Ask ten racers what they'd change on their kart to find another tenth and you'll hear tires, gear, clutch, shocks. Almost nobody says "the seat." Which is strange, because the driver is the single heaviest thing bolted to an outlaw kart — roughly a third of the total package once you add up kart, driver and fuel. You can spend a Saturday moving lead around in one-pound increments, or you can move the biggest weight on the kart two holes and feel it immediately.
Here's how we set up seats and seat cradles at the shop, and what each adjustment actually does once you're on the track.
The seat is a chassis part
A seat does three jobs. It holds the driver in place so he isn't fighting the kart through the middle. It puts driver weight where you want it relative to the axle and the left rail. And on a bad night, it's part of your safety package.
Those three jobs pull against each other. The lowest, most rearward seat position might feel great on the stopwatch and terrible on your neck. The most protective seat might be the one that takes an inch of shoulder room you don't have. Getting it right means deciding what you actually need before you start drilling.
Sizing the seat
Measure the driver, not the kart
Kart seat sizes are hip measurements, taken sitting down, in the gear the driver races in. Not jeans. Firesuit, rib protector, whatever he wears on the track — measure hip to hip across the widest point and that number is your size. A 12 means twelve inches between the seat sides.
Snug is the goal. A seat that's a half-inch tight will feel awful in the pits and perfect on lap four, because the driver isn't sliding and bracing with his arms. A seat that's two inches loose lets him move around, which means his weight is moving around too, and it puts him in a worse spot in a crash. When a driver is between sizes, we go down and pad the difference — half-inch adhesive seat padding lets you dial the fit in without buying a new seat every growth spurt.
Containment or not
Full containment seats wrap the shoulders and head with built-in wings. The Kirkey 35 Series full containment seat is the one we sell the most of for that — 18 degrees of layback built into the shell, offered in 10, 12 and 14. If the driver is young, if you run a rough bullring, or if you just want the extra margin, this is the direction to go. Cover it with a containment cover so the aluminum isn't against the driver.
Non-containment seats are lighter, cheaper and easier to get in and out of. The Kirkey Junior 24 Series runs 8 degrees of layback and comes in 10 through 14. Plenty of racers run these with a good head and neck restraint and are perfectly happy.
Check your class rules before you buy either one. Some series specify containment for certain age brackets, and the seat is not the place to find out you're non-compliant on race morning. Browse the full range in our seats collection.
What the cradle actually does
The cradle is the adjustable frame between the seat and the chassis rails. Without one, the seat is where the seat is. With one, you get real adjustment range in two directions and a repeatable way to get back to a setup that worked.
Our seat cradle bolts to the rails and gives you a slotted platform to hang the seat from. If you're putting one on a Wraith or Stealth chassis that didn't come with it, the retrofit install kit has the weldments and hardware in one box. The adjuster bar is the piece with the hole pattern that actually sets your fore/aft, and it's a cheap spare to keep in the trailer.
The four adjustments you actually have
1. Layback angle
How far the seat back reclines off vertical. Most outlaw kart seats live somewhere between 8 and 20 degrees. More layback drops the driver's center of gravity and gets his weight further back, which generally helps forward bite. It also costs forward visibility and makes it harder to get leverage on the wheel. Less layback sits him up, which most drivers prefer for feel and sight lines but puts more of him higher up.
If your seat's built-in angle isn't where you want it, an adjustable seat strut lets you set the angle rather than living with whatever the shell gives you.
2. Seat height
Lower is calmer. Drop the driver and the kart rolls less, transfers less, and feels more planted — good on slick, good on a big fast track, good for a driver who's overdriving. Raise the driver and you get more weight transfer, which usually shows up as more forward bite off the corner and a kart that's easier to rotate. Height is the adjustment people are most scared of and it's often the one that changes the kart the most.
3. Fore/aft position
Sliding the seat back on the adjuster bar adds rear percentage and forward bite. Sliding it forward adds front grip and sharpens turn-in. This is the easiest change to make at the track and the easiest one to overdo. Move it one hole at a time and run laps between changes — if you move two holes and also change air pressure, you've learned nothing.
4. Left-side offset
On left-turn-only dirt, sliding the whole seat toward the left rail raises left-side weight percentage using the driver instead of lead. It's free weight in the right place. It also puts the driver off the chassis centerline, which some drivers hate and some never notice. Rules vary on how far you can go here, so read your class sheet first.
Mounting it right
Use hardware built for the job. Seat mounting bolts see load in every direction and they see it constantly. Our seat bolt kit covers the seat-to-cradle fasteners, and the complete cradle-to-chassis bolt kit handles everything from the cradle down. Grab whatever else you need out of hardware.
A few things we've learned the hard way:
- Use large-diameter washers or backing plates on aluminum seats. A bare bolt head will eventually pull through the shell. Rubber bottom seat washers take some of the harshness out of the mount too.
- Rubber back spacers let you fine-tune the seat back without adding another hole pattern.
- Mark your holes before you drill anything. Sit the driver in the kart, in gear, and check that his hands land on the wheel and his feet reach the pedals without stretching. A perfect setup number means nothing if he can't drive from it.
- Re-torque seat hardware in your normal maintenance pass. Everything on a kart loosens.
A sane starting point
If you're mounting a seat from scratch, start in the middle of the cradle's range with the seat as low as it'll comfortably sit, no offset, and whatever layback the shell came with. That's a neutral baseline. Then change one thing at a time and write it down — hole number, height, offset, date, track. Two months from now that notebook is worth more than anything you'll read online, including this.
Seat position works with the rest of your setup, not instead of it. Once the driver is where you want him, the front end and steering and the rear axle and hubs are the next places to look. If you're building up a kart from a bare chassis, our Stealth X packages and the flat kart to outlaw conversion kit both cover what comes next.
Not sure what size you need?
Give us the driver's hip measurement and what class you run and we'll tell you what fits — and whether you need containment for your series. Shop seats and seat cradle parts, or call the shop and we'll walk through it with you. We race this stuff too.