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Old 11-26-2013, 03:30 PM   #1
Millhouse_5
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95 JDM STI RA
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Default 215 vs 235 total grip

I've been thinking about upgrading my tires when my star specs run out, but I'm not sure if I want to stick with my current size 215/40/17 or go to 235/40/17. Would there be a noticeable grip difference by adding the 20mm or would I be better off just sticking with what I have.

I don't track my car but I do like the get the most out of what power I have. I'm running a little shy of 300whp, and have 17x7.5" sparco wheels.
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Old 11-26-2013, 03:46 PM   #2
sc00by4life
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Quote:
Originally Posted by Millhouse_5 View Post
I've been thinking about upgrading my tires when my star specs run out, but I'm not sure if I want to stick with my current size 215/40/17 or go to 235/40/17. Would there be a noticeable grip difference by adding the 20mm or would I be better off just sticking with what I have. I don't track my car but I do like the get the most out of what power I have. I'm running a little shy of 300whp, and have 17x7.5" sparco wheels.
Maybe a 225, I wouldn't do a 235/40 on a 7.5" wheel.

Are you having traction issues right now? Otherwise you're only adding weight.
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Old 11-27-2013, 03:15 PM   #3
Millhouse_5
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Default

I wouldn't say I'm having issues with traction, I've got lots, just always nice to have more cornering ability and stopping power.

One reason I'm looking at 235/40 is the older JDM sti's ran 205/50/16 from factory so I'm trying to stay closer to OEM size. Also, if I get a wider tire, I might be able to get one that last a little longer than my star specs and provides about the same amount of grip due to the extra surface area.
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Old 11-27-2013, 06:24 PM   #4
sc00by4life
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wider tires won't help you corner any faster than you are now.

and the reason i say i wouldn't do a 235/40 is because its a little short to run on a wheel that narrow. you could do a 235/45, but then you have to deal with softer sidewalls and more roll over.

if you aren't having traction issues, i see no reason to change.
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Old 11-27-2013, 08:10 PM   #5
memmek2k
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I agree, if you're not at the limits of the current tires, you won't notice a difference with wider tires. 235 mm section width is at the wider limit of recommended sizes for a 7.5" rim.

Also, your current size is... Strange. There's like a 1" overall diameter difference between your current size and what you're considering. Going to throw off your speedo by quite a bit (or it's already off).
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Old 11-29-2013, 07:03 AM   #6
Uncle Scotty
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Quote:
Originally Posted by Millhouse_5 View Post
I wouldn't say I'm having issues with traction, I've got lots, just always nice to have more cornering ability and stopping power.

One reason I'm looking at 235/40 is the older JDM sti's ran 205/50/16 from factory so I'm trying to stay closer to OEM size. Also, if I get a wider tire, I might be able to get one that last a little longer than my star specs and provides about the same amount of grip due to the extra surface area.

fauly logic....stay with a 225/45 for a 7.5 wide wheel and star specs last a long time for the kind of tire they are

stay with what works
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Old 11-30-2013, 02:01 PM   #7
thejaredhuang
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I went from a 245 on a 8" rim to a 225 on the same rim and I could notice the difference. Same tyre, Michelin PS2, all 4 corners. There was less grip and no change in sharpness.
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Old 11-30-2013, 03:09 PM   #8
Radeon
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People are installing 235/40 Dunlop ZII on a 7"-wide rim and are going faster in a BRZ. So it's totally sidewall-stiffness dependent. I would totally do it on a 7.5" rim.

Wider rubber will totally give you more grip. However, 235/40 will be taller than 215/40 and you'll have effectively taller gearing and a couple of hp, due to heavier tire.
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