Hi

I did just buy some 18" Compomotive for my FD.

It is 9 x 18 ET 44 in the front and 10 x 18 ET 44 in the back.

What would the perfect size of tyres be if I do not want to roll the fenders..??

I want them to be as wide as possible. Is 275/35-18 in the back ok..??

Thanks

 

I would run 255/35 front, 275/35 rear.

You can fit a 285/30 in the rear, but it's going to be significantly shorter than a 255/35 front. A 245/35 would work in that case.

 

depending on the tire make and model there are some good combos that work with a nice and short O.D. both front and rear in that 18" size range.

I thought some tires had a 265/35 that was similar in o.d. to the 285/30 but I cant rememeber. a 255/35 might also work well, but it all depends on the tires exact real world measurements, you cant just go by the size callout on the sidewall.

 

Ok Thanks. I think I will try 275/35 in the back. Does the 255/35 fit in the front with out touching the fender..?? Or is it more safe to have 245/35..??

 

Hmm... I would try the Yokohama A048 but they only makes them in 265/35-18 and 285/30-18 for the rear tyres. Do you think the 285/30-18 would fit to the car without touching the fender..?

In the front they make 245/35-18 so i think that is what i am going to try...

 

I did some calculating yesterday and came up with this combo:

245/40/18 Diameter = 25.56
275/35/18 Diameter = 25.58

OEM 225/50/16 Diameter = 24.86

These are almost identical to one another in diameter and also very close to the stock size. Your speedometer will read %2.9 lower than your actual speed.

 

go with the 255 front and 275 rear. thats what im running with no prob and you have better offsets than me. i will put 5mm spacers in the rear and be the same 44 in the back as you but if you check out the pic i posted you have room. mine are 49 in the back. https://www.rx7club.com/showthread.p...29#post7994629

 

You'll want to go a little shorter than that up front. Tall tires are what rub up front, the wheel wells are small. Go w/ the 255/35

 

I don't understand really.. Cuz I'm listing the actual diameters and it looks like those tire sizes are VERY close to stock.

Why would it rub when the circumference is only very slightly larger than stock?

IE the stock (225/50/16) Circ. is 78.09
The 245/40/18 Circ. 80.79

I think I must be missing something...

 

So now that I understand the numbers better;

a 245/40/18 is 0.70 inches taller than stock tires. I guess that is enough to cause problems?

In comparison, a 255/35/18 is only 0.17 inches taller than stock.

The 275/30 are even taller than the 245/40, but it doesn't matter as much in the rear.

 

^^^

Yes.