A 136 cm setting makes for a rather narrow track. So, with high-grip tires like Vega Whites and the rubbery track conditions we had (after a full weekend of racing), we were expecting excessive bite on the rear end, with understeering in corner-entry and side bouncing through curved sections.

As expected, the rear end was tied down way too much with a heavy understeering effect. To counter this, we had to turn the steering wheel excessively for the entire duration of the bend and especially in the initial segment. Corner-entry also required a huge steering effort, due to insufficient rear end glide. In medium-fast bends, like the inside “L”, the rear-bite effect was so severe as to cause the chassis to bounce sideways.

The graph generated by the AIM data acquisition system shows that in the hairpin before the S, the excessive rear-bite given by the136 cm setting (green line) demanded excessive braking and steering, to the point that the rear tires suddenly slipped away, causing a significant speed loss throughout the bend. On the other hand, the high grip helped at corner-exit. Not only, with the narrow setting making the kart very reactive and quick with direction changes, we were able to keep good speed through the S. On the last wide bend leading to the straight, instead, the excessive rear grip again made it hard to enter corner and keep in control through it, with a subsequent loss of speed in the first acceleration segment.

With the narrow 136 cm setting and a track with high grip conditions, our front tires were sliding away too much and not “working” as they should. And since they heated up more quickly than ususal over the first laps, it was impossible later on to set the pressure right (Vega recommends 0.78 – 0.82 bar). In the rear, instead, the kart’s excessive bite caused the tires to overheat and go well beyond the recommended driving pressure. These combined effects showed clearly from the look of the rear tire footprint at the end of our test: the surface was quite rough and ragged