HPDE and Track Events

[jmagnus87]

Yep, ditch the nittos. Also, if I understand your set up correctly, you have a 345 on a 12" rim? If so, I'd argue that is WAY too much tire for the rim. Ideally, you want tires slightly stretched. That will give you a much more responsive feel in the car at turn in, and TBH, all around.

TireRack shows how wide each tire is (315 is variable depending on the MFG), and if you have have a tire slightly stretched, and ideally a square set up, your car will feel much more balanced. If your rim is 11" rim, you want a tread contact patch about 10.75" to 11". IMO.

I used to run a 315 on an 11.5" rim on the rear, and went down to a 305 because I wanted that stretched wheel. My run times have dropped, and the car rotates when I ask it to, and has gotten incredibly predictable.

Also, based on your description, going into the corner slowly is indicative that you are not 100% certain how the car is going to react as you go into the corner (That's what it was for me at least). That is where seat time comes into play. The more you drive, the more that comfort will come to you, and the faster your entry will become.

Good luck, and enjoy the hobby!

so can i run a 305 on the 12 inch rim?? i would love a square setup, just think the money i spent on wheels was wasted if i wanted to drop the rear tire size down. 13.58" of tire is cool, looks neat and is fun for bragging rights but if i can have something that suits me well both on and off track, i'd much rather go that route. i love the michelins but they too chew up on track QUICK how small can i go on the 12? given that 305mm is just about 12 inches, the 305 should be jsut about perfect, no?

edit: yes, i'm very uncertain about how the car is oging to handle when i throw it into the corner with lots of entry speed. so that's comforting that i can get more comfortable with that with seat time. thanks for that.

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[NightmareMoon]

there's two parts to the corner, entry and exit. and personally, i like to be able to hammer out of a corner but take it a bit slower on entry. ideally, would rather just carry speed all the way through though and not need so much power to put down on exit, which i believe is the point of being able to drive a slow car fast. but i'm not selling my mustang to buy a miata to learn

Well if you want to be as quick as the other mustangs, you'll need (eventually) to learn to push both entry AND exit... but let your instructors decide when to start working on entry.

While there's some balance to trade between front grip and rear grip with swaybars, springs, and tire widths, you don't need an extreme tire width bias from front to rear to get a nice stable understeer on exit which allows you to confidently put power down.

If your wheels are 19x11 and 19x12, then maybe try a 315 in the rear and a 305 in the front. Maybe try Falken RT660s or something 200TW like that. You'll want need camber front and rear with camber plates on the front to get the front 305s set up right for cornering. Springs and swaybars would be interesting to talk about to see what your current setup is w/r/t your goals of hammering out of corners.

 

[WItoTX]

so can i run a 305 on the 12 inch rim?? i would love a square setup, just think the money i spent on wheels was wasted if i wanted to drop the rear tire size down. 13.58" of tire is cool, looks neat and is fun for bragging rights but if i can have something that suits me well both on and off track, i'd much rather go that route. i love the michelins but they too chew up on track QUICK how small can i go on the 12? given that 305mm is just about 12 inches, the 305 should be jsut about perfect, no?

edit: yes, i'm very uncertain about how the car is oging to handle when i throw it into the corner with lots of entry speed. so that's comforting that i can get more comfortable with that with seat time. thanks for that.

You will have to check, a 305 may be way too stretched on a 12" rim, a 315 might be better. It really depends on each tire. Tire rack has the tire specs you are searching for.

 

[jmagnus87]

You will have to check, a 305 may be way too stretched on a 12" rim, a 315 might be better. It really depends on each tire. Tire rack has the tire specs you are searching for.

ok so interesting development here... the wheels all around measure to 12" outside to outside (can't measure where the tires go) so, this leads me to think a square setup would be good on it but tire rack says 345 should be the smallest on a 12" rim? i can't measure where the tires go so where are you supposed to measure from for the number tire rack is giving?

 

[NightmareMoon]

The wheel width is inside lip to inside lip.

Find your receipt, but if they're SVE wheels and outside to outside is 11,12 then they're probably 10,11 inside widths, which means you shouldn't be trying to run 305,315, but more like 285F and 305R.

 

[jmagnus87]

The wheel width is inside lip to inside lip.

Find your receipt, but if they're SVE wheels and outside to outside is 11,12 then they're probably 10,11 inside widths, which means you shouldn't be trying to run 305,315, but more like 285F and 305R.

found out from the guy i bought them from. 19x11 50mm offset all the way around. so i can run the 305s square and if i feel i would liek to try 315 square, can do that too. i DO run a 25mm spacer in front

 

[Bluemustang]

ok so interesting development here... the wheels all around measure to 12" outside to outside (can't measure where the tires go) so, this leads me to think a square setup would be good on it but tire rack says 345 should be the smallest on a 12" rim? i can't measure where the tires go so where are you supposed to measure from for the number tire rack is giving?

Use the tread width figure published on the tire rack. You will be able to know roughly how to fit the tire. Not all 305s will be the same and will vary based on tire brand and size. MotoIQ did a great article on this. How to fit a tire for performance driving.

 

[Bluemustang]

I was looking at Falken RT660s. 315/30R19 shows a tread width of 11.7". That should work well IMO with a 12" rim. Ideally you want the tread width equal to or 0.5" less than the rim width. This is per the MotoIQ article by Billy Johnson (racecar driver).

 

[jmagnus87]

I was looking at Falken RT660s. 315/30R19 shows a tread width of 11.7". That should work well IMO with a 12" rim. Ideally you want the tread width equal to or 0.5" less than the rim width. This is per the MotoIQ article by Billy Johnson (racecar driver).

yeah so they're 11x19s officially. so i can run 305s but ill try the Falken RT660s. the mach 1 that was about 16 seconds faster than me was on those. any benefit to going 315 square?

 

[Bluemustang]

yeah so they're 11x19s officially. so i can run 305s but ill try the Falken RT660s. the mach 1 that was about 16 seconds faster than me was on those. any benefit to going 315 square?

For 11" rim, the 295 would be a better fit. 315s are too wide for that rim to handle best. 295 would be the best fit (10.6" tread width) and tire diameter would be 27.2" so, close to stock. 305 has tread width of 11.4" and tire diameter of 26.3" so much shorter. The 305 would fit but I suspect the 295 square would be better. It would have a slightly larger sidewall due to the aspect ratio also. I am just going by the MotoIQ rule of thumb based on tread width figure.

The Falken RT660 will run rings around your Nittos. When I went from 285 Firehawk Indy 500 (a respectable summer tire) to 305 RE71R I dropped 7 seconds at Dominion Raceway in a roughly 90 second sprint. RT660 is a very similar tire to RE71R which is discontinued. Seriously coming from your Nittos, the Falkens will make it feel like a serious machine on the track. I did 1.2G+ on RE71R and I am a beginner so I am sure it can do 1.3 or higher with someone who is fast. You can't believe how much grip they have if you've never driven a tire like that.

 

[Bluemustang]

yeah so they're 11x19s officially. so i can run 305s but ill try the Falken RT660s. the mach 1 that was about 16 seconds faster than me was on those. any benefit to going 315 square?

FYI @NightmareMoon has used the RT660 and claims it is actually better than the RE71R that I have. He also uses Yokohama A052 in 18s which is a very very fast tire also. He has a lot of experience so I listen when he speaks.

 

[NightmareMoon]

found out from the guy i bought them from. 19x11 50mm offset all the way around. so i can run the 305s square and if i feel i would liek to try 315 square, can do that too. i DO run a 25mm spacer in front

Good, so 11" square, you can run 295, 305 and 315. 315 square is not as easy w/o *extra* long studs (not just the usual +1" kind) and extra wide spacers (more than 25m), so lets set those aside for now.

You have plenty of tire options in 295/35 (RE71RS) or 305/30 (Falken RT660 and others). Don't be timid about the 295 tires, good 200TW models are plenty fast.

 

[WItoTX]

yeah so they're 11x19s officially. so i can run 305s but ill try the Falken RT660s. the mach 1 that was about 16 seconds faster than me was on those. any benefit to going 315 square?

Look at Tire Rack, and what Nightmare and Blue are saying. Good rules of thumb.

 

[Bluemustang]

Good, so 11" square, you can run 295, 305 and 315. 315 square is not as easy w/o *extra* long studs (not just the usual +1" kind) and extra wide spacers (more than 25m), so lets set those aside for now.

You have plenty of tire options in 295/35 (RE71RS) or 305/30 (Falken RT660 and others). Don't be timid about the 295 tires, good 200TW models are plenty fast.

He will destroy his previous times over the Nittos with either of those tires lol. It's like driving a donkey vs. a Belmont stakes throughbred.

 

[jmagnus87]

Ok awesome input here guys i really do appreciate it. I'll get the camber plates over the winter too. Then i can try the complete setup all together sometime in spring. I'll do some research on both and see which one i like best for price point and such. Do either suggestions last any longer than the others on the track? 8000 street miles is fine with me for tire life
Do you guys run negative camber in the rear on track? I can get mine pretty negative with the bmr control arms

edit: my times are pretty consistent though

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