All vehicles have bump stops, but you may need an upgrade if you plan to take your rig off-road.
Bump stops are essential to protecting your suspension and improving the stability of your ride.
Because rigid bump stops wear out with repeated use, you should plan to replace them if you notice signs of damage and or hard and or noisy bottom outs.
“Death wobble” manifests as the steering wheel violently moving back and forth under your hands.
Vehicles that utilize a track bar with solid front axle are more likely to develop a death wobble.
To eliminate the effect, you need to determine which parts of your vehicle’s suspension are causing the issue.
A mid-travel kit is going to be more affordable than a long-travel alternative. You won’t have the same articulation, but you’ll have an affordable easy modification to improve your on and off-road experience.
Long-travel suspension systems offer unbeatable articulation, surprisingly soft landings, and excellent rideability. Compared to a mid-travel kit, these kits are a larger investment into your rig and people will notice your investment. Choose a long-travel option if you’re a serious off-roader who wants the best suspension option on the market.
We advise running 180 psi of nitrogen in all of the shocks we manufacture. This needs to be set with the shock fully extended “can be fully extended on the vehicle”. The nitrogen charge effects the performance of the shock, you can run a higher nitrogen pressure than that but that does not effect the compression of the shock like most people think it will mainly increase the rebound speed of the shock. The nitrogen charge also loads all of the seals an o-rings a shock that has not been charge will sweat.
We offer all of our shocks with either a 1.5” or 1.25” mount width. This is the dimension of the shock rod end with both misalignment spacers installed. The 1.5” option is the most common and will have slightly more articulation than the 1.25”.
- Step 1: Fully extend the shock you can extend the shock by charging it with nitrogen or by manually pulling out on the lower rod end.
- Step 2: Loosen the Allen bolts on the upper preload adjuster as well as the dual-rate stop. The upper preload adjuster is the main adjuster that the springs will rest on, it has only 1 Allen bolt in it and is closest to the shock top cap. You will then want to rotate the upper preload collar to the top of the shock.
- Step 3: Slide your tender spring (this will be your upper spring usually shorter than the primary and lighter in weight) over the shock shaft and let it rest on the upper retainer.
- Step 4: Install your spring divider (the black piece the will sit between your 2 springs) some of our dividers one end is longer than the other if that is the case face the longer end of the divider up. Pointing to the top cap of the shock.
- Step 5: Slide on your primary spring (the lower coil) After you slide on your primary spring you will want to slip in your lower spring retainer. You will then want to add preload to the springs to keep the lower retainer in place. You add preload by turning the upper spring retainer until you remove any slack in the springs.
- Step 6: After you get the shocks mounted on the vehicle, you will need to set your dual rate stop (the small stop with two Allen bolts which is now under your tender spring) with the vehicle at ride height.
Using a Rate-Plate
The term “Rate-Plate” is that name given to an immovable plate placed on the compression side of your shock piston. Rate-Plates’ are generally recommended for bypass shocks, racing and or other high-speed applications. If you are experiencing high speed shock shaft travel often in your travels you might benefit greatly from the addition of a rate-plate.
A rate plate will limit your “Blow Open Events” (BOE) to a max set amount. The one draw back is to change your BOE set point, you have disassembled the shock absorber to do so. By setting the height of your rate-plate up or down, that will make the adjustment.
The increments of change can be as little as .010” , up or down, which is the height of a single shim. There are many scenarios to consider when deciding your rate-plate height and talking to an F-O-A tech should be your first stop, in your decision-making process.
Check out F-O-A’s “Blow Open Event” post and that will give you more detail on the flows that you will be allowing/stopping with a rate-plate addition to your shock absorber.
“Blow Open Event”
The term above “Blow Open Event” (BOE) is a term coined by F-O-A and is defined as: A rapid shock movement when the shock absorber valving has lost control of the rate of shock shaft movement.
BOE events are often necessary, especially on longer travel shocks, 14” and up. On your shorter travel shocks 6-10” or even 12” often the inertia/force seen by a shock shaft can be contained with the correct springs rates and the correct valving. Rate plates, which are an unmovable valve shim can also largely limit/eliminate a BOE.
BOE events on longer shocks, that see very fast movement, are often desirable for at least a portion of the shock travel. The shims in a shock stack of valving as they opens increases the amount of flow/relative to the fixed amount of oil in the shock, in a exponential manner so that once the stack is at a certain height flow is no longer meaningfully contained and you have your BOE. The height of the stack while open X the stacks circumference will give you its flow area. In
our 3.5” stock we use a 2.7” diameter largest valve. 2.7” X 3.14 X the opening will give you the flow area.
The cross section of oil in the shock is constant, but the opening is going up. The ratio between those two is falling and that is what leads eventually to your BOE. A good place to start your comparison of flows is with a bypass tube. A ¾” bypass tube has .44” square” of flow. To get to that square inch of flow, your valving stack is only open .051” in height. If you had two bypass tubes, you stack would be .103” in height. If you have three bypass tubes .155 height. I will suggest around this point .15 and .25” of stack height in a 3.5” piston is where you have lost control and you have your BOE.
We offer a lifetime exchange program for all of the Viper Coil Springs that we sell. That means that no matter when you purchased them, if they are in resalable condition, we will exchange the spring FREE of charge. Please note if the spring is scratched, damaged, covered in mud or dirt, spider webs, overspray, or painted/powder coated a different color they will be shipped back to you at your charge. When you ship the springs back to us please include the following Name, Phone#, Return shipping address, Springs sent back, and Springs you are exchanging for. If you include this info as well as a pre-paid return call tag from UPS that will expedite the process.
All F-O-A products are shipped via UPS ground in the USA, unless otherwise requested. Out of country shipping may vary.
Orders are typically shipped within 14 business days from receipt of order. All products are custom built to order, and as such delays are possible depending upon current order levels.
Please allow approx. 1 week shipping transit time for the east coast.
Bypass shocks can take up to 6 weeks if we are out of your requested body.
Note: Additional charges for shipping may apply for shipments outside the contiguous United States.