Advanced Driving Hub

akirk wrote:the z3 has different tyres front and back - quite different, as do a number of more sporty cars, so that is an obvious exception...

That applies to a fairly small proportion of the population, but the principle of keeping better tyres on the back still applies.

akirk wrote:would it make a difference if the car is FWD / RWD / 4x4 / ???

No, the risk is the same.

Will odd size tyres or tread depths cause a problem with my 4x4 all-wheel drive system?

Yes, all 4 tyres must be of the same size, circumference, speed symbol, load index, construction, manufacturer, brand (tread pattern) and degree of wear. Subaru recommends that the tyres are rotated every 10,000km (6,200 miles). Please check your Owner’s manual for further information.
- See more at: http://subaru.co.uk/customer-support/wi ... qGKbi.dpuf

Nicked from Subaru 'site, also applies to other awd and 4wd systems.

Gareth wrote:...I quote advice from tyre companies but follow advice from StressedDave, happily they are the same.

Spooky that

akirk wrote:then would it make a difference if the car is FWD / RWD / 4x4 / ???

Strictly speaking, no.

The idea of "good tyres on the back" does not stem from which tyres are connected to the engine, but rather from which tyres are connected to the steering wheel. The tyres are not connected to the wheel are those that provide the stabilising effect that counters the destabilising side-effect of steering.

Still, there are good arguments for having good tyres on the front (namely, good braking) so I hold that good tyres belong on all wheels. A big difference in tyre wear or degradation between the axles is never a good thing.

That makes sense, my thought process though was around modern cars and the electronic systems we now see, so my Skoda Octavia Scout has I think a haldex 5 system where the % of drive to each wheel is decided electronically, surely the quality of tyres on the wheels is going to affect that decision in some way?
Alasdair

This page has quite a good explanation.

http://kumhotyre.co.uk/kumho-news/shoul ... t-or-rear/

Kwik Fit, Michelin and some other tyre manufacturers give the same advice.

GTR1400MAN wrote:This page has quite a good explanation.

http://kumhotyre.co.uk/kumho-news/shoul ... t-or-rear/

Kwik Fit, Michelin and some other tyre manufacturers give the same advice.

Quote from that 'site.

"Hi Daz – the rationale behind putting the new tyres on the rear is that understeer is easier to control than oversteer for the average driver. It’s the lesser of two evils. Added to this, if a tyre was to suffer a puncture or premature failure it is again preferable that this happens on the front axle because again it is more controllable. Many are now recommending this set-up which is also suggested by The AA. Hope this helps."

Note, "average driver". Then too, my post about AWD should be remembered.

During Volvo winter driving courses on ice, they let us play with winter tyres on the front and summer tyres on the back of front wheel drive cars. The cars were hilarious - extraordinary levels of oversteer at really slow speeds. We are talking full opposite lock at 5 mph. They called them the 'wibbly-wobbly' cars.

Actually, it's an example better made at an higher speed. The idea is that an unstable car (as would be the case where the rear is significantly more worn than the front) can reach a speed where - in a straight line - any little excitment (even a small bump) can cause a spin.

Still, I hold that if the difference between both pairs of tyres are too pronounced - both aught to be replaced. Bad tyres on the front are also never a good idea.