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New edge front tire width

Discussion in 'SN-95 and New Edge Mustangs' started by ninetynine, May 13, 2012.

  1. ninetynine

    ninetynine New Member Established Member

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    I was wondering if it is possible to fit 285/30/18 in the front of my 99. Will i have clearance issues? I tried running 275's up front in one of my sn95's and the steering didnt feel right. It looks like i might be able to pull it off but looking for feedback.
     
  2. KLeech

    KLeech 2V FTW Established Member

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    yeah their shouldnt be any problems at all, it might be a little tight, but no big deal.
     
  3. Stanger00

    Stanger00 Well-Known Member Established Member

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    I've ran 285/35/18's and they only rubbed a little at full wheel lock.
     
  4. ninetynine

    ninetynine New Member Established Member

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    Any major difference in handling?
     
  5. Stanger00

    Stanger00 Well-Known Member Established Member

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    They tracked pretty bad and bumpsteer was worse. I ended up going back to a 17" rim...

    My car only had eibach pro-kit springs.
     
  6. DaBigBone

    DaBigBone Well-Known Member Established Member

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    Whats the the reasoning behind wanting to do a 285?

    I ran a 275 last year and HATED it... Went down to a 265.
     
  7. KITT

    KITT Member Established Member

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    I ran 275's up front and thought it was just too much tire up front for the street, so I went down to a 255. Plus I wanted my 315's in the rear to be more dominant looking.
     
  8. ninetynine

    ninetynine New Member Established Member

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    Well my problem is that im runnuing 285/30 out back and the side profile is lower than the 265/35's that are up front. So im trying to match the side profile because right now it looks odd with more side profile up front than in the rear. If that makes any sense.....
     
  9. Stanger00

    Stanger00 Well-Known Member Established Member

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    How wide is the rim on the rear?
     
  10. tobynt

    tobynt Active Member Established Member

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    If you want to match the side profile. You will need to do the math.

    You may already know this, but for those that stumble across this this. Here is how you break down a tire size and what all of those numbers represent.

    Tire size and how to read them.

    285/30/18

    285 is the width in metric. If you want to convert the metric to inches simply divide 285 by 25.4 (25.4 millimeters equals 1 inch.) 285 millimeters is 11.22 inches. So the tire width is 11.22 inches.

    30 is the sidewall height of a tire. It represents the percentage of the width. So 30% of 285 millimeters. Simply take 285 and multiply it by 0.3 and that gives you a sidewall height of 85.5 millimeters. take what you learned on converting millimeters to inches and you get 3.366 inches. This number needs to be multiplied by 2 in order to get an overall tire height.

    18 is the rim diameter in inches.

    A 285/30/18 is 11.2 inches wide with a sidewall height of 3.36 inches and fits a 18 inch tire. 3.36 multiplied by 2 gives you 6.73 inches plus the 18 inch rim diameter and you have a 24.73 overall diameter tire.

    Stock on a GT is 245/45/17 which has a 25.68 overall diameter. The first issue I see is that you are 0.95 inches undersized from the original tire size. that is an actual ride height difference of almost an inch. It also shows you why your front tire looks bigger then the back...because it is! Your front tire is almost a half inch taller then the back tire.

    When you start staggering tires for the front and the back. And, you want the car to have the same "side wall" height. Just need to do the math for each tire. Your back tires have an overall height of 24.73 (when they were new). Now, all you have to do is find a front tire in the width you want that has a side profile that will add up to 24.73 when using an 18" rim.

    265/45/18 is 27.38" overall
    265/40/18 is 26.34" overall
    265/35/18 is 25.30" overall
    265/30/18 is 24.25" overall

    Looking at the above, you either have to pick between running a 265 tire in a 30 series (which is about a half inch shorter then the rear) or from a 265 tire in a 35 series (which is a little over a half inch bigger then the rear). I would pick a 265/30/18 that is 24.25" overall for the front if I was going to run a 265 on the front with the tires you currently have on the back.

    255/45/18 is 27.03" overall
    255/40/18 is 26.03" overall
    255/35/18 is 25.02" overall
    255/30/18 is 24.02" overall

    Looking at the above, you either have to pick between running a 255 tire in a 30 series (which is about a 3/4" shorter then the rear) or from a 255 tire in a 35 series (which is a little over a 1/4" bigger then the rear). This one would be tough. Its either going to be slightly bigger on the front....or drastically smaller on the front. Depending on how "worn" your rear tires are....the slightly bigger 255/35's may look a lot bigger on the front. But its closer to the over all tire height as the rears (when they were new). A 255 tire on the front would be a toss up and I would probably not look at running a 255 in front with a 285/30/18 in the rear.

    275/45/18 is 27.74" overall
    285/40/18 is 26.66" overall
    275/35/18 is 25.57" overall
    275/30/18 is 24.49" overall

    Looking at the above, you would want the 275 tire in a 30 series (which is about a 1/4" shorter then the rear). Again, Depending on how "worn" your rear tires are....the 275/30's may look perfect on the front.

    Also keep in mind, the difference in the overall tire height from the rear to the front...needs to be divided by 2. So, in appearance....the 275/30/18 will only be 1/8" smaller then the front. (1/8" per side of the tire...)

    Now, to be honest. The 285/30/18 is not the best tire to run. As you can see from the available tire sizes. None of them match up very well and its over all tire height is about an inch shorter then stock. Unless the car is lowered...your finder to tire gap should be pretty darn big.

    A better rear tire to run in a 285 width. Would be a 285/35/18 That gets you within 0.174" of the stock design. At an overall tire height of 25.85 v/s stock of 25.68
    This will also open up the door to use a 265 wide tire on the front. But, the 265/35/18 is still about a 1/2" shorter.

    Lets step back and go even further down on tire width and take a look at the 245 wide tires in an 18" rim size.

    245/45/18 is 26.68" overall
    245/40/18 is 25.71" overall
    245/35/18 is 24.75" overall
    245/30/18 is 23.78" overall

    Now, the absolute best tire to run on the front...that will give you a sidewall appearance that matches the rear tire of 285/30/18 is the 245/35/18. This over all tire height is within 0.020 of an inch. A human hair is about 0.005 of an inch. So, the side wall height of the 245/45/18 is within 4 human hairs of being the same size of a 285/30/18...in regards to side wall height.

    With all of that being said. If you are not running staggered width rims....8" in front and at least a 9" in the rear. Then that set up will bring an all new problem to the table. If your running the same width rim on front and back with that set up. Honestly, its going to look very stupid. The difference in the sidewall bulge will be a lot worse then the difference of a tire looking taller or shorter. A 245" tire looks great on an 8" rim. But it usually makes the sidewalls tapper in too much when running it on a 9" rim.

    So, what is the width of the front and rear rims you have? Are they the same or different.

    Also, depending on the manufacturer of the tire depends on how they measure the width of the tire. some measure from the bead width and some measure from the tread width. Depending on sidewall construction depends on how the tire will look on the rim. If its not reinforced it will be relaxed and give a bulging look. If it's reinforced street/open track tire. You will have a nice sharp corner as it comes off the sidewall and goes into the tread.

    However, for a safety reasons.....I always look at what the tire manufacture says. Because one manufacturer will say his 255 can be ran on an 8 inch rim and another will say it can't. The construction of the tire determines whats safe for the rim width tire fitment not just the mere size of the tire.
     
    Last edited: May 15, 2012
    CashMoneyKC likes this.
  11. tobynt

    tobynt Active Member Established Member

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    I guess to sum up the above. If the tire width doesn't budge too much from the front to the back running a 265 front and a 285 rear. The cheaper and easiest solution would be to replace the rear tires with a 285/35/18 rather then swapping the front with something else. This will at least swap the appearance and make the rear tire look a little taller then the front. If you keep the rear tires and just want the front to match up..(sidewall)...to the front, you will have to drop way down to a 245 tire on the front. You're already really undersized on the tire height with the back...so, I personally wouldn't want the front tire to be even smaller (overall tire height) then what the back currently is.

    In my opinion, keep the front tires and swap the rears for 285/35/18
     
    Last edited: May 15, 2012
    CashMoneyKC likes this.
  12. Stanger00

    Stanger00 Well-Known Member Established Member

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    What he said...That rear tire is small and most likely stretched too, especially if its on a 10" rim <hellaflush>
     
  13. ninetynine

    ninetynine New Member Established Member

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    Thanks guys for all the info. Im actually gonna save all that for future reference. The rims im running are 18X9 Cobra R's. So after a couple of brainstorming sessions, i decided to replace the rear tires. I think that makes more sense. I appreciate all the info guys, it really helped me decide the easiest route to take!
     
  14. Stryker27

    Stryker27 2Vbeliever Established Member

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    Thats alot of great info for guys who have 18's that are staggered like me. I have 18x9 with 265/35/18 in front and 18x10 with 285/35/18 it looks really good IMO.
     
  15. MrCaliKrome

    MrCaliKrome New Member Established Member

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    TobyNT, thanks for the informative breakdown!
     
  16. CobRoush-00

    CobRoush-00 Active Member Established Member

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    Man, that's math 1 on 1. Great explanation! Will save that for future reference!
     
  17. CashMoneyKC

    CashMoneyKC Member Established Member

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    Hi I must say you know your shit. I’m impressed. I was reading about front tire sizes and would like your opinion. I know this thread is old but I need some help. I have 18x9 front and 18x10 rear.
    265/35 front and 305/35 back. I wanna keep the back size. But as for fronts should I keep that 265/35 or go to something else you suggest. I’m making sure before I buy them. Thanks
     
  18. robvas

    robvas Active Member Established Member

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    Wider fronts pull and track all over every crack/rut in the road
     

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