SRAM Red RD with 28t cassette

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NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

I have just switched to a 28 tooth cassette with my SRAM Red RD (original series) and am having trouble dialling it in. The 25 shifted perfectly. Chain is the same and there was enough length that I can just run big big. After adjusting the B adjustment screw so the derailleur clears the 28 the derailleur will have trouble dropping into the 11. If the cable tension is reduced to drop into the 11 quickly the shifting and running in the top three sprockets is awful.

Hanger is straight. Cables and housing are smooth, limits are correct.

I notice that on the newer SRAM Red (Yaw) series the derailleur description says improved clearance for 28 tooth cassettes. Is this a know problem. Anyone have this problem and have a fix?
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

by Weenie


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aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

You can stick a washer under the mounting bolt for the rear derailleur to move the whole derailleur assembly over a bit, which gives it a bit more clearance.

You could also check if your frame has different rear derailleur hangars for larger tooth counts - Specialized has a longer hangar for instance - my SL3 tarmacs had the exact issue you describe with the shorter hangar.

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

I have a new and an old one, both on 11s drivetrains, and the new one is perfect even on an 11-32 cassette, while the old one is hard to dial in on 11-28.

I'll probably try the washer trick too.

UpFromOne
Posts: 1181
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

IIRC, the old version of that derailleur was only rated to 27t, but maybe that wouldn't factor into the travel?

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

aaric, thanks, it is a SL3. I will check which hanger it has (long or short) i hadn't even thought of that. The washer behind the derailleur bolt has been tried and didn't help. Thanks to all responders.
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

diopena1
Posts: 2
Joined: Fri Jul 08, 2011 2:16 am

by diopena1

NiFTY wrote:I have just switched to a 28 tooth cassette with my SRAM Red RD (original series) and am having trouble dialling it in. The 25 shifted perfectly. Chain is the same and there was enough length that I can just run big big. After adjusting the B adjustment screw so the derailleur clears the 28 the derailleur will have trouble dropping into the 11. If the cable tension is reduced to drop into the 11 quickly the shifting and running in the top three sprockets is awful.

Hanger is straight. Cables and housing are smooth, limits are correct.

I notice that on the newer SRAM Red (Yaw) series the derailleur description says improved clearance for 28 tooth cassettes. Is this a know problem. Anyone have this problem and have a fix?



I chased this unicorn, and managed to get it to work. My setup is a 10 speed Yaw, and its on a Cannondale Supersix. Now, Originally I was running a Dura Ace cassette (11-27) without issues on my 11 spd compatible freehub. I did some scrounging about, and found out that there was a difference in the cassette spacing for Sram, after changing out the Dura Ace for a new xg1090 11-28. Now, I also have the short rear derailleur, which has been rated to handle a 28t cog max... My fix however took me down the "rabbit hole", I ended up getting a thicker spacer (1.8 instead of 1.7mm), B screw was adjusted a bit, and it's working, just not as smooth as my 11-26. Spacer cost me all of $6. In your case, I'd suggest getting the longer hanger, as it will move the derailleur down a bit, thus, allowing easier mobility into a bigger cog. This is the same theory behind running a Medium derailleur cage. Extending the derailleur arms reach, allows you to run the larger cogs easier.

rpenmanparker
Posts: 216
Joined: Wed Dec 29, 2010 1:47 pm

by rpenmanparker

aaric wrote:You can stick a washer under the mounting bolt for the rear derailleur to move the whole derailleur assembly over a bit, which gives it a bit more clearance.

You could also check if your frame has different rear derailleur hangars for larger tooth counts - Specialized has a longer hangar for instance - my SL3 tarmacs had the exact issue you describe with the shorter hangar.

I only use 26-tooth largest cog Red cassettes, but I also had a similar problem of not being able to drop the chain onto the smallest cog with a new, replacement cassette even with the high limit screw all the way out. Manufacturing defect in the width of the cassette? I don't know what it was, but I found the spacer trick mentioned above to work great. I put a 2 mm washer between the RD and the hanger and voila, shifting to the smallest cog was fixed. Still plenty of derailleur travel to also get up on the largest cog at the other end after resetting the low limit screw. Works great.
Robert

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Hmm I think I'll try a smaller top pulley, have one sitting around.

Rascal
Posts: 273
Joined: Fri Sep 15, 2006 9:20 pm
Location: California, USA

by Rascal

I've just finished setting up my 2004 TCR running Red with a DA 11-28. I used a 1mm washer behind the rear D, also using Wheel's Manufacturing hanger and a KMC 11spd chain. No problems with bike in stand; need to get out and test it on the road.
-Giant TCR
-CAAD5
-Klein Rascal

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

Yep, spacers behind the RD works.
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addictR1
Posts: 1878
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

Marin wrote:I have a new and an old one, both on 11s drivetrains, and the new one is perfect even on an 11-32 cassette, while the old one is hard to dial in on 11-28.

I'll probably try the washer trick too.


how did you get the old RED RD to run 11/32? when i tried.. the jockey would be so close to each other that it's mushing the chain in between.

NiFTY
Posts: 1493
Joined: Sat May 26, 2012 11:26 pm

by NiFTY

I think the problem is also the geometry of the RD body rather than just cage length and upper pulley clearance. I have a wifli cage to run an 11-30 ( think the long cage seems to make it shift more reliably than my old sram red black as there is so much chain take-up capacity.
Evo 4.9kg SL3 6.64kg Slice RS 8.89kg viewtopic.php?f=10&t=110579" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

addictR1 wrote:
Marin wrote:I have a new and an old one, both on 11s drivetrains, and the new one is perfect even on an 11-32 cassette, while the old one is hard to dial in on 11-28.

I'll probably try the washer trick too.


how did you get the old RED RD to run 11/32? when i tried.. the jockey would be so close to each other that it's mushing the chain in between.


I didn't?

addictR1
Posts: 1878
Joined: Sun Jun 10, 2012 1:11 am

by addictR1

marin, guess i misread.. thought you had tried the washer trick to get the 11/32 to run on the red RD.

I was able to get the Ultegra 6700 - 12/30 to run with Red RD (10sp)

by Weenie


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