Car Tyres Info

Mark_Hewitt

Premier wrote: »

The legal position on tyre speed ratings is that they have to be rated for the intended purpose of the vehicle.

However the manufacturer will recommend tyres that match or exceed the maximum design speed of the vehicle as the manufacturer doesn't know what the customer's intended usage will be. e.g. the customer may decide to take the vehicle to a track day or perhaps to Germany onto an autobahn without any speed restriction (if they can still find one)

I guess as insurers have to allow usage throughout the EU, then the German autobahn situation is one they have to consider a potential purpose they are insuring.

Most insurance I've had if you are taking the car out of the UK you have to tell them what countries you are going to and when you are going there.

I told More Than I was going to France and it didn't attract any additional premium (even for breakdown cover) but I wasn't insured for going to Germany.

Chippy_Minton_2

Premier wrote: »

I guess as insurers have to allow usage throughout the EU, then the German autobahn situation is one they have to consider a potential purpose they are insuring.

I still don't see how that could apply to a collision/claim in the UK.

SCOTTEX

I've had practical experience running a Vx Signum 2.2 petrol auto for 4 years & 42K. It originally came with Bridgestone Turanza tyres ( 225/55/16). Again they were noisy tyres but wore well. At the time of sale it still had one original left offside tyre left at 1.6mm. The fronts went at 22K and were replaced by Federal Formoza's which at the time of sale had done 20K and had about 2-2.5mm left. They were a lot quieter than the Turanza and I remember paying £ 55 each from Camskill. I had no problems with grip or uneven wear and would recommend them as a good value for money product. Hope this helps.

AdrianHi

On my current car I've had Continetal Premium Contact 2's which lasted about 20K miles but the fronts wore unevenly on the outside edge despite perfect alignment and tracking.
They were good in the wet, especially going through standing water.

My vote goes for Michelin Pilot Primacy HP's, 15,000 mile in and I see even wear and loads of tread life left. Although not quite as good as the coninentals going through standing water they perform as well if not better in every other respect including noise and ride quality. Have these tyres on both cars in the family, run flat version on my 3 series.
Michelin spend more on research than anyone else, perhaps they can get more life out of their rubber compounds without compromising performance.

Omega_1

Can anyone forsee a problem then with the Bridgestones from front put on rear and replaced with Pilot Primacy HP put on front ?

ailuro2

Premier wrote: »

Tyres are optimised by the vehicle manufacturer in conjunction with their tyre suppliers. This results in unique compounds for that type of vehicle & manufacturer (at least for the big car manufacturers).

Unfortunately, what you get in the after market is pot luck, so any comparison is quite meaningless as it usually doesn't specify the compound ... and even if it does, you wouldn't be able to specify it to buy.

unique compounds on OE = not strictly true - there's nothing to say the same compounds won't be used to make a replacement market tyre. They may have different profiles of products, different tread patterns, maybe differing amounts of rubber, and they will most certainly have been fine tuned for the car manufacturer, they will also be checked 100% for any defects and be made to tighter tolerances. But to rule out getting the same compound is an inaccurate leap to make.;)

A replacement tyre of the same type should last just as long as an OE tyre.

My advice is to buy what you can afford, it's only an area the same as the palm of your hand that's in contact with the road. Lots of good deals around at the moment - buy three get one free, energysavers will save 1/4 of their price in fuel etc....

darich

Rallydriver wrote: »

I've been in motorsport for 15 years and , although I'm not a chassis engineer (though I do know a couple), I am well read on the subject and I can tell you straight off that nothing is that simple.

These super low profiles just aren't liked in motorsport and there is good reason for that. On the road, so called "rubber bands" are just a fad for vain people.

So why to top end cars all have lower profile tyres than lower end ones?
A typical ford focus tyres size might be something like 205x55x16
A focus RS tyres is something like 215x35x19.
3series BMW typically is 205x55x16
M3 BMW is more along the lines of 235x35x19

Why is that?

The above are essentially the same cars but one is a base model while the other is a performance version.

Is it purely because the ford and bmw motor engineers are simply boy racers at heart and think it looks good or is it because the higher performance car will corner/brake/accelerate/respond better with the lower profile tyres??

Chippy_Minton_2

darich wrote: »

So why to top end cars all have lower profile tyres than lower end ones?
A typical ford focus tyres size might be something like 205x55x16

Well the basic Range Rover as a 255/55R19 tyre same profile as you Focus. At almost 65k would you call that bottom end?

tomstickland

darich wrote: »

I can corner faster in my own car with lower profile tyres than i can in my gf's car which has higher profile tyres.
Lower profile tyres deflect less and are more responsive under braking, steering and accelerating.
The trade off is a harder ride.

It's not really a trend, nor is it vanity....and there's a distinct advantage in having them if you have a performance car.

Up to a point that is true. However, the current profile sizes are more about vanity than performance.
I've got a good book on tuning and it lists recommended tyre sizes for enthusiastic driving and they are all higher profile that what most hot hatches come with nowadays.

tomstickland

darich wrote: »

Is it purely because the ford and bmw motor engineers are simply boy racers at heart and think it looks good or is it because the higher performance car will corner/brake/accelerate/respond better with the lower profile tyres??

It's because their marketing research shows that that's what people want.
Read the reviews in Evo mag etc and you're nearly always find that they don't like the lowest profile tyre choice available.

Furthermore, look at the skinny tyres rally cars use on ice or in the wet. Wide tyres offer less grip in the wet.

Drag cars use really soft, large tyres to give the best grip for launching.

The advice in the tuning book I looked at was the manufacturer's were pandering to the market and providing cars with tyres that were lower profile than they needed to be. People then complain that the ride is harsh and so run lower pressure in the tyres. They'd be better off with higher profile tyres and higher pressures.

I'm not advocating tractor tyres though.