Tyre Skip

[Tony Marshall]

Hi all, could anyone recommend the best tyre to minimise the dreaded cold tyre skip. We are on 20inch wheels.
Currently on Pirelli but have been told that Continental or Michelin are a better option ?

Thanks, Tony.

 

[Timrice]

It is a function of the steering geometry (see Ackermann effect), so there is little you can do. It is worse with stiffer rubber (I.e. in the cold) and with less tread. My experience on several cars is that there is little difference between tyres.

 

[Wollemi]

It only really happens in cold weather with summer tyres. If you put a set of winter tyres on then the “problem” will disappear.
There’s no real difference between different makes of summer tyres. Worn tyres are worse than new ones.

 

[911hillclimber]

Yes, exactly as said above. Mine does it in a very limited way in reversing on full lock cold, in the wet. Bridgestone tyres, 19" dia rims.

My AUDI A4 was much much worse!
My Skoda Superb does not do it at all, my old 911 does not either.
Just the geometry of the cars I think.
My 987.2 does not do it on full lock forwards.

Above about 5 mph there is nothing to report.

 

[Scrounger]

As mentioned, perfectly normal. As an addition, my wifes previous car (Merc GLC) did it a lot worse than the Caysters.

Dan

 

[ianthow]

Hi all, could anyone recommend the best tyre to minimise the dreaded cold tyre skip. We are on 20inch wheels.
Currently on Pirelli but have been told that Continental or Michelin are a better option ?

Thanks, Tony.

The best way to avoid this is to move off with the tyres straight ahead before turning the steering. Moving off with a lot of lock will tend to push the non-rotating front wheels straight ahead rather than allowing them to roll at an angle. Once the front wheels are turning, they are able to release the tread forces progressively rather than skipping as lock is applied.

 

[Motorhead]

Just to provide my take on this, Ackerman geometry is only applicable at very low speeds and essentially was derived for narrow-wheeled horse drawn carriages. Modern cars use modified Ackerman geometry commensurate with improved high speed handling.

The use of wide, low profile summer tyres designed for ambient temperatures above 7 degC makes them less suitable for winter use and leads to the front end juddering phenomenon often reported when reversing slowly at low temperatures. The wide tyre means that at or near full lock the outer edge of the tyre is moving faster than the inner edge, leading to a rotational moment about the centre of the contact patch and this, compounded by high sidewall tyre stiffness and a less flexible rubber compound and tread block design leads to a stick-slip mechanism at the contact patch which is sensed as the juddering of the front end of the car. No doubt front suspension geometry is also playing its part here due to angular conflicts between the two wheels?

Although manufacturers will use different tyre compounds and tread patterns, some tyres could be less susceptible to the juddering. The best solution is to fit either winter or cross-climate tyres with suitable compounds and tread patterns for winter use and on smaller diameter wheels with taller, more flexible tyre sidewalls.

Only my tuppence-worth of course!

Jeff

 

[ianthow]

I agree with everything Jeff says here but, for those not willing to invest in spare wheels and tyres for winter use, moving off with no or minimal lock appied will help reduce the severity of the 'skipping'.

For those unfamiliar with the Ackerman principle, and why it needs to be modified for modern wide tyres, the link below provides an explanation.

Tech Explained: Ackermann Steering Geometry

In this Tech Explained article, we will cover the origins and purpose of what is known as Ackermann Steering geometry and how its variations can affect tyre performance across a vehicle's operating range.

www.racecar-engineering.com

By the way, I do have winter wheels and tyres and strongly recommend their use by anyone using their Porsche all year round.