A7 vs. R1-S?

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DanB
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A7 vs. R1-S?

Post by DanB » Tue Jul 28, 2020 8:51 am

How do these compare in terms of relative lap times vs. number of heat cycles? Other options?
I'm *thinking* about getting a set of real tires and "classing up" :P Probably only use them for 6 - 10 heat cycles this year...
'17 Subaru BRZ PP, #7 T60
Gone but not forgotten: Datsun 240Z, #7 SPB :cry:

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Re: A7 vs. R1-S?

Post by TunaNoCrust » Tue Jul 28, 2020 10:44 am

I like where this is going!
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Re: A7 vs. R1-S?

Post by dtlemoine » Tue Jul 28, 2020 11:19 am

Can't speak for the A7, but re: R1-S, there are performance plateaus for sure, but they wear like iron and last a ton of cycles, at least on the heavy cars...

I ran a set of 245 width with 40+ HC throughout the weekend at Thompson, and ultimately ran better times with that set than with a sticker set of 235 width in the TT. Too many variables to compare apples to apples (obviously tire width, track temp was WAY up in the TT, etc.). But, impressive that the 40+ HC leftovers from last season came in to their own throughout the event. Your first 1 or 2 cycles are magical, then you get some really solid performance from cycles 3-10ish, then another small drop for the next 20 cycles, etc. Flip them halfway through their life, or make sure your alignment is solid, and you'll be good to go. Unless you throw a bunch of short cycles at them, they'll probably wear to the cords before they really cycle out.
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Re: A7 vs. R1-S?

Post by 962porsche » Tue Jul 28, 2020 11:59 am

I have used both on our 9 MX5 cars weight 2505 full wet with driver lighter when the wife is driving.
the R1's we only used up one set they lasted 6 events then they fell off sharply. felt like we were driving on ice once they fell off they fell off at LRP and we when from no braking for the uphill and west bent to needing to brake. times went from low 59's to high 101's when they fell off. they were fine for the two morning run sessions. swapped over to the R7 for the afternoon runs and times went to very high 58's. we run 9 events some of them the wife and I dual drive the event's with only a driver change between our two run sessions. I like the way the R7's are they tend to fall off slower and we have run many sets so far. two of the set we ran the rears just about down to the cords with no huge loss in lap times.
when it comes to tires there are so many factors that come into play. how your car is set up and your driving style both play a big roll in how your tires will work and how they last.

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Re: A7 vs. R1-S?

Post by TroyV » Tue Jul 28, 2020 8:36 pm

I've run them both on the #5 car. The R1S wants load. It wants a heavier car than the Hoosier of the same size. I look at in very simple terms. Car weighs above 3k...R1S. Car weighs below 3k, A7, or R1S of narrower width. Dan, for your driving style, I'd go R1S of the narrower width, assuming you are running the BRZ. .....and if you come into come into 50 with that shit, I'm going to very seriously depressed.
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Re: A7 vs. R1-S?

Post by DanB » Wed Jul 29, 2020 3:23 pm

The die is cast! A7s...

I realized I can't run 245s due to clearance issues (drawback of saving a single point by running stock-diameter lowering springs vs. height-adjustable coilovers!), cuz 245 R1S and A7 are like 260-265mm wide! So 225s. And A7s come in 225/40-17, 23.8" diameter, 1/2-inch lower c.g., yay!

A7s vault me way into T60. A certain fellow BRZ driver found a set of take-off slicks and wound up there, I figured it'd be interesting to join him there!
'17 Subaru BRZ PP, #7 T60
Gone but not forgotten: Datsun 240Z, #7 SPB :cry:

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Re: A7 vs. R1-S?

Post by brucesallen » Thu Jul 30, 2020 11:41 am

WARNING: I found A7 245 to be wider that A6 and wider than specified on Hoosier Web site. Had to go to A7 225, ship 245s back.
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Re: A7 vs. R1-S?

Post by dtlemoine » Thu Jul 30, 2020 4:31 pm

brucesallen wrote:
Thu Jul 30, 2020 11:41 am
WARNING: I found A7 245 to be wider that A6 and wider than specified on Hoosier Web site. Had to go to A7 225, ship 245s back.
This is definitely true for the BFG's as well. Wouldn't trust the specs on the site, I'm sure someone on the forums can take a tape measure to theirs... The 225 R1S runs wider than a 235 street tire.
Dave

E36 328is | SD #14

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