Home Forums Chassis & Handling Tuning for a driver with large upper body

This topic contains 7 replies, has 4 voices, and was last updated by  Greg Wright 1 year, 2 months ago.

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  • #53930

    Greg Wright
    Participant

    It’s pretty rare that I ask for opinions on any forum but I’m dealing with something a bit different.

    Currently working with a driver who is not overweight in fact he’s right on the class weight for Yamaha Masters. What is unusual at least to me is that he’s spent a number of year body building and has a very large upper body and that’s where he carries most of his weight.

    This creates a pretty serious weight shift that isn’t responding well to normal trackside tuning. More than anything else I’m wondering if lowering his shoulders as much as possible would be better as long as it doesn’t put to much weight on the rear of the kart.

    Any thoughts or ideas? I mean this guys upper body is uhhhhhh really big.

     

    Greg Wright
    Rapid Racing Inc.

    "When in doubt Gas it, It won't help but it ends the suspense."

    #53933

    FREDDY SANDOVAL
    Participant

    Greg

    How tall or short is the driver? What type of kart is he driving?

    Can you install a flat bottom seat, and lower it all the way down?

    Maybe slide the seat a little forward? anything that would create the kart to wanna pancake, maybe try a soft axle?

    You mention he’s a the right legal weight, but do you have to ad weigh to the kart at all, or he needs no weight at all?

    #53935

    Greg Wright
    Participant

    Fast Freddy, driver is about 5′ 10″, flat bottom seat in kart now, moving seat forward is a priority as is a soft axle. He needs no weight at all.

    Greg Wright
    Rapid Racing Inc.

    "When in doubt Gas it, It won't help but it ends the suspense."

    #53944

    Gary Lawson
    Participant

    What kart? Seat style and location is definitely priority #1 when dealing with a larger driver. While you see many successful tall drivers in classes like tag, they all have something in common. They are skinny and don’t have much muscle mass. Even at 6′ plus they are 170# max and a lot of that weight is long legs. They essentially mount their seat in the same position as a 5’8″ 150 driver. What I’m getting at is basically very few think outside of the box in regards to seat mounting. Because of my size you won’t ever see me in a standard seat mounted mounted in the same way as you typically see.

    #53963

    Greg Wright
    Participant

    Gary, He’s in a late Top Kart Flash, currently has a Top Kart Tillet style seat installed but a new seat will be going in. There’s little question that the inside tire is not staying unloaded long enough. Any suggestions will be appreciated, I’ve never tuned for somebody with this body type and it changes almost everything.

    Greg Wright
    Rapid Racing Inc.

    "When in doubt Gas it, It won't help but it ends the suspense."

    #53974

    TJ Koyen
    Participant

    As far as setup goes, if you are seeing the inside rear wheel drop too quickly, it’s because your rate of lift is too quick, obviously because of your driver’s size.

    Max rear width is a must, as well as taking caster out of the front end to try and settle that lift down. If you slow down the lifting action, it will have a longer duration.

    This might even be one of the rare occurrences where you throw the rear torsion bar in to see if you can limit the flex in the rear.

    Team Driver - Innovative Performance/Tony Kart // Owner - Oktane Visual Custom Helmet Paint and Graphic Design

    #53975

    FREDDY SANDOVAL
    Participant

    Greg

    Remove front torsion bar, go 2-2 on the camber and toe, try hard axle, 2 seat struts on each side, and 54″ at rear track, move the seat about 2″ to  3″ forward and lean it back about 8.5  to 9.5″ from lip to axle.

    I am not an expert, but with my fat ass, and my hight this seems the only thing that works for me.

    I hope this helps, or at least give you a good starting point, and if he doesn’t like it, then you can put it back where it was and try something else.

    And after that if he doesn’t like it, tell him “life is not for everyone” No, I’m just kidding, sorry. Lol

    #53987

    Greg Wright
    Participant

    More interesting all the time, a little more information, kart at this time has a hard axle in it and I just discovered that the owner raised the seat which I”m sure didn’t make things better.

    TJ oddly enough adding caster helped a little, working on seat location and height and ***axle. I don’t think it’s coming down to soon I don’t think it’s unloading enough period.

    Still digging!!

    Greg Wright
    Rapid Racing Inc.

    "When in doubt Gas it, It won't help but it ends the suspense."

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