Christa’s 2013 Ride- 2013 Top Kart Twister


Since a kart does not have a differential, the chassis must be tuned to transfer as much weight as possible to the outside wheel in a turn.  This is done by controlling flex in the chassis and axle.  The degree to which this can be done in a kart is mind boggling.  The axle itself is available in many different stiffnesses.  We are going to test the stock axle but we fear that it’s large 50mm diameter will be too stiff for Christa’s 100 lbs.  We will probably have to run a softer thin wall axle.  We had to do this in her old Cadet kart to keep it from losing speed on corner exit due to scrub.
Most powerful karts have this third bearing to absorb torque loads.  Usually most opt to leave it unattached at the axle to help promote flex.  We also chose to run ours unattached and achieved this by removing the set screws.
The Twister comes with an adjustable front torsion bar.  It works like a blade type adjuster on a car sway bar.  The Twister also has provisions for a rear torsion bar but that is useful only for heavy drivers.  We left it off.
On a kart the seat is an important part of chassis tuning.  It’s flex contributes to the overall chassis flex.  For lightweight drivers one trick is to isolate the seat so the chassis can flex more.  The special fasteners and plastic seat bushings allow this.
The seat stays also help the driver to control weight transfer.  On some turns Christa leans to the outside to lift the inside wheel to reduce drag.  The seat stays that attach to the axle help make this more effective.  Tuning seat stays is another trick used by kart chassis experts.
The tightness of the front bumper can also be used to tune chassis stiffness.  It has special bolts that allow for this as well.

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