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This topic contains 9 replies, has 5 voices, and was last updated by  TJ Koyen 1 week, 2 days ago.

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  • #30258

    Joe Morales
    Participant

    Hello  kartrs i have a crg dark knight running a rotax sr. I have been told in the passed that widening the front with of the kart will increase front grip and give it more jacking affect. Just recently i was told by a reputable guy that i was wrong and you narrow the front of the kart to git the jacking affect and grip….. so i looked at the specs for a crg and the front with should be 40 to 40 1/2 in wide. im at 46in wide in the front. so what do i do the get the kart to jack up and turn better?

    #30259

    Joe Morales
    Participant

    im sorry to track better around the turn. to free up. to grip in the front and grip in the back  but pick up the tire so it is free.

    #30267

    Ted Hamilton
    Participant

    Wider front increases jacking effect at rear, but narrowing increases grip (usually) so it’s a balancing act. If the rear doesn’t pick up properly you’ll feel like the front is pushing until the rear goes into a snap oversteer, so make sure you analyze what’s happening in each portion of the turn that you want to correct. If you want more grip at both ends, I’d narrow both track widths until you’re almost bicycling. Alternatively, you can leave the track widths alone and raise seat height to increase weight transfer and jacking effect — especially helpful in the rain — but hard to do quickly. Some just sit on an extra pad for rain races…

    Good luck.

    #30283

    Ted Hamilton
    Participant

    …and FWIW, driving style plays a big part too — perhaps you’re not turning in vigorously enough, or turning in too soon and too gradually. There’s a lot of factors to get handling “right” for the kart AND you and a plethora of adjustments to try (axle flex affects it, Cg affects it, Seat and arm rigidity affect it…etc etc.)

    #30296

    TJ Koyen
    Participant

    The reputable guy you talked to is incorrect, wider front width increases front grip because it accentuates the affect of the caster and will jack more weight to the rear, resulting in more lifting action on the inside rear wheel.

    Narrowing the front will remove weight jacking and give slightly quicker steering response, but it does not increase front grip.

    Other things to increase jacking would be stiffer front bar, more caster, narrower rear, or more seat struts.

    As Ted said, it could also be driving. 6″ wider than standard is pretty far out of the box, you also maybe are so far off in the front that the kart isn’t going to ever cooperate. My first suggestion any time someone can’t figure out a handling problem is to go back to the baseline setup and start over. It’s very easy in karting to keep going down one chassis tuning path and ultimately never get what you want and become so far off the setup that the kart does wonky things and fixing it is impossible.

    #30323

    Joe Morales
    Participant

    Thank you this helps.

    #30339

    Gary Lawson
    Participant

    TJ is spot on with his advice. Im guessing the 40″ measurement reference you read was misunderstood. Check again and I’m sure you will find that number to be somewhere between 46-48 probably. Maybe they measure to the center of the tire vs others measuring to the outside…

    #30352

    Brian Degulis
    Participant

    There are a few different CRG chassis tuning manuals. One of them does say 40″ front width it must be an error.

    #30388

    Joe Morales
    Participant

    Yes Gary the manual is 46 to 46 1/2 and thank you for your input. I will start 46 and see what it dose. I want the kart as free as possible then I can tune from there. I know how to tighten it up because that all I fight.  AND GARY CONGRATS ON THE WIN!!!!!!

     

    TJ- I was told that by narrowing the front of the cart it creates a triangle effect and lets the inside rear tire pick up off the ground easier. Dose that sound wright?

     

    #30425

    TJ Koyen
    Participant

    Joe,

    This applies to the rear of the kart, not the front. A narrower REAR track width will raise the relative center of gravity by making that side of the triangle shorter (the other sides of the triangle being the seat struts to the bearing carriers).

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