315/30 up front on the GT350R - Permanently

IainD90

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I couldn't find any definitive answer for this so here goes.. Just came home from the track - early - due to a nail puncture on a front tire from the paddock not being cleaned after a weekend event. I was one of 3 guys that went home due to punctures!

My tires are still in good shape overall and I've got another track day booked for next week. I was wondering if I could throw my current rear 315's up front and get a new set of 315s for the back and just run a square setup until the fronts are done, then either replace with 305s or continuing to run square.

I really would like to avoid buying a brand new set when my current tires are surely good for another few HPDE events. I don't drive at 11/10th's :)

Edit: Should clarify my reasoning here, I don't want to replace the two front's and have worn rears and new fronts, I'd rather have newer tires in the back. Tires are also slim picking right now, so the other option is to just forget track days for this year and possibly move to the Falken RT660 next year when they become more available.
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IainD90

IainD90

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I've run three different tires with plugs

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LMAO. I heard mixed thoughts at the track about it - care to elaborate and make me feel better about just leaving it the way it is?
 

Wildcardfox

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I couldn't find any definitive answer for this so here goes.. Just came home from the track - early - due to a nail puncture on a front tire from the paddock not being cleaned after a weekend event. I was one of 3 guys that went home due to punctures!

My tires are still in good shape overall and I've got another track day booked for next week. I was wondering if I could throw my current rear 315's up front and get a new set of 315s for the back and just run a square setup until the fronts are done, then either replace with 305s or continuing to run square.

I really would like to avoid buying a brand new set when my current tires are surely good for another few HPDE events. I don't drive at 11/10th's :)

Edit: Should clarify my reasoning here, I don't want to replace the two front's and have worn rears and new fronts, I'd rather have newer tires in the back. Tires are also slim picking right now, so the other option is to just forget track days for this year and possibly move to the Falken RT660 next year when they become more available.
Will it fit, yes.


From Tire Rack:

Rim Width Range:
  • 10.5-11.5"

Should you do it? It’s what the handling characteristics will be like?

Excerpt from an article on tire sizing from Billy Johnson, the Ford test driver who perfected our cars n track

“On the other hand, if a tire is too wide for a given wheel width, the sidewall ‘bulges”. This usually results in sloppy handling characteristics, vague steering feel, excessive tread squirm, and the carcass of the tire can also distort and have uneven pressure across the surface of the tire.”

Here’s the full article which everyone should read, especially if you are thinking of changing your tire setup.

https://motoiq.com/how-to-properly-select-and-size-tires-for-performance/2/
 
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IainD90

IainD90

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Will it fit, yes.


From Tire Rack:

Rim Width Range:
  • 10.5-11.5"

Should you do it? It’s what the handling characteristics will be like?

Excerpt from an article on tire sizing from Billy Johnson, the Ford test driver who perfected our cars n track

“On the other hand, if a tire is too wide for a given wheel width, the sidewall ‘bulges”. This usually results in sloppy handling characteristics, vague steering feel, excessive tread squirm, and the carcass of the tire can also distort and have uneven pressure across the surface of the tire.”

Here’s the full article which everyone should read, especially if you are thinking of changing your tire setup.

https://motoiq.com/how-to-properly-select-and-size-tires-for-performance/2/
Oh nice, thanks for that. I actually have some experience running a 255 Trofeo R on a 9" wheel. A 255 Trofeo is more like 265 to be honest. It was a FWD car though and you pretty much want to sacrifice just about anything you can in favour of rotation!
 

honeybadger

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LMAO. I heard mixed thoughts at the track about it - care to elaborate and make me feel better about just leaving it the way it is?
It's a personal choice based on your comfort with risk. Here's how I look at it:

  1. A tire with patch in the middle of the contact patch is most likely to leak, not explode (assuming a good patch job - not just a plug)
  2. My TPMS sensors will help me detect a leaking tire
  3. If the tire were to explode, I'm comfortable with the risk of the tire indeed failing on the track I drove them on
  4. I proactively limit where I use patched tires (I wouldn't run VIR, Daytona, etc. with a patched tire - the loads are too high and the run off not good enough).
Regarding using a 315 on the front, you can absolutely run them. And regarding Billy's comments - the only thing I'd note is that Billy is a lot better driver than all of us, so he can utilize the tires to a much higher degree. :)
 
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IainD90

IainD90

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It's a personal choice based on your comfort with risk. Here's how I look at it:

  1. A tire with patch in the middle of the contact patch is most likely to leak, not explode (assuming a good patch job - not just a plug)
  2. My TPMS sensors will help me detect a leaking tire
  3. If the tire were to explode, I'm comfortable with the risk of the tire indeed failing on the track I drove them on
  4. I proactively limit where I use patched tires (I wouldn't run VIR, Daytona, etc. with a patched tire - the loads are too high and the run off not good enough).
Regarding using a 315 on the front, you can absolutely run them. And regarding Billy's comments - the only thing I'd note is that Billy is a lot better driver than all of us, so he can utilize the tires to a much higher degree. :)
The tire shop at the track used one of those plug-patches, where it's about a 1.5" or so circle that secures the plug on the inside of the tire. The nail was about 3" away from the sidewall as well so it was close to not even working to begin with.

As far as the track I go to, it's Canadian Tire Motorsport Park - Formerly Mosport.. Not a whole lot of run off and pretty much all high speed corners, although a ton of stress is put on the drivers side. My plug is on the front passenger side. Feel free to check it out and let me know what you think..
 

Dr. JL

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I run 315 Cup2s on the front rims with no issues.
 

honeybadger

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The tire shop at the track used one of those plug-patches, where it's about a 1.5" or so circle that secures the plug on the inside of the tire. The nail was about 3" away from the sidewall as well so it was close to not even working to begin with.

As far as the track I go to, it's Canadian Tire Motorsport Park - Formerly Mosport.. Not a whole lot of run off and pretty much all high speed corners, although a ton of stress is put on the drivers side. My plug is on the front passenger side. Feel free to check it out and let me know what you think..
Mosport is wicked fast when driven hard. I'd never run a plugged tire there. I wouldn't necessarily apply that across the board, though. I push tires a lot harder now than I did a few years ago.
 
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IainD90

IainD90

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Mosport is wicked fast when driven hard. I'd never run a plugged tire there. I wouldn't necessarily apply that across the board, though. I push tires a lot harder now than I did a few years ago.
Yeah thats what I figured you would say. So, there are no 315/30/19 available anywhere near me but it looks like I can get my hands on a pair of 305/30 for the front. Would you reccommend against replacing the front 2 tires and leaving the rear as they are?
 
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