The link between air pressure and rebound damping


Lee,

I own a new OEM 2008 Fox TALAS RL 32. The rebound has 14 clicks. The slowest rebound takes about 2 seconds – very SLOW. The fastest rebound is just “normal.”

I would expect a very bouncy feel – but no. Others have written that their fastest setting just knocks them off the bike. Is my rebound circuit in need of service despite it being new? Is this normal for FOX forks? How do I test to make sure my rebound is working properly?

I weight 195 pounds geared, and my fork has 70 PSI. That gives 25% sag. How much correlation is there with air pressure and rebound?

Thanks, James

Hey James,

Your rebound damping controls the return of your air spring. The higher your air pressure, the stronger the return, and the more rebound damping you need. Put simply:

More air pressure = more rebound damping

Less air pressure = less rebound damping

With those 14 clicks of rebound adjustment, FOX has to account for the full range of expected air pressures. As you can see in this chart, your FOX TALAS is designed to work with 50-125 psi.


At 70 psi, you’re near the lower end of the range. This would explain why your fork feels like it’s rebounding slowly. According to the FOX chart, you should be running about 90 psi. If you add air, you’ll find that the fork rebounds faster in all settings. As long as you can find a “normal” setting, you’re all good.

BTW: Whenever you change your air pressure, you oughta check your rebound as well.

Rip it,

— Lee


5 replies
  1. James says:

    Absolutely FANTASTIC advice; Particulary with the chart.

    It would seem though that FOX’s reccomendation base dupon the chart are only a guildline. Based upon my calculations, 70 PSI give me a 25% sag at 195 pounds. Yet, FOX recommends 90 PSI.

    Would I achieve the BEST performance from the fork at 90 PSI , DESPITE my own calculations that 70 PSI is correct for my weight?

    Where would the best place to start for setup knowing that the more air you add, the more rebound there will be.

    Should the rebound adjuster be at the slowest, fastest or middle when setting the sag?

  2. leelikesbikes says:

    Hey James.

    – The FOX chart is just a guideline.

    – Run whatever pressure gives you the right sag*. If you just sit on the bike, the fork won’t fully sag. Be sure to bounce up and down on the bike, let it settle, then push the o-ring against the sliders. Leave the rebound at your normal setting.

    – If 70 psi works for you, great. If you bottom your TALAS 32 RL harshly and frequently, you definitely need more air pressure.

    – Whenever you change the pressure, just test the rebound and adjust it to feel the way you like. This is personal preference; I like my rebound as fast as possible without feeling bouncy.

    * This is a good starting point. When you really get into suspension setup, it gets really complex.

  3. James says:

    After changing my original stem from a 90mm 6 degree to a 70mm zero degree, wouldn’t this adjustment affect the pressure on the front wheel and ultimately change the presure/sag settings on the fork?

    Maybe this is why 70PSI is my optomal presure. I wonder how FOX came up with this cart, not knowing what setup the fork would be installed on.

  4. leelikesbikes says:

    Your neutral attack position should place all of your weight on your feet — and none on your hands. Your stem setup should make no difference in your fork sag.

    Dude — it’s snowing!!!!

  5. Chay says:

    I also have found setting up the fork with 25% sag required a lot less air pressure that what the Fox factory recommendation says. But when I was sitting on the saddle / standing on the pedal in a attack position makes the fork sag differently. In the end, I have gone back to the factory recommendations, if Fox engineer recommends it, I am sure they know suspension lot better than I. I also run the rear shock with factory recomendation as well, I have found they work much more in sync with each other.

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