I’m new to mounting seats. I’ve tried several times on my 2024 Tony Kart 401RR. Finally I decided to just get an OTK seat and use the exact measurements from their setup guide. I’m 5’9’’ running a single speed. So it should be 660/665mm back from the front rail.
Is this OTK guide for the 2024 model?
I literally could not get the front of the seat back to 650/655mm. The seat stays hit the lip of the seat. The closest I could get was ~630mm and my arms are basically straight when trying to reach the steering wheel. It seems WAY too far back.
Do you measure from this point on the frame? (blue line)
Is the seat bottom flush and parallel with the bottom rails?
If you measure from the spine of the seat to the leading edge of the axle what do you get?
I’ve given up on measuring from the front edge of the seat ears, just too much variance between seat shapes and even the same brand and size being trimmed differently. Spine of the seat to the axle is what I do now and just eyeball the seat straight in the chassis.
Also it would help if you flipped those bottom brackets so the L-shape was facing backwards giving you more room for the bolt and spacers underneath the seat.
Also, also this is a shifter chassis? I see a brake bias adjuster and you are trying to mount the seat for single speed?
The seat is parallel to the bottom rails about 1/2 way between the top/bottom. Last seat was flush with the bottom of the rails and I’m trying to get more side bite.
I’ll flip the brackets later, good call. I was just in a rush doing it.
It’s 113mm from the spine to the axel (closest point).
Yes it’s a shifter chassis that I converted to single speed. Doesn’t have front brakes anymore.
That’s close to where it should be. I’ve been in the 12cm-14cm range on seats for single speed. It’s probably going to be tough to get the kart to do exactly what you want being a shifter chassis (probably why you are raising the seat to get the chassis to flex more and work the outside rear) and I’m guessing the seat posts are in a different spot on the shifter chassis versus TAG chassis.
My gut feeling is that seat is really far back. OTK and Tillett both, the leading edge of the seat should be about at the trailing edge of the center bar. That looks 20-25mm further back.
To try another measurement that’s very repeatable - try measuring from the centerline of the kingpin to the leading edge of the center of the top of the seat spine. 106cm left/108cm right. And then measuring from the leading edge of the seat at the thighs to the front bar clamps it should be 5mm longer on the right side than the left. That’ll work for an OTK 2/3/4 or Tillett Man/Har/MS/ML.
I’m not an OTK expert, but assuming this is a perpendicular measurement, that’s puts you firmly in shifter seat placement territory, which is probably 2-3+cm too far back for single speed (depending on the engine package).
I just put it on the scales and the weight distribution is 35/65. Should I just go by that instead of the recommended distance? Seems like it needs to move up quite a bit.
