We test the Yokohama AD08R on street and track
We test Yokohama’s AD08R street/track tyre on street… and track.
IF YOU REGULARLY DRIVE YOUR CAR on racetracks then you’ll probably want more specialised, track-oriented tyres. Now it is entirely possible to drive tracks on standard tyres, particularly if your car already comes fitted with high-performance tyres.
That wasn’t the case with my Toyota 86 GT, which came with the same tyres as fitted to a Prius… and the GTS model uses Michelin Primacys which are a budget sports tyre. I’ve used both on track, and the result is plenty of fun if not grip. As you’d expect, neither stand up well to the rigours of track use, but there’s a solution to that. Many 86/BRZ owners replace their stock tyres with aftermarket as soon as they buy the car, which means there’s a steady supply of near-new ones on the secondhand market for very little money and the tyres almost become disposable.
The main reason that standard tyres don’t work effectively on track is because the heat generated by track use is far in excess of that generated on the road. Not only is the car going faster so the tyres flex more per second, there’s far greater cornering forces which also creates heat, and even more heat generated by the brakes. This is why standard tyres pretty much melt their tread, and at that point they don’t perform well, sliding more than they should.
A race-oriented tyre will be designed for much hotter operating conditions, but conversely won’t work anywhere near as well in low temperatures even to the point where it’s dangerous. Try driving a race-oriented tyre on a cold morning and you’ll find out for yourself.
Despite what you hear from the marketing people, all tyres are a tradeoff. In this case, the quicker the tyre, the more specialised it is, the more expensive it is, and the less life you get. And, in the case of ultra-grippy R-spec tyres, the design is a bit less forgiving at the limit – one moment there’s grip, next moment it’s hello to the barriers.
So I decided to try a set of street/track tyres mainly out of interest as I’m not too bothered about outright laptimes, but I did want to see what sort of difference aftermarket tyres would make.
My first selection for the 86 was the Toyo R1R which you can read all about here, and then when those wore out I got a set of Yokohama AD08Rs. These are on a set of secondhand 17″ stock rims and are only fitted to the car for track events and the drive there and back. The rest of the time the car runs Dunlop Sport Maxx STs.
The AD08Rs have been on now for four events across Phillip Island, Winton and Sandown. Pressures are set according to Yokohamas guide, which recommends 35psi hot. In practice, this means I go out at 30psi, warm up, and then come in after a few laps and bleed the pressure back to 35. The next session is flat out, and there’s a little more bleeding of air and then that’s usually the job done. On all subsequent sessions after the first one the first lap is a warmup as the tyres need a bit of time to start working again to best effect.
So after four events, all driven hard, this is what the tyres look like:
Pretty good. Still life in them yet – grip levels remain good, no uneven wear, no melting, no blisters. These are directional tyres so they can’t be swapped left and right, but I do swap them front to rear which helps with the wear. The stock tyres, Maxxes or R1Rs never looked that good after that much work.
Grip levels are impressive too. In order to properly give a precise comparison of grip you need the same driver with the same car in the same conditions, back to back. I wasn’t able to do that, so I can’t be precise about differences. However, I have done enough running at Winton, Phillip Island and Sandown to be pretty confident the AD80Rs are the quickest tyre I’ve used as I’ve set personal bests each time, and in the order of 0.5 to 2 seconds compared to the R1Rs. The AD08Rs are used by the Clubsprint class in the World Time Attack series (timed laps) which is a good indicator that the tyres are designed for motorsport.
There’s no complaints about the handling of the AD08Rs either. Any higher-grip tyre will give the car a sharper turn-in, and that’s the case here. However, what I’m more concerned about is on-the-limit forgiveness. I drive my car to the track, and so far have driven it home again after the event and that’s my plan for the future. Now the way to drive fast on a racetrack is not to throw the car around, but every now and again the traction limits will be reached or exceeded, and that’s when you need a tyre that progressively reaches the limit of traction. You don’t want a situation of grip, grip, grip and then nothing.
I’m happy to report that the AD08Rs are progressive and forgiving when traction limits are exceeded. I’ve not done any actual drifting with them and don’t intend to, but there have been moments on track that have been easily recovered and the car has made its own way back home after each event.
The AD08Rs aren’t over-grippy either. By this I mean that they don’t grip so much that I need to upgrade the brakes to parachutes, and the dynamics of the car are not completely changed. With extremely grippy tyres you need very strong brakes so you can use that grip when stopping, and as your corner speeds are so much higher the whole car dynamics change, or rather, need to change in order to maximise the tyre’s high grip levels.
The AD08Rs are also road-legal, although I don’t run my set on the road any more than I have to. I can report that they work well as a road tyre, certainly the grip is there and the noise level is about the same as the other tyres. However, I’d say that these tyres are overkill for the road in a low-powered car like the 86 – it would be better to trade a bit less grip for tyre life, and especially so if you’re driving in very cold conditions.
So overall I’m happy with the AD08Rs. They grip well, handle nicely and are strong enough for the rigours of track driving.