What Tyres Do I Need?

[02_FNE]

Ok so ive got an r32GTR with the standard 16x8 +30 with 225/50

and ive just bought a set of rims that are 18x9.5 +25 and from ive read everyone with these size and offset rim has got 255/35's but i was under the impression that with each inch in rim size you go up that you go down 5 series accordingly... as example 16 has 50 standard and 17 has 45 so i assume that 18 would be 40 series? so why does everyone have 18inch rims but have 35 series tyres? whats the go? please explain? wouldnt it put the speedo out?

[Taleb Tyres]

theres no rule that you go down in series by that much for every inch, although it may appear often.

its the whole rolling diameter that affects the speedo not just the profile of the tyre, use an online tyre size calulator and you can work out the best size for your car.

[blind_elk]

I thought standard tyres were 55 profile.

As a "rule of thumb" (a very rough guide), you should be running a 35 profile on 18" rims (10 units profile per inch change in wheel diameter). But, as Taleb said, you then need to start checking more definitively as to the exact tyre size that gives the right rolling diameter. But I would start in the 35 profile sizes.

[Bullet32]

The middle number in tyre measurments represents that tyres aspect ratio, its not a measurment in mm... For example - 265 / 35 R18 = 35% of the tread width (approx 265mm) equals the height of the sidewall, therefore you have to factor in the tyres width and aspect ratio together to get the overall diameter.

If you are changing from a 225 / 50 R16 with an approximate o.d of 631mm to an 18" tyre that needs to be wide enough for a 9.5" rim then your best bet is a 255 / 35 R18 (although it will be a little streched on a 9.5") which will have an o.d of about 653mm, this will help to keep your speedo and gearing as close to factory as possible.

Note: Overall diameters will change from brand to brand, as tyre sizes and o.d's are only comparable within each brand so do some checking before you buy.

I hope this helps

[02_FNE]

oh ok, i understand what you mean..

so what tyre would be best? ive gotten prices for a few, Falken, Kuhmo, and nankang in a 255

so would you suggest i get a 265?

as it is i figured 255 is big enough + i dont want to have to modify the car to fit the rims so im hoping it all works out..

i seen in the other thread that people with 255*35*18 could fit with out mods.. so i hope that works for me..

my other concern is that my car is low..

[Bullet32]

I would suggest fitting the rim to the car without a tyre on it to see how close it will be to the guard (obviously dont lower the car down onto the ground though ).

Then if you have enough room go for the 255's because they will be as close to standard overall diameter as you will get, the other benifit will be that the walls will lean inward slightly giving you a bit more clearance.

As for brand of tyres - Federal 595's are a great tyre for the right price (Im a bit bias though), 595's are excellent for dry traction and they arent overly expensive, I use them and have all my friends using them and the only complaint I have had is from a mate of mine who goes drifting - he said that they grip to much

Have a look at www.federaltyres.com.au

[02_FNE]

yeh true ill do that.. as for the federals what are they worth.. ill have to make some calls,

ive been looking at the falken and kuhmo's..

are the federals good on wear.. and what are they like in the wet?

[infamous_t]

My R32 GTR runs 18x9 (maybe 9.5), 255/35, stock suspension(lowered springs up front) no problems.

Edited March 27, 2008 by infamous_t

[Bullet32]

yeh true ill do that.. as for the federals what are they worth.. ill have to make some calls,

ive been looking at the falken and kuhmo's..

are the federals good on wear.. and what are they like in the wet?

Shop around, you might find a dealer that will look after you on four tyres, use the dealer locator on the website to find one in your area.

The 595's will normally last for about 20 - 25,000kms but if you look after them theres no reason that you shouldnt get 30,000kms from a set.

As a dry traction tyre the 595's are excellent, in the wet they are not bad either, I find them to be pretty predictable and controllable in the wet and if you dont have a lead foot they will disperse the water pretty well and provide good traction.