Michelin Pilot Super Sports vs Firestone Firehawk Indy 500 - Street Review

I've been a huge fan of Michelin PSS tires and exclusively bought them for the Mustang over the last four years. So how did I end up here? This year, I was hugely interested in trying an "R-comp" tire. I had my eyes set on Bridgestone Potenza RE-71R's for two simple reasons: price and reputation. Although not a true "R-comp" tire on paper, it performs like one by the account of every single test and review I've read (down to wear rates...). They seem like they're easily the most affordable (from a big brand) R-comp tire and combine that with a reputation for having tons of grip, it was an easy top contender. I had my concerns, though. For one, I'm told and have read that they are an autox tire, not really designed for high speed, pressure, and temps associated with open track. For another, the Mustang is a heavy car (as far as track cars are concerned) being roughly 3,800 lb. (including driver), which will amplify the unwanted open track loads. Combine that with the fact that I drive a good amount on the street during the summer, and I was very worried that they wouldn't last more than a handful of track days and a month or two of driving.

Nevertheless, I thought I was going to buy them and came as close as putting them in the "cart" and going to buy but I waited a few days to think it over and by the time I went to buy, a $125 mail-in rebate offer had expired. I took that as a sign from my bank account to put off R comps for another season and went and searched for my usual - Michelin Pilot Super Sports. But an alternate showed up, one that I had to consider: Firestone Firehawk Indy 500's. They were less than half the price of the Michelins, although in one size down - 275/35/18 vs 285/35/18. The PSS were about $420/tire CAD and the Firestones were $210/tire CAD, but there was a $100 rebate. The decision came down to this question: are they half the tire?

I was mainly concerned about two things; section width and tread depth. Mustangs like a lot of tire on track (as do all cars this heavy). 285 is barely passable on the fronts without excessive shoulder wear (there is still plenty with 285's and -2.3 deg camber, but more manageable). I once talked to the folks at Vorshlag and they said they'd never run anything less than 285's on the fronts on a Mustang, and recommend at least one or two sizes up. The Michelin's had a section width of 11.4" for the 285/35/18 vs 10.9" for the 275/35/18 Firestones (specs on Tire Rack). Strike one against the Firestones. With that said, 275's are a better fit for my 9.5" wide wheels, so that would help reduce the width gap (285's are measured on a 10" wheel) and better control tire movement under load. As far as tread depth, it was obviously a concern because of potential squirm. The Michelins had a UTQG wear rating of 300 vs 340 for the Firestones, but tread depth is 10/32" for both (specs on Tire Rack), so I wasn't sure what to make of the tread wear rating. Perhaps just a harder compound? Tempted by the price, though, and excellent reviews online (on the street) I pulled the trigger... They were at my doorstep less than a week later.

First impressions were poor. Looking at them side by side next to the PSS's on the car, tread spacing looked massive on the Firestones in comparison and, being new, tread depth was much larger. Smaller and taller tread blocks? I figured tread squirm would be a massive problem on track. On the plus side, tire sidewall felt noticeably stiffer uninflated compared to uninflated PSS, which gave me hope that they might wear more evenly compared to the PSS's, since those have a tendency to chew sidewalls on track - a problem that I attributed to relatively soft sidewalls combined with a lot of grip and a heavy car. The problem seems to be consistent on Mustangs and M3s running PSS's on track. Things started to get better from there on for the Firestones.

After mounting them and waiting for the top layer to wear off, grip on the street was excellent and still well over what you can safely explore. They were also flawless in the wet for a good summer tire. I didn't notice any increase in noise (although Boss 302's tend to be a little loud and mine is even more so with a few harder bushings in the rear suspension). Better yet, they had more straight line grip - amazingly, being narrower and supposedly a less sticky tire - and were more resistant to wheel hop with a slight spinning start. Keep in mind, though, that they are probably a less aggressive compound than the Michelin's and I was driving in about 70 deg F/21 deg C weather and somewhat overcast so not exactly warm asphalt and the Firestones might have had a temperature advantage. But whatever the reason, they did really well. And although overall tread depth and seeps looked disappointing, the chronic PSS problem of too much shoulder wear seemed like it might improve by larger tread blocks on the outside shoulder, not just stiffer sidewalls.

Overall, I was quite pleased with them on the street and couldn't wait to try them on track. Luckily, I didn't have to wait long since the first of the two annual BMW Club Atlantic HPDE weekends was only a couple of weeks away. Make sure to like The Ram's Eye on Facebook (side bar) to find out what they're like once I finish that post!

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A post shared by Michael R (@ramseyethetrackguy) on Sep 8, 2020 at 4:43pm PDT