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Old 12-10-2015, 09:09 PM   #1
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Default SM7 vs. R7

Looking for anyone that has first hand experience with the time differential between an SM7 and a 205/50R15 R7.

Only thing that came up when searching was opinions on how they drove or how long they lasted. On a 1 minute per lap course does anyone think the SM7's are within say 0.5 seconds of the R7? Or maybe nearly the same?
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Old 12-11-2015, 12:38 PM   #2
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No direct A-B experience, but something to consider.

I was talking to the local Hoosier dealer and he brought this to my attention when I asked the same question. The SM7 still has the full line grooves whereas the R7 has the "dashed" grooves. It may not seem like much, but the dashed groove collectively produces a 15% larger foot print over the full lined groove. He also told me the R7 and SM7 share the same compound, but have a different carcass. No A to B testing, but the R7 will be faster. A guesstimate of at least 0.5 to 0.7, track dependent of course.
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Old 12-12-2015, 01:04 AM   #3
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I've found that on both the R7 and R6, whether it has the dotted grooves are not, tends to fill up with rubber anyways after the first couple heat cycles so I don't think the transition to dotted grooves vs. solid lines on the same compound would produce 0.5 seconds a lap.

I'm just more curious if anyone has had a chance to compare them. Most people I've talked to either run one or the other.
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Old 12-12-2015, 10:25 AM   #4
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I may be the only person that has done back to back testing between sm7 and 205 r7.
My lap times at Sonoma
Sticker Sm7: 1:51.9
Sticker R7: 1:50.8
Sticker A6: 1:50.1

And I will say that the R7's are incredibly consistent over heat cycles. If you are using them for TT, they are good for 15 heat cycles or so before they start to noticeably slow down. It is unbelievable. I went through 5-6 sets of stickers this year and the stickers where never really better than my "practice sets".

And if you think it's because I don't drive them hard enough... Lol, look into that
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Old 12-12-2015, 11:20 AM   #5
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Quote:
Originally Posted by circuitmstr74 View Post
I may be the only person that has done back to back testing between sm7 and 205 r7.
My lap times at Sonoma
Sticker Sm7: 1:51.9
Sticker R7: 1:50.8
Sticker A6: 1:50.1

And I will say that the R7's are incredibly consistent over heat cycles. If you are using them for TT, they are good for 15 heat cycles or so before they start to noticeably slow down. It is unbelievable. I went through 5-6 sets of stickers this year and the stickers where never really better than my "practice sets".

And if you think it's because I don't drive them hard enough... Lol, look into that
A full second, nice!

Did you sell your PTD/TTD car yet?
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Old 12-12-2015, 11:48 AM   #6
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Quote:
Originally Posted by circuitmstr74 View Post
I may be the only person that has done back to back testing between sm7 and 205 r7.
My lap times at Sonoma
Sticker Sm7: 1:51.9
Sticker R7: 1:50.8
Sticker A6: 1:50.1

And I will say that the R7's are incredibly consistent over heat cycles. If you are using them for TT, they are good for 15 heat cycles or so before they start to noticeably slow down. It is unbelievable. I went through 5-6 sets of stickers this year and the stickers where never really better than my "practice sets".

And if you think it's because I don't drive them hard enough... Lol, look into that

Just wanted to say, I have "looked into it" in the past.


The guy fukin gets after it.
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Old 12-12-2015, 06:01 PM   #7
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Quote:
Originally Posted by circuitmstr74 View Post
I may be the only person that has done back to back testing between sm7 and 205 r7.
My lap times at Sonoma
Sticker Sm7: 1:51.9
Sticker R7: 1:50.8
Sticker A6: 1:50.1

And I will say that the R7's are incredibly consistent over heat cycles. If you are using them for TT, they are good for 15 heat cycles or so before they start to noticeably slow down. It is unbelievable. I went through 5-6 sets of stickers this year and the stickers where never really better than my "practice sets".

And if you think it's because I don't drive them hard enough... Lol, look into that
Thanks. This is exactly what I was looking for and looks like I'll stick to R7's.

I've been through about 2 sets of R7's so far and found the same thing, start falling off at about 14 to 16 heat cycles for me and at 20 heat cycles they're about a second off the pace of stickers. I do mostly 20 minute sprint races with them and the occasional TT session.

Also don't worry, I believe you lmao. This is Aaron from Facebook. Purple fire suit.
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Old 12-12-2015, 11:45 PM   #8
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Yes, my car is sold... Sad and happy about it. I love the car but I have some paid rides in addition to my full time stunt driving gig and can't keep spending all my own money to race.
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Old 12-15-2015, 10:49 PM   #9
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Quote:
Originally Posted by flier129 View Post
No direct A-B experience, but something to consider.

I was talking to the local Hoosier dealer and he brought this to my attention when I asked the same question. The SM7 still has the full line grooves whereas the R7 has the "dashed" grooves. It may not seem like much, but the dashed groove collectively produces a 15% larger foot print over the full lined groove. He also told me the R7 and SM7 share the same compound, but have a different carcass. No A to B testing, but the R7 will be faster. A guesstimate of at least 0.5 to 0.7, track dependent of course.
Your Hoosier dealer may be dumb. 15% of a 225mm tread width tire (what the 205s are) is 33mm.
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Old 12-16-2015, 11:43 AM   #10
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Originally Posted by FatKao View Post
Your Hoosier dealer may be dumb. 15% of a 225mm tread width tire (what the 205s are) is 33mm.
Maybe it was 10%? Even still..... I always take anything a vendor, that's selling me a product, with a grain of salt. Results speak louder than the pitch
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Old 01-13-2016, 04:51 PM   #11
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Quote:
Originally Posted by circuitmstr74 View Post
I may be the only person that has done back to back testing between sm7 and 205 r7.
My lap times at Sonoma
Sticker Sm7: 1:51.9
Sticker R7: 1:50.8
Sticker A6: 1:50.1

And I will say that the R7's are incredibly consistent over heat cycles. If you are using them for TT, they are good for 15 heat cycles or so before they start to noticeably slow down. It is unbelievable. I went through 5-6 sets of stickers this year and the stickers where never really better than my "practice sets".

And if you think it's because I don't drive them hard enough... Lol, look into that
Can you comment how the SM7s held up? I have only used the SM7s once at Sonoma, but haven't seen them fall off yet (only 5 HCs). I'll say that they were super greasy at Laguna last weekend (50F ambient); I should have switched to the A7s sooner.
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