MotoIQ tire article
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MotoIQ tire article
Anyone else catch this article?
http://www.motoiq.com/MagazineArticles/ID/3974/How-to-PROPERLY-select-and-size-TIRES-for-PERFORMANCE.aspx
Good read, though most of the info is common knowledge if you're really into motorsports.
The one point I found interesting was the sizing by using tread width. According to the authors opinion, something like a 255 width tire (having a tread width around 9.7"-9.9" for most performance tires) would require a 10"+ wide wheel. Makes sense but kind of crazy at the same time. What do you guys think?
http://www.motoiq.com/MagazineArticles/ID/3974/How-to-PROPERLY-select-and-size-TIRES-for-PERFORMANCE.aspx
Good read, though most of the info is common knowledge if you're really into motorsports.
The one point I found interesting was the sizing by using tread width. According to the authors opinion, something like a 255 width tire (having a tread width around 9.7"-9.9" for most performance tires) would require a 10"+ wide wheel. Makes sense but kind of crazy at the same time. What do you guys think?
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From: Why do they always call the Evo the Dark Side?
The one point I found interesting was the sizing by using tread width. According to the authors opinion, something like a 255 width tire (having a tread width around 9.7"-9.9" for most performance tires) would require a 10"+ wide wheel. Makes sense but kind of crazy at the same time. What do you guys think?
A lot of folks have found that over-tiring does not necessarily make the car faster with street tires, the way it does with DOT R-compound tires like the A6. So this is not that surprising.
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Right. Putting a 275 street tire on a 8" rim would not be a good combo, no surprise there. What I found interesting was that his minimum recommended size wheel is the maximum most tire manufacturers recommend. R-comp or not, most of us would consider a 255 on a 9-9.5 rim appropriate or a 275 on a 9.5-10 rim, and so on. It's all opinion at the end of the day, to a point obviously. Just thought it was interesting.
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I have wondered about this topic for a long time. Most top level autocrossers I have seen have at least SOME over-tiring going on (say, 245s on 7 inch rims like above).
Below is testing done by Danny Kao (national level autoxer at WDCR region). The test seems to suggest that over-tiring is not necessarily faster with street tires. However, when I asked him about the test, he told me on heaviers cars (like the FoST he was running at the time), over-tiring could actually bring a noticable improvement.
Someone needs to do some back-to-back testing with a B-Street evo!
Below is testing done by Danny Kao (national level autoxer at WDCR region). The test seems to suggest that over-tiring is not necessarily faster with street tires. However, when I asked him about the test, he told me on heaviers cars (like the FoST he was running at the time), over-tiring could actually bring a noticable improvement.
Someone needs to do some back-to-back testing with a B-Street evo!
My Non-Scientific Autocross Tire Test - Hoosier A6, Dunlop Star Spec 245/45/18, Star Spec 265/35/18, and Hankook RS3 245/40/18
by Danny Kao on Saturday, November 3, 2012 at 11:10pm ·
Like lots of autocrossers, I am a Hoosier fan because it really makes autocrossing fun. But also like many other autocrossers, I don't like to spend lot of money on tires. ($7000+ just on tires and tons of DFLs this year was very painful) I tried running street tires on my C5Z Chicken on two separate occasions: Toyo T1R during course setup once and Toyo RA1 (R-comp I guess) and the car was absolutely not fun to drive. After I sold my '70 Mini, I got a space to park another car; so of course the autocrosser in me begin to look for a car that is competitive, fairly inexpensive, can be used as a DD, and I can drive on street tires to the events. I found a 2007 Pontiac Solstice Club Sport from a fellow autocrosser in Norfolk, it came with Magnaflow Catback, SSR rims on Goodyear Eagles, and stock rims with 245/40/18 Hankook RS3s about 1/2 tread. Shortly after I got the car (like the 2nd day), I called Sam Strano for some Koni yellows and a K&N filter. After a quick visit to fellow autocrosser's Andy Thomas' alignment shop with Sam's alignment advise, a C-stock RTR was born.
I actually test drove the Solstice with the Hankook in the rain the day I bought the car. Hankook was pretty miserable in the wet and 40 degrees. I picked up a set of Star Specs sized 245/45/18 and mounted it on the SSRs and went to the next weekend's AI event. I did decently but I still don't have the reference on how good are the Star Specs or the car. Shortly after the event Sam told me about the AI member play day at Waldorf on November 3rd; and at the last AI event Eric Kriemelmeyer told me I can test his 265/35/18s Star Specs on OZ if I want to. Once I told Sam about this, Sam managed to get a fairly fresh set of Hoosier A6 295/35/18 stored at Big Mike Snyder's house for me. I found a set of Saturn Sky wheels cheap from someone who lived 3 miles away from my house by chance; after some muscling with 295 A6s onto 8 inch rims. I now have four sets of tires and rims to conduct my non-scientific autocross tire test!
For me, I wanted to find out the following from the test: (The order of importance to me)
1. Is 265 Star Specs faster than 245 Star Specs?
2. How bad is Hankook really in the cold weather?
3. Just how good is Solstice Z0K in C-Stock?
But Sam has other ideas... He wants to know if Rick Ruth's 0.975 RT tire multiplier is a realistic multiplier. Now we have good Hoosiers, good Star Specs, and 1/2 life RS3s. If we can run the test and collect all the times in similar conditions, we should be able to tell if the multiplier is fair. Well, for a 2800 lbs 170 HP car anyway.
Fast forward to today, November 3rd. Sam and Big Mike took the last AI event course and modified a little to make the course a tiny bit longer in the long slalom. But basically the course didn't change and all of us are very familiar with the course. (Video of the course can be found here: http://www.youtube.com/watch?v=ibHkzJOc8N4 ) The course has both tight and bigger sweepers, small offsets, fast offsets and fast slalom. It's not as long as a National style course, but big enough to have similar elements.
Now we need the test drivers. I recruited three other drivers plus myself. My idea was to get a top level driver who has won Nationals, and fortunately I got one. I also wanted to get two other good drivers that wins locally and trophy at multiple Nationals, and fortunately I got two. And I want a really bad driver to balance the test - the one that never wins anything. It turned out that was the easiest to find. :-/ So my test drivers are: Sam Strano, Big Mike Snyder, Eric Kriemelmeyer, and ME!
The plan is I am the tire warmer and try to hog as many runs as I can. I will take each tire set out and run it until they get some heat, and that was about 2-3 runs. Then I will time two of my fastest runs and hand the car to Big Mike for three runs and record two of his fastest time; then to Eric, and finally to Sam. Sam will have the hottest tire and since he is the most consistent so the data will mean something. The temperature was 50 degrees for most of our test day, cloudy and windy and almost no sun; so the test condition was similar all day. We decided to run 245 Star Specs first, follow by 245 Hankooks, then A6s, then 265 Star Specs and end with 245 Star Specs again to finish out the test. We started our runs at 9:30am and ended at 4:45pm.
So now the stage is set (certainly a long winded stage), here are the test results:
Drivers: Danny Kao, Mike Snyder, Eric Kriemelmeyer, Sam Strano
1st tire: 245/45/18 Star Specs, initial Tire Pressure 35/37
Danny 46.481 45.891
Mike 46.321 45.690
Eric 45.722 45.538
Sam 44.773 44.961 Tire pressure 38/35
2nd tire: Hankook RS3 245/40/18, Tire Pressure 32/32
Danny 46.531 45.641
Mike 45.962 45.162
Eric 45.200 44.733 dirty
Sam 44.788 44.153 44.148
3rd tire: Hoosier 295/35/18, Tire pressure 32/30
Danny 43.936 43.935
Mike 44.500 43.813
Eric 43.836 43.906
Sam 43.612 43.225 42.999
4th tire: Star Specs 265/35/18, Tire Pressure 32/32
Danny 45.524
Sam 45.221 44.581
(Only Sam and I tested the 265 because time is running out)
5th tire: Star Spec 245/45/18 baseline test at the End
Danny 45.454 45.620
Mike 45.012 45.318
Eric 45.290 44.901
Sam 44.173 44.490
Other baseline: Sam's Fastest SS C6GS time: 41.274 - PAX 35.413
Sam's best Star Spec 245 time at the beginning of the day: 44.773 - PAX 36.364 with .975 RT Multiplier
Sam's best RS3 245 time: 44.148 - PAX 35.856 with .975 RT Multiplier
Sam's best Solstice CS time: 42.999 - PAX 35.818
Sam's best Star Spec 265 time: 44.581 - PAX 36.207 with .975 RT Multiplier
Sam's best Star Spec 245 baseline at the end test time: 44.173 - PAX 35.876 wth .975 RT Multiplier
Based on Sam's time, I have conclude the following:
In the race of Sam vs. Sam: Sam lost to Sam by 0.405. Sam's GS is pretty well set up already and the Solstice is missing the K&N filter and lighter rims plus an occasional brake lock up problem (the ABS sometimes doesn't want to work), so I am pretty impressed on how the Solstice work right out of the box as a C-Stock car. To me what is more interesting is how close Rick Ruth's 0.975 RT Multipler is. Sam's fastest Star Spec 245 adjusted time is 0.058 off the Hoosier time. Sam's fastest adjusted RS3 time is 0.038 off the Hoosier time. If we use Sam's test data, the RT multiplier is 0.974, amazing....
A quick check to see the RT Multipler fared with the other three test drivers shows the following:
Eric: 43.839 (A6) / 44.901 (Z1-245) = 0.976
Mike: 43.813 (A6) / 45.012 (Z1-245) = 0.973
Danny: 43.935 (A6) / 45.454 (Z1-245) = 0.966
Not sure if it's appropriate to draw this conclusion; but I think the better driver you are, the more 0.975 RT multiplier applies in my particular car. My inability of handling street tires probably contributed a lot more towards the lower RT multiplier. I am sure is not a popular thing to say, but better the driver, the more accurate the 0.975 RT multiplier it is.
Now for my benefit: Also Amazingly, between the three street tires, my time difference between the fastest to the slowest is a grand total of 0.187; and with the best tire run being my last run. Sam prefered RS3s and he was faster in RS3 by 0.025. Mike was 0.150 faster in the 245 Star Specs, and Eric was 0.168 faster in the RS3. I am 0.070 faster in the 245 Star Specs than 265s. Even though my 245 Star Specs are 2 events old and RS3s only have 1/2 thread, they are basically even. I did noticed that when the Hankook is cold, it pushes and get loose and it takes longer than the Star Spec to warm up. But once is warmed it just as good as Star Specs.
So this concludes my non-scientific autocross tire test. For me I found out that the Solstice is a fun car to run in R-Comps and I am comfortable running it against any other C-Stock cars out there. I also think Rick Ruth is a genius for coming up with a RT multipler that is amazing accurate based on our test. I would probably run Star Specs in the colder days and rainy days but I will run RS3s in the warmer days; and the size of the street tires, even though they feel a little different, probably didn't have much time differences. So I would just save money and buy whatever is cheaper.
I like to thank Sam Strano, Big Mike Snyder and Eric Kriemelmeyer to be my guinea pigs for the test. I definitely want to thank Kate and Alan, Kevin, Lance, Steve, Adam, Sam V, Carl, Les, and Henry to letting me play at the AI day today. Thank you for letting me being a slacker and play autocross data geek all day. I had a lot of fun!
by Danny Kao on Saturday, November 3, 2012 at 11:10pm ·
Like lots of autocrossers, I am a Hoosier fan because it really makes autocrossing fun. But also like many other autocrossers, I don't like to spend lot of money on tires. ($7000+ just on tires and tons of DFLs this year was very painful) I tried running street tires on my C5Z Chicken on two separate occasions: Toyo T1R during course setup once and Toyo RA1 (R-comp I guess) and the car was absolutely not fun to drive. After I sold my '70 Mini, I got a space to park another car; so of course the autocrosser in me begin to look for a car that is competitive, fairly inexpensive, can be used as a DD, and I can drive on street tires to the events. I found a 2007 Pontiac Solstice Club Sport from a fellow autocrosser in Norfolk, it came with Magnaflow Catback, SSR rims on Goodyear Eagles, and stock rims with 245/40/18 Hankook RS3s about 1/2 tread. Shortly after I got the car (like the 2nd day), I called Sam Strano for some Koni yellows and a K&N filter. After a quick visit to fellow autocrosser's Andy Thomas' alignment shop with Sam's alignment advise, a C-stock RTR was born.
I actually test drove the Solstice with the Hankook in the rain the day I bought the car. Hankook was pretty miserable in the wet and 40 degrees. I picked up a set of Star Specs sized 245/45/18 and mounted it on the SSRs and went to the next weekend's AI event. I did decently but I still don't have the reference on how good are the Star Specs or the car. Shortly after the event Sam told me about the AI member play day at Waldorf on November 3rd; and at the last AI event Eric Kriemelmeyer told me I can test his 265/35/18s Star Specs on OZ if I want to. Once I told Sam about this, Sam managed to get a fairly fresh set of Hoosier A6 295/35/18 stored at Big Mike Snyder's house for me. I found a set of Saturn Sky wheels cheap from someone who lived 3 miles away from my house by chance; after some muscling with 295 A6s onto 8 inch rims. I now have four sets of tires and rims to conduct my non-scientific autocross tire test!
For me, I wanted to find out the following from the test: (The order of importance to me)
1. Is 265 Star Specs faster than 245 Star Specs?
2. How bad is Hankook really in the cold weather?
3. Just how good is Solstice Z0K in C-Stock?
But Sam has other ideas... He wants to know if Rick Ruth's 0.975 RT tire multiplier is a realistic multiplier. Now we have good Hoosiers, good Star Specs, and 1/2 life RS3s. If we can run the test and collect all the times in similar conditions, we should be able to tell if the multiplier is fair. Well, for a 2800 lbs 170 HP car anyway.
Fast forward to today, November 3rd. Sam and Big Mike took the last AI event course and modified a little to make the course a tiny bit longer in the long slalom. But basically the course didn't change and all of us are very familiar with the course. (Video of the course can be found here: http://www.youtube.com/watch?v=ibHkzJOc8N4 ) The course has both tight and bigger sweepers, small offsets, fast offsets and fast slalom. It's not as long as a National style course, but big enough to have similar elements.
Now we need the test drivers. I recruited three other drivers plus myself. My idea was to get a top level driver who has won Nationals, and fortunately I got one. I also wanted to get two other good drivers that wins locally and trophy at multiple Nationals, and fortunately I got two. And I want a really bad driver to balance the test - the one that never wins anything. It turned out that was the easiest to find. :-/ So my test drivers are: Sam Strano, Big Mike Snyder, Eric Kriemelmeyer, and ME!
The plan is I am the tire warmer and try to hog as many runs as I can. I will take each tire set out and run it until they get some heat, and that was about 2-3 runs. Then I will time two of my fastest runs and hand the car to Big Mike for three runs and record two of his fastest time; then to Eric, and finally to Sam. Sam will have the hottest tire and since he is the most consistent so the data will mean something. The temperature was 50 degrees for most of our test day, cloudy and windy and almost no sun; so the test condition was similar all day. We decided to run 245 Star Specs first, follow by 245 Hankooks, then A6s, then 265 Star Specs and end with 245 Star Specs again to finish out the test. We started our runs at 9:30am and ended at 4:45pm.
So now the stage is set (certainly a long winded stage), here are the test results:
Drivers: Danny Kao, Mike Snyder, Eric Kriemelmeyer, Sam Strano
1st tire: 245/45/18 Star Specs, initial Tire Pressure 35/37
Danny 46.481 45.891
Mike 46.321 45.690
Eric 45.722 45.538
Sam 44.773 44.961 Tire pressure 38/35
2nd tire: Hankook RS3 245/40/18, Tire Pressure 32/32
Danny 46.531 45.641
Mike 45.962 45.162
Eric 45.200 44.733 dirty
Sam 44.788 44.153 44.148
3rd tire: Hoosier 295/35/18, Tire pressure 32/30
Danny 43.936 43.935
Mike 44.500 43.813
Eric 43.836 43.906
Sam 43.612 43.225 42.999
4th tire: Star Specs 265/35/18, Tire Pressure 32/32
Danny 45.524
Sam 45.221 44.581
(Only Sam and I tested the 265 because time is running out)
5th tire: Star Spec 245/45/18 baseline test at the End
Danny 45.454 45.620
Mike 45.012 45.318
Eric 45.290 44.901
Sam 44.173 44.490
Other baseline: Sam's Fastest SS C6GS time: 41.274 - PAX 35.413
Sam's best Star Spec 245 time at the beginning of the day: 44.773 - PAX 36.364 with .975 RT Multiplier
Sam's best RS3 245 time: 44.148 - PAX 35.856 with .975 RT Multiplier
Sam's best Solstice CS time: 42.999 - PAX 35.818
Sam's best Star Spec 265 time: 44.581 - PAX 36.207 with .975 RT Multiplier
Sam's best Star Spec 245 baseline at the end test time: 44.173 - PAX 35.876 wth .975 RT Multiplier
Based on Sam's time, I have conclude the following:
In the race of Sam vs. Sam: Sam lost to Sam by 0.405. Sam's GS is pretty well set up already and the Solstice is missing the K&N filter and lighter rims plus an occasional brake lock up problem (the ABS sometimes doesn't want to work), so I am pretty impressed on how the Solstice work right out of the box as a C-Stock car. To me what is more interesting is how close Rick Ruth's 0.975 RT Multipler is. Sam's fastest Star Spec 245 adjusted time is 0.058 off the Hoosier time. Sam's fastest adjusted RS3 time is 0.038 off the Hoosier time. If we use Sam's test data, the RT multiplier is 0.974, amazing....
A quick check to see the RT Multipler fared with the other three test drivers shows the following:
Eric: 43.839 (A6) / 44.901 (Z1-245) = 0.976
Mike: 43.813 (A6) / 45.012 (Z1-245) = 0.973
Danny: 43.935 (A6) / 45.454 (Z1-245) = 0.966
Not sure if it's appropriate to draw this conclusion; but I think the better driver you are, the more 0.975 RT multiplier applies in my particular car. My inability of handling street tires probably contributed a lot more towards the lower RT multiplier. I am sure is not a popular thing to say, but better the driver, the more accurate the 0.975 RT multiplier it is.
Now for my benefit: Also Amazingly, between the three street tires, my time difference between the fastest to the slowest is a grand total of 0.187; and with the best tire run being my last run. Sam prefered RS3s and he was faster in RS3 by 0.025. Mike was 0.150 faster in the 245 Star Specs, and Eric was 0.168 faster in the RS3. I am 0.070 faster in the 245 Star Specs than 265s. Even though my 245 Star Specs are 2 events old and RS3s only have 1/2 thread, they are basically even. I did noticed that when the Hankook is cold, it pushes and get loose and it takes longer than the Star Spec to warm up. But once is warmed it just as good as Star Specs.
So this concludes my non-scientific autocross tire test. For me I found out that the Solstice is a fun car to run in R-Comps and I am comfortable running it against any other C-Stock cars out there. I also think Rick Ruth is a genius for coming up with a RT multipler that is amazing accurate based on our test. I would probably run Star Specs in the colder days and rainy days but I will run RS3s in the warmer days; and the size of the street tires, even though they feel a little different, probably didn't have much time differences. So I would just save money and buy whatever is cheaper.
I like to thank Sam Strano, Big Mike Snyder and Eric Kriemelmeyer to be my guinea pigs for the test. I definitely want to thank Kate and Alan, Kevin, Lance, Steve, Adam, Sam V, Carl, Les, and Henry to letting me play at the AI day today. Thank you for letting me being a slacker and play autocross data geek all day. I had a lot of fun!
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