VF2 SSV advice on moving to smaller diameter wheel size

[RevNev]

For track days (and you don’t care about speedo accuracy) the 40-series would have to be better; stiffer firewall & less weight, also lower … I’ve forgotten the correct term, rotational momentum (ie. the car’s fighting the tyres less when accelerating as the bulk of the tyre’s mass is closer to the axle).

Check around for available tyres though, you may find that it’s hard to find good tyres in the right size. That might end-up dictating what you go with.

*edit*
Just had a look at the Jax site; interestingly they don’t have any Michelin tyres in 245mm & 40-aspect for an 18” wheel, but they DO have a 35-series Pilot Sport Cup 2 Connect … I don’t know what the Connect part is, but the Cup 2 is a very good road+track tyre, almost a semi-slick and probably the style of tyre you’d want if the track isn’t dry. Dunno if a 35 is too small for some reason, nor if you want to focus solely on dry days & stick to slicks …

A bit of sidewall meaning a tyre that isn't too low in profile is easier to drive the car harder on the track as a car moving around on the tyres a bit is easier to catch when the tyre breaks traction. A low profile tyre is more like breaking traction in the wet and taller profile tyre is like breaking traction on dirt. M3/M4 BMW's are faster on 19's than 20's even with a good race driver steering the car.

We use Cup2's on our M4 for track days 265/35x19 at the front and a 315/30x19 at the rear. The "Track Connect" one's have a sensor inbuilt into the tyre for datalogging but are otherwise the same.

Here's a set of our Cup2's virtually brand new

 

[VS 5.0]

faster on 19's than 20's

Top Gear Aus tested a VE with both.

19s also faster.

 

[RevNev]

Top Gear Aus tested a VE with both.

19s also faster.

Most of the fast circuit cars don't have low profile tyres, Formula 1, NASCAR, V8 Supercar tyres are all fairly tall sidewalls. 20's look the best on a VE/VF and they work fine on the street, but they're not the best size for maximum speed and handling. On their more track dedicated cars, BMW and Mercedes use 19's on the front and 20's on the rear and the base models, 20's all round.

 

[Forg]

Most of the fast circuit cars don't have low profile tyres, Formula 1, NASCAR, V8 Supercar tyres are all fairly tall sidewalls.

How much of that is due to regulation to keep ‘em all the same & potentially add the same limitation for all?

 

[vc commodore]

How much of that is due to regulation to keep ‘em all the same & potentially add the same limitation for all?

Interesting question...I do know, they V8's have 2 different height tyres.....A 650 and a 680 height, with the same width.....There is a wider tyre too, which is a different height again....I'll try to remember Tuesday to get all sizes for the V8's if people wish....

 

[07GTS]

F1 has gone to 18'' rims for 2022, will change it a bit as the squish in the side walls was part of the suspension setup, it may also help stop the tyre failures from last year, less flex is less heat created within the tyre

 

[RevNev]

How much of that is due to regulation to keep ‘em all the same & potentially add the same limitation for all?

If they're on a controlled tyre, they're all in the same boat, but they'll tend to select tyre sizes and profiles that provide the better handling based on several test driver opinions of various tyres.

 

[vc commodore]

If they're on a controlled tyre, they're all in the same boat, but they'll tend to select tyre sizes and profiles that provide the better handling based on several test driver opinions of various tyres.

Kumho V8's run 3 or 4 different size and profiles with that series.....Those cars are ex-main game cars.....

They run the 17" tyres and 18" tyres....

I'll try to remember to get all the sizes on Tuesday they run and post up

 

[RevNev]

Kumho V8's run 3 or 4 different size and profiles with that series.....Those cars are ex-main game cars.....

They run the 17" tyres and 18" tyres....

I'll try to remember to get all the sizes on Tuesday they run and post up

The Kumho tyres they did run were 280/680x17 and 280/680x18 on the later models.

 

[vc commodore]

The Kumho tyres they did run were 280/680x17 and 280/680x18 on the later models.

2 other sizes ran as well....From memory and will double check Tuesday, were 280/650X18 and 310/680X18 or it might have been 310/650X18...