A little explanation for the Bump Stop Kits.
A little explanation for the Bump Stop Kits.
The Raptor comes with a Fixed Bump Stop and all fixed bump stops are designed to be short and come into effect late in the final distance of suspension travel. As such, they have a drastically increasing compression rate. That is to say that they stop the suspension movement very quickly and typically in a harsh manner. So, removing the factory "Fixed Bump Stop" and installing an aftermarket "Hydraulic Bump Stop" for your Raptor is a great idea.
The main purpose of a hydraulic bump stop is to serve as some final suspension cushion to keep the metal parts from coming together or from the suspension traveling too far, which might in some way damage the suspension or chassis. If the suspension bottoms too violently, something is bound to break sooner or later. That is why the hydraulic bump stop kit is used in the final bit of travel in a suspension. It behaves much like a variable (or rising rate) spring. This allows a vehicle to use a softer spring rate than would normally be needed if there were no bump-stop control. Using a bump stop allows the suspension to soak up large bumps while still allowing use of that soft spring for normal suspension travel conditions.
There are several types of bump stop kits available for the Raptor. See Below:
Fox 2.0 supplied by Outlaw Raptor
Fox 2.5 supplied by RPG (Raptor Performance Group)
King 2.0 supplied by Addictive Desert Designs
Light Racing supplied by SDHQ (Super Duty Headquarters)
All these listed above are all hydraulic bump stops and yes they have a desired amount of nitrogen called out by the manufacture for the amount of valving inside. Yes, they all have compression and rebound valving inside them and yes they work pretty much the same as your nitrogen filled shocks. The nitrogen is to return the shaft at the rate needed to keep up with the rebound valving inside the bump stop.
Now, what nitrogen pressure should you run? Ideally what the manufacture calls out for. But, since the Raptor has very limited suspension travel the axle come in contact with the bump stop very easy, especially if you have an extra load your hauling around town you might want to lower it a bit like BIGJ suggested. The reason is that with high nitrogen pressure you feel engagement of the bump stop. By lowering the nitrogen you will not feel it hit as hard and YES you still have the same protection for that big impact because you haven't changed the valving inside. But, if you lower it and run a bunch of small bumps or big bumps the bump stop may not return to fully extended in time for the next impact. Thus losing some of your added bump travel protection.
So, you know the Light Racing Bump Stop is the only one that has external adjustments for compression and rebound. The FOX and Kings Bump Stops are fixed valving and that works just fine for what we need with the Raptor Suspension.
I hope this helps!