I am entering my third year running an LO206 kart in an area that the class is still growing, so there isn’t so much information on chassis setup for low power karts floating around. Additionally, I’ve begun shopping around for a new chassis and have seen some interesting specs from different kart manufactures 4 cycle specific karts.
I am currently running a 2012 TonyKart EVRR that was a Yamaha kart in a previous life, and has a 50MM axle and 7.1in rear tires. To me, the kart has always felt very fast and neutral - it’s never had any bad handling characteristics that I can feel. the rear end has never felt tight, as the internet says it should, even with the big axle and rear tires.
Looking into new chassis, there doesn’t seem to be any sort of consensus on what the hot setup for a 4 cycle kart is. To name a few, here are how manufactures spec their 4 cycle karts:
Margay 4.15: 32/28 frame, 40mm axle, 2 bearing
BirelART AM-29: 30/28 frame, 40mm axle, 2 bearing
Comet Eagle: 32/30 frame, 1.25in axle, 2 bearing
Coyote: 1.125in (28.5mm) frame, 1.25in axle, 2 bearing
Arrow X3 4s: 32mm frame, 40mm axle, 3 bearing (?)
Intrepid FK4: 30mm frame, 50mm axle, 2 bearing
So clearly there is no consensus that has yet developed regarding chassis construction. What gives? How can so many different manufactures who (supposedly) know what they’re doing come to such varied conclusions?