Nobody buys a cage, a bumper or a set of nerf bars because they're fun to shop for. You buy them because you got into somebody in turn three, because your kid moved up a class, or because you finally looked at that bent front hoop in the shop light and admitted it's been tweaked since last season. This is the stuff on your kart that only gets your attention when it's already done its job.
The trouble is that outlaw kart impact hardware isn't standardized. Receivers come in multiple tube sizes, and bumpers mount two completely different ways depending on how your chassis is built. Order the wrong one and you're not making the feature. You're standing in the pits with a part that won't bolt on. Here's how the whole structure fits together and how to buy the right piece the first time.
The four pieces that keep you inside the kart
Think of it as four separate systems that happen to bolt to each other. The cage is the box around the driver. The receivers are the weld-in sleeves on the chassis that the cage legs drop into. The bumpers take the front and rear hits and keep other people's tires off your chassis. The nerf bars run down the sides and stop wheels from interlocking, which is the hit that actually flips karts.
Every one of those can be replaced independently, and that's the whole point of the design. A hard hit should bend a bumper or a nerf bar, not your frame rails. If you're crashing and the chassis keeps taking the damage, something in this group is either missing, wrong, or already spent.
The outlaw cage
The Outlaw Cage for Wraith & Stealth is the modern shape: taller, squarer, built around the full outlaw body and wing package that most classes run now. If you're building anything current, or you're planning on a wing, this is the one. It pairs with the Outlaw Cage Brackets and Hardware kit, and if you'd rather buy the whole thing in one shot, the Outlaw Cage & Component Kit comes in white or black with the brackets and hardware already in the box. Browse the full Cages & Components collection to see everything side by side.
Receivers: measure your tube before you order
Receivers are a common ordering mistake we deal with, and it's always the same problem: somebody orders by part name instead of by measurement.
The front receiver comes in two bottom-tube sizes: 1-1/4" and 1-1/2". Those are not close enough to fudge. Go out to the kart with a caliper or a good tape and actually measure the chassis tube the receiver is going to sit on before you click buy.
Out back it depends on your cage and how the kart was built. Standard outlaw karts use the Back Receiver Standard Outlaw Cage, and if you're coming off a flat kart you likely want the conversion back receiver, the same family of parts covered in our flat kart to outlaw conversion guide. Smaller-tube chassis have their own small tube back receivers. The whole set lives in the Cage Receivers collection.
One more thing on receivers: they're weld-in parts. If you're not comfortable laying a bead on a structural piece that's holding a roll cage, pay somebody who is. This is not the place to practice.
Bumpers: chassis-mount or receiver-mount
Up front it's straightforward. The front bumper ties into the nose of the chassis and the floor pan. If you're replacing a bent one, grab the front bumper bolt kit while you're at it. The old hardware has been through the same crashes the bumper has, and stretched bolts in a bumper mount are not a thing you want to find out about at speed. Rebuilding the whole nose? The Front Bumper Floor Pan & Bolt Kit does it in one part number.
Out back you've got a real choice to make. The Chassis Mount Rear Bumper bolts straight to the frame rails. The Receiver Mount Rear Bumper picks up off the cage receivers instead. Which one you need is decided by how your kart was built, not by preference. Look at where the mounting points actually are before ordering. There's also a flat rear bumper for flat kart setups. Everything's in the Bumpers collection.
Nerf bars: cheap crash insurance
Nerf bars are what stop a sliding kart from climbing your rear tire. A wheel that gets under yours in the corner is how karts end up on their lid, and a set of side bars is a lot cheaper than a bent chassis and a night in the emergency room.
The Axis Nerf Bar Set covers both sides, and you can buy the left or right individually when you only tweaked one, which is usually how it goes. If you're running side pod covers, the Side Pod Nerf Bar Cover Dzus Kit gets them on and off fast; the same quarter-turn logic we covered in the clamp-on Dzus bracket guide. For the left-rear specifically, a Leatherneck tire guard is worth having on a track where you're spending a lot of time on the bottom.
Don't forget the small stuff
A set of cage springs keeps the cage located and takes some of the buzz out of it, and cage tube protection and vibration dampener saves both the paint and your hands. Neither one is expensive. Both are the kind of thing you notice the absence of.
What to inspect, and when
Give the cage a real look after every hard hit, not just at the end of the year. What you're hunting for is bent tube, cracked or elongated bracket holes, receivers that have started to work loose from the chassis, and hardware that turns easier than it should. Sight down the bars from the front of the kart. Tweaks show up better as a crooked line than they do up close.
Bumpers and nerf bars get straightened in the pits all the time, and that's fine once. Twice is pushing it. Steel that's been bent back and forth work-hardens and cracks, usually right at a weld, usually at the worst possible moment. When a bar has been straightened and you can see paint flaking off the bend, replace it.
The off-season is the right time for all of this. Your kart's already going to be apart for the off-season teardown, and this is the one window where a bent receiver isn't a race-week emergency. While the body's off, check your front end and steering too. Impact damage that shows up in the bumper usually left a fingerprint somewhere else.
Frequently Asked Questions
What size front receiver does my outlaw kart need?
The front receiver comes in two bottom-tube sizes, 1-1/4" and 1-1/2", and they are not close enough to fudge. Measure the chassis tube the receiver will sit on with a caliper or a good tape before you order. If you are unsure, call the shop with your chassis and we will confirm the part.
Should I buy a chassis-mount or receiver-mount rear bumper?
It is decided by how your kart was built, not by preference. The chassis-mount rear bumper bolts straight to the frame rails, while the receiver-mount rear bumper picks up off the cage receivers. Look at where the mounting points are on your kart before ordering, and note there is also a flat rear bumper for flat kart setups.
What do nerf bars do on an outlaw kart?
Nerf bars run down the sides of the kart and stop wheels from interlocking, which is the hit that flips karts. A sliding kart cannot climb your rear tire as easily with a set of side bars on. You can buy the left or right bar individually when you only bent one side.
How often should I inspect my kart cage and bumpers?
Check the cage after every hard hit, not just at the end of the year. Look for bent tube, cracked or elongated bracket holes, receivers working loose from the chassis, and hardware that turns easier than it should. A bumper or nerf bar can be straightened once, but if paint is flaking at the bend, replace it.
Can I weld in cage receivers myself?
Receivers are weld-in parts that hold the roll cage, so only do it if you are comfortable laying a bead on a structural piece. If you are not, pay somebody who is. This is not the place to practice.
Ready to order?
Start in Cages & Components, Bumpers and Cage Receivers. And while you're thinking about what happens in a crash, it's worth reading the outlaw kart safety gear guide. The cage only does half the job.
If you're not sure whether your kart takes a chassis-mount or receiver-mount rear bumper, or which front receiver your tube size calls for, call the shop before you order. Tell us what chassis you're on and what body you're running and we'll get you the right part number the first time. That's a two-minute phone call instead of a return.