Can someone check my tire sidewall math?

[MCS]

Hi All,

CONTEXT: My stock GT Premium has 255/40R19 tires (Pirelli P-ZERO). I bought some Steeda Trident rims that are wider and will be using Nitto 555 tires. She will also be dropped 0.5" with the Steeda springs. Trying to gauge the overall impact on ground clearance before ordering my new hood.

Time for the math.

As mentioned the stock tires that came with the car are the Pirelli P-ZERO and are 255/40R19 so the sidewall height would be

40% of 255 which equals 102mm (right?)

The new tires are 275/35R19 (fronts) and 305/35R19 (rear)

Fronts: 35% of 275 = 96.25mm sidewall
Rears: 35% of 305 = 106.75mm sidewall

So the front tires will be 6mm shorter and the rears will actually be 4mm taller?

Essentially negligible decrease in height due to the tire sidewall height?

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[Andy13186]

https://tiresize.com/comparison/

 

[DRAGOON]

https://www.1010tires.com/About/Tech

 

[MCS]

/me SMH

I should have looked for this. Thanks guys!!

FRONT TIRES (OLD and NEW)

REAR TIRES (OLD AND NEW)

 

[MCS]

So basically the distance between the bottom of the front bumper and the road (with the 0.5" Steeda drop + the new tires) should be just a smidgen below 1" lower than the stock.

Time to bug the guys with the GT500 front bumpers on their GT Premiums (who are not lowered) and see what the distance is. Need to still be able to drive this thing around town without hitting the front end every time I go over a bump.

 

[MidwayJ]

So basically the distance between the bottom of the front bumper and the road (with the 0.5" Steeda drop + the new tires) should be just a smidgen below 1" lower than the stock.

Time to bug the guys with the GT500 front bumpers on their GT Premiums (who are not lowered) and see what the distance is. Need to still be able to drive this thing around town without hitting the front end every time I go over a bump.

Seem to be plenty of people running 275/35 tires with a 1 inch drop in front. You will probably need to be more careful about scraping in certain situations, but it shouldn't be low enough to hit when just going over bumps. For what it's worth, I have 285/35r19s on my 10 inch Steeda Tridents. Diameter is 26.85 inches.

 

[MCS]

Seem to be plenty of people running 275/35 tires with a 1 inch drop in front. You will probably need to be more careful about scraping in certain situations, but it shouldn't be low enough to hit when just going over bumps. For what it's worth, I have 285/35r19s on my 10 inch Steeda Tridents. Diameter is 26.85 inches.

Thanks @MidwayJ I'm not worried about the stock front end. I would be worried about adding a GT500 front bumper. One of my colleagues drives a GT500 and he said the book says it has 4 in of clearance from the road to the bottom of the front bumper and he's riding on 20s with tires that are ever so slightly bigger. And no drop.

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