Rear skid float help.

[jeffheart153]

I have upgraded the rear shock with the Evol upgrade. Im 230ish with gear. Ive got the shock set to 135main and 220 evol. I still find that I'm bottoming out. Kinda nervous in putting more air into the evol. Not sure what the breaking point is? I know Fox said 300psi, but that seems like a lot.
Any one?

 

[bholmlate]

I would add a more PSI to the main chamber and see if that helps. That is what is being used primary by the shock to absorb the impact. The evol chamber only comes into effect once the travel in the shock has reached a certain distance. What might be happening is that you over overpowering the main chamber so badly that the Evol chamber is not able to compensate. Be careful that you only add a little PSI at a time because the shock curve will get more progressive as you add PSI to the main chamber which will effect the overall ride characteristics obviously Please be aware that I don't have Fox Evol shocks. just using knowledge i have using Fox air shocks in general

 

[jeffheart153]

Thanks, Ive tried lower pressure in the main. I started at 100psi and it basically flattened out the suspension. So I then just added more. Feels rally awesome (for me) at 135. Any higher and the ride really stiffens up I tried 145 and I couldn't even move it. Ill try adding more to the evol.

 

[bholmlate]

That is the problem a lot of people have with the Air shocks because the shock curve in air shocks are so progressive when compared with a coil over spring. Just remember the air pressure in the shock is acting and taking the place of the coil-over spring. The Evol chamber helps by adding air volume. A small change in air pressure make a BIG difference. Have you tried going up in the main chamber say 138-140 then go with 218-215 in the Evol chamber. just a idea. The experts suggest only going up a max of 5 PSI at a time because it make a big change in the overall shock performance

 

[JSCC]

I have upgraded the rear shock with the Evol upgrade. Im 230ish with gear. Ive got the shock set to 135main and 220 evol. I still find that I'm bottoming out. Kinda nervous in putting more air into the evol. Not sure what the breaking point is? I know Fox said 300psi, but that seems like a lot.
Any one?

Set the Primary chamber for ride height and sag, and evol chamber for bottoming control and progression is how I understand it.
So if you are happy with ride height and sag, keep adding air in the evol until it's progressive enough to stop it from bottoming out. Up to the 300 psi. If you add too much to the primary to stop bottoming, ride will suffer.
I'm 200 ready to ride, and my front shock is about 120 in the primary and 150 in the evol. Rear is 110 in the primary and 140 in the evol. I'm still working on the adjustments though..

 

[powdermuncher]

I ran evos in several aftermarket skids. Usually I ended up at around 280+ psi in the evo chamber.
As said before main chamber for ride hight and compliance Evo chamber for bottoming resistance. The evo chamber will give once the main camber goes up to higher than the pressure in the evo chamber essentially smoothening out the bottom end of the shock stroke. The actual working pressure on these shocks is way beyond the static settings. So crank up the eve chamber to 300 by the time you take of the valve it will drop down to 280 some anyway. Also 300 PSI in a heated shop is no where near 300 in below 0 weather.
So crank em up and keep the main chamber compliant.

 

[jeffheart153]

Nice! Thanks guys.

 

[stingray719]

If you have an MTX with stock front skid shock spring that is the problem. Need a 160 pound front skid shock spring or better to balance the sled. And I have no idea why a modern sled manufacture would put a 110 pound spring in a sled let alone a 4 stroke. Even the trail Vipers have a 135!

 

[tar]

The 16 viper has a different relay rod and pivot arm.
Changes the geometry of the shock.
8JR-67494-10 Relay rod, this rod is shorter than the 15 rod
8JR-67332-20 Pivot arm, this arm has different shock and rod mounting holes.

Tar.

 

[InRBigness]

I am not sure what sled you have but I have a 16xtx LE and I am 240 dressed. I run my skid shocks at 150 mains and 220 in the evols. I bottom out once in a while off of big bumps. The ride is good. At any less than 150 and the sled sags about an inch on its own weight.

 

[jeffheart153]

I am not sure what sled you have but I have a 16xtx LE and I am 240 dressed. I run my skid shocks at 150 mains and 220 in the evols. I bottom out once in a while off of big bumps. The ride is good. At any less than 150 and the sled sags about an inch on its own weight.

2015 xtx ill give it a try. I haven't run the main that hi since I put on the evol chamber. Im just kinda going off of what i had in the shock before the evol.

 

[tar]

The 16 viper has a different relay rod and pivot arm.
Changes the geometry of the shock.
8JR-67494-10 Relay rod, this rod is shorter than the 15 rod
8JR-67332-20 Pivot arm, this arm has different shock and rod mounting holes.

Tar.

A quick update, with the new relay rod and pivot arm the rear skid is very firm. My sled would bottom out very easily and even bent my tunnel before the new parts.
Tar

 

[julio]

tar

can you update the 15 to the shorter bars from the 16?

 

[tar]

can you update the 15 to the shorter bars from the 16?

Yep, bolts in

 

[Motorbreath_]

A quick update, with the new relay rod and pivot arm the rear skid is very firm. My sled would bottom out very easily and even bent my tunnel before the new parts.
Tar

any pics?

 

[jeffheart153]

I ended up adding more to the main and evol. 150/260 seems to be good, not perfect. A little stiff. But didn't bottom out until I had to double a buddy. Im going to give 145/260 a try and see how it goes. I did notice the front spring to bottom out this time. Was hitting some pretty good bumps on the trail. I think I might look into this 160 lb spring.