End of the square vs staggered
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From: Milwaukee, WI
I think there probably are some diminishing returns on tire width, but 255 is not it with this car, and since that's all you can reasonably squeeze up front, logic says limiting yourself to a 255 in the rear of the car to run "square" isn't the all out best performing option. We are talking unlimited set up here.
On my car we recently switched from 255 RE's to 285 RE's and I don't feel they are that much faster (255whp). I wish we had done a back to back comparison on the 255 vs. the 285, maybe in spring we will.
Anyway, my point is that overall I agree that more tire is generally better, but I think there is diminishing return for sure. I'm confident that if I ran the 315/335 setup that big bad wolf runs I would be slower over most laps than on my 285 square setup.
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I think it depends on the car. This is not data driven evidence but I know Jackie Ding has said that he has no benefit to going to 285's at the moment because he doesn't have the power to push them (220ish whp), although I think he attributed that more to having to go to 18's.
On my car we recently switched from 255 RE's to 285 RE's and I don't feel they are that much faster (255whp). I wish we had done a back to back comparison on the 255 vs. the 285, maybe in spring we will.
Anyway, my point is that overall I agree that more tire is generally better, but I think there is diminishing return for sure. I'm confident that if I ran the 315/335 setup that big bad wolf runs I would be slower over most laps than on my 285 square setup.
On my car we recently switched from 255 RE's to 285 RE's and I don't feel they are that much faster (255whp). I wish we had done a back to back comparison on the 255 vs. the 285, maybe in spring we will.
Anyway, my point is that overall I agree that more tire is generally better, but I think there is diminishing return for sure. I'm confident that if I ran the 315/335 setup that big bad wolf runs I would be slower over most laps than on my 285 square setup.
Last edited by s2000Junky; Oct 8, 2018 at 11:19 AM.
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From: Windsor, CA
One potential wrinkle I haven't explored is that if you take a balanced square setup of X width and add width to the rear, the only way to re-balance and exploit the newfound extra grip at the rear is to increase rear roll rate bias, which can bring some penalties as the rear starts to get stiff enough to unload the inside rear wheel on the stock differential. I'm guessing a balanced staggered setup would have greater need for a clutch-type LSD upgrade than a balanced square setup.
The other wrinkle is the tire size issue, even on 18's. As you start getting over 295, you don't have any options that don't increase overall diameter. So if you're taking the rear over 295, you're starting to gear taller, which might start being detrimental depending on your shift points on a particular track and/or power levels. Plenty of shorter diff ratios available, but again you're looking at a diff upgrade.
The other wrinkle is the tire size issue, even on 18's. As you start getting over 295, you don't have any options that don't increase overall diameter. So if you're taking the rear over 295, you're starting to gear taller, which might start being detrimental depending on your shift points on a particular track and/or power levels. Plenty of shorter diff ratios available, but again you're looking at a diff upgrade.
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From: Milwaukee, WI
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You might need to do it a 3rd time, because apparently its not that clear. I think there probably are some diminishing returns on tire width, but 255 is not it with this car, and since that's all you can reasonably squeeze up front, logic says limiting yourself to a 255 in the rear of the car to run "square" isn't the all out best performing option. We are talking unlimited set up here. Serves no point in talking what's best within a certain sanctioned rule based class, which some people tend to forget. I don't care what works best within a class. I look at how to maximize the performance threshold of the car period.
Sadly the best 100tw tire is a 200tw tire.
The RE71R/RivalS is faster hands down than the RC1/NT01.
Ive got both and in 255/40/17 on the same wheels (I have 2 sets of 17x10 949's) the RE71R/RivalS is 0.5 sec faster on a 2min course (measured at both buttonwillow and CVR).
I still usually run RC1 because they last longer and are overall cheaper but if youre looking to buy time that's it lower treadwear isnt faster. Also skip on the 275/35/17 RC1. We just did a test and the extra width costs too much top speed (tested on a SC car with 380rwhp we measured a 10mph vmax drop on vs 255 trofeo-r's).
The treadwear thing is a total lie.
The RE71R/RivalS is faster hands down than the RC1/NT01.
Ive got both and in 255/40/17 on the same wheels (I have 2 sets of 17x10 949's) the RE71R/RivalS is 0.5 sec faster on a 2min course (measured at both buttonwillow and CVR).
I still usually run RC1 because they last longer and are overall cheaper but if youre looking to buy time that's it lower treadwear isnt faster. Also skip on the 275/35/17 RC1. We just did a test and the extra width costs too much top speed (tested on a SC car with 380rwhp we measured a 10mph vmax drop on vs 255 trofeo-r's).
The treadwear thing is a total lie.
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This post is kinda confusing to me.
Can you tell me what full aero means? Just wing and splitter? Multi-element wing? Ducted fenders? Hard top? Diffuser? Flat floor?
Can you tell us exactly what you changed? Which tire and size combo you went from and to? I'm failing to see how adding front tire, and causing more oversteer, fixed your corner entry oversteer problem.
What size staggered RE's? What track? What were your previous times?
Can you tell me what full aero means? Just wing and splitter? Multi-element wing? Ducted fenders? Hard top? Diffuser? Flat floor?
Can you tell us exactly what you changed? Which tire and size combo you went from and to? I'm failing to see how adding front tire, and causing more oversteer, fixed your corner entry oversteer problem.
What size staggered RE's? What track? What were your previous times?
-previous RE71R were 225/255
-comparable times were on Mid-Ohio club course, which I have driven probably as much as anyone on here.
I literally changed nothing but wheels and tires. The times were only slightly faster, but there was more traffic and the conditions were not as great. I did get a good lap in on the Pro course and based on that time I would have been about .75-1sec faster on the club course.
The bias wasn’t drastically changed, just maybe slightly more oversteer and better turn it, but it was FAR more controllable at the limits. This combo made the car feel perfect and much less “edgy”.
Admittedly I didn’t expect it to feel nearly as stable and confident inspiring, but I can’t make stuff up just to appease Junky.
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. I could care less what about 95% of the guys think on here. The other 5% I know they can actually drive these cars and trust their opinion, which so far not a one of those people have debate that square isn’t better.
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And your quote on the 275 doesn't jive with the conclusion of unsprung weight/rolling resistance since if you noticed its a 275/35/17 which is a shorter then stock sidewall/overall diameter, hence the problem with less top speed. It would likely not be from weight and drag since its a smaller overall size tire, it would be from lack of gear with his 380whp. He would have been better off with an even wider tire closer to stock rolling diameter.
Remember, you are running camber on this car, which is only seeing roughly 2/3rd of the contact patch on the strait anyway. But 100% in the corners where it can be fully realized. You are relying on corning entry/exit speed if doing it right, not on power throughout all but long gradual turns, so rolling resistance is not at play in these areas, grip is. Also where is most of the time made up on your specific course, in the turns or down the strait? Again once size shoe doesn't fit all.
Last edited by s2000Junky; Oct 8, 2018 at 01:56 PM.
