2019 RockShox Reba RL – damper upgrade/hack

Forums Mountain Bike Forum 2019 RockShox Reba RL – damper upgrade/hack


This topic contains 4 replies, has 2 voices, and was last updated by  XC Cyclist 1 month ago.

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  • #256873

    I’m back on an MTB after a 20-year period of road cycling. Just bought a new XC hardtail with a 2019 Rockshox Reba RL (100mm, 29 inch, Boost)(https://www.decathlon.fr/vtt-xc-500-29-12v-id_8518393.html).

    So far, I run with 10% sag, no token, and fully-open rebound, Which works fine for me. But I can’t tune the compression damper on the Reba RL the way I want to.

    Not locked-out, I’d like to be able to increase the compression damping ‘a bit’.

    Locked-out, I’d like to increase massively the compression damping, or even achieve a real lock-out of the damper (which the stock Reba RL doesn’t provide). Locked-out, the compression damping only increases marginally. The most notable difference the lock-out makes is increase the damper noise as the oil passes through the damper (‘squishy’ noise of the oil bubbling through the damper holes)

    Any recommendation to achieve those goals of increased damping? Maybe change the compression damper unit? or change the complete damper unit (compression and rebound) with a Charger-like unit designed for a SID fork (if compatible with the Reba)? Plug 1 of the 2 drillings in the compression damper piston? Maybe run a higher viscosity oil in the damper (which hopefully won’t slow down too much the rebound)? Any other suggestions…

    Thanks for your help

  • #256877

    It sounds to me that your damper is faulty – the “L” in “RL” designates that it should be a full lockout, rather than a slight tweak on the low speed compression as the “RC” on other forks would designate. I certainly wouldn’t go drilling holes in the damper. Return it to Decathlon for a warranty repair/replacement.

    • #256897

      Thanks Sam for your feedback.

      I actually got a first bike delivered by Decathlon a few weeks ago. I thought the Lock-out was faulty, and got the bike exchanged (BTW, the Decathlon customer service was great and very easy to deal with to organise the swap).

      A week later, I received a new bike. And the behaviour of the compression damper was exactly the same. I drove to my local Decathlon shop, and ‘pushed’ on the RockShox Reba RL they had in their inventory on similar bikes. Turns out, that none of the Reba RLs actually fully lock-up. They all felt ‘squishy’ when locked-out. And they all felt pretty inconsistent. That’s why I’m thinking of updating/hacking the compression damper myself.

      I pulled out the compression damper out of my fork. Everything looks normal. In the unlocked position, the 2 holes in the compression damper line up (between the aluminium and the plastic part). In the spring-loaded locked position, the holes don’t line-up. The o-ring on the outside of the daper seems to seal well againt the fork leg.

      My guess is that the leak between the aluminium and the plastic parts (the ones with the calibrated holes) is so large that the control of the oil flow is poor. I guess that more oil leaks between those 2 parts than through the 2 holes.

      The rest of the fork works reasonnably well. And the fork is pleasantly rigid (especially compared to simalarly-priced Fox forks). So, I’m inclined to change the damper (either the compression damper, or the complete compression/rebound unit) for a higher spec model. But I don’t know which model will fit? Charger? Charger 2? Are they available for 29″ 100mm Rebas? and especially, which damper models actually offer a ‘real’ lock-out?

  • #256898

    Huh, interesting. Previous versions of the Motion Control damper have had a full lockout. Interesting. Anyway.

    First thing to do would be to try a heavier weight oil. Obviously that will change your damping throughout the whole range, including fully open. But this is the cheapest/least destructive thing to do.

    As for the charger damper, I don’t think there’s one available for 32mm stanchion forks. That said, I’ve been wrong before.

    EDIT: yes I was wrong, the SID uses a charger. It’s not really a full lockout either, but the damping is vastly improved and is much better controlled, definitely a good upgrade if you’re thinking of doing it.

    • #256920

      Thanks Sam, I’ve found a hack that makes the Reba RL works (ish): No impact on the ‘open’ compression damping, but at least the lock-up works as intended (almost fully locks-up after 3/4mm of travel).

      I replaced the spring at the bottom of the compression damper assembly with a much stiffer spring (not quite the right dimensions, but it works). It’s the spring that maintain the blue-anodised valve closed during compression and open during rebound.

      Compression damper assembly

      Valve in open position (during rebound)

      After a ride, the modification seems to works consistently. I’ll see over time if I try with a higher viscosity oil, but I’m concerned it would slow down too much the rebound damper.

      For now, this will do the trick. I wish someone at Rockshox will read this post and apply the modification to the gazillion different versions of the Reba RLs, or at least offer a replacement spring for their exiting customers.

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