Excellent article as always. As a numbers nerd I would love to see durometer testing before during and after as well as pyrometer results. Have a great track season.
Photography Credit: Anna Overman
Every tire test we conduct represents but a single data point, and though we try to minimize variables in our comparison process, there will always be the chance that different results will be obtained with different weather, venue, driver, vehicle and setup. So what do we do? Test again.
When we compared the current crop of R-comp tires a year ago–these are the theoretically street-legal tires solely designed for track work–we used our One Lap CRX and found that the Goodyear Eagle RS DOT lacked in a key front-wheel-drive quality: combined loading. It was not happy when the front tires were asked to simultaneously turn and accelerate or decelerate.
[Tire test: Hoosier R7 vs. Goodyear Eagle RS vs. Yokohama Advan A055]
Perhaps they’d perform better in a rear-drive application like our Triple Threat ND Miata project car? Another reason to retest.
We also changed the relative sizing used for this test. Both the Hoosier R7 and the Goodyear Eagle RS DOT are physically large for their marked size, while the Yokohama Advan A055 better aligns with the industry’s standard dimensions. By using tires all marked with the same size, last year’s results likely penalized the narrow Yokohama.
This year, we chose tire widths that were more dimensionally equitable–so that means 225/40R17 for the Hoosier and the Goodyear and 245/40R17 for the Yokohama. When mounted on our 17x9-Kogeki wheels from Flyin’ Miata, each tire had a perfectly supported, straight-up sidewall with very similar tread widths.
As it is with painting a car, preparation is key to optimal tire performance. Each set of tires was given a six-lap heat cycle prior to actual testing and then allowed to cool for 24 hours before subsequent use. This conditions the rubber, allowing for more grip and better temperature control.
From left to right: Goodyear Eagle RS DOT, Yokohama Advan A055, Hoosier R7. Photography Credit: Andy Hollis
We were given permission to share partial results from our private developmental work that compared a new tire to both the Hoosier R7 and Yokohama A055. In that test, the prototype tire was run at both the beginning and end of the test, and while we can’t divulge the actual data, the two sessions produced similar results, so we’re confident that we successfully minimized variables in our comparison.
For logistical reasons, we lapped Harris Hill Raceway, our usual track for tire testing, in the atypical counterclockwise direction. Weather was cloudy throughout with temperatures hovering in the low 70s.
Yokohama Advan A055
The Advan A055 came up to temp rather quickly, and full grip was available after about a lap and a half. Steering response was extremely progressive, with small inputs making increasingly larger turning moments as cornering loads increased.
Breakaway was a little edgy, especially at the rear of the car. This required constant attention to consistently drive at the limit, but the tire’s pace never slowed. Looking at the data, there was no more than a tenth or two available by combining the best sections.
Hoosier R7
The R7 took several laps to build heat and fully activate the compound. Driving characteristics were very natural: medium response, progressive breakaway. The tire was especially good at combined loading asks–like trail-braking along with corner-exit power-up.
Handling balance shifted to a slight oversteer, though, resulting in a spin on the fourth lap in Turn2. It’s an especially tricky section to get consistently in the clockwise layout, requiring trail-braking, a downshift and a subsequent power squeeze just as the car crests some bumps. Add tire swaps to the equation, and mistakes can happen.
Unfortunately, the spin overheated the rear tires, and subsequent laps did not deliver the same level of grip. Looking at the data, though, the quickest lap had all the best segments.
When talking R-comps, what about Goodyear? We’d been told that its Eagle RS DOT recently received an updated compound.
A month later, a perfect weather window opened up just after the new Goodyears arrived. With those mounted and heat-cycled, we loaded them up along with our two-cycle Yokohamas and Hoosiers. This would possibly give a slight advantage to the Goodyears, but given how far back they placed in the last test, we were okay with that.
Test day dawned in the low 50s, with temps climbing to 60 through our morning of lapping. Tires were kept in our motor home at about 70 degrees until called to action. We ran Harris Hill Raceway in our usual counterclockwise direction.
Goodyear Eagle RS DOT
Despite the low track temps, the Goodyear compound turned on immediately. Response of the Eagle RS was a bit sluggish compared to the others, however, and breakaway was vague.
Much as it did last year, though, the Goodyear delivered strong longitudinal grip–both braking and putting down power–but only when the steering wheel was mostly straight. Combined loading was not its strong suit, nor was mid-corner grip. It was especially unhappy in Turns 2 and 5, where hard braking is quickly followed by uphill, off-camber turning.
Hoosier R7
As before, the R7 took a little time to come in but then delivered some consistent laps before falling off a bit. Data analysis showed about two more tenths available for the perfect lap.
Yokohama Advan A055
Yet again, the Yokohama was very consistent and fast after a single warmup lap. Per the data, nothing was left on the table on that single flyer.
Goodyear Eagle RS DOT (retest)
Thanks to the added familiarity, we were able to extract a bit more pace out of the Goodyear on the retest, but doing so put so much heat into the tire that it fell off sooner than in the earlier session. Still, it was close enough that we were comfortable that track evolution was not a factor in our results.
The big takeaway from this year’s testing was the pace and consistency of the Yokohama Advan A055. When physical sizing is taken into consideration, it is the equal of the vaunted Hoosier R7–and that is saying something.
This makes the Yokohama a strong option for classes like NASA Super Touring that govern via sizing templates, or in cases where physical wheel well packaging is the defining limit. Given the distinctly different handling characteristics, both the Yokohama and Hoosier should be tried to see which best matches the car and driver.
Sadly, we just never connected with the updated Goodyear. On a relative basis, it was no quicker for us than last year, and the accelerated wear was concerning. While the pattern was fairly even, suggesting our pressures and camber were good, it was heavily grained. We even ran them again a couple of days after this test in warmer weather with no better results. At that point, with only 40 laps on the clock, the tread cap began to wear through.
But Goodyear has had good success at the SCCA National Championship Runoffs on big cars with big power, so perhaps we just need a faster test mule to find its sweet spot. That said, they were recently selected as the spec tire for SCCA’s B-Spec class of small, low-powered, front-drive econoboxes for 2024. We’ll be watching closely.
Excellent article as always. As a numbers nerd I would love to see durometer testing before during and after as well as pyrometer results. Have a great track season.
Curious why you pay no attention to Hankook Z214. I've used them for years. Good tire with slightly less peak grip than R7, but flatter torque curve good for half a dozen more HC's. Would love to see how you compare them to others in this test.
^ Agree with the performance assessment. I tried a set of Z214 in the medium compound, 205/50R15. However, at about 14 HC (20 minute sessions), one of them failed with an internal tread belt separation during a session. I exited early before anything catastrophic happened (it was hard to miss...), but that scared me off. I can understand defects and imperfections in something as highly consumable as a track tire, but that kind of failure is unacceptable as a safety hazard.
Performance-wise, they just aren't up there with the current crop.
I'd love to see some numbers for full 20-45 minute duration sprint race sessions.
Am I the only person put off by how GRM recycles their "+" content? This article was first published in Feb (approx 120 days ago) and as far as I can tell, just extended themselves another 180 days by rebooting an old article as new. Total bait and switch for clicks imo. Bummer.
In reply to Driving4fun :
Hey, thank you for the heads-up! The paywall for that article should have been 180 days from its born-on date. Somehow it reset and we're looking into that. It's back to 180 days from its born-on date.
Thanks for fixing, J.A. And FWIW we're looking back through other articles to make sure their expiration dates are accurate, too.
Driving4fun, I wouldn't be doing my job if I didn't now plead with you to spend the $3/month (or get a print subscription) to support our small, family-run business. Reader support (and our small, passionate staff) is the reason we're able to post all of these articles, and the reason we're still testing tires when so many of our competitors have disappeared or resorted to nothing but rehashed press releases.
To use my mother's old metaphor: You're welcome to hang around our coffee shop for as long as you'd like without drinking, and it's great to see new faces here, but the people buying coffee are the ones paying to keep the doors open.
....and while you're subscribing to the magazine, add a subscription to Classic Motorsports, too. That way you get more pictures!!
What rim are you running on the 245s?
MCoupeLTW said:Curious why you pay no attention to Hankook Z214. I've used them for years. Good tire with slightly less peak grip than R7, but flatter torque curve good for half a dozen more HC's. Would love to see how you compare them to others in this test.
Good suggestion...certainly one to consider for the future.
This particular test started out with a notice that GY had a new compound they wanted us to sample. Combine that with the desire to explore the physical sizing discrepancy we noticed last time (GY & Hoosier = fat boys, Yoko = normal), and we had our contenders. Testing logistics dictate a max of three candidates for best back-to-back comparisons. So that became the slate.
We are privvy to one other new r-comp in the dev stage, so perhaps when that one arrives we can add Hankook to the mix.
The other thing to note is that not all manufacturers want us to test their products and are therefore unwilling to furnish product for evaluation.
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