Hoosier A7 or R7 for track?
08-09-2015 | 07:45 PM
#46
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Joined: Jan 2002
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From: Clovis, CA
Chad,
Not sure if it matters, but on my '71 RSR bodied racecar I had at BW with you guys, I use the 16" 245/275 combo like you. Switching to the R7/A7, I found that the 275 did not change any in width, just the 245. Now, it's actually difficult to tell the 245 from the 275 when they are laying flat on the ground. Discount tire mounted them backwards once (245 rear and 275 front), I almost walked out because I couldn't tell they were different until I started loading them in the truck, as the 275's are taller 25.5 vs 24.5". Had to take them back in to swap to the correct rims.
They do make a 275/35 tire. But its really short, like 23.5" I think.
Erik
Not sure if it matters, but on my '71 RSR bodied racecar I had at BW with you guys, I use the 16" 245/275 combo like you. Switching to the R7/A7, I found that the 275 did not change any in width, just the 245. Now, it's actually difficult to tell the 245 from the 275 when they are laying flat on the ground. Discount tire mounted them backwards once (245 rear and 275 front), I almost walked out because I couldn't tell they were different until I started loading them in the truck, as the 275's are taller 25.5 vs 24.5". Had to take them back in to swap to the correct rims.
They do make a 275/35 tire. But its really short, like 23.5" I think.
Erik
Good to know on the 16's. I guess I can call Hoosier to see if the 275/50 R15's changed in width.
08-10-2015 | 12:34 PM
#47
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Joined: Jan 2002
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From: Clovis, CA
I just confirmed with a Hoosier Engineer that any R7- 255 width and higher is the same tire mold of the old R6. So sizes are pretty much the same. Anything 245 width and under on the R7's is a new tire mold and wider than the R6 by a "Fair" amount.
So the info is right on. Thanks Erik.
So the info is right on. Thanks Erik.
08-10-2015 | 06:44 PM
#48
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From: Portsmouth, Ohio
There is a pic on Rennlist somewhere showing a 275 R6 and a 245 R7 laying side by side. Or was it a 275 R7? anyway, I went with the 245 R7 onthe rear of my SC and my lap times are down.
Found it Pic of 4 Ho's side by side
Found it Pic of 4 Ho's side by side
08-10-2015 | 08:48 PM
#49
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From: Northeast
I just confirmed with a Hoosier Engineer that any R7- 255 width and higher is the same tire mold of the old R6. So sizes are pretty much the same. Anything 245 width and under on the R7's is a new tire mold and wider than the R6 by a "Fair" amount.
So the info is right on. Thanks Erik.
So the info is right on. Thanks Erik.
There is a pic on Rennlist somewhere showing a 275 R6 and a 245 R7 laying side by side. Or was it a 275 R7? anyway, I went with the 245 R7 onthe rear of my SC and my lap times are down.
Found it Pic of 4 Ho's side by side
Found it Pic of 4 Ho's side by side
08-11-2015 | 08:56 AM
#50
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Joined: Jan 2002
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From: Ann Arbor, Michigan
Although a little different, I tried a set of BFG R1s, their autocross tire, for some early Spring events. I didn't want to use Pirelli take offs in 40-50 degree weather. I had the same size variation problem, and had to go from front 245 to 205 to get them to fit, and they still rub a little. But they are very good in cold weather, and my times were only a little off my best times at the Glen. The cold weather changes the mix, though, and I would expect better times at a high horsepower track like the Glen when it is cool due to hp increases.
I do not plan on using them again until the cool weather in the Fall returns, possibly at VIR in late October. But I am guessing that the A7 would act in a similar way. Good in cool weather.
I do not plan on using them again until the cool weather in the Fall returns, possibly at VIR in late October. But I am guessing that the A7 would act in a similar way. Good in cool weather.
08-12-2015 | 11:55 PM
#51
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Joined: Jan 2002
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From: Clovis, CA
Maybe the R15 tires are different.
. Rules are rules, I wish I could run 17's .