Hydraulic bumpstops replace the fixed units and allow for smooth, controlled, tunable susp
When it comes to building the suspensions under our rigs, we’re faced with many choices when choosing parts. As a matter of fact, we dare say that there are more choices now than in the history of four-wheel drive. This is good, but it can create a dilemma for us wheelers. Questions arise about the pros and cons of these upgrades and whether they’re a good fit for a specific type of off-road travel and/or vehicle. Naturally, cost is also a major player in the equation as well.
To answer some of these questions, we’ve listed a few of the most commonly modified suspension components and we’ve split them into budget, better, and best. We’ve also listed basic information for each as well as pros and cons. Finally, since we always have something to say, Editor John Cappa, Technical Editor Sean P. Holman, and Senior Editor Ken Brubaker have weighed in with their preferences and thoughts in each category.
Bear in mind that how these are graded (budget, better, best) may be open to interpretation. For example, if you have a pickup truck that’s used to plow snow, you probably don’t need race-ready bypass shocks. Even though they’re arguably the best in the shock world, their numerous features would probably be overkill on a plow truck, and a quality set of monotube or twin-tube shocks may work just fine. On the other hand, if you use your “other” rig to bomb across the desert, bypass shocks may in fact be the best choice.
The bottom line is that hopefully this info will help you determine what’s best for your rig based on how you use it, and your budget.
Lowdown: Bumpstops control how much upward travel your suspension can have. If your rig didn’t have bumpstops, the suspension could over-compress when you hit a bump and this would wear out the springs and potentially allow damage to the shocks and other components. A bumpstop isn’t just a “stop” though, it also offers additional suspension damping as it compresses.
These bumpstops are what’s usually installed at the factory (though there are some other materials used nowadays). Rubber bumpstops are inexpensive and durable. They function and hold up well to direct force and most have a tapered shape that provides some damping as it is compressed. Many aftermarket lift kits simply offer a system to lower the factory bumpstops to compensate for suspension lift. The downside to rubber bumpstops is that they can be adversely affected by oil (which can cause them to soften) and after a few years rust can cause the bumpstop to part ways with its mount. It’s also worth noting that they dissipate energy into the suspension rebound, which has to be damped by the shocks.
Pros: Inexpensive, adequate for general low-speed wheeling
Cons: Subject to damage from oil, rust can damage the mount, they dissipate energy into the suspension rebound
Often considered a step up from rubber, polyurethane bumpstops are available from a number of aftermarket companies. They often follow the same design characteristics as rubber, but they can also be found in progressive-style, which offers light damping and then stiffer as the bumpstop compresses. Poly bumpstops have great longevity, are inexpensive, and more oil resistant than rubber. They’re stronger than rubber and have less deflection under load. However, they’re typically stiffer than rubber and they can crack under heavy compression. Like a rubber bumpstop, polyurethane bumpstops dissipate energy into the suspension rebound, which has to be damped by the shocks.
Pros: Oil resistant, long life, inexpensive
Cons: Can crack under heavy compression, stiff, dissipate energy into the suspension rebound
Born of desert racing, these are basically small shock absorbers that replace the stationary bumpstop. Most often they’re filled with shock fluid and nitrogen gas. They gradually damp the final segment of suspension uptravel and work great to absorb the forces of high-speed off-road travel or jumping where full suspension uptravel is the norm. They also help to damp downtravel, too. These bumpstops are typically adjustable so they can be fine-tuned for your application. They work very well in both solid axle and IFS/IRS applications. Most require welding to install the mount, but some use bolt-on mounts. Hydraulic bumpstops are on the high end of pricing in the bumpstop world.
Pros: Gradual damping of uptravel and downtravel, tuneability
Cons: Expensive compared to fixed bumpstops, more labor intensive to install
Cappa: In most cases the factory rubber or EVS foam bumpstops are plenty adequate. Urethane bumpstops are often too harsh and rigid. They can crush and tear if designed poorly. Hydraulic/air bumps are able to absorb a lot of energy but they are best suited on 4x4s that see a lot of high-speed use, hard impacts, or airtime. The Daystar Stinger is a good budget alternative to full hydraulic bumpstops.
Holman: For most wheeling needs, I am a fan of the factory bumpstops. They are usually durable, compliant, and adequate, even with heavier wheels and tires. Once you mix in some speed, hydraulic bumpstops are hard to beat.
Brubaker: For me, hydraulic bumpstops are mandatory on the front of IFS-equipped rigs where the lower A-arms sit on or near the factory bumpstops at rest (like on late model GM trucks and SUVs). In this situation, adding hydraulic bumpstops significantly improves handling both on- and off-road because instead of traveling into fixed bumpstops the uptravel is gradually damped by the tuned hydraulic bumpstops. I was skeptical of hydraulic bumpstops price-versus-return until we installed Light Racing JounceShocks on our project Trailhugger Hummer H3. The improved handling and ride both on- and off-road was extraordinary. I run rubber bumpstops on my solid-axle rigs and they work fine, but I wouldn’t hesitate to install hydraulic bumpstops given the opportunity.