Walker Evans Shim Stack and Damping Curves - 2013 PRO

[mud99]

Hey guys, I thought i'd post up the stock valving and damping curves for the WE front shocks on the 2013 Pro RMK. Maybe it will shine some light on how these shocks perform.

Compression
1.3 x .008
1.2 x .008
1.0 x .008
0.8 x .0125
0.8 x .0125
1.2 x .008
1.1 x .008
1.0 x .008
0.9 x .008
0.8 x .008
0.7 x .0160
0.6 x .06 Clamp

Rebound
1.25 x .008
1.2 x .008
1.1 x .008
1.0 x .008
0.9 x .008
0.8 x .008
0.7 x .008 Clamp
0.9 x .09 Backer

Compression Damping Curve:

Rebound Damping Curve:

 

[mud99]

FWIW I've never seen a shock with more rebound dampening than compression dampening. The compression looks ok, but with that amount of rebound dampening, it's going to be packing like crazy through sequential whoops....the rebound ports are way too small.

Probably the reason that the suspension works well when you hit one bump, but turns downright scary when you hit a string of them.

 

[mountainhorse]

Thank you for putting this up for us.

 

[mud99]

Thank you for putting this up for us.

No problem. And if anyone else has shim stacks for other shocks I can run them through the same software (Restackor). I'd like to compare these to some of the premium shocks to see what is different.

After playing around with the software a bit more, i've come to the conclusion that the compression stack only actively uses 3 shims. The pair of .8 x .0125 shims are so tall they don't actually function as a crossover, instead they become a clamp and all the shims below them are useless at any reasonable velocity.

I'm not sure why anyone would design a shim stack like that unless they were drunk, or maybe they just like putting extra parts in a shock? Usually a crossover is 0-100% height vs the shim above it, not 300%

 

[geo]

I see. It's a software program not a dyno. Good for reference. Thanx.

From my experience, most aftermarket shocks get there biggest benefit from piston design (higher flow, less oil shearing design), internal sealing (keep compression separate from rebound) and rigid body-shaft (for oil-shock life and consistency in function).

Stacks are important for tuning but valve body design-flow is just as important. Some times you can tell just from the stack who designed it if you've looked at a few.
The big names have taken different paths over the years and I'm not as familiar with all as I once was.

One example of different valve bodies is in Fox. You can take the same stack but apply that to a stock Cat Fox valve body, then to generic Fox of old, then to high flow racing Fox of present and have completely different effects. All with the same bleed hole size.
Some of it is because of flow alone. Some of it because of internal sealing. Some of it is because of les shear.

The dual or sometimes step tripling, instead of just one shim is used often in premium stacks. Especially on the low stack. Extra shims cost more money lol. The effect this type of stack has is quicker response so less resistance so less heat but same flow. All good if you are building a shock to respond and stay consistent.

2 .008"s instead of 1 .010" is a good example of this.

 

[boondocker97]

No problem. And if anyone else has shim stacks for other shocks I can run them through the same software (Restackor). I'd like to compare these to some of the premium shocks to see what is different.

After playing around with the software a bit more, i've come to the conclusion that the compression stack only actively uses 3 shims. The pair of .8 x .0125 shims are so tall they don't actually function as a crossover, instead they become a clamp and all the shims below them are useless at any reasonable velocity.

I'm not sure why anyone would design a shim stack like that unless they were drunk, or maybe they just like putting extra parts in a shock? Usually a crossover is 0-100% height vs the shim above it, not 300%

First thing I thought when I looked at the stacks!

Along the lines of what GEO said, I think to get a fair comparison you are going to have to know the piston geometries of the aftermarket shock and what size the rider is. Then you could compare say a Fox setup to a Raptor setup for the same size/type of rider.

 

[geo]

Also most sleds shocks are biased to strong rebound stock because bumps are more likely to be spaced far apart. More like rollers.
And, the compression side is light for the test rides lol.

Same difference as setting a bike up for sand track or hardpack. Sand track would require a heavy rebound stack to be stable and light on low-speed compression for traction.

 

[RMK935VA]

FYI. Carl's rebuilds the WE shocks with Fox internals and custom valving. They are far superior to stock in every way. The price is less than buying an aftermarket shock. I run their setup on my 13 Pro with a heavier spring on the rear track shock for my weight (235 lbs.). I love it with their mods. I have used Zero Pros in the past and these revalved shocks work just as well in my opinion.

 

[boondocker97]

FYI. Carl's rebuilds the WE shocks with Fox internals and custom valving. They are far superior to stock in every way. The price is less than buying an aftermarket shock. I run their setup on my 13 Pro with a heavier spring on the rear track shock for my weight (235 lbs.). I love it with their mods. I have used Zero Pros in the past and these revalved shocks work just as well in my opinion.

Do you know if they use the older Fox pistons with six holes and a bleed hole, or do they use a newer, high-flow style piston?

 

[mud99]

First thing I thought when I looked at the stacks!

Along the lines of what GEO said, I think to get a fair comparison you are going to have to know the piston geometries of the aftermarket shock and what size the rider is. Then you could compare say a Fox setup to a Raptor setup for the same size/type of rider.

Yeah, restackor calculates all this based on the port size, so with measurements from the Raptors or Fox shocks, you should be able to do a direct comparison.

 

[mountainhorse]

FYI. Carl's rebuilds the WE shocks with Fox internals and custom valving. They are far superior to stock in every way. The price is less than buying an aftermarket shock. I run their setup on my 13 Pro with a heavier spring on the rear track shock for my weight (235 lbs.). I love it with their mods. I have used Zero Pros in the past and these revalved shocks work just as well in my opinion.

Holz... who has a long time relationship with Carls... uses all Walker parts to get to the same place.

Essentially Carls makes the shock, internally, a fox zero-pro which they have a very good "vocabulary" with and tons of experience with as well as a long standing relationship with Factory Fox.

Holz does the same thing and has the same degree of experience and factory WE relationships.

Different ways to bake a cake..






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