll try both, and see where the best feel and function comes out.

[Too Tall]

If you can take a link out than do it. Sounds like you are close.

[dirtdigger88]

I dont see HOW a rapid rise could work with brifters----

downtube sure-

I could be wrong- but I dont think I am

Jason

[BoulderGeek]

Well, we'll see. It's got to be a coin toss.

Regular (small-normal) and Rapid Rise XTR ders with the same Rapid Fire trigger shifters, after all.

[BoulderGeek]

If you can take a link out than do it. Sounds like you are close.

I popped 2 (or 4 depending on how you look at it) links out of the chain already. Hope that wasn't too many for a 32, now.

[Johny]

I dont see HOW a rapid rise could work with brifters----

downtube sure-

I could be wrong- but I dont think I am

Jason

Jason,

The XTR RD on my Kirk is rapid RISE. It works fine; you just have to get used to it.

John

[BoulderGeek]

Oh, so it does reverse the shifting order of the levers, eh?

Oh, well, one bike is Campy, one Shimano. I'm always adjusting when I go between them.

Thanks for the confirmation, Johnny!

[BoulderGeek]

Bump my thread! :rolleyes:

I just popped on the XT RapidRise rear der with the 12-30.

It naturally has none of the closeness friction that the DA had with the 30T cog.

Shifting is fine, not as dialed in as the DA, but I might be able to tune it closer. The Rapid Ride does insert some sloppiness into the shifts from smaller to larger cogs. And I can only downshift one click at a time. On the upside, a long throw of the Dura Ace lever will dump 4 sprockets if I want.

Next we'll see how I like it with a new 32T mountain cluster.

I just fitted a seatpost pannier rack with panniers for the three weeks that I'll be noodling about in Belgium and Italy with this bike. So, with extra weight, I think I'm going to want some real low gears.

By this time, going to a triple might have been the smarter move.

[BoulderGeek]

My poor thread.

It's all neglected.

This can be the last post.

My testing showed that going to a 12-32 SRAM 970 aluminum cassette was the best choice. Paired with the XT rear der, it is smooth, quiet and has the range I need.

Looks a little funky, but it was cheap and light.

Next stop, Galibier.