Race Tracking Your Supra - Information exchange

[Islindur]

Went off at the end of riverside.... probably going 100. The dirt is soft so it caught and rolled. So don't do that today and good luck on the 1:55!

So how did 275's work out for U compared to 305?

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[Evolution]

So how did 275's work out for U compared to 305?

They actually got up to temp! Because of that, I would say more grip than the 315s. Car also felt a little bit more alive since I dropped a few lbs per corner. They did get greasy towards the end of the sessions so I think 295s are going to be perfect.

I think a spring rate bump is in the near future. There was one turn that I would come into around 100 and you could hear the splitter scraping the ground.

 

[kyle9]

They actually got up to temp! Because of that, I would say more grip than the 315s. Car also felt a little bit more alive since I dropped a few lbs per corner. They did get greasy towards the end of the sessions so I think 295s are going to be perfect.

I think a spring rate bump is in the near future. There was one turn that I would come into around 100 and you could hear the splitter scraping the ground.

Stretched tire will perform much better than pinched tires… contact patch size in this scenario is determined by tire pressure anyway so the wider tires probably aren’t even providing more grip

 

[Islindur]

Stretched tire will perform much better than pinched tires… contact patch size in this scenario is determined by tire pressure anyway so the wider tires probably aren’t even providing more grip

What Your take on 275 vs 295 Kyle? 400whp
18x9.5 wheel vs 18x10.5 ( Dunlop recommended sizes for Direzza Z03G, narrower/wider works too but they recommend as above to be best performing)

 

[razorlab]

What Your take on 275 vs 295 Kyle? 400whp
18x9.5 wheel vs 18x10.5 ( Dunlop recommended sizes for Direzza Z03G, narrower/wider works too but they recommend as above to be best performing)

295 is not optimal on a 10.5. Like Kyle stated, it will be pinched, not stretched.

 

[Islindur]

295 is not optimal on a 10.5. Like Kyle stated, it will be pinched, not stretched.

So U say Dunlop themselves are wrong recommending wheels size for their own tire? Coz its their idea + confirmed by biggest tire shop here in PL who sells tons of motorsport tires.
Im thinking between 265 vs 295 (so irl 279 vs 299)

 

[razorlab]

So U say Dunlop themselves are wrong recommending wheels size for their own tire? Coz its their idea + confirmed by biggest tire shop here in PL who sells tons of motorsport tires.
Im thinking between 265 vs 295 (so irl 279 vs 299)

You can see that from EVERY tire manufacture, just because it technically fits, doesn't mean it's optimal.

 

[Islindur]

You can see that from EVERY tire manufacture, just because it technically fits, doesn't mean it's optimal.

Sure, but those mid values are Dunlop recommended, confiremd with tire supplier.

 

[razorlab]

Sure, but those mid values are Dunlop recommended, confiremd with tire supplier.

Sounds like you have it figured out. Why ask the question?

 

[Islindur]

Sounds like you have it figured out. Why ask the question?

Coz I wonder if 295 is faster and should move to it, but have no expeience with bigger tire so I ask ppl who had? I'm not asking for wheels size.

 

[razorlab]

Coz I wonder if 295 is faster and should move to it, but have no expeience with bigger tire so I ask ppl who had? I'm not asking for wheels size.

Right, but you have to think of them both together as a system. It's been proven time and time again that a tire too wide for the wheel it's on will not be optimum as far as grip and feel.

If you don't believe me or Kyle, maybe you will believe this test?

https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=296

 

[Islindur]

Right, but you have to think of them both together as a system. It's been proven time and time again that a tire too wide for the wheel it's on will not be optimum as far as grip and feel.

If you don't believe me or Kyle, maybe you will believe this test?

https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=296

I know that, just saying what Dunlop says. So if 295 then prob 18x11 would be more optimal?
Just speculating on tire size alone here, wheel will be matched accordingly.

 

[kyle9]

So U say Dunlop themselves are wrong recommending wheels size for their own tire? Coz its their idea + confirmed by biggest tire shop here in PL who sells tons of motorsport tires.
Im thinking between 265 vs 295 (so irl 279 vs 299)

sorry man, these aren’t recommendations for performance in any way

on a 10.5 a 275 and a 295 will run about the same pace. Feel is subjective but the 295s will tend to squirm… I personally would only put 275s on a 10.5

On an 11” rim, 295 is faster and feels okay but it’s less of a difference than you’d probably expect vs 275. Around 1 second at most tracks, but could be less.

on 9.5 both tires are too wide. You could run a 275 but narrower tires would have better sidewall support and better turn in and stability under breaking.

for reference, the fastest time attack guys that run 255 tires (due to rules) use 10.5” rims. Just some food for thought.

 

[kyle9]

I know that, just saying what Dunlop says. So if 295 then prob 18x11 would be more optimal?
Just speculating on tire size alone here, wheel will be matched accordingly.

for 295, I think a 12” is optimal. Usually add 0.5” to the max width on those charts and that’s the fastest setup.

11” is the minimum for a 295 to see a performance benefit in my experience

 

[Evolution]

for 295, I think a 12” is optimal. Usually add 0.5” to the max width on those charts and that’s the fastest setup.

11” is the minimum for a 295 to see a performance benefit in my experience

So what would you do?

Keep my 275s on my 10" wheels?

Move my 275s to my 11" wheels?

Run 295s on my 11" wheels?

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