This may be slightly stupid question but what are the pros and cons of different wheel sizes?

Is there much difference between, say, having the 17 inch and the 18 inch wheels on the Vrs? Is one clearly superior to the other or is it more a matter of taste (or fashion)? Presumably the other specifications of the car (acceleration, mpg, and so on) will be unaffected. Is it, then to do with handling? If so, is it a trade off between traction and comfort? The fact that the 18 inch wheels are now standard when previously they were an upgrade suggests that they are better, but are there any reasons to prefer the 17 inch (or not to bother about it at all)?

I have driven both but only to a limited extent in a few test drives and not one after the other. I don't think I would have been able to say which size was on the car without having had a look first.

I don't think its a stupid question at all but you can get a lot of silly answers. I have seen some good info on this site about the scientific reasoning behind it and it was not that straightforward. Summary was:

1.) Larger wheel for same rolling diameter means lower profile tyres

2.) In many cases wheels with lower profile tyres are also wider

3.) All thing being equal wide tyres can de made of softer compound rubber without overheating

4.) Softer compound rubber grips better hence more traction.

BUT all things being equal low profile tyres have less resilience in them so you will feel the bumps more.

On the other hand if you are asking about varying only the size of the wheel without varying the rolling diameter or width of tyre then there should be no effect on traction but there is another effect on the handling. I cant remember the reasoning there, something to do with the slippage angle on the steering. High profile tyres can also throw you back quite harshly when regaining traction in a slide.

I think you'll find with low profile tyres that their sidewall is is smaller which means there's less flex-and as its already been metioned you feel the bumps a lot more than a larger profile tyre-the good thing being that having less flex they react quicker to any changes of direction giving a sportier tighter line when on the limit.

The main difference is ride quality really. I'd recommend trying two cars, one with 17s and one with 18s.

On the Octy, the sidewall profile drops one notch between the two, from 45 down to 40. 225/45/17 size tyres on one, 225/40/18 on the other.

A lot of it is down to personal preference, but 18s do look quite a bit better on the car

Cheers,

Steve

Little difference I feel. The FL VRS I drive has 18 inch Neptune wheels but the ride is not harsh.

We use to have a Leon Cupra on 17 inch and that was much harsher so it depends on the suspension and wheel combination.

18 inches are standard on VRSs now but the suspension has been changed also I gather.

I tend to live by the rule, with all modern cars and motorcycles, they are so advanced you cannot improve on them over factory settings. They have spent billions developing in interaction between suspension, tyres brakes etc so best not to mess. If you want more power, less body roll or whatever chop the car for one that fits that spec as 99 times out of 100, or more, changing settings makes overall performance worse. What do I know I only have a BSc where as the VAG guys are professors etc.

Edited 21 September, 201015 yr by lol

You note that change because the Cupras are generally running insufficient damping - Seat seem to feel that this attributes to a 'sporty' ride... :wonder:

Can't agree with you on not being able to improve cars from the factory though I'm afraid. But we'll agree to differ! They're built to a budget after all, so some areas will be compromised by design, to keep to a set build cost.

Steve

I will be running 205/ 55 /16's on my vRS in the winter.

The ride should be a little softer, but not expecting much..

Its all down to the suspension setup

I think you'll notice a fair difference Chris, but will be interesting to hear your feedback when you swap over.

Steve

You note that change because the Cupras are generally running insufficient damping - Seat seem to feel that this attributes to a 'sporty' ride... :wonder:

Can't agree with you on not being able to improve cars from the factory though I'm afraid. But we'll agree to differ! They're built to a budget after all, so some areas will be compromised by design, to keep to a set build cost.

Steve

Cupra felt like its spring rate was too high.

Not sure which component you are thinking can be improved, tyres maybe. Always worried about people chipping cars when brakes etc not up to the provision of more power. 1.8 TSI I have ordered with DSG which, for instances, is not suppose to take more than 250 Nm so you clearly should not chip it else you would exceed the maximum allowable torque.

As Users we do not know all the tolerance etc of these machines and to tinker, with anything more than which tyres one prefers is something the Skoda, VAG and insurance companies regards as reason not to pay out on warranty, insurance claims etc IMHO.