Taller Tires on 4S

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Machu009
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Taller Tires on 4S

Post by Machu009 » Mon Aug 13, 2018 10:43 am

So, I know my speedo is a little off reading probably 7% high. I think the Sumitomo's I'm running are probably smaller then the factory approved tires causing this issue to be exaggerated. I can't find any evidence of this being the case but it's the only conclusion I can come to. So, what do you guys think about getting a taller size tire?

Factory and proposed size:
225/40/18 --- 225/45/18
295/30/18 --- 285/35/18

I did 285 since it was available in the same sumi's and the rotations per mile were nearly the same rate of change front to rear. I don't really see a problem with doing this other then it will lift the car a little due to taller side wall. Could possibly make me put on the H&R springs I've been sitting on for a while.

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32wildbilly
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Re: Taller Tires on 4S

Post by 32wildbilly » Mon Aug 13, 2018 12:24 pm

Machu009 wrote: Mon Aug 13, 2018 10:43 am So, I know my speedo is a little off reading probably 7% high. I think the Sumitomo's I'm running are probably smaller then the factory approved tires causing this issue to be exaggerated. I can't find any evidence of this being the case but it's the only conclusion I can come to. So, what do you guys think about getting a taller size tire?

Factory and proposed size:
225/40/18 --- 225/45/18
295/30/18 --- 285/35/18

I did 285 since it was available in the same sumi's and the rotations per mile were nearly the same rate of change front to rear. I don't really see a problem with doing this other then it will lift the car a little due to taller side wall. Could possibly make me put on the H&R springs I've been sitting on for a while.
Welcome to 996outpost! Sooo are you proposing the taller tires to correct the speedo or just because the Sumi's are available in these combos and the front/rear ratios were close to OEM? Reason I ask is I just read a thread where it was discussed that Porsche intentionally sets the speedo a little high by 5-7% because of some Europe deal. I dunno if that is fact.
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Machu009
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Re: Taller Tires on 4S

Post by Machu009 » Tue Aug 14, 2018 6:31 am

A little of both. I think the sumi’s are small in the current stock sizing. I like the look of the new Porsche’s with the slightly taller and larger tires (even with bigger wheels). Bonus would be correcting the speedo some. I’m also thinking of installing my H&R springs and effectively lifting the car half an inch then lowering an inch should provide a very nice stance and minimal issues with clearance for my driveway. I don’t forsee there being a clearance issue in the wheel wells either as there seems to be plenty of room.

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TheDeckMan
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Re: Taller Tires on 4S

Post by TheDeckMan » Tue Aug 14, 2018 7:36 am

The 4S uses the same tire size as the Turbo with the AWD systems being the same. I went to a 245/40-18 front and 315/30-18 on the rear and it really transformed the car in its quality of ride with the H&R coil overs. I did have to modify my rear fender liners with a little bending of the IC/Fender Liner brackets.
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Machu009
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Re: Taller Tires on 4S

Post by Machu009 » Tue Aug 14, 2018 12:12 pm

Thanks, those sizes are really only track compound tires. Just shopping around and looking for input though, so thanks!

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Re: Taller Tires on 4S

Post by B3DAWG » Tue Aug 14, 2018 1:14 pm

Machu009 wrote: Mon Aug 13, 2018 10:43 am So, what do you guys think about getting a taller size tire?

Factory and proposed size:
225/40/18 --- 225/45/18
295/30/18 --- 285/35/18
IMHO, you may have scrubbing moving up to 45 series tires on the front. The backs shouldn't be a problem with stretching the 285/35/18 on the 11" OEM wheels.

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Re: Taller Tires on 4S

Post by 5chn3ll » Fri Aug 24, 2018 1:11 pm

I have had issues with OEM-sized tires rubbing the fender liner ahead of the front tires. I corrected this with an alignment, but I was surprised by how little clearance there actually is, especially when the steering is at full lock.

You might want to visually verify that you have clearance for any additional sidewall before you spend the dough.

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

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