Wheel/Tire Fitment

[vyel8ers]

Probably been discussed to no end but when it comes to wheels/tires, offset etc im just dumb and i did search the forums but want to be certain before i purchase. I got a 22 Mach 1 w/ HP and looking at running 20x10 fronts (+25mm offset) and 20x11 rear (+28mm offset) and i was gonna put michelin PS4's 305/25R20 fronts and 325/25R20 rears. will i have fitment issues? do i need a 20mm spacer for the rear? Apologize in advance cause im dumb as shit when it comes to wheels/tires
Thanks

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[MAGS1]

You’d want more like a +35 to +40 up front and +50 or +52 in the rear with those wheel widths. 305 is a pretty wide tire for a 10” wheel. You’re going to have some bulge, it’ll feel a bit mushy.

 

[MAGS1]

This is a good site, will give you an idea of what the different fitments look like

https://www.willtheyfit.com/

 

[Gen 6 Mach1]

Hi Something to consider, My Mach had 20s when I purchased , Original Owner put them on (sold the stock wheels) and then didn't like the look , he told me . You will have a 1" difference in height (Diameter) will effect speedo and gear ratio, MO I wouldn't go 20s for that and also looked like a Donk ( not that there is anything wrong with that look just not my style ) your car is not geared for 20s . The GT500 can make up the difference with 280 more HP and different Trans and Rear ratio. Happy Hunting for a Wheel / Tire Combo

 

[Skye]

A few references follow.

This first site will allow you to study an acceptable tire and rim width. You don't want to squish a too-wide tire onto a skinny rim, or stretch a too-skinny tire on a wide rim. Doing so looks weird. But more importantly, the handling characteristics of the tires and the car become compromised.

https://akalloys.co.uk/pages/rim-wi...2gTSyOorHJNoYgFRCCNmsPgNC6JhMnh56RpXRR-uatwc9

The second will give you tire circumference differences in percentages. I try to stay within +/- 3% of the original tire. Straying further can affect shift points, ABS systems or produce noticeable differences in RPM at a given speed.

https://tiresize.com/

https://tiresize.com/comparison/

Finally, the OEM rim and tire sizes, to help with any comparisons. The car is programmed for the tires orignally installed. See the placard in the door jamb. These figures can be used when checking circumference differences at any site.

GT500 CFTP wheels are +32 front, +50 rear, 305/30/20, 315/30/20, 20x11, 20x11.5.

GT500 Base wheels are +32 front, +50 rear, 305/30/20, 315/30/20, 20x11, 20x11.

GT350R wheels are +24 front, +56 rear, 305/30/19, 315/30/19, 19x11, 19x11.5.

GT350 wheels are +30 front, +62 rear, 295/35/19 and 305/35/19, 19x10.5, 19x11.

Mach HP wheels are +24 front, +52 rear, 305/30/19 and 315/30/19, 19x10.5, 19x11.

Mach non-HP wheels are +40 front, +52.5 rear, 255/40/19, 275/40/19, 19x9.5, 19x10.

GT/PP2 wheels are +24 front, +48 rear, 305/30/19, square, 19x10.5, 19x11.

GT/PP1 wheels are +45 front, +52.5 rear, 255/40/19, 275/40/19, 19x9, 19x9.5.

GT/CS rims appear to be 8.5" square, 255s all-around. Offset To Be Confirmed.

Edit,

A 25 profile tire with a 20" rim. You're aware of the road conditions in your area. Think about that while sizing rims and tires and how it could affect Noise, Vibration or Harmonics.

 

[Mach VII]

Front looks fine as far as fitting, almost the exact same footprint as your stock setup. The rear however is going to stick out (poke) over an inch from stock. Pretty sure that is going to rub and there's no way to compensate for that much with camber. As mentioned already you should consider how short the sidewall will be on those 25 aspect ratio tires vs the condition of the roads you frequent.

 

[WItoTX]

Lots of really helpful research info here, so I won't dwell on that. I will add to MAGs point. You are going to lose a lot of the HP feel going to a heavier tire/wheel combo, and especially when you pinch that tire down onto those wheels. You can go to a stiffer sidewall to help manage, BUT it's still going to bend and flex. And the weight is something you just can't get around.

If the HP sharpness feel isn't so critical to you, you will probably be fine. I stuffed a 315 on the stock 10.5" wheel and it wasn't bad, but when I put a 315 onto an 11.5, my confidence in the front end going where I pointed it increased dramatically.

 

[robvas]

Hi Something to consider, My Mach had 20s when I purchased , Original Owner put them on (sold the stock wheels) and then didn't like the look , he told me . You will have a 1" difference in height (Diameter) will effect speedo and gear ratio, MO I wouldn't go 20s for that and also looked like a Donk ( not that there is anything wrong with that look just not my style ) your car is not geared for 20s . The GT500 can make up the difference with 280 more HP and different Trans and Rear ratio. Happy Hunting for a Wheel / Tire Combo

Nothing wrong with a 27.x" tall tire

26.x" (especially the closer you get to 26.0") are too small IMO

305/25R20 is not the right size, you would want a 305/30R20

 

[Gen 6 Mach1]

Nothing wrong with a 27.x" tall tire

26.x" (especially the closer you get to 26.0") are too small IMO

305/25R20 is not the right size, you would want a 305/30R20

All's good , but I said or suggested nothing about a 305/25-20 and I didn't mention anything was wrong with a 27 , OP has a Mach1 HP which came with the 26.2 and 26.44 Dia . Tires stock and as long as he doesn't care about his gearing and ratio the taller 20 s will effect his car, all is good. 20s will take him 1 dia taller than what his car was designed to have . His speedo can be adjusted.

 

[robvas]

All's good , but I said or suggested nothing about a 305/25-20 and I didn't mention anything was wrong with a 27 , OP has a Mach1 HP which came with the 26.2 and 26.44 Dia . Tires stock and as long as he doesn't care about his gearing and ratio the taller 20 s will effect his car, all is good. 20s will take him 1 dia taller than what his car was designed to have . His speedo can be adjusted.

He said he wants to order a 305/25R20

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