NEED HELP: Tire Fitment Question!

Discussion in 'Tires and Wheels' started by Nardy504, Oct 8, 2019.

  1. Nardy504

    Nardy504 Junior Member

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    Hello all,

    I am seeking to purchase tires, but I dont want to make the same mistake twice as I've purchased too small/short tires for the front.
    The distance between the top sidewall of my front tire, and the fender is approximately 2". The rear fitment is perfect.

    I drive a 2013 Ford Mustang GT Cali Special Spec with lowering springs 1.3 " Front, 2.0" Rear.

    I have on my car Nitto Invo
    Front 255/35/19 & Rear 295/35/20.

    I've been considering Nitto NT555 G2 Front 275/40/19 & Rear 305/35/20. I need to know if the fitment of these tires will give me any issues and if they will fill in my wheel well on the front. Also will I have any issues going wider in the rear?

    Thanks in advance,
     
  2. 08MustangDude

    08MustangDude Resident Fuktard

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  3. Pentalab

    Pentalab forum member

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    275/40/19 = 27.66" diameter
    255/35/19 = 25.4763" diameter

    Your proposed 275/40/19 will be... (27.66" - 25.4763" ) = 2.1897" BIGGER diameter than your existing 255/35/19's.

    2.1897" / 2 = 1.09485"

    Your proposed 275/40/19 will REDUCE the distance between tire and fender by.... 1.09485".

    You can do similar calcs for any proposed tire combo. A few secs on a calculator.
    ................................................................................................................................................
    Here's the simple calc.

    275 X .4 = 110m sidewall. ( the '40' means sidewall is 40% of rated tire width).
    110 x 2 = 220 mm (total of both sidewalls at 12 + 6 o'clock. ).
    220 / 25.4 = 8.6614" ( 25.4mm = 1")
    8.6614" + 19" wheel = 27.66" total diameter
     
    Last edited: Oct 8, 2019
  4. Nardy504

    Nardy504 Junior Member

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    Thanks for the information.
     
  5. Norm Peterson

    Norm Peterson corner barstool sitter

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    You'll need at least 19x9 and 20x10 wheels for those new sizes. Better yet, 19x9.5 and 20x10.5.


    255/35-19 tires measure approximately 26.03" OD, not 25.48". Why not run 255/40-19 tires (27.03" OD).

    I'm surprised that you haven't mentioned the ABS acting a bit unexpectedly with over 2" difference in front tire height vs rear tire height. Since this situation could under hard braking make the ABS module think the front wheels were about to lock up and dump front braking earlier than it should when you're needing it the most, it's definitely NOT a good place to be. What I've heard is a 3% tolerance being minimum system acceptable, but your current tire sizes would require almost 8%.


    Norm
     
  6. Nardy504

    Nardy504 Junior Member

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    Thanks for the reply. I have 2011 GT500 wheels on my car I'm definitely not running those tires on factory wheels. My stock tire size was orginally a 245/45/19 all the way around.

    Could you elaborate what you mean by having issues with the ABS? I've never heard of such a thing.


     
  7. Norm Peterson

    Norm Peterson corner barstool sitter

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    The way ABS works is by comparing wheel rpms. More specifically by comparing how fast all of the wheels are dropping rpms against each other. Typically this would require a small tolerance due to possible differences in tire wear (think front vs rear for a GT Mustang for the obvious reason).

    In your current setup, your front tires turn at about 803 revs/mile and the rears only 736 revs/mile. That's actually a 9.1% difference (slightly worse even than what you're proposing), and it also means that the front tires are going to be telling the ABS unit that they're slowing down 9.1% faster than the rear tires. Which the ABS control module would interpret as getting close to locking up.

    Add sudden, very hard braking to that and the ABS would likely conclude that the front tires are actually in the process of locking up, and it would then release line pressure to one or both front wheels - even though they'd still be a few % away from actually locking up.

    With any of the fairly recent ABS systems, I'd expect the ABS instrument panel lamp to be lit.


    Norm
     
    Last edited: Oct 11, 2019
  8. Pentalab

    Pentalab forum member

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    Max difference between front and rear diameters can't be more than 3%....otherwise the ABS braking will malfunction.
     
  9. 08MustangDude

    08MustangDude Resident Fuktard

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    Good for me though, I don't have ABS, thus don't have TC either. SO, I can use
    any rear larger to front smaller combination.
     
  10. Norm Peterson

    Norm Peterson corner barstool sitter

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    No ABS on a 2013?

    Well, assuming that's true at least you won't have electronic consequences. However, your basic front to rear brake balance will be shifted away from what the system was hydraulically and mechanically designed around at least a little. Slightly more apt to lock the fronts during extreme braking, I suspect.


    Norm
     
  11. 08MustangDude

    08MustangDude Resident Fuktard

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    No, I have an '08, and it did not come with it. I did not remove any components,
    it didn't come with it. Also, pulling the ABS fuse on one with, would be the same
    thing. If I could add it, I would, just not sure on how easy or hard that would be.

    I have driven many rear wheel drive cars without ABS, from 1969 cars and
    up. My first car didn't have ABS. It was a 1969 BMW 2002. Shifter and
    dash gauges were in German. Had a 1970 Plymouth Satallite, few vans, ALL rear
    wheel old school, so this doesn't bother me a bit.
     
  12. Norm Peterson

    Norm Peterson corner barstool sitter

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    Was thinking of OP's car, so that much is on me. Sorry.

    But I am surprised that your '08 doesn't have it. Mine certainly does.


    With as much non-ABS driving on your driving resume as that list implies, you won't ever hear it from me that you should add it. FWIW, I'd been driving nearly 40 years before buying a car that actually did have ABS (the Max in my sig). I've even had the ABS on my '08 go inop during a road course track day session - and generally ran better lap times with it offline than when it was working properly.


    Norm
     
  13. 06 T-RED S/C GT

    06 T-RED S/C GT forum member

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    I also find it very difficult to accept as well that your 2008 doesn't include ABS, as both my previous 2005 and current "06" GT have ABS which IIRC come standard on all models, including non-premium, base models. At any rate, if your certain that your "08" doesn't have ABS? Under the only scenario I can possibly think of that might make any sense, is that for whatever reason someone was able to somehow either bypass it or uninstall it altogether :shrug:
     
  14. 08MustangDude

    08MustangDude Resident Fuktard

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    It doesn't, no ABS, which also means no Traction Control.

    [​IMG]

    [​IMG]
    Here is where the ABS pump should be, and as you can see from both pictures, it's not there...
     
  15. 06 T-RED S/C GT

    06 T-RED S/C GT forum member

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    From the images you posted, it appears your "08" is a base V6 model. However, I assumed that all V6 base models also came standard with ABS and traction control. According to the images you posted, it appears that I was wrong :shrug:
     
    Last edited: Oct 12, 2019
  16. 08MustangDude

    08MustangDude Resident Fuktard

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    Window Sticker says V6 Premium, but all there are, is Premium and Deluxe...
    I was surprised when I saw it didn't have ABS or TC. When I got the cluster
    replaced, all those lights were on; ABS, BRAKE, and TC. So, when they
    looked it over, they were like, huh, this doesn't have it... In the end, their
    Ford dealer had to program the cluster with my build data, so those lights
    would be off. They replaced the cluster twice, before realizing it has to be
    programmed.. Their ACURA dealer had no business doing it in the first place
    when they have a Ford dealer down the road. It ended up costing them
    over $1000 in parts and labor, getting it right the 3rd time. I only took
    one key with me, and they said they need two. So, they made another key,
    for free. So now, I have three. Also, they had a problem cutting the key,
    and it took three tries to get it right. They are double sided keys, yet they
    will only work one way. The keys have ford logos on them. The logo has to
    face the rear for the door. Has to face up towards the window for the
    ignition, and left for the trunk. They have no idea why it is like that. With
    the double sided key, you should be able to insert it in any direction. Nope,
    if I put it in the wrong way, it won't turn. NEVER had that happen before.
    This was all courtesy work, when I bought the car and the temp gauge
    was not working properly. I bought it from Smail Kia, their Smail Acura
    tried to fix it, for it to end up at Smail Ford; where it should have gone
    in the first place...

    There was more wrong, but I didn't find it till later... Rear brakes NEVER
    worked. The pads and rotors were replaced before purchase. The
    rear calipers and slides were froze... I was running off fronts, and didnt
    realize it. When I finally changed the hardware, the rear pads were still
    brand new... So, I have all new calipers and brackets...

    They didn't even snap the intake lid on properly, it was open...

    Well, they went from $9800 to $5913, I got them to knock another $100
    off, plus that $1000 worth of work they ended up paying...
     
  17. 06 T-RED S/C GT

    06 T-RED S/C GT forum member

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    As previously stated, I assumed that all S197 models from 2005-14 all came standard with ABS and TC, including V-6 base, deluxe and premium editions. Therefore I honestly don't know what else to tell you, as I'm completely stumped :shrug:
     
  18. Norm Peterson

    Norm Peterson corner barstool sitter

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    There was some MVMS document a few years back that did note that for the 2005 V6 S197, ABS was optional. Since option availabilities can vary from year to year, I dug a little deeper, finding in the 2008 advertising brochure that ABS was listed as "-" (meaning "not available") for both sixxer trims. Which still has me thinking "typo" where the "-" symbol in the availability table should have been an "O" but which still means it wasn't the standard sixxer fitment.. In the 2009 advertising brochure, ABS was part of the "Safety & Security" package that was optionally available for all sixxer trim levels.

    Hope that helps.


    Norm
     
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