Sunday, October 5, 2014

How to Adjust SRAM XX1 Rear Derailleur

The most common adjustment need to be done regularly for mountain bike is rear derailleur. Periodic maintenance and adjustment will enable our rides to be smooth and fault free. SRAM XX1 Rear Derailleur is designed for ease of maintenance and adjustment. All you need to remember are 4 adjustments:
(1) b-adjust screw - to adjust the space between pulley and socket (Photo 01)
(2) H-limit screw - to adjust the outer limit of the smallest socket (Photo 01)
(3) L-limit screw - to adjust the outer limit of the largest socket (Photo 01)
(4) Barrel adjuster - for fine tuning (Photo 02)

 (Photo 01: SRAM XX1 Rear Derailleur b-adjust screws)

(Photo 02: SRAM XX1 Barrel Adjuster)

(1) Adjust space between pulley and socket
Shift the chain to the largest socket. Refer to Photo 03 & 04, use a 3mm allen key to adjust the space between the pulley and socket to about 13mm. Too wide space will cause delay in shifting, whereas too near will cause harsh shifting. Play with the distance (12mm to 15mm) to identify the ideal space for your bike. If you are unsure, adjust to recommended 13mm spacing.

(Photo 03: SRAM XX1 b-Adjust Screw)

(Photo 04: Ideal Space Between Pulley and Socket = 13mm)

(2) Adjust outer limit of the largest socket
Ensure the chain is on the largest socket. Adjust the L-limit screw (see photo 05) with 3mm allen key to align the pulley with the largest socket. I usually spin the crank with one hand and adjust the L-limit screw with another hand concurrently. Adjust the L-limit screw until you hear and see the chain run smoothly over the largest socket. Once that happen, the largest socket will be aligned with the pulley. The chain will fall out of the largest socket if the L-limit screw is over adjusted, or gear down to the lower socket if under adjusted. 

(Photo 05: SRAM XX1 Rear Derailleur High-limit Screw)

(3) Adjust outer limit of the smallest socket
Shift the chain to the smallest socket. Adjust the H-limit screw (see photo 06) with 3mm allen key to align the pulley with the smallest socket. I usually spin the crank with one hand and adjust the H-limit screw with another hand concurrently. Adjust the H-limit screw until you hear and see the chain run smoothly over the smallest socket. Once that happen, the smallest socket will be aligned with the pulley. The chain will fall out of the smallest socket (between smallest socket and bike frame) if the H-limit screw is over adjusted, or gear up higher socket if under adjusted. 

(Photo 06: SRAM XX1 Rear Derailleur Low-limit Screw)

(4) Fine tuning
Spin the crank and play with the rear shifter to see if the chain shift smoothly and precisely across all sockets. If there is any delay in up or down shift, fine tune it by rotating the barrel adjuster (see photo 07). The barrel adjuster basically adjust the tension of the shifter cable.

(Photo 07: SRAM XX1 Barrel Adjuster)

If you perform the above 4 adjustments correctly, the gear shift should be smooth and precise. If you still unable to get it done despite performing the above 4 steps, you may need to tighten or replace the shifter cable. Otherwise, the hanger or the derailleur cage may be twisted. Other possibility may include loose chain, test it with a chain gauge (seldom the case if you have set up properly in the first place).  

(Table: SRAM XX1 Rear Derailleur Troubleshooting)

The above table illustrates the problems, possible causes and remedy actions (Source: SRAM Service Manual).

17 comments:

  1. Thanks, good to know the 13 mm gap is required.

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    Replies
    1. You are welcome. Glad it helps.

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    2. For the b-screw adjustment, Im confused on how to measure such a fine gap when youre talking mm? And is it from top of pulley to tip of large cog or from top of chain running over pulley to tip of cog? Thanks

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    3. The distance between the tips of largest cog and pulley. You may want to use vernier calliper to measure if you were unable to do it with ruler.

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  2. Great article, and spot on for hardtails. But for dual suspension, particularly those with longer rear travel, it's best to remove air form the shock such that the shock lowers down to the % sag value the rider uses. ONLY then, do they follow these instructions.

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  3. I think you have the H and L screws referring to the wrong sprockets (cogs) in your descriptions. H is for the smallest, L for largest

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  4. did someone here notice a weird feel while pedaling on the 12T and 14T cogs?

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    Replies
    1. What kind of weird feel?

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    2. like the contact with the chain and cogs is not perfect, its like i am feeling the bite on the cogs while pedaling. everything is new i also ran an XX1 chain. I check my XTR BB92 and I cant find any problem. I ran a raceface 32T NW on a XT 2X crankset.

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  5. Chris, this is great information, but you have the "H" and "L" adjuster screws the wrong way round:
    "H" = High gear or "Hardest Gear" or smallest cog.
    "L" = Lowest Gear or Biggest cog

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    Replies
    1. My bad, error amended. Thanks.

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    2. Actually, I think the photos are still wrong. The outside screw adjusts low. Inside adjusts high.

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  6. There are some photos on SRAM's service manual page. I think the High adjustment photo is wrong on that page though. https://sram-cdn-pull-zone-gsdesign.netdna-ssl.com/cdn/farfuture/-Vkw_ydeVVRl5A_2nKCOtSdWbesZaa6f3LuYFvH7qHQ/mtime:1434749969/sites/default/files/techdocs/95-7618-001-000_reva_mtb_derailleurs_emanual.pdf

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  7. So does anybody have any idea which is the L screw and which is the H?

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  8. Here you can see in practice:
    https://www.youtube.com/watch?v=ajZAcRP0euI

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