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AutoX Tire Help

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#1
I've been all over this forum and others doing research on AutoX tires. The consensus seems to be Bridgestone RE71R in 205/45-16 or 205/50-16.

So my question is why?

I am just a casual, local only racer looking to stay in SCCA HS class. In doing tire research, I found that 99% of people switch to another tire and I would like to know the reasoning.
Specifically, I would like to know:

  • What is better about other tires than the stock? Especially the RE71Rs that most people prefer.
  • Does treadwear factor in other than the rules? Stock tires are 140 which seems legal at the regional level because they are OE tires. Does that mean they are better if I stay local and don't go to national events?
  • Why do many people move down to a 16 inch wheel/tire?

Thank you for your help.
 


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Bucks
#2
?better grip
?treadwear value is mostly arbitrary. Your OE tires are not better, the legality is accurate but no sane person will care if you run them... anywhere
?people move down because it lowers your CG and the loss of weight helps, slightly, with its acceleration in all dimensions. The trade off is with the reduced surface area of the rubber, it gets hotter faster. And, you can lose a couple mph's of top speed.
 


OP
A
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Thread Starter #3
Wow thanks for the info.

With the better grip, I wrongly assumed treadwear was a metric for grip (lower the treadwear equals more grip). Are there metrics for grip? or is it all based on experience and individual testing? I like stats haha.
 


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#4
1. Way higher grip levels, higher heat capacity, much stiffer sidewalls etc.
2. The manufacturer sets tread wear rating. Hence why the RE-71R is so much better than the other 200TW's because it's not really "200TW" haha
3. Mainly people move down for weight savings, and the ability to run a higher ratio sidewall height. 50 series vs. 40/45 series etc.
 


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Thread Starter #5
So would RE71Rs on stock wheels give me a pretty good performance increase or do I need to get lighter and smaller wheels to make it worth it?
 


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#6
215 or 205 17" re71 on your stock wheels will be great. You do not need different wheels.
 


M-Sport fan

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#7
Are there metrics for grip? or is it all based on experience and individual testing? I like stats haha.
Sadly, NO, there are no 'metrics' save for word of mouth experience, and maybe some of the testing done by Tire Rack themselves, or Grassroots Motorsports rag.

Even if these manufacturers gave actual durometer reading numbers for their compounds, it still would not tell the full story. [:(]
 


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#8
Wow thanks for the info.

With the better grip, I wrongly assumed treadwear was a metric for grip (lower the treadwear equals more grip). Are there metrics for grip? or is it all based on experience and individual testing? I like stats haha.
The information on https://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=219 is the closest your going to get to quantifiable data. But otherwise no, there is no stat that can be compared to to tire because there's too many metrics like to account for. That being said, if you want some assurance that the RE-71R's are the one to go to, google "2016 SCCA Nationals Results". Like 95% of the cars are running them.
 


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#10
I don't think a 40 exists in 205 or 215.
Both are good, I like the cheaper size... the fast people I know would choose the 205.
 


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#11
Have you considered any of the Federal 595 tires? I just put a set of 595 rsrr tires on in 215/40/17 and I like them over stock even though they are LOUD. If you haven't heard of them you should at least check out the pricing. It's hard to beat.
 


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#12
Have you considered any of the Federal 595 tires? I just put a set of 595 rsrr tires on in 215/40/17 and I like them over stock even though they are LOUD. If you haven't heard of them you should at least check out the pricing. It's hard to beat.
The RSRs and RSRRs are a NO GO for H/S SCCA autocross class, even locally/regionally, IF that is what he wants them for.
I plan on using one of the Federal 595s in 215/40-17 on my 1.2s when they show up though, since I refuse to do SCCA a/x with their draconian, biased to certain cars'/drivers', rules!

B-Stone REFUSES to produce the RE71Rs in any 40 series sizes we could use, and I do not understand WHY. [???:)] [mad]
 


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#13
The RSRs and RSRRs are a NO GO for H/S SCCA autocross class, even locally/regionally, IF that is what he wants them for.
I plan on using one of the Federal 595s in 215/40-17 on my 1.2s when they show up though, since I refuse to do SCCA a/x with their draconian, biased to certain cars'/drivers', rules!

B-Stone REFUSES to produce the RE71Rs in any 40 series sizes we could use, and I do not understand WHY. [???:)] [mad]
Oh snap, that's news to me. I thought they were legal since they were 200tw. Where have you seen/heard that they were a no go?

Edit- I order s the rsrr's recently thinking they were 140 tread wear but they say 200 right on the tire. Did they change the formula?
 


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#14
They are all 140 per Federal, maybe that was a misstamp on the tire or maybe their site is out of date. I am not sure how that would go down showing up with 200tw tires that everyone thinks are 140. I have some 595 EVOs on the way, at 240tw they will pass class restrictions .Has anyone here run the 595 EVOs in autox?


Though it doesn't matter for me, my rear motor mount apparently puts me up to STX class so I will just run what I want tire wise as long as its safe and really care where I get classed. I found a Corvette club to run with and since its just for fun I can do pretty much anything I want.
 


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#15
They are all 140 per Federal, maybe that was a misstamp on the tire or maybe their site is out of date. I am not sure how that would go down showing up with 200tw tires that everyone thinks are 140. I have some 595 EVOs on the way, at 240tw they will pass class restrictions .Has anyone here run the 595 EVOs in autox?


Though it doesn't matter for me, my rear motor mount apparently puts me up to STX class so I will just run what I want tire wise as long as its safe and really care where I get classed. I found a Corvette club to run with and since its just for fun I can do pretty much anything I want.
From what I can tell Federal has switched the tread wear rating to 200 in order to sell them to autocrossers in the US. It's said that Bridgestone did the same thing with the re-71 which is probably also more like a 140.

I'm just going to see what happens at my first scca AutoX this weekend. They are a little looser in my region (for HS they told me to put my stock intake back but Cobb RMM is okay...) so I don't think it's gonna be a huge deal. But something tells me it will be okay since Federal has 200 on the tire as well as the sticker that was on the tire. Everyone seems to think the treadwear ratings are BS, seems like they need a different metric.
 


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#16
Oh snap, that's news to me. I thought they were legal since they were 200tw. Where have you seen/heard that they were a no go?

Edit- I order s the rsrr's recently thinking they were 140 tread wear but they say 200 right on the tire. Did they change the formula?
That's interesting that they state 200 on the tire, since their actual SITE still has them @140 tread wear for BOTH the RSRs, and the RSRRs. [???:)]

Maybe they did increase the rating number to compete with the other 200 tread wear a/x compound tires out there, and just did NOT update the site yet? [dunno]

If they really are 200 tread wear, then YES, they ARE SCCA H/S legal for sure!
 


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#17
I checked their site as well and saw they still list them as 140. They're having this same debate in other forums right now. I saw one other person did find a Federal webpage where they listed them as 200 but I didn't see that. Maybe I should find it so I can pull it up if anyone gives me a hard time next weekend. I'm especially pushing it since I got them in 215 width. I wasn't planning on doing much AutoX when I ordered them but things changed.
 


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#18
The federal will not be competitive on a national level. There was 1 year where they had a hope and prayer, but after the re71's came and the rival got an update, the fed can't hang.

My 2 go to's are the stone and the bfg. the bfg likes a little less slip, and thus is a little less of a beginner tire. the stone is a great all arounder.
 


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#19
^^^AGREED!

But, local level people, with low aspirations (NEVER plan on going to Lincoln, nor doing the 'National Tour') do not need to be spending almost twice as much for a tire which is going to burn away very quickly anyway, just to 'have some fun' with their cars. [wink]
(Given, of course, that the RS-RR IS in fact a labelled 200 tread wear donut.)
 


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#20
^^^AGREED!

But, local level people, with low aspirations do not need to be spending almost twice as much for a tire which is going to burn away very quickly anyway, just to 'have some fun' with their cars. [wink]
(Given, of course, that the RS-RR IS in fact a labelled 200 tread wear donut.)
But in that case, you can use the oem tire. If you're spending money in this hobby to go faster, at least do it right. and tbh, the Falken is a better tire for that purpose than the fed. spend money to go faster. How much you spend is how much faster you go.... so to go really fast, buy hoosiers. lol

but, for real. the federals have some of the worst characteristics of a street tire for autox I've driven on aside from the toyo r1r(yes, the pixie dust 195's)..
 


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