tire size help needed.

[gameovergt]

Just got AM Magnetic charcoal wheels. Front is 20x8.5 offset 30mm & rear 20x10 offset 48mm. AM recommended 255 35 for front & 305 35 for rear. On Steeda non adjustable pro action struts/shocks/linear 1 inch springs with 1/4 spacer.

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[chuckhammer]

My measurements and calculations show the lateral distance from the hub wheel mounting face to the fender outer surface as approximately:
Front 92 mm
Rear 89 mm

Here's what I did:
H = W/2 - O + F + G + sin(C)*D

Where:
H = Hub wheel mount surface to outer fender surface (mm)
W = Wheel width (bead-to-bead; mm)
O = Wheel offset (mm)
F = Wheel flange thickness (mm)
G = Measured gap between wheel flange and fender outer surface (mm)
C = Camber angle (always negative; deg)
D = Wheel diameter (mm)

The above values are from my car:
Front 19x10 ET35 wheels, 7.5 mm measured gap, -1.6° camber.
Rear 19x11.5 ET56 wheels, 3 mm measured gap, and -1.2° camber.
Measured gaps are approximate.
Camber angle should always be negative.

Edited to modify equation format and fix error.

 

[chuckhammer]

Assuming your wheel flanges are 6 mm thick like mine and your camber is the same (after 1" drop like me) you'll end up with:
Front wheel inset 22 mm* from fender outer surface.
Rear wheel inset 15 mm* from fender outer surface.

This assumes no wheel spacers.

I would go with 285/30-20 tires on your 20x10s out back. 305/35s are pretty tall at 1"+ larger in diameter than stock and will also bulging on a 10" wide wheel.

*Edited to reflect corrected calculation in previous post.

 

[gameovergt]

Assuming your wheel flanges are 6 mm thick like mine and your camber is the same (after 1" drop like me) you'll end up with:
Front wheel inset 15 mm from fender outer surface.
Rear wheel inset 9 mm from fender outer surface.

This assumes no wheel spacers.

I would go with 285/30-20 tires on your 20x10s out back. 305/35s are pretty tall at 1"+ larger in diameter than stock and will also bulging on a 10" wide wheel.

Thanks.

 

[MidwayJ]

I would go with 285/35 in back and 255/35 in front. A 285/30 would have a smaller diameter than the front, which I wouldn't want.

 

[chuckhammer]

I would go with 285/35 in back and 255/35 in front. A 285/30 would have a smaller diameter than the front, which I wouldn't want.

Good point there. The 285/35-20s will be about 0.8" taller in diameter than the 255/35-20s up front. Whereas the 285/30-20s would be about 0.3" shorter in diameter.

My 325/30-19 rears are technically 0.18" shorter in diameter than my 285/35-19 fronts but I don't think it's noticeable.

 

[gameovergt]

Can I reuse factory lug nuts? AM customer support on phone had no idea. Just wanted me to purchase their cheap 6 spline.

 

[gameovergt]

@americanmuscle @AmericanMuscleMelissa

 

[lew]

FWIW
When I bought my PP1 replica wheels I was advised to upgrade to Gorrilla lug nuts. The stock lugs are plated chrome over cheap cast alloy, they can deform if lugs are too tight upon removal. An improperly seated 12 pt socket can strip before loosing, leaving a problem. Six point quality socket with impact will help with wheel removals. The Gorrila's are smaller in size but are made from quality solid steel. Your tires and wheels are larger than stock. Lug nuts should be upgraded too.

 

[gameovergt]

FWIW
When I bought my PP1 replica wheels I was advised to upgrade to Gorrilla lug nuts. The stock lugs are plated chrome over cheap cast alloy, they can deform if lugs are too tight upon removal. An improperly seated 12 pt socket can strip before loosing, leaving a problem. Six point quality socket with impact will help with wheel removals. The Gorrila's are smaller in size but are made from quality solid steel. Your tires and wheels are larger than stock. Lug nuts should be upgraded too.

Ordered from Steeda. Thanks

 

[chuckhammer]

Thanks.

Please note the corrections I made to my previous posts. Looks like your wheel insets will be a bit deeper than what I stated previously.

 

[gameovergt]

285 35s & 255 35s. Got black gorilla lug nuts also.

 

[gameovergt]

Good weather finally as storm passed. Size & offset are perfect.

 

[MidwayJ]

Good weather finally as storm passed. Size & offset are perfect.

Looks nice! You got the best sizes for those wheels. Glad you upgraded the lug nuts, too.

 

[Geodudes550]

I’ve got those exact same wheels (but bronzed) and I’m running 245/40/20 up front and 285/35/20 in the rear. No rubbing or any other issues.

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