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The odds of someone spiraling out of a corner and hitting you is far less than someone failing to come to a stop in a timely fashion. Who in their right minds drives on the limit of lateral grip on the highway???

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etc etc... Directional tyres, asymmetric tread patterns went some way to helping but are more to do with straight line stability but some are particularly good at water diversion on wet roads.

Tread on a tyre on a dry sealed even road does nothing to contribute to 'grip'... either cornering, braking or accelerating. Thats is why F1 and all other racing cars run slick tyres (NO tread)... to maximise grip (contact patch friction) in the dry (and perhaps also in the damp too!)

However, tyre tread indeed has a massive contribution to play in the wet when there is water 'standing' between the road surface and the tyre contact patch, shedding water at many litres/second when moving which allows them to maintain contact with the road surface beyond what is theoretically possible above aqua-planing speed, 9√p, where p is tyre pressure. So at 40psi, this predicts a Defender will aquaplane at 56 mph... when in reality it's probably more than that, given experience on wet motorways at 70 mph.

Road cars legally must have tread... because the roads get wet from time to time!! 4WD specialist tyres have more because we like to play in mud/sand/rocks etc etc!

(The Boeing aircraft I used to fly had the tyres inflated to about 170 PSI... which gave an aquaplaning speed of about 121 mph. However, they also had a simple grooved 'circumferencal tread' which moved them up towards the normal landing speeds of circa 145 mph...)

All good stuff.  YOLO... You Only Live Once...

Rickydodah wrote:

anti lock braking can cause the tyre with the best grip to do the least of the braking.

Rickydodah wrote:

Interestingly as you've mentioned lateral forces versus braking efficiencies this tends to be more influenced by car design and weight distribution,

Rickydodah wrote:

Directional tyres, asymmetric tread patterns went some way to helping but are more to do with straight line stability but some are particularly good at water diversion on wet roads.

Cupboard wrote:

Have you seen this video miker?



Start at about 1 minute.

Excellent video and great advice

Cetane wrote:

Rickydodah wrote:

anti lock braking can cause the tyre with the best grip to do the least of the braking.

Absolute tosh

Do you understand how ABS works?

The system looks for a wheel locking then "releases" it. So if a wheel has more grip it will retard the vehicle more before locking and subsequently being unlocked by the ABS system.

Rickydodah wrote:

Interestingly as you've mentioned lateral forces versus braking efficiencies this tends to be more influenced by car design and weight distribution,

Physics applies to all cars, and they will all have load transfer to the front under braking. That is unless the CoG is below the tyre contact patch.

Rickydodah wrote:

Directional tyres, asymmetric tread patterns went some way to helping but are more to do with straight line stability but some are particularly good at water diversion on wet roads.

Wrong. Asymmetric tread allows water to be cleared in a straight line but offers a more "dry" focus in cornering. Have another look at a good asym tread. The outside usually has fewer channels/sipes and more rubber in contact with the road. As you load up the tyre laterally the contact patch changes and you will be running on thie dry focused part. This layout allows for tyres to be a decent "all rounder"

Please don't lecture me on vehicle dynamics. It's my background.

 I started with nothing and still have most of it left!