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Johnny-5

Porsche 911 rear wheel max tire size

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Some tire size issues are manufacturer related. All manufacturers 285 should work fine. A few 295's will fit with little or no rubbing.

I am running 285's on the rear of my MY99 C2.

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Some tire size issues are manufacturer related. All manufacturers 285 should work fine. A few 295's will fit with little or no rubbing.

I am running 285's on the rear of my MY99 C2.

Loren,

What size did you end up going up front? Did you keep the stock size?

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I put GT3 front wheels on my car so they are 8" rather than 7.5.

I would go with a 235 front. 245's will rub at full lock.

So just want to confirm if this will be ok?

Fronts: 235.40.18

Rears: 285.35.18

Since Im going bigger in size should I bring the middle numbers down as well?

For ex. Fronts 235.25.18 or Rears 285.30.18 ?????

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i run 285x30x19 in back with no issues

I run 245x35x19 in frount and they will rub in extreem low speed u turn but not when driving

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Front is fine but I think you want 285/30 x 18 rears.

If I was to go with the 285.35.18 do you think that will cause any issues? I really dont want to go that low of a profile. Roads around here arent the greatest either.

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That 35 series will over 1 inch larger in overall diameter and cause your speedometer to read high.

If you have PSM I would stick with Porsche's recommended 30 series in the rear - and make sure you keep the recommended 44 PSI in them.

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That 35 series will over 1 inch larger in overall diameter and cause your speedometer to read high.

If you have PSM I would stick with Porsche's recommended 30 series in the rear - and make sure you keep the recommended 44 PSI in them.

Whats the recommended PSI for the current tires now? I have them at 35? Should I put them higher?

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I'm running 235's fronts and 305's in the back.

Love the wide stance at the back

joel

I'm running

235 x ? on the front

295 x 30 on back (19" Wheels)

Having the PSS9s help a lot too though, cause I can adjust the ride height.

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Front is fine but I think you want 285/30 x 18 rears.

Loren,

Would you please you confirm that 235/40/18 on an 8.5" front rim is ok with the stock 285/30/18 on the 10" rim? That's about a 2.7% difference in size front to rear. I'm more concerned with the difference in diameter front/rear than any rubbing issues.

I did lots of searches, but they left me wanting of a Loren confirmation.

Thanks!

PH

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The 235/40 x18 should not rub on the front as long as you are using factory offsets (40mm). That is exactly what the GT3 (narrow body) uses. A 245 WILL rub at lock on tight turns.

A 295/30 x 18 would be better on the rear - that will just fit a 10" wheel. If you want the GT3 setup then you would go with an 11" rear with offset 63 mm (same size tire).

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The 235/40 x18 should not rub on the front as long as you are using factory offsets (40mm). That is exactly what the GT3 (narrow body) uses. A 245 WILL rub at lock on tight turns.

A 295/30 x 18 would be better on the rear - that will just fit a 10" wheel. If you want the GT3 setup then you would go with an 11" rear with offset 63 mm (same size tire).

Thanks Loren!

So, just to confirm: Will there be a problem with systems in the car with the difference of 2.7% between the front and rear total diameters?

I asked because I already ordered the 235/40/18 tires for front 8.5" rims and the 285/30/18 for the rear 10" rims. If I must change the order, I am going to get hit with extra shipping costs, but I will do it if I need to do it.

I should have confirmed the sizes before placing the order, but I did one of those impulse buys which are so easy online.

PH

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I don't think so - as I said this is the same setup as the GT3.

If the GT3 has 295/30 versus my 285/30 on the rear, the calculators show a 1.7% difference front/rear versus the 2.7% I will be running if I stay with these new tires. I'm hoping the 2.7% will be ok.

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I am in the same boat but my car is a 2004 40th AE.

I want to go 235/40/18 up gront and 295/30/18 in rear using stoc rims.

Will that fit with NO rubbing issues? Tires will be Hankook v12's.

I don't think so - as I said this is the same setup as the GT3.

If the GT3 has 295/30 versus my 285/30 on the rear, the calculators show a 1.7% difference front/rear versus the 2.7% I will be running if I stay with these new tires. I'm hoping the 2.7% will be ok.

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