Suspension tuning help

Shawnk

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I need some guidance. I can do the work just need to know where to start. I have a rail that beats you up on washboard roads. I think I need to revalve the shocks. I have fox coilovers on a beam car. They are off the shelf so valving should be 40 compression 60 rebound. The spring rates are 100/150. I'm thinking I need to soften the compression. The rears might need attention also. The spring rates are 300/350. The valving in those is unknown. When I go over washboard roads or even small whoops it beats you up. The rail even rocks side to side. Pictures for reference.
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jon coleman

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little bit bigger rear tire , what psi? in rear tires?, looks like ride hight is a little low, spring rates?, , after we( rDc buggy community know that, then a better idea on valving& correct rates will have more info to make that buggy a plush Cadillac.i have read other threads on rDc on this subject .do a little more searching, you'll get some good info
 
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Shawnk

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Rear tires are 31's. I usually run 10-12 psi. Front spring rates are 100/150 and rear are 300/350. After doing some research, I think the rear spring rates are high. Also the psi in the shocks are 200.
 

partybarge_pilot

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Front, flip the stacks, way to much rebound. Open up all the bleed holes.

Rear, your going to need to know what's in it.

Baseline should be about .012 comp and .008 reb with 2 bleed holes open.

On a light car like that, low speed damping is what is beating you up the most.
 

partybarge_pilot

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Your rear spring rates are pretty close but it looks like it's almost sitting on the secondary stops. Try moving them up an inch.

And always make one change at a time so you can see what it does.
 

Shawnk

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Front, flip the stacks, way to much rebound. Open up all the bleed holes.

Rear, your going to need to know what's in it.

Baseline should be about .012 comp and .008 reb with 2 bleed holes open.

On a light car like that, low speed damping is what is beating you up the most.
So make compression 60 and rebound 40? The bleed holes must be the disc that is in between the valves? Sorry for the dumb questions, off-road shocks are new to me. On the rear I'll move the stops. Do you think the spring rates on the rear are ok, or to stiff? Most of my driving is either at ocotillo or johnson valley.
 

partybarge_pilot

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There are 4 places on the piston for bleed holes some are drilled and tapped so you can plug them if needed. If they are not drilled, use a 3/32 drill which is used for a 4-40 tap.

Yes 60comp 40reb.

How much preload on the rear springs?
 

Shawnk

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There are 4 places on the piston for bleed holes some are drilled and tapped so you can plug them if needed. If they are not drilled, use a 3/32 drill which is used for a 4-40 tap.

Yes 60comp 40reb.

How much preload on the rear springs?
1 inch.
 

Josh 8

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I admire your willingness to dive into the shocks with out fear. Most people don’t have that. There just mystical tubes that are to complex to understand.

The first thing that need to be understood is a basis of terminology. I as with most people on the thread have no idea what 40/60 valving is. That just some wild percentages of an unknown shim stack on the piston.

So what you need to do is scatter the shocks. Using a dial caliper measure the dia and thickness of each shim. And record the order that they are in on the piston. From there one can begin to give advise as to how the stack shims to change valving. With out this your just shooting blindly in the dark.

And remember. The shims on the bottom of the piston are compression and the shims on the top are rebound.

And partypilot is right about free bleed. Note the free bleed hole too. That’s important. Don’t worry about tire size.
 

Shawnk

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I admire your willingness to dive into the shocks with out fear. Most people don’t have that. There just mystical tubes that are to complex to understand.

The first thing that need to be understood is a basis of terminology. I as with most people on the thread have no idea what 40/60 valving is. That just some wild percentages of an unknown shim stack on the piston.

So what you need to do is scatter the shocks. Using a dial caliper measure the dia and thickness of each shim. And record the order that they are in on the piston. From there one can begin to give advise as to how the stack shims to change valving. With out this your just shooting blindly in the dark.

And remember. The shims on the bottom of the piston are compression and the shims on the top are rebound.

And partypilot is right about free bleed. Note the free bleed hole too. That’s important. Don’t worry about tire size.
I'm a industrial mechanic by trade. Do working on things doesn't scare me, I'm just new to shock tuning. But thank you.
 

partybarge_pilot

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I as with most people on the thread have no idea what 40/60 valving is. That just some wild percentages of an unknown shim stack on the piston.
This is why Fox has shim charts. It also lets you see what smaller changes would do rather than just jumping from 10's to 12's.
 

partybarge_pilot

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After looking at the rear shocks on my computer instead of my potato phone, the secondary spring stops look like they are far enough away from the sliders.
 

cosmo

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With the front shocks and tires off, can you move the spindles freely? Three bleed holes are plenty. You cannot just "flip the valving". You will need an additional 1.6 dia. shim. Look at the valve chart. You can also drop your gas pressures to 175 psi. .
 

cosmo

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Is the front a 5/8" or 7/8" shaft? SAW shocks I think have a threaded bleed hole ? You should have two bleed holes open in the rear. Rear valving, SAW uses 4 shims? If so, you may be able to remove one.
 
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