Fox 2.5 Shim Stack

[Jhollowell]

I'm rebuilding a set of front shocks and I'm contemplating doing some shock tuning in the future. no particular reason, except to learn a little more about suspension tuning and how changes affect the ride. I searched but couldn't find any info on the shim stack dimensions, so i measured mine and created this table. I'm unsure if these shocks came from a SCREW or a CREW but at least i have a baseline. Hopefully this info is useful. If anyone wants the excel sheet, just send me a PM and i can email it to you.

 

[Jhollowell]

Also, the shim stack referenced above is from an unknown truck. I've heard the SCABS and SCREWS have different valving so if anyone knows which one this is that'd be good to know. I'll have a set of SCAB shocks shortly and will document that shim stack as well as my SCREW shocks when i rebuild those.

 

[Jhollowell]

Here is the Rear SHim stack from a 2010 6.2L SCAB

 

[FishFreak]

Also, the shim stack referenced above is from an unknown truck. I've heard the SCABS and SCREWS have different valving so if anyone knows which one this is that'd be good to know. I'll have a set of SCAB shocks shortly and will document that shim stack as well as my SCREW shocks when i rebuild those.

I guess that makes sense, if the SCREW is heavier, it'll need more compression damping and a little less rebound right? Jeez this gets more complicated the more we look! Now if we can only do this for the Gen 2 3.0 Fox, keep track of truck models and then compare what others have changed when going to Geiser or Eibach Fr, Deaver XX Rr springs, then we can rebuild and revalve our shocks ourselves! Thanks @Jhollowell....

 

[Jhollowell]

Here is a set of SCREW Shocks with a flutter stack. I won't disclose the company that did the build.

Front shocks


SCREW Rear Flutter

 

[eastreich]

If you really want to play with the stacks and see what something is capable of (without experimentation) download ReStackor:

https://www.shimrestackor.com/

I have only played with the demo version, but that is just because after being inside shocks for the last 30 years I can usually get exactly where I want to go just by looking at the stacks I take out. Granted, I don't do this as a business, so the only people I would upset are family or friends, but if I were to do it for $$$ I would invest in ReStackor. I have played with the demo version, and know of guys that do use it regularly.

Another thing you can do is go over the "standard" Fox shock valving charts (you can find them on Kartek where you order individual shims) and those will give you a good idea of what shim change results would be as far as individual steps. For example, the Screw rear rebound stack directly above is a #40 on the 2.0 Fox shock valving chart.

Just a reference point, Fox 2.5 IBP shocks use valving for 2.0 series shocks (C/R top shim diameters of 1.600/1.425 respectively), Fox 3.0 IBP shocks use valving for 2.5 series shocks (C/R top shim diameters of 1.800/1.600).

I find it funny that everyone on the truck side calls these "flutter" stacks when dirt bikes have been using multistage stacks for decades...