The Expert Advices | 8 curious facts (you certainly will not know the 4th) about kart tyres

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The Expert Advices

8 CURIOUS FACTS (YOU CERTAINLY WILL NOT KNOW THE 4th) ABOUT KART TYRES

TKART Staff

16 October 2020

The second and last episode of the article "Ask" with Stefano Mantese as the protagonist. After submitting your questions about tyre pressure, Stefano decided to answer even the most curious questions we selected from the hundreds we received.

1 What pressure can a tyre reach before it explodes?
Simon S.

Kart tyres resists up to 15 bar without suffering any structural damage or consequences for the tread compound.
This is therefore a much higher value than the maximum inflation pressure of 4 bar. In fact, this limit is designed more to avoid damaging the wheels than the tyres, whose mechanical properties are not affected in the slightest when you force the them a little using the compressor when you fit them. This does not mean that you have to exaggerate, as many do, when fitting tyres: you can also leave them under pressure for a minute or until the heels sit on the edge of the wheel by themselves, without continuing to pump air into them to speed up this process.

Grip and high performance: this is what we think of when we see a kart on two wheels, like the one in action shown on the left dating back to the 1990s. However, it makes no sense to compare tyres from different eras (a modern kart is shown on the right) which conform to technical regulations from different historical periods.

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2 Is the performance of modern tyres worse than those of 20/30 years ago?
Gianluca G.

Many attribute the alleged drop in performance to the change from natural to synthetic rubber. In reality, natural rubber provides absolutely no grip and has always been used only in the carcass compound or in the sidewalls of tyres. The polymers of the tread have always been of the synthetic type combined with oils and resins that have taken the place of aromatic oils, which have been abolished because they are carcinogenic.
The reason why many think that tyre performance in recent years has worsened is due to the fact that the federation requires a minimum duration of 150 km (for medium tyres) and 250 km (for hard tyres), while previously with super soft tyres it was more or less 30 km.
Paradoxically, tyres now last longer because the materials are much better than before, but since they leave less rubber on the track, they also wear more.

3 Is the performance of hard tyres more consistent?
Jacopo D.

False! It is often the other way around. In fact, the greater grip offered by a tyre with a softer compound only allows you to maintain a higher speed when cornering and to delay the braking point. It seems trivial to say, but the very fact that the tyres do not slip, or in any case do so in a limited way, protects them from overheating. This risk is greater with harder tyres, especially in the summer months or when the asphalt temperatures are close to 45°C. In these cases, the decline in performance of a soft tyre is much more limited than that of a hard tyre.

The worsening in terms of lap time (compared to the best lap) of a hard compound tyre (for example, the green Vega) can be up to double that of a soft compound tyre (such as the white Vega).

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The worsening in terms of lap time (compared to the best lap) of a hard compound tyre (for example, the green Vega) can be up to double that of a soft compound tyre (such as the white Vega).