(Large) Tyre sizes.....

[Ericc B]

see this is why i hate picking wheel sizes out you say 10" on front and 265 yet steeda above says they run 275 on 9.5"

Well you can run that, it's just not optimal. Standard GT rear tires are 275 on 9.5 as well. I get your point though, there is no perfect match in 20" for the GT sizes. At least not without getting a huge stagger like 255 front and 305 rear which will drive like crap.

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[Enoch]

I used this as a guide...

I have 10" fronts and 11" rears. So I've gone 285f and 305r

 

[Nookie]

I originally referenced an identical guide to the one [MENTION=13920]Enoch[/MENTION] has posted, but having received my new rims and taken 'real life' measurements, then completely ignored it and recalculated things myself - so I'm running 20x9 et25 front with 265/35 MPSS and 20x10.5 et45 rear with 295/35 MPSS-K1 and the fit is absolutely perfect (flush front and rear). There's no bulge or stretch on the front MPSS tyres and a very slight bulge on the rear tyres which is only due to the fact that they are MPSS-K1's which have a rounder sidewall profile.

The tyre and wheel situation could give Einstein a headache sometimes. It has to be remembered that wheel sizes are based on the bead diameter and bead width, but tyres sizes are based on the bead diameter and section width.

Take just about any alloy wheel and run a tape measure over it and you'll find that the rim to rim diameter is around an inch bigger than what you may have thought (so if it's a 20" wheel you'll find it's normally about 21" outer diameter) and the same for the width (so if it's a 9" wheel you'll find it's normally about 10" outer width).

My logic was my 9" fronts are in reality 10" wide which equals 254mm and the standard MPSS have a flat sidewall so + 10mm approx. for a bit of rim protection gave me a 265mm optimum, and my 10.5" rears are in reality 11.5" which equals 292mm and the MPSS-K1 tyres have a slightly rounder sidewall so +5mm approx. for a bit of rim protection gave me a 295mm optimum.

What offset are the wheels you're looking at [MENTION=21204]kapiteinlangzaam[/MENTION] as this is relevant?

 

[kapiteinlangzaam]

I've got no idea of the ETs. Even Velgens own site doesn't list the split 5 wheel yet.

Maybe [MENTION=22385]Steeda UK[/MENTION] could update us with the ET info?

 

[Manders Mustang]

I used this as a guide...

I have 10" fronts and 11" rears. So I've gone 285f and 305r

I used this too to buy my new tyres. I got quite lucky. I found 4x 275/40/19 MPSS's for £540 :lol::lol::lol:.

 

[Steeda UK]

Quick reply is my personal recommendation rather than anything "official", but tyre choice depends on the use and what the end user wants.

My personal normal recommendation for "street" user 20" wheels is 265/35/20 front and 295/35/20 rear which give a meaty section and nice muscle car look. However if you want track action you might want to maximise rubber all round for high speed cornering and maximum braking, or if you are sprinting you might want a lot less rubber for maximum nimbleness. The "look" might also influence the width choice, with Carlos Fandango leading the way stylistically....

As with most things "car" (and life) there is no one "right" answer.... it's usually "it depends"

 

[kapiteinlangzaam]

Finally ordered my tyres today.

Ill absolutely agree its a right old headache picking the sizes... moreso as some tyres are not available in the front and rear sizes.

In the end ive gone for:

Vresestein Ultrac Vorti R

UHP tyre. Rated in the ADAC tests as better than the MPSS in dry grip and braking, and about 8/10ths as good in the wet.

The biggest difference is the price, particularly as Vreds are on offer here at the moment.... so much so that the rears were cheaper than the fronts!!

In order to find a matching set of 4, ive ordered:

Rear: 305/30 R20 @ €165 each!!
Front: 265/35 R20 @ €205 each

All done for €750. PS4S or MPSS were over €1200 for the set of 4.

I actually really like Vred tyres, so ive no qualms.

Thanks for the advice all.

 

[hinch]

doesn't that make your overall diameter different between front and rear though now ?

 

[kapiteinlangzaam]

doesn't that make your overall diameter different between front and rear though now ?

Near as makes no difference.

1.25mm difference in diameter, with the fronts being slightly larger. This is actually a plus for me, as at the moment the car has a little bit too much +ve rake from the coilover install, this will help that (a little!).

 

[Centurion07]

I ran the Ultrac Vorti's prior to switching to MPSS.

As you've said, the difference in performance is far less than the difference in price would suggest.

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