225/40 front 255/40 rear ???

[Warranty]

So I posted on Audi forums a while back about having this tire set up. I was told that it should be fine, as long as the second number (40) is the same from front to back. I just had to replace my back tires because I had a radial out in one of my tires. Well, I put the back tire next to the front for a heigth comparison. The backs were noticeably taller(maybe a 1/2"). I'm a little worried about the difference in rolling diameter. Any (good) advice would be helpful.

[Cincy]

who told you this? The total height needs to be the same (or as close as possible). Some people say the haldex doesnt like them to be off by very much. You should be using 35 in the reat atleast

use this http://www.miata.net/garage/tirecalcold.html

A 255/35 will make them .1" different

[Cincy]

Found and read that thread (http://audiforums.com/forum/showthread.php?t=117656), didnt see that posted anywhere. Post number 3 did say

the rears cant be taller than the fronts or the other way around.
i dont know what the 255 and 225 means as far as tire size... if that is width or something like that then it is fine. But if thats how tall the tire is then you shouldnt

not sure if you knew or not that the middle number is a ratio of the first number. The wider the tire, the lower than number needs to be to match a thinner tire. width/height/rim size

[l88m22vette]

I run 235/40-18 front and rear and its very nice, I have better ride, its quieter, and you have the extra rim protection. I am not going back to 225. BTW, I have Michelin Pilot Sport A/S+ (http://www.michelinman.com/tires/ultra-high-performance-sport/pilot-sport-as-plus/51032/), they rock in the snow, have very predictable handling (ie stick and grip), and are warrantied for 45k; totally worth the $220 per tire.

[Warranty]

who told you this? The total height needs to be the same (or as close as possible). Some people say the haldex doesnt like them to be off by very much. You should be using 35 in the reat atleast

use this http://www.miata.net/garage/tirecalcold.html

A 255/35 will make them .1" different

that link doesnt do anything for me. I need to find out what other options I have for the rear.

[KrissrocK]

woah...no way are 225 and 255 ok. the second number (sideway height) is a percentage of the first number. So the higher the first number the higher the sidewall height... those are wayyy to far apart.

[Cincy]

you add in both tire sizes and it will compare them. If you put in 225/40/17 and 255/35/17, they are only .1" off from each other in total height which is what you want.

[Warranty]

I couldnt get the calculator on my computer ..? So if I run 255/35/18(rear) I should be ok?

[Cincy]

100%

[Warranty]

Just got off the phone. I think I'm just going to go with 225/40 on all 4. :( I know my need for same diameter tires is a no brainer, but Damn! That stance was sexy!

[Cincy]

if you really like the look, they are basically identical.

side wall - both 3.5"
radius - 12"
diam - 24.1" vs 24" (225 - 255)
circumf - 75.7 vs 75.5
revs/min - 837 vs 839

where the 255/40 is 24.5 in diam and 12.5 in radius

[myslow1]

Im going to run 215/45/17 for the front and 225/45/17 for the rear.

I thought the second number was the height of the tire and the first was the width?

[Cincy]

width/height, which is a % of the width/rim size

So a stock 225/45/17 is a tire that is 225mm wide, the height is ~45% of 225mm and made for a 17" rim

[Warranty]

That daewoo emblem makes me want to vomit

[Cincy]

Sorry, hope the new ones better

[Warranty]

Sorry, hope the new ones better


Nope, still looks like a jock strap. LOL

[Cincy]

I never thought about that.... sadly it does ewwwww

[Warranty]

Maybe daewoo translates to "athletic supporter"..? But that emblem looks like one for sure. LOL

[myslow1]

I never thought about that.... sadly it does ewwwww

it really does though? thats weird lol

[l88m22vette]

Put your junk in a piece of junk!

[myslow1]

:lol::lol:

[Warranty]

So I've got 2 225/40/18 hankook ventus on the way. I'm starting to wonder if there is any damage done to my haldex from driving with unequal sized tires..? LOL, I was thinking I might want to put the car on a lift and let it run with no load on the wheels. In a half asses effort to release any tension bound up in the system(I know it might sound stupid, but it's a thought).

[KrissrocK]

Nope, still looks like a jock strap. LOL

holy crrrap it does!