Earlier this year, I wrote an article about highlighting the importance of driver seat position, in relation to your kart setup. Now, I wasn’t suggesting throwing the seat placement out the window in order to make it a cruiser, but I see so many people focusing so much on the ideal seat position, that when they sit in the kart, they don’t fit.
I have this problem when I get “new” karts. Every person is a different shape and size, so we if tried to fit everyone in the exact same place, then in my opinion, the balance of the kart will be off more for some people than others.
Others I’ve met don’t think that way. They think that the seat should always be in one place, and the driver should just need to adjust around it.
Well the issue I have with my seat is where the motor mount. I bought a birel ry30 that had a tag motor on it. This year I’m running the LO206 class and the seat strut next to the motor is right in the way. I had to trim the chain guard and shim the seat over to get away from the clutch. My seat is probably in a less than ideal position since I has to shift it over to the left but it’s what works. I feel I can make other adjustments to make up for the seat position.
The seating charts the factory provides are designed to get the weight in the correct spot, based on your height. Obviously not all people who are the same height are the same weight or have their weight distributed the same throughout their body, but placing the seat in the factory setting should always get you close to the right spot.
Having the seat in the right position doesn’t just make the kart start off with a better balance, but it will also help once you start adjusting the chassis. If you have your seat way off the factory settings, it won’t respond to adjustments the way it’s supposed to and it could take a really bizarre setup to get it balanced. Personally, I’ve never seen any driver complain about being uncomfortable when we’ve put their seats in according to the chart. And it removes one of the hundreds of chassis variables out of the equation when it comes to narrowing down a handling issue. I’ve seen it dozens of times; folks wondering why they can’t tune out an over or understeer condition, only to find that their seat is in the wrong place. Moved back to factory settings and boom, instant turnaround.
Of course, moving the seat a few centimeters this way or that for comfort isn’t going to ruin the kart’s handling, but it should at least be close.
All the karts I’ve driven have required a slightly different placement of the seat, giving me a slightly different posture in each one. But they all worked best when I put the seat where the factory told me to.
I think it’s important to consider comfort overall, or at least ergonomics. The seat should start in the standard position of course. But for weekend warriors it’s easy to overlook how having an awareness of ergonomics (including hand position on the wheel) can affect your performance.
Somewhat related to that… I remember at the end of 2010 I figured the biggest “limiter” in my performance was fitness. Not chassis, tires or motor (although they were not great), but fitness. So I worked on a program over the winter only to find myself still winded during sessions when the 2011 season started.
Turned out my rib vest combined with how I was sitting in the kart (stock OTK seat position) was compressing the area in my abdomen near the diaphragm, making it hard for me to breath. I was too busy “trying to drive through it” to notice until I was sitting on the grid one day after having to run up to the kart.
I wonder what it would be like to compare a table of baselines that for F/R weight distribution, rear track width and CoG height for specific weight and tire combos.
A 200lb driver is going to exert more download on the rear axle compared to a 160lb one, making the kart “more stuck” on the rear both with load transfer and mechanically.
I’ve learned that nobody ever talks about seat height. And bringing it up gets you weird looks back.
As a smaller driver (5’5", 27" inseam, 165lbs), I found that the seat position in my Praga Invictus (and my old Intrepid Sirius)requires me to have the seat mounted at the top of the chassis. If its mounted down low, the kart will always stay flat in the rear as well as lose all front grip as the day gets hotter. Changes made little difference until the seat was up as well. I’ve always had to run a custom MRC steel front bar in my karts. One thing I noticed the first time I had the seat all the way up is that mid day when it got hot and grippy is that I had to put the nylon bar back in. I do have to use different pedal mounts in order to comfortably reach my feet.
Like an axle or torsion bar, the seat is just another tuning tool, you move it around, change the stiffness, in some case cut bits out.
Ideally you start at the manufacturers position and most people will never need to move it. The same applies for axles and torsion bars. Most never need to change them.
One thing that is somewhat lacking in karting is an easy way to adjust them, beyond taking them out and drilling them. Fitting a seat can be quite daunting for even the most experienced karter.
Do you know where I could locate a seating position chart for The Arrow AX-9 4s? I just purchased the kart, and would like to get the seat right. I looked at the Arrow site tech downloads, and did not see a specific document for the 4s.
I have massive respect to DPE for posting not just all their base setups but also guides on how to tune around certain tires and/or based on their pro driver’s recommendations. Seriously impressed with that level of confidence. I’d love to see OTK/iPK/some other big company do that
Great topic, and something I am struggling with. I would appreciate input. I am 5’ 1" 115 pounds running TAG Sr. with a class weight of 370 pounds. We run Evinco reds/MG whites. I have a size 1 OTK seat in a new tony kart racer. OTK suggests mounting seat 10 mm below frame an I have heard up to a and including even with top of frame. Help with seat height appreciated.
