21" vs 20" wheels

[Bluesnose1812]

.... I do think the 21" seems to fill the wheel arches......

It's an optical illusion. The diameter and circumference of 18,19,20 and 21 wheels and tyres is the same. The only difference is the tyre wall thickness

That’s not strictly true though as 20” and above are wider and therefore fill the arches more than the smaller diameter wheels.

They may be wider but the profile ratio is different. If there was any difference in the diameter of the whole wheel then the speedo would have to be recalibrated.

[Kleynie]

It's an optical illusion. The diameter and circumference of 18,19,20 and 21 wheels and tyres is the same. The only difference is the tyre wall thickness

That’s not strictly true though as 20” and above are wider and therefore fill the arches more than the smaller diameter wheels.

They may be wider but the profile ratio is different. If there was any difference in the diameter of the whole wheel then the speedo would have to be recalibrated.

Yeah I know the rolling diameter is the same, what I’m saying is the wider wheels fill the arches more because they are wider and sit closer to the wheel arch. This is why cars that came with 20” and above have the little black arch extenders/protectors.

[Bluesnose1812]

That’s not strictly true though as 20” and above are wider and therefore fill the arches more than the smaller diameter wheels.

They may be wider but the profile ratio is different. If there was any difference in the diameter of the whole wheel then the speedo would have to be recalibrated.

Yeah I know the rolling diameter is the same, what I’m saying is the wider wheels fill the arches more because they are wider and sit closer to the wheel arch. This is why cars that came with 20” and above have the little black arch extenders/protectors.

I see where you're coming from

[Deleted User 4788]

I have 21" Spyders with air. I don't regret it even when cleaning them.
Go with what you want, everyone has their own opinions, .
Your'e money your choice.
If I'd listened to half the people on here I wouldn't have the car I've got today

[Deleted User 4788]

Before I got the new S I had a 2nd hand 69 plate S on 19" alloys.
It was like riding on a bouncy castle. Granted it certainly smoothed the pot holes out and uneven roads.
Prefer the ride on my new S with 21" and Air, far better.

[Skyway]

I have 21" Spyders with air. I don't regret it even when cleaning them.
Go with what you want, everyone has their own opinions, .
Your'e money your choice.
If I'd listened to half the people on here I wouldn't have the car I've got today

I'm sure the half you did listen to were a help though

[Percymon]

I had 21" and PASM, no complaints on ride quality in normal setting, even on the dreadful roads we have locally. Handling another matter, far too much roll - sports setting helped but its no sports car and needed better roll stiffness imho

[rhinoman]

For looks I'd choose 21's, we had 21's on our previous Q7 and it had many many many refurbs over the six years we owned it. On air, the ride was fine.

Our Macan is also on air as well but I chose 20's this time and so far so good. Ride is great. Handling is plenty sharp, very impressed and my car is a 997.2. If only I drove the Macan it it would probably have 21's for looks but its so much less stressful with 20's and the extra sidewall for both me and the wife

Spiders are very slow to clean though even with a ceramic coat, wouldn't choose them again.

[ultrabelse]

I had 20” with air and now have 21” with air

The ride on both is the same to me (and very good at that)

The 20” were much more forgiving on the kerbs but still not infallible

The 21” look much better to me are not forgiving at all but I have surround cam on this latter car which massively helps mitigates the risk

In conclusion I’d go 21” with surround cam and have your cake and eat it!

[Skyway]

I think the Gen 3 standard wheels look great and are just less volatile than the 21s