Home Forums 250 Superkarts F1 Chassis

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    • #16495
      mark crook

      Hi all,

      Anyone on here from the UK have any historical knowledge on the F1 chassis?

      Im currently practicing on short circuit, not currently racing as of yet. i have a CR250 motor and now have a choice of two F1 chassis.

      the chassis im building up for next year is an unused 2012 F1 frame, using mostly new parts, however i have a 2004 partly built frame which i am told is one of the last built by the original owners of F1 karts and apparently a very good year for the F1 chassis.

      would anyone be able to give an opinion on which chassis i should pay more interest. The 2004 frame is apparently lighter and more flexible so should give better handling however on short circuit can put too much heat into the tyres, whereas the more rigid 2012 chassis looks after the tyres alot better??

      although the 2004 frame is almost ten years old it seems very straight with no visible signs of any cracks and has been modified to meet current standards so would seem a shame to pass it on unnecessarily.

      thanks for any replies

      "When In Doubt, Flat Out" - Colin McRae

    • #16509
      Shaun Everard

      I’m sure Ian Harrison would be able to help.

    • #16572
      mark crook


      I seem to pester Mr Harrison every time something is up with my motor. Don’t want to be a nag.

      I have found that the 2004 chassis does understeer on first gear corners and I find myself trying very hard to get the back end around. Although on faster corners the rear is stuck to the ground which Is great but when I push hard it hops around like hell. Maybe a sign of too much rear grip??

      Quite new to karting so please bare with me if I sound like I’m talking rubbish

      "When In Doubt, Flat Out" - Colin McRae

    • #16683
      Ian Harrison

      Hi Mark

      The excess of rear grip that manifests itself through the rear end hopping was a characteristic of the older F1 chassis, which was a bit soft for a 250 single. Virtually impossible to cure 100%

      As you have found you have to drive round it by just giving enough throttle to smoothly break rear traction, any more than that and you get the grip-release-grip-release situation that manifests itself as hopping. Either way it doesn’t make for good lap times and the hopping is tedious, tiring and destructive!

      I’m afraid that I don’t have hands-on experience of the newer chassis that Chris Purdie (CPR) produces, but I know that he has been addressing that issue.


      Best Regards


      Ian :-)

    • #16697
      Matthias Schümann

      Hi Mark

      You could stiffen up the rear end a bit, by mounting bracket’s from the rear axle bearing mount to the seat, we used to have to do that when we raced in formula A 100cc in the late 80’ties early 90’ties, to prevent the rear end from hopping, sometimes we ran up to 4 of these brackets, 2 on each side. Moving from a 30 mm axle to a 40 mm one helped a bit.

      But with a soft chassis you should be fast in the rain :)

      Best regards Matthias

    • #16723
      mark crook

      Thanks for the replies,

      I have decided to sell the older chassis on and go with the more rigid 2012 frame. Need money to put towards building the new frame up and it seems silly to have two chassis on the go.

      I wonder if the older 32mm frame would have worked well with 125 gearbox on long circuit? (if you could keep the weight down)

      I like the idea of having extra support from the seat to the axle, may just try this in the future :) would this also transfer more weight onto the rear tires under load?

      An adjustable wishbone across the rear of the kart is what you need :D



      "When In Doubt, Flat Out" - Colin McRae

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