SRAM Force/Type 2 shifting issue

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Guy

by Guy

I've got SRAM Force 10spd shifters along with an X9 short-cage clutch rear mech, 11-28 cassette and 39T Absolute Black narrow/wide chainring. Chain is shortened using the +4 links method. I can't seem to get the shifting spot on and read somewhere this might be down to the inability to get the jockey wheels close enough to the cassette despite winding out the B-tension screw. Would a larger upper jockey wheel help?

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Firstly an aside - sure your narrow/wide ring is 39tooth? An odd numbered tooth count means either consectutive narrow or consective wide teeth in a row which wouldn't work.

I've played a lot with this. I've not tried a larger jockey wheel. A larger jockey wheel in theory would help, but it'd have to be big enough that it takes up the difference between a 28 tooth cog and a 32 tooth cog. I suspect that'd be too much and you'd run into other issues. I gave in and just ran an 11-32 cassette. If you do try it with a bigger jockey wheel be sure to report back.

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Guy

by Guy

Sorry, chainring is a 38T.

The SRAM manual states to get the jockey wheels within 6mm of the cassette but I probably have double that (on all ratios). Why would changing to a 32 alter the gap on the other ratios? Can the X9 short cage handle a 32?

Thanks.

Briscoelab
Posts: 1513
Joined: Thu Jan 26, 2006 6:01 pm

by Briscoelab

Short cage should handle the 32T OK.

What do you mean by not "spot on"?

Hesitation in one direction or the other? Chain skipping?

Did you install an inline adjuster? Since the MTB RD doesn't have a tension adjuster, this will help dial in cable tension.

Guy

by Guy

Yes, I've installed an in-line adjuster.

I can't get it to index sweetly. If shifting up is OK then coming back down the cassette is hesitant. And vice-versa.

The dropout on the frame was slightly bent in a crash previously but I've had this straightened and checked. Shifters, mech and cables are new.

I just wanted to know if this was a common issue or particular to my setup.

Briscoelab
Posts: 1513
Joined: Thu Jan 26, 2006 6:01 pm

by Briscoelab

Any chance you can get a new der hanger? What you are describing does often happen from an out of alignment rear end/hanger. You can get it good in one direction, but not the other. Then if you fine tune it for the other way, the opposite direction isn't smooth.

Also, check your cable runs. Extra cable friction can cause problems when switching to smaller cogs.

I've found my type 2 setups to work pretty well overall. You probably have a few small issues that are working together against you.

Guy

by Guy

Cheers. I think my cable runs are fine but I'll definately get a new hanger.

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

briscoelab, what range cassette are you using?
guy, I believe SRAM mtb derailleurs call for a 12mm gap. 6mm gap is for SRAM road derailleurs.

when saying type2 we're all referring to x7/x9/x0 derailleurs that can accomodate multiple derailleurs yes? not xx1/xo1/x1/cx1 derailleurs that also have a clutch but are designed only for single chainrings as they accomodate different cassette ratios.

i've tried type2 derailleurs on various cx frames. all with hangers checked, new cables with good runs. new chains/cassettes/chainrings.
each time the cassette is 32 cog or bigger it works perfectly
if the cassette is smaller than 32 it always hesitates in one direction

i believe it's due to the position of the cage forward of the low point of the cassette cog once you bring the b-tension down far enough to get the pulley close to the smaller ratio cassette. something odd with the chain trying to shift onto the cog as the cog is rotating down not up. it just doesn't look right. this is why i say a bigger upper jockey wheel may work as it would get to the correct distance from the cassette before the cage starts to move forward of the low point of the cassette.

if you are committed to the single ring drivetrain i'd just go to a cx1 derailleur. it is for cassettes of 26 to 32 big cog, has a barrel adjuster and you get the benefit of the horizontal body movement for less noise and better chain retention.

Briscoelab
Posts: 1513
Joined: Thu Jan 26, 2006 6:01 pm

by Briscoelab

Yes, x9 and x0 type 2 is what I'm referring to.

For cassettes, it's a variety. 11-28, 12-27, and 12-30 (all shimano) 10 speed.

I've not have any issues. I think a lot could depend on dropout geometry though, if it is sensitive to gap from the pulley to cog. Although, as mentioned, that would really only be relevant in the largest cog, correct? The relative position of say a 13T cog is the same if it's on an 11-32 or a 12-27.

But, if an 11-32 makes it work better for you, no reason not to use one.

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FIJIGabe
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Location: The Lone Star State

by FIJIGabe

Before getting a new hanger, get a hanger alignment tool. I recently replaced the hanger on my road bike, and the new hanger was out of alignment. Get an alignment tool, check your current alignment (probably out of alignment) and adjust it. If that doesn't clear up your shifting, then look at other issues, including resistance or a bad cable.

Guy

by Guy

As I said, I've had both the dropout and hanger checked and fixed. A friend has a frame building business and has the various Park Tools. But I'll replace the hanger anyway as it has been crashed in the past.

Switching to a CX1 mech is out of the question - I'm not spending that amount of money on such a vulnerable component. I'll try hanger/jockey wheel/cassette in that order to see if things improve.

Thanks all.

drider85
Posts: 183
Joined: Fri Apr 13, 2007 4:53 pm

by drider85

When I set up my bike that way (really Rival X9 type 2)I followed the instructions for chain length and found it to be to short. I added a few more links and that brought the lower pulley quite a way back and up but the shifting improved. Chain tension and retention have been good as well. I did that this spring and found no down sides as of yet.

Guy

by Guy

+4 links too short? Normally the debate is about adding 2 or 4, not any more. Judging by the angle of the rear mech when using the extremes of the cassette chain length seems OK on my setup but perhaps I'm missing a trick there.

by Weenie


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Briscoelab
Posts: 1513
Joined: Thu Jan 26, 2006 6:01 pm

by Briscoelab

I always size by just putting it in the biggest cog in the rear, actually feed it through the der, and size it pretty tight in with the largest cassette I'm likely to use. I've always had good luck with this. I really dislike the +4 link method, etc. I like to see a partial "S" shape to the chain as it passes through the cage.

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