Tyre Size Options & Combinations

[Avalanche]

I currently have 225/35/18 fronts and 255/35/18 rears (Goodyear F1's).

I'd bought a set of new 18" spiders specifically to fit with winter snow tyres.
Come next summer I wanted to replace the Goodyears with Toyo R888's.

Now I'm being told the R888's don't exist in 225's and I can't find snow tyres in 225...

Reading past threads it seems that I don't necessarily have to stick with the current sizes, right?
E.g I've seen quotes of F:235/40/18 and R:245/40/18
a) So as my spiders are 18", that can't change, right.
b) I could change the "aspect ratio in % (the height of the sidewall divided by the tyre's width)" from 35 to 40 on the Front, as long as the Rears change too, right? Understand this just makes the ride a bit softer, downside is cornering, right?
c) Regarding the "tyre section width in millimetres". Do the Rears have to be greater than the Fronts? Can they be the same - the front spider is slightly smaller, right? Do certain ratios have to be respected rear<-->front? Are there limits for a Tuscan with 18" wheels?

If anyone can clarify for me, I'll restart my tyre search.

many thanks!

[The Surveyor]

Can't help you with all your questions, but if it helps, the Tuscan II 's' models had 255's both front and back.

Paul

[The Tivster]

I'm running 255 on both front and back of a Tuscan 1. The car had these fitted when I got it and I'm told by my local indie that it appears to ride better on the wider front tyres.

I guess that's why they changed on the mark 2's.

[Avalanche]

Thanks for this great news. I guess we can assume we have the same spider sizes, so I'll just go ahead and put 255's on the front as well!

[WISHY]

255 's all round on a 2003 S and rides great!

[Avalanche]

Power gave me new geometrics for 255's alround.
I've bought 4 Dunlop snow tyres in 255.
Will let u know when they're on and how they do in rain/snow!

[s6boy]

Is there a big difference between 235 and 255 geometry?

[Fume Troll]

Avalanche said:

I currently have 225/35/18 fronts and 255/35/18 rears (Goodyear F1's).

I'd bought a set of new 18" spiders specifically to fit with winter snow tyres.
Come next summer I wanted to replace the Goodyears with Toyo R888's.

Now I'm being told the R888's don't exist in 225's and I can't find snow tyres in 225...

Reading past threads it seems that I don't necessarily have to stick with the current sizes, right?
E.g I've seen quotes of F:235/40/18 and R:245/40/18
a) So as my spiders are 18", that can't change, right.
b) I could change the "aspect ratio in % (the height of the sidewall divided by the tyre's width)" from 35 to 40 on the Front, as long as the Rears change too, right? Understand this just makes the ride a bit softer, downside is cornering, right?
c) Regarding the "tyre section width in millimetres". Do the Rears have to be greater than the Fronts? Can they be the same - the front spider is slightly smaller, right? Do certain ratios have to be respected rear<-->front? Are there limits for a Tuscan with 18" wheels?

If anyone can clarify for me, I'll restart my tyre search.

many thanks!

Snow tyres? You're my new hero!

Cheers,

FT.