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High Speed Compression and Fox 2010 RLC

edited March 2016 in MTB workshop & tech
Hi All, it's my first post in years, so please be gentle!
I have a pair of 2010 Fox Float 120mm RLCs which I'm struggling to get the best out of. I'm a really really old-school biker, started MTBing in 1987, so some of this new-fangled technology has me a little bamboozled. I've tried following the guidelines on Fox, and looked at the manual, and watched YouTube videos too. However I weigh 97kg (218lb), more with kit, so I may be outside the normal operating envelope of the forks...

Essentially the problem is this; I can set the sag to 30%, but unless I run a lot of compression damping, the fork dives more than a (insert disliked football team here) forward. I increased the (low speed) compression damping, and the diving decreases (still gives me more travel under brake dive than impacts) but the fork is exceptionally hard, and I only get about 50% travel (maybe 55% with big hits).

I have also tried running with 18mm sag as per the instructions for "Firm", with the compression backed off slightly. Even harsher, and some improvement on the brake dive, but not much.

What AM I doing wrong? Alternatively, if the above sounds sensible, what impact would changing the fork oil weight have? Tempted to go for a lighter weight oil (spec is 10wt, thinking 7 or 5, both of which Fox make), if I understand right, that would increase the small bump sensitivity. Did anyone else try that?

Thanks all for your help.


  • RockmonkeySCRockmonkeySC Posts: 15,247
    When was the fork last serviced?
    30% sag is a bit much, try 20%
  • Thanks RM. Did anyone ever try running different weight oils in fox forks?
  • HerdwickHerdwick Posts: 523
    I did experiment with a fox evo 34 ctd, but used heavier oil than fox 10wt because the damn thing at descend mode is under dampened, dives to much and at big hits crumbles like a mallow :)

    The heavier oil helped as it kept the small bump sensitivity but harder impacts are more manageable now, also added some fox fluid to the air chamber to make it more progressive
    “I am a humanist, which means, in part, that I have tried to behave decently without expectations of rewards or punishments after I am dead.”
    ― Kurt Vonnegut
  • RockmonkeySCRockmonkeySC Posts: 15,247
    I hated my old F120RLC Float. Too much flex and rubbish damping so I never bothered with tuning and just replaced them with a Rockshox Reba
  • Above, seems like a common thing with Fox now.

    Not tried the newer forks with the new damper. But don't think I would want to as my fist and only Fox forks put me off.
  • Thanks all for your thoughts. I'll try a service first, make sure I'm not suffering from amnesia!
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