Yokohama A052
11-11-2018, 10:12 PM
#1
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Yokohama A052
Anyone have any feedback on how these compare to RE71Rs or Rivals?
11-13-2018, 02:31 AM
#2
They last as short as RE71R's in longevity, but grip a level above RE71Rs, and after 2-3 heat cycles they grip at around RE71R's. My friend who owns a few track records on his s2k says the A052 are about 2 secs a lap faster than R888R as an example at sub 2min tracks such as laguna seca and sonoma raceway here in cali.
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PRE-Z06 (07-06-2019)
11-13-2018, 09:28 AM
#3
I have a set I used on my Z06. This is the copy and paste of what I told the S2000 guys that asked about them.
So i havent had a chance to back to back my tires but i have the following 4 sets and have tested em 2 at a time. 295/30 AD052s on 18x10.5s. 275/35 goodyear R3s on 18x10.5s , 315/30 18 Rivals S on 18x10.5s and 315/30 A7s on 18x10.5s. I tested goodyear vs Ad052 at Road Atanta and Goodyear was 2.6 seconds a lap faster. I tested Goodyear vs Hoosier at a Nationals Autox Practice course and the hoosier was 2.1 seconds faster on a 30 second course then the goodyear. I tested the AD052 vs the Rival S at NCM a month ago. Ultimately the Rival was 7 seconds faster but i was using the AD052s to learn the track. I can tell you that learning the track when I swapped from the AD052 to the Rival my very first lap on the Rival was some 3.5 to 4 seconds faster. It was noticeable how much more grip the rival had. However the Rivals dont like being hot and fall off on lap 2. The yokos did not. The Rivals Look used up after just a few laps. The AD052s despite loads of laps at road atlanta and another 10 or so at NCM look hardly used.
So i havent had a chance to back to back my tires but i have the following 4 sets and have tested em 2 at a time. 295/30 AD052s on 18x10.5s. 275/35 goodyear R3s on 18x10.5s , 315/30 18 Rivals S on 18x10.5s and 315/30 A7s on 18x10.5s. I tested goodyear vs Ad052 at Road Atanta and Goodyear was 2.6 seconds a lap faster. I tested Goodyear vs Hoosier at a Nationals Autox Practice course and the hoosier was 2.1 seconds faster on a 30 second course then the goodyear. I tested the AD052 vs the Rival S at NCM a month ago. Ultimately the Rival was 7 seconds faster but i was using the AD052s to learn the track. I can tell you that learning the track when I swapped from the AD052 to the Rival my very first lap on the Rival was some 3.5 to 4 seconds faster. It was noticeable how much more grip the rival had. However the Rivals dont like being hot and fall off on lap 2. The yokos did not. The Rivals Look used up after just a few laps. The AD052s despite loads of laps at road atlanta and another 10 or so at NCM look hardly used.
Last edited by Mrsideways; 11-13-2018 at 09:52 AM.
11-13-2018, 11:03 PM
#4
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They last as short as RE71R's in longevity, but grip a level above RE71Rs, and after 2-3 heat cycles they grip at around RE71R's. My friend who owns a few track records on his s2k says the A052 are about 2 secs a lap faster than R888R as an example at sub 2min tracks such as laguna seca and sonoma raceway here in cali.
11-13-2018, 11:06 PM
#5
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I have a set I used on my Z06. This is the copy and paste of what I told the S2000 guys that asked about them.
So i havent had a chance to back to back my tires but i have the following 4 sets and have tested em 2 at a time. 295/30 AD052s on 18x10.5s. 275/35 goodyear R3s on 18x10.5s , 315/30 18 Rivals S on 18x10.5s and 315/30 A7s on 18x10.5s. I tested goodyear vs Ad052 at Road Atanta and Goodyear was 2.6 seconds a lap faster. I tested Goodyear vs Hoosier at a Nationals Autox Practice course and the hoosier was 2.1 seconds faster on a 30 second course then the goodyear. I tested the AD052 vs the Rival S at NCM a month ago. Ultimately the Rival was 7 seconds faster but i was using the AD052s to learn the track. I can tell you that learning the track when I swapped from the AD052 to the Rival my very first lap on the Rival was some 3.5 to 4 seconds faster. It was noticeable how much more grip the rival had. However the Rivals dont like being hot and fall off on lap 2. The yokos did not. The Rivals Look used up after just a few laps. The AD052s despite loads of laps at road atlanta and another 10 or so at NCM look hardly used.
So i havent had a chance to back to back my tires but i have the following 4 sets and have tested em 2 at a time. 295/30 AD052s on 18x10.5s. 275/35 goodyear R3s on 18x10.5s , 315/30 18 Rivals S on 18x10.5s and 315/30 A7s on 18x10.5s. I tested goodyear vs Ad052 at Road Atanta and Goodyear was 2.6 seconds a lap faster. I tested Goodyear vs Hoosier at a Nationals Autox Practice course and the hoosier was 2.1 seconds faster on a 30 second course then the goodyear. I tested the AD052 vs the Rival S at NCM a month ago. Ultimately the Rival was 7 seconds faster but i was using the AD052s to learn the track. I can tell you that learning the track when I swapped from the AD052 to the Rival my very first lap on the Rival was some 3.5 to 4 seconds faster. It was noticeable how much more grip the rival had. However the Rivals dont like being hot and fall off on lap 2. The yokos did not. The Rivals Look used up after just a few laps. The AD052s despite loads of laps at road atlanta and another 10 or so at NCM look hardly used.
11-14-2018, 01:19 PM
#6
Burning Brakes
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Just keep in mind if you are considering the A052 for autocross it is excluded from most classes due to both its tread depth being below the minimum required molded depth, and insufficient size range.
11-14-2018, 02:01 PM
#7
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I've ran both RE71Rs and Rivals in autocross this year and did not find the heat they needed to come in substantially different. If it is below 55F then the Rivals need half a run to come in but since you are in Texas you should be fine. They are definitely just as fast in equivalent sizes, and overall make for a faster car if you can use the bigger sizes available. Didn't find the sidewall stiffness to be an issue either. They just drive differently.
11-14-2018, 03:35 PM
#8
We tested Rival vs 71R on the STR Miata and atleast with our car it was much better on the Rival. But I look for a tire that likes some slip angle and the 71R's most certainly don't. so maybe that was driver more then anything.
11-14-2018, 09:24 PM
#9
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I've ran both RE71Rs and Rivals in autocross this year and did not find the heat they needed to come in substantially different. If it is below 55F then the Rivals need half a run to come in but since you are in Texas you should be fine. They are definitely just as fast in equivalent sizes, and overall make for a faster car if you can use the bigger sizes available. Didn't find the sidewall stiffness to be an issue either. They just drive differently.
Miata size is going to be the Rival 1.5s which are a different compound is my understanding, what psi did you run in both for comparison? What I'm considering is can a square 315/30r19 RE71R be as fast as a 335/30r18 Rival since a 315/30r18 A052 isn't legal apparently.
Last edited by PRE-Z06; 11-14-2018 at 09:27 PM.
11-15-2018, 03:55 PM
#11
Good point, didn't realize that.
We ran our last event this past weekend and it was in the 40s, was able to still take FTD though had co-driver and used tire blankets to keep heat in them. I know Lincoln can be cold in September, so want what can be as fast as possible since there's only 3 runs to get'er done.
Miata size is going to be the Rival 1.5s which are a different compound is my understanding, what psi did you run in both for comparison? What I'm considering is can a square 315/30r19 RE71R be as fast as a 335/30r18 Rival since a 315/30r18 A052 isn't legal apparently.
Last edited by Mrsideways; 11-15-2018 at 04:04 PM.
11-15-2018, 05:46 PM
#12
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11-15-2018, 06:23 PM
#13
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So that brings up an interesting legality question. SCCA states the tire must be made in 4 diameters. If the Rival S and the Rival S 1.5 are in fact different tires via compound then I believe neither would be SCCA legal due to the Diameter rule. When I brought this up at Nationals I was informed that the Rival S in the larger sizes is in fact just the same as a 1.5 in the smaller sizes due to something different in the tread pattern that had always existed in the larger sizes. Maybe that was just some CYA explanation to avoid a messy protest DQ'ing 600+ people. I don't know. As far as pressures we tested the Rival vs the RE71 on similar pressures. We then started playing with the Rival and a Skid pad and found they like being soft... like barely holding the weight of the car soft. I won STR on those super soft pressures in 2017 so I guess we did something right. Comparing skid pad data, IIRC on a 15 second skid pad lap the Rival was consistently .1 - .15 faster then the 71R with both drivers. Dropping pressures bought us another consistent .3 to make some of the skid pad laps as much as .5 faster then the 71R. What was interesting was it got faster and faster the softer we got till it hit a cliff and went the other way radically. It made it tricky because when we started them really soft to try to get them to come up to our target pressure they wouldn't.
11-16-2018, 09:34 AM
#14
Interesting point, here's some good for thought on why it's not an apples to apples comparison and possibly an explanation as to why you were successful with low psi in the Rival 1.5s as is the case with the RE71Rs. The load rating is the same in 245/40r17 on both bfg and stones where as in 275/35r18 the Rival S is not the same and the RE71Rs are higher rated which I translate to having a stiffer sidewall and able to support the same load at a lower psi. I'll add my buddy who was the 2018 BS national champion tested with a 275/315 Rival S combo though was faster on 275/285 RE71Rs fwiw.
11-16-2018, 02:14 PM
#15
Burning Brakes
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Interesting point, here's some good for thought on why it's not an apples to apples comparison and possibly an explanation as to why you were successful with low psi in the Rival 1.5s as is the case with the RE71Rs. The load rating is the same in 245/40r17 on both bfg and stones where as in 275/35r18 the Rival S is not the same and the RE71Rs are higher rated which I translate to having a stiffer sidewall and able to support the same load at a lower psi. I'll add my buddy who was the 2018 BS national champion tested with a 275/315 Rival S combo though was faster on 275/285 RE71Rs fwiw.
Last edited by RX7 KLR; 11-16-2018 at 02:49 PM.
11-16-2018, 06:28 PM
#16
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Wheel width limitations will often impact tire performance. People got away with cramming super wide Hoosiers/Kumhos on skinny wheels back in the R comp days of Stock classes, this does not work as well with 200tw Street tires. Pinched tires typically feel floppy, stretch that same tire on a wider wheel and it can feel completely different.
https://www.mustang6g.com/forums/thr.../#post-2392540
https://www.mustang6g.com/forums/thr...r.99038/page-4
Last edited by PRE-Z06; 11-16-2018 at 06:30 PM.
