Why an off-road truck needs something other than the shock to stop the suspension at full droop, how limit strap length is set, and which kit fits your Raptor, TRX, RHO, Bronco, Bronco Raptor or Ranger Raptor.
The Short Answer
A limit strap stops your suspension at full droop so the shock does not have to. When a wheel drops away, over a crest, off a ledge or when the truck gets airborne, something has to stop the suspension at the bottom of its travel. Without a strap, that something is the shock, topping out at the end of its shaft and taking the whole load through its top mount. A limit strap is a short, heavy-duty strap mounted between the frame and the control arm or axle. It catches the suspension at the end of its travel, so the strap takes the load instead of the shock. Done right, the strap does not cost you any travel: it stops the suspension at about the same point the shock would have, it just takes the hit instead.
Two Ends of the Travel
Suspension travel has two ends, and most owners only think about one of them.
Full Compression
The suspension comes up. That end belongs to the bump stop, which catches it progressively so the last inch is a squeeze instead of a hit. See What Is a Bump Stop?
Full Droop
The suspension drops away. That end belongs to the limit strap. Without one, the shock shaft runs to the end of its stroke and stops the suspension by itself.
Protects the Shock and Its Mount
The strap arrives first, so the load goes into a strap and its mounting tabs instead of the shock's top mount and internal stop. That extends the life of the shocks and the rest of the front suspension.
Keeps Everything in Range
Controlling droop also controls the geometry at full extension. On the rear of a Gen 3 Raptor, the links, Panhard bar and driveshaft stay inside their working range instead of being asked to reach further than they were designed to.
How Limit Strap Length Is Set
This is the part most people get wrong, and it is the reason a limit strap kit is a system, not just a strap.
Limit straps stretch about 1" per foot of length under load. A 12" strap stretches about an inch when it catches the suspension; an 18" strap stretches about an inch and a half. So the length that matters is not the strap sitting on the bench. It is the strap fully stretched, with the weight of the suspension hanging on it.
FMI designs each kit so that the suspension's droop matches the length of the strap when it is stretched. In other words, the fully extended suspension without a strap stops at about the same place as it does with a fully stretched strap. You keep your travel, and the strap takes the load the shock used to.
Why That Matters
A strap that is too short steals droop travel and makes the truck ride worse. A strap that is too long never gets tight before the shock tops out, so it protects nothing. The length has to account for the stretch, which is why we build the mounts and the strap length together for each truck instead of selling a universal strap.
What About a Lift?
A preload lift, like a spring collar under the factory coil, does not change where the suspension stops at full droop. The shock mounts stay where the factory put them. So the same limit strap still fits after a preload lift. The front kits are especially recommended once you run aftermarket springs, which change where the suspension wants to sit and how hard it extends. For more on how lift methods affect droop, read Lift Collars vs. Top Spacers.
If you are running a long travel kit, the strap length has to suit the travel you actually have. Call us before ordering so we can match the strap to your build.
How FMI Limit Straps Are Built
Four-Layer Webbing
Every FMI strap uses four layers of military-grade webbing, built to hold its length instead of wearing out the way a cheap strap does.
Plated Steel Tabs
Steel mounting tabs at each end, black plated for corrosion resistance.
Welded Frame Mount
The upper strap mount welds to the frame. A strap mount sees the full load of a falling suspension, and a welded mount ties straight into the chassis and stays where you put it.
Made in Mesa, Arizona
Brackets are MIG welded in-house and finished in Hammer Black powder coat.
Front Limit Straps by Truck
Every FMI front kit works with the factory stock lower control arm. The lower bracket bolts around the factory cast aluminum arm, and the upper mount welds to the frame, so installation should be done by a qualified welder or fabricator. Most front kits include a front bump stop mount as well, so one kit handles both ends of the travel.
| Truck | Front kit | Strap length |
|---|---|---|
| Gen 1 Raptor, 2010–2014 | Limit strap and bump stop kit | 12" |
| Gen 2 Raptor, 2017–2020 | Limit strap kit or limit strap and bump stop kit | 12" |
| Gen 3 Raptor and Raptor R, 2021–2026 | Limit strap kit or limit strap and bump stop kit | 12" |
| Ram TRX, 2021–2024 | Bump stop and limit strap kit | 12" |
| Ram TRX, 2027 | Limit strap and bump stop kit | 12" |
| Ram RHO, 2025+ | Limit strap and bump stop kit | 12" |
| Bronco Raptor, 2022+ | Limit strap and bump stop kit | 9" |
| Bronco, 2021+ | Limit strap and bump stop kit | 9" |
| Ranger Raptor, 2024+ | Limit strap and bump stop kit | 9" |
The Gen 2 and Gen 3 Raptor strap-only kits have the bump stop mounting built into the bracket, so you can add the front bump stop later without redoing the install.
Front Kits in Place
Lower bracket bolted to the factory cast aluminum arm, upper mount welded to the frame.
Shock compatibility: some front kits will not work with Fox upgraded 3.0 hoses without rebuilding the shocks and hose kit, and some are not compatible with race-series or remote reservoir front shocks that mount on the frame. Check the product page for your truck before ordering.
Rear Limit Straps for the Gen 3 Raptor
Get a Gen 3 Raptor airborne and the rear axle drops away until something stops it. With no strap, that something is the rear shock topping out. The Gen 3 Raptor rear limit strap kit catches the axle first.
Converting a Gen 2 Raptor or F-150 to Gen 3 5-link rear suspension? Once it is converted it runs Gen 3 rear geometry, and the rear limit strap kit is part of that build. See how to convert a Gen 2 Raptor or F-150 to Gen 3 suspension. Building a Gen 3 rear onto a different axle housing? The weld-on lower link mounts include limit strap tabs.
Where to Start
Limit Strap FAQ
What do limit straps do?
A limit strap stops the suspension at full droop so the shock does not have to. It catches the control arm or axle at the end of its travel and takes the load that would otherwise go through the shock's top mount and internal stop.
Do limit straps reduce suspension travel?
Not when they are sized correctly. FMI designs each kit so the suspension's droop matches the length of the strap when it is stretched, which means the suspension stops at about the same place it would without a strap. The strap simply takes the load instead of the shock.
Do limit straps stretch?
Yes, about 1" per foot of strap length under load. That stretch is designed in. The strap length and mounting points are set so the stretched strap stops the suspension where the factory droop would.
Do I need limit straps on a stock truck?
They are an absolute must-have once you run aftermarket springs, and they are worth having on any truck that gets driven hard off-road. On a stock truck, the shock is the only thing stopping full droop, and that is how shock mounts get damaged.
Do I need a different strap if I lift my truck?
Not for a preload lift like a spring collar. It changes where the truck sits at ride height but not where the suspension stops at full droop, so the same strap still fits. A long travel kit is different, and the strap length needs to match it.
Do FMI limit strap kits require welding?
Yes. On the front kits, the lower bracket bolts to the factory lower arm and the upper mount welds to the frame. On the Gen 3 Raptor rear kit, both the frame and axle mounts weld on. A welded mount ties straight into the chassis and does not work loose under repeated loads. Installation should be done by a qualified welder or fabricator.
What is the difference between a limit strap and a bump stop?
They work at opposite ends of the travel. The limit strap stops the suspension at full droop. The bump stop stops it at full compression. Most FMI front kits include both.
How long are FMI limit straps?
12" on the Gen 1, Gen 2 and Gen 3 Raptor, Ram TRX and Ram RHO front kits; 9" on the Bronco, Bronco Raptor and Ranger Raptor front kits; and 18" on the Gen 3 Raptor rear kit.
Do you make rear limit straps for the TRX, Bronco or Ranger Raptor?
Right now the rear limit strap kit is for the 2021–2026 Gen 3 Raptor and Raptor R. Call us about your truck.
Pair your limit straps with the right bump stops in What Is a Bump Stop?, browse the FMI bump stop kit collection, which includes the front limit strap and bump stop kits, or call the shop and tell us what you are building.