# Rival 1 Noise in small cog



## DLHVA (Mar 1, 2017)

Just finished a gravel bike build with SRAM Rival 1X with 10-42 cassette. I've always been a Shimano rider, so have no previous experience with SRAM or 1x. Everything worked out fine except a have a little drivetrain noise, but only in the 10T cog. All others are extremely quiet. It almost seems like a chainline issue, rather than RD adjustment. Works great in all other cogs, including 42T. It also acts up if I back pedal in in the 10T cog. Chain does not derail, but gets very rough. I gone over the RD settings a bunch of times and cannot get it right. I admit that I 'm not very familiar with SRAM, especially the clutch RD's. One other difference is that I'm running an Absolute Black direct mount chainring on a Rival 1 crank arm -- no spider with this setup. I wonder if this changes the chainline and might require a crank shim to make it better???


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## aussie_yeti (Feb 9, 2006)

High limit screw could be too far in. Put the bike in the stand and pedal with chain in 10 cog. Back the high limit screw out slowly as you pedal. See if the noise changes. Find the quietest spot.

B tension. I find SRAM a lot more sensitive to B tension than Shimano. Check SRAM specs but I believe with a 42 cog and Rival 1 derailleur you need 12mm between 42 cog and upper jockey wheel. Chain length is also critical. Big-big plus 4 links for Rival1 derailleurs. The offset upper jockey wheel is what maintains distance from the cogs as you shift down the cassette (as the derailleur body only moves horizontally, not vertically). But if it works out that you're chain length falls at 3 or 5 links, or your derailleur hanger is longer or shorter than average you'll get a funny gap between 10 cog and jockey wheel. So do the same thing. Bike in stand, pedal, slowly release b tension. See if it gets quieter. Just make sure you then recheck that the jockey wheel isn't now too close to the 42 cog when you shift back up there. It's about finding a happy middle point.


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## DLHVA (Mar 1, 2017)

aussie_yeti -- thank you for the great info!!! I'm out of town for a couple of weeks on the road bike, but I'll try your suggestion on the gravel rig when I get back. Thanks again!!!


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