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Running 255/30/19 and 325/30/19 on 997.1 Turbo?

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Old 03-13-2017, 05:00 PM
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mister993
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Default Running 255/30/19 and 325/30/19 on 997.1 Turbo?

Picked up a set of rims that are slightly wider:
19x9" ET53 front
19x12" ET44 rear

So I'm thinking of running slightly wider tires to match as well.

Anyone know if going with front 255/30/19 and rear 325/30/19 on those offsets will work on 997.1 Turbo? Or will it have rubbing issue? Car has H&R lower springs on it already (1" drop).

Thank you all in advance!
Old 03-13-2017, 05:04 PM
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djillusion
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i run a pretty close 20" HRE setup.

you should be ok in the rear, but you may rub in the front with the lower springs & wider tires. i think final tire decision (and if they run wide/narrow in 255 size) will make an impact.

i run 245s up front (with the same offset of ET53) but on stock suspension. no issues rubbing here.
Old 03-13-2017, 05:04 PM
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Dennis C
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I would be just as worried about the difference in rolling diameter of the wheels/tires and the impact on the electronics and the AWD system.
Old 03-13-2017, 08:20 PM
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mister993
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Originally Posted by Dennis C
I would be just as worried about the difference in rolling diameter of the wheels/tires and the impact on the electronics and the AWD system.
255-325 combo has a smaller rolling diameter difference than the stock 235-305 according to TireRack. Hence I'm looking at 255 front, instead of the safer 245 front.
Old 03-13-2017, 08:21 PM
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Dennis C
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Excellent. I didn't do the math, I was just commenting on the issue in general.

Hopefully you can get it to work.
Old 03-13-2017, 10:06 PM
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Dodaleca
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Originally Posted by mister993
255-325 combo has a smaller rolling diameter difference than the stock 235-305 according to TireRack. Hence I'm looking at 255 front, instead of the safer 245 front.
I'd be worried that the Porsche differential gearing is set up to account for that difference in rolling diameters front to rear.
Old 03-13-2017, 11:48 PM
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TT Surgeon
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Not sure that's a safe combo, I'd double check with somebody that's actually run them on his whip.
I run the 245-35-10/325-30-19, good combo.
Old 03-14-2017, 01:01 AM
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Kevin
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I run the 245-35-/325-30-19 near perfect with 9 and 12" F & R wheels.
Old 03-14-2017, 08:13 AM
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C's Turbo
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Rubbing will be the least of you're worries if you smoke your front diff. I stuck with 235/305. Many guys have run the 245/325 with no prob for years. Besides those two set ups i'd be careful experimenting. Also, those offsets are going to give you a very aggressive look (especially on the rears) if thats your taste,
Good luck
Old 03-14-2017, 12:47 PM
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mister993
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Thanks everyone! Looks like I'll be going with 245/325.
Old 03-14-2017, 01:27 PM
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245/345 20s here no problems
Old 03-15-2017, 09:45 AM
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Don't know if physically possible (or even if desireable) but 255/35-19 F & 325/30-19 R would be almost the same F/R diameter ratio as stock; also don't know if slightly different F/R ratio from stock then would going bigger or smaller be better (less likely to cause drivetrain mechanical failure)? Car would sit 0.25" higher (0.5" tire height increase).
Old 03-15-2017, 08:49 PM
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o7silverturbo
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As long as the rolling diameter is the same as stock or very close your will not have problem with abs/traction lights and will not do any damage to your rear diff or final drive
Old 03-19-2017, 11:07 PM
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Originally Posted by o7silverturbo
As long as the rolling diameter is the same as stock or very close your will not have problem with abs/traction lights and will not do any damage to your rear diff or final drive
What's "very close"? Curious, because I have 12" rear rims and the 305's looked too stretched to me.
Old 03-20-2017, 09:32 AM
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o7silverturbo
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Originally Posted by fosbibr
What's "very close"? Curious, because I have 12" rear rims and the 305's looked too stretched to me.
Rolling diameter is whats important because if your diameter is too much of a difference between front and rear it will stress the drive line.

305 on a 12inch wide wheel is a little too small would be better with 315 or 325 but the width of tire is not the issue its the height that is important


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