quick tire size question

[official_style]

i am about to order some american racing torq thrust 2 rims, 18x8 fronts, and 18x10 rears. if i went with 255/45/18 on the fronts and 285/40/18s on the rear, would these be the same diameter as the stock tires? i dont want them to be any bigger or smaller than the orignal tires. thanks for the help! (05 GT)

 

[nonsensez9]

i am about to order some american racing torq thrust 2 rims, 18x8 fronts, and 18x10 rears. if i went with 255/45/18 on the fronts and 285/40/18s on the rear, would these be the same diameter as the stock tires? i dont want them to be any bigger or smaller than the orignal tires. thanks for the help! (05 GT)

stock 235/55/17 are 85.38 inches circumference
255/45/18 are 84.93 inches
285/40/18 are 85.38 inches

It might be wise to check with your tire store, though, my arithmetic might be off. You can always tune your speedo for the new tire size.

 

[mobydickdog]

Go to http://www.discounttire.com/dtcs/infoTireMath.dos

enter in your existing tire size and the new tire size. You then can change the MPH at the bottom to give you various speedo differences.

 

[scarypat2001]

Just a quick observation: you really have to make sure you get the same circumference front/back, as any major difference will cause problems with TC and ABS.

 

[2mnytoys]

i have 275/40/18 on my 05 mounted on 18x10 rims all around, no problems in 2000 miles.

 

[gp001]

For those wanting to calculate tire sizes here's the math:

Section width in inches = (section width in mm / 25.4)

sidewall = (section width / 25.4) * (aspect ratio /100) = (section width * aspect ratio) /2540

Overall diameter = (2 * sidewall) + rim diameter

For the stock 235/55-17

Section Width = 235/25.4 = 9.25 inches

Sidewall = (235 * 55) / 2540 = 5.09 inches

Overall diameter = (2 * 5.09) + 17 = 27.18 inches

 

[allie]

i went with

i am about to order some american racing torq thrust 2 rims, 18x8 fronts, and 18x10 rears. if i went with 255/45/18 on the fronts and 285/40/18s on the rear, would these be the same diameter as the stock tires? i dont want them to be any bigger or smaller than the orignal tires. thanks for the help! (05 GT)

you need to go with 255/45/18,,,, because they have to be approx the same, or the computer has to be re programmed for the different circumference. with 255/45 18, and 9 inch wide,,, there is no problems whatsoever.

 

[WSD42]

Try this web site for reference:

http://www.1010tires.com/TireSizeCalculator.asp

You can compare several tire sizes at once with the calculator.

 

[samckernan]

Just a quick observation: you really have to make sure you get the same circumference front/back, as any major difference will cause problems with TC and ABS.

Any opinion on what a "major difference" would be? I ordered 285/40-18's for the rear. Tire diameter is: 27.38". I got the front ones in: 255/40-18. They are 26.03" tall. Basically the rear tires are 1.35" taller. Is my TC/ABS going to be constantly struggling?

I haven't got them yet. Suppose to be here Friday. Should I order 255/45-18's for the front instead? The diameter of those would be: 27.04"

Thanks for any feedback.

 

[delurker]

If it were me, I'd go with the 255/45 fronts (or wider and closer to the height of the rear). I know there's at least one GT around with 295/35/19 rear, 275/35/19 front (.5" difference), and that's the combo I'm planning to ditch my 255/45/18s for.

 

[official_style]

i wish i could go with the 19s. i use my car for work, i am driving around alll day, and i live in manhattan. almost all of my driving is in the bronx, manhattan, queens and bklyn. i didnt want to have to worry about bending a rim if i hit a pothole, and it would ride way too stuff and be uncomfortable. if i lived out of the city, i would definetly go with the 19s.

 

[official_style]

i ordered the rims, american torq 2, dunlop sport 9000s 255/45/18 and 285/40/18. 6-8 weeks

 

[lostsoul]

has anyone put 275s on the stock rims.. places state that it can do it.. but I have never heard fo anyone putting mroe then 255s on it.. ?? can I really do it.. oe will it look like sheet?

 

[pwhite05]

Quick question about Revs per mile. If stock revs per mile is 770 and your new wheel and tire is say 840 does that mean you will be going faster than before?

 

[Power Surge]

Hey guys, great thread, lots of good info here.

I have a Sonic Blue 05 GT coming next week and want to change the wheels as well. I want to use 18x9 03 Cobra replica wheels. I see mention of a 285/40-18 rear tire. Does this large of a tire fit the 05 with no problems? Like most, I'd like to run the widest tire I can out back.

Also, can someone suggest a good place to buy the twin over car Shelby stripes? I don't really care for what's being offered on ebay.

Thanks much!

 

[official_style]

get them painted on

 

[samckernan]

pwhite05,

Go to: http://www.discounttire.com/dtcs/infoTireMath.dos, punch in the tire size of stock and the size you want, at the bottom it will tell you if there is any speedo error and how much it is.

CobraIILover,

There probably lots of sources for stripes... I know of one. In the 05 Mustang accessory catalog they have white or silver. About the 285's, a bunch of people have posted pictures/specs on large wheels/tires. Do a search on "wheels" or "tires".