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1966 mustang coupe
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Discussion Starter #1
Hi, i am about to buy some 17" wheels to be able to put some good sticky rubbers on my '66 coupe.

I know this has been already discussed but whats the conclusion with 17x8 wheels in front of a 65-66?

My plan is to go with a square setup of 235-45-17 tires, wheels would be torq thrust M 17x8 with 4.5 backspace.

Can i expect that to fit if i only roll the fenders?

I am slowly building my car so i could do some non competitive hpde events next season and the big sidewall rubbers on the 15" wheels just wont do it.

Thanks!
 

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I am building my car so i could (can?) do some non competitive hpde events next season and the big sidewall rubbers on the 15" wheels just won't do it.
Since when? Multiple thousands of automotive racing enthusiasts over the last (roughly) 75 years or so would beg to differ.
 

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1966 Mustang GT 4sp Nightmist Blue
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17x8 4.75 back spacing you should be able to run that without issue. I’m running 225/45F & 245/45R
763871


763873


Chris
 

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Discussion Starter #4
I did write this comment on purpose to have you old school guys to chime in.

Lets continue i am all ears ;)
 

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Discussion Starter #5
17x8 4.75 back spacing you should be able to run that without issue. I’m running 225/45F & 245/45R


Chris
Ive seen that 4.75 back spacing may be better yes. I would like to run a square setup if possible for tires rotation, i just dont know if those 235 would fit in front....
 

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I did write this comment on purpose to have you old school guys to chime in.

Lets continue i am all ears ;)
Old school?
How about educated. ;)

Chris
 
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Discussion Starter #8
Old school?
How about educated. ;)

Chris
Didnt apply to you and i was joking anyway. :)

I am just curious too see what tires do the 15" folks are running on the track (road course)

i have some 15" magnum 500 on my car right now but tires choice is horrible in that size over here....
 

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1966 Mustang GT 4sp Nightmist Blue
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Nice ride badbendz!
Thank you! It’s a big work in progress.

Didnt apply to you and i was joking anyway. :)

I am just curious too see what tires do the 15" folks are running on the track (road course)

i have some 15" magnum 500 on my car right now but tires choice is horrible in that size over here....
I know :)

Not sure, Im curious too. I know the big complaint is lack of options in that tire size, hence why most performance orientated go to a larger wheel.

Chris
 

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Discussion Starter #10
I know :)

Not sure, Im curious too. I know the big complaint is lack of options in that tire size, hence why most performance orientated go to a larger wheel.

Chris
Exactly, and low profiles 15" dont look especially good on our cars.....
 

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I'm running 17x8 wheels in all corners. 4.75 BS. 225/45 in front, 245/40 in the back. I DID have to roll the front fenders in order not to rub,. But there are many others on this forum that have not had to do that. Rears do not rub at all. As a matter of fact I could probably go up to 255 in the rear and be ok.

235/45 may work in the front, but you'll probably need to roll the fenders.

-Shannon
 

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I think the 245s are too much and will rub on the 66. As stated, 225s are the way to go for that car. It m running 245/45/17 on all corners on my 70. I have 1 inch adapters up front, and 0.75” in the rear.
 

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I did write this comment on purpose to have you old school guys to chime in.

Lets continue i am all ears ;)
How about us old school guys with a couple of decades contemporary experience racing wheel to wheel and building race cars?

A good many club sports car classes use 15s. All circle track uses 15s. Indycar is using a 15. Smaller tire off road uses 15s and one of the reasons the big buggies and trucks use 17s is because you can’t get a 40” tire on a 15.

The reason many manufacturers have limited 15” tire sizes has nothing to do performance and everything to do with modern looks. The 15” styling is not in fashion these days. With late model cars it’s all 16-18 and those selling primarily street tires aren’t going to stock a wide selection non DOT tires. If you look at race specific non DOT there are scores of choices. It’s possible your 17” DOT tire will need to be shaved to match the performance of an R compound 15. Even then it’s likely a 15” race tire will out perform a high performance 17” street tire.

There are plenty of good reasons to go with a 17” wheel, looks, type of wheel or tire width/profile combination. Geometry and performance of the 15” isn’t one of those considerations for hobby racing. If you don’t want 15s for the look that’s all well and good. Make sure you’re not making the decision based on myths and misconceptions.
 

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I'm running American Racing VN215 Gray Classic Torq-Thrust II One-Piece Wheels VN2157866 wheels with 4.81" back space with 245/40/17 Bridgestone RE71's. All fenders are rolled and it is super tight out back with less than a 1/4" to spare inside and outside the wheel-well. I don't think you can run 245/45 or 245/40 on a stock front suspension unless you run at least 2º negative camber and I'm running -3º on a modified coil over setup. When I had 225/45/17's on the same wheels I only had to roll the drivers rear fender a little.
 

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Discussion Starter #17
How about us old school guys with a couple of decades contemporary experience racing wheel to wheel and building race cars?

A good many club sports car classes use 15s. All circle track uses 15s. Indycar is using a 15. Smaller tire off road uses 15s and one of the reasons the big buggies and trucks use 17s is because you can’t get a 40” tire on a 15.

The reason many manufacturers have limited 15” tire sizes has nothing to do performance and everything to do with modern looks. The 15” styling is not in fashion these days. With late model cars it’s all 16-18 and those selling primarily street tires aren’t going to stock a wide selection non DOT tires. If you look at race specific non DOT there are scores of choices. It’s possible your 17” DOT tire will need to be shaved to match the performance of an R compound 15. Even then it’s likely a 15” race tire will out perform a high performance 17” street tire.

There are plenty of good reasons to go with a 17” wheel, looks, type of wheel or tire width/profile combination. Geometry and performance of the 15” isn’t one of those considerations for hobby racing. If you don’t want 15s for the look that’s all well and good. Make sure you’re not making the decision based on myths and misconceptions.
Youre absolutely right, id say sidewall is the main thing with 15s on a sreet/track driven mustang.

For example, my current tires have a 65 profile soft sidewall, the amount of play is ridiculous with that sidewall, my rims move from left to left a lot when i am just pushing the car with 1 hand, can you imagine what it does when you enter a curve....

And yeah, in my opinion low profile 15" tires dont look good at all on the mustang, so ill move to 17" and ill get more tire choices at the same time.

We would have a different discussion if my car was a dedicated track car.....
 

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Discussion Starter #18
I'm running American Racing VN215 Gray Classic Torq-Thrust II One-Piece Wheels VN2157866 wheels with 4.81" back space with 245/40/17 Bridgestone RE71's. All fenders are rolled and it is super tight out back with less than a 1/4" to spare inside and outside the wheel-well. I don't think you can run 245/45 or 245/40 on a stock front suspension unless you run at least 2º negative camber and I'm running -3º on a modified coil over setup. When I had 225/45/17's on the same wheels I only had to roll the drivers rear fender a little.
I was able to go to -0.8 camber only on my stockish setup with #600 springs.

I may have to reconsider the 235's square setup and do 225F/245R.

I will have my fender rolled thats for sure.....
 

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How about us old school guys with a couple of decades contemporary experience racing wheel to wheel and building race cars?

A good many club sports car classes use 15s. All circle track uses 15s. Indycar is using a 15. Smaller tire off road uses 15s and one of the reasons the big buggies and trucks use 17s is because you can’t get a 40” tire on a 15.

The reason many manufacturers have limited 15” tire sizes has nothing to do performance and everything to do with modern looks. The 15” styling is not in fashion these days. With late model cars it’s all 16-18 and those selling primarily street tires aren’t going to stock a wide selection non DOT tires. If you look at race specific non DOT there are scores of choices. It’s possible your 17” DOT tire will need to be shaved to match the performance of an R compound 15. Even then it’s likely a 15” race tire will out perform a high performance 17” street tire.

There are plenty of good reasons to go with a 17” wheel, looks, type of wheel or tire width/profile combination. Geometry and performance of the 15” isn’t one of those considerations for hobby racing. If you don’t want 15s for the look that’s all well and good. Make sure you’re not making the decision based on myths and misconceptions.

I hate spending $800 on the RE71's every year and I'd really hate spending $1600 on Avon tyres!
 
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