Tyre sizing

[jonbarrett]

My current tyres are: 255/35/ZR/18 (Rear) and 225/35/ZR/18 (Front). I need to replace all four. The tyre chap says this is the wrong mix and the fronts should be 40s not 35s. He said there are two benefits. Firstly, the car would then have the same rolling circumpherence front and rear. Secondly, because this is the right setup the fronts will be more plentyful and cheaper.

The only problem I can see is that the outside diameter of the front would be a little larget that current and might hit the body.

I need some advice rather fast because I need to change the tyre for its MOT on Thursday.

[ridds]

Yep I think the fronts were 40's from the factory. Will totally depend on your body shape/thickness as to whether your tyres touch or not.

[Gazzab]

The tyres (18s) were originally 35s from the factory both front and rear. Later they changed to 40s all round. As I recall it. I would stick with 35s if that is what you already have got.

[warpig1]

not long had 35 series rubber on my 18's, well chuffed, ride and handling are spot on

[touching cloth]

Specs on the last Cerbera show it as 225/35 so gawd only knows why they sent some out with 40's if they then went back to 35. Most people I know run 35 so if that is what you had before then I would just stick with that.

Oh and Gazzab, what you still hanging round here then ???

[Byker28i]

I thought it was 35 profile on the 18's and 40 profile on the 17's

[jonbarrett]

The tyre guy is trying to sell me Avon ZZ3s. Any comments?

[JR]

jonbarrett said:

The tyre guy is trying to sell me Avon ZZ3s. Any comments?

Get a different tyre guy. F1 GSD3s (or Falken 451s on a budget) seem to perform best.

[ancol]

i have just re shoed with toyo proxes had bridgstones before, you will get lots of advice from different people on various manufacturers its hores for courses really go with your own gut feelings after reading all replies, btw my tyres now stick like sh@t to a blanket after doing about 600 miles i was chucking round corners the weekend having plenty of fun

[jonbarrett]

I've found some Toyos locally so I'll give them a go. Everyone seems to like them, including some TVR garages I've spoken to.

[Byker28i]

Toyo's are great dry weather tyres. I prefer eagle F1's as an all round tyre. Great grip in the dry and very predictable in the wet

IMHO of course

[Full SP]

225/40 18 tyres were never fitted to the front of Cerberas by the factory. Having the 40 profile at the front might indeed give it the same rolling radius as the rear (but so what???) - more importantantly it will raise the front of the car thus reducing its rake; the rake being a critical factor in aerodynamic (i.e. high speed) stability.

The moral of the story: tyre outlets might know a lot about tyres but they don't necessarily know a lot about cars (especially the more specialist variety). Thank heavens for Pistonheads to help you get the RIGHT advice. P.S. T1-Rs are really very good in ultra-low profile form.

[brummiewedge]

40's on the front WILL rub, been there and done it, Pirellis espesh as they are bigger, they are in danger of rubbing when the suspension is unloaded and on lock, you might get away with putting up with it but i wasnt willing to risk it, so took em off.