Soft or hard, that is the question!

Columns: On the technical side
A doubt that has always plagued the kart driver is the one about tires: are soft better, with more grip (and probably more expensive), or go with harder tires, less performing but longer lasting (and theoretically cheaper)?

In an attempt to shed light on the issue, we went on track on a simple test day in Castelletto di Branduzzo, where some interesting questions emerged, especially on the durability of the tires and their relationship with the chassis. In some one-make trophies, chosen by many drivers because - at least on paper - they are more "economical", they use tires that are on average "harder" than in the regional and national championships when they raced with the international categories and therefore with the same tires of the Top categories worldwide.

To be honest, however, few people on the track are fully satisfied with these 'new' tires. The fact is that although this type of tire is very unlikely to show its plies even after more than 150 laps, the drop in performance is very early (35-40 laps from what we have seen). In practice, the tires look immaculate from the outside, but lap times rise considerably. In winter, things get more complicated: to make it work properly you have to wait 10 laps - even in a race! The performance response also changes considerably depending on the chassis, something that did not happen so much with the tires of a few years ago. In some cases, tires with these characteristics tend to make certain chassis slide, while others, on the contrary, tend to stick too much.

If the objective is to reduce costs, the tire should work from start to finish in a fairly constant way. If a harder tire remains constant in performance for at least one hundred laps (with a difference of, say, half a second per lap), costs do indeed decrease. But if in racing, after 30-40 laps you have to change the hard tires because they are no longer performing, the costs actually don't go down at all! At that point, you might as well have a softer (slightly more expensive) but more consistent tire until you get to the plies. At this point, talking about hard tires would make sense only for amateur Sunday drivers who do not compete and therefore pay less attention to the drop in performance after 40 laps and who can find themselves with a tire that isn’t driven to the plies even after 150-200 laps (avoiding the related risks of explosion/puncture). Let's also consider the price: a set of tires can cost up to 200 Euro. Does it make sense in the racing world to use "unstable" hard tires, to be changed after 40 laps?

One proposal we've often heard from teams of all levels is that it would be better to use a higher performance tire in races - and consequently in pre-race testing - with fewer jolts or variations in lap times even if with a lower final life cycle? This might actually be one solution. Another would be to push for a single-compound philosophy, so as to standardize behavior and be able to work better with chassis tuning.

Created by: scorradengo - 25/01/22

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