Not sure if this is the correct forum, but anyway...
Updated 03/01/2012 12:26pm
I finally got around to some tyre testing following the recent GT5 update. I decided to do it in the Chevrolet Corvette ZR1 (C6) RM 09 that we're about to start using in the newest GT5 league. I also chose the first circuit in the league calendar, Laguna Seca. Hopefully this data will be useful for everyone, not just for league entrants.
The times recorded were all set under league entry regulations, in identical conditions to those the events will be hosted under. In each tyre test, I did a single run on each of the Racing tyre compounds (Soft, Medium and Hard) pushing the tyres to destruction rather than running 3 race simulations (my knees are knackered) with pit stops etc... I saved the replays for each run, and then ran through the replay laps noting each lap time from there. I might upload these to youtube if I can find time. The runs were also made with my high downforce, maximum grip setup. It's actually tuned specifically for Hard tyres, but the settings transferred okay and the results are still very interesting. Tyre wear is so close to 50/50 front and rear with this setup that I can't measure any difference.
The times are my maximum attack race pace times (as opposed qualifying laps). No attempt was made to save/preserve the tyres in any way. Here's the raw data
Make of it what you will and I hope you find the data useful. I'll add my own observations later.
A few comments. The blip on lap 6 with the Racing Hard tyres was driver error. The blip (fast lap) on lap 18 with Racing Hard tyres was just one of those sweet laps, not a corner cut, so there's more potential in those tyres than I can extract with effort.
Observations.
The fastest lap was clearly and easily set with the Racing Soft tyres as you'd expect. They came into their optimum window between lap 2 and 5 at this circuit. The rate performance dropped off caught me by surprise around lap 6, most notably my braking distances lengthened and understeer started creeping in. I adjusted for this on lap 7, still pushing hard hence the faster lap time, but the extra grip and pace that sets the racing softs apart from the other compounds was now gone. By lap 9, the soft tyres were fractionally slower than the mediums, and only marginally faster than the hards, but they were drivable until around lap 10. By lap 10 I was down to between 5 and 10% rubber left on the tyre indicators, at which point it all went badly and my lap times took a dive. Braking distance jumped considerably, and both understeer and oversteer were daft. I stuck out another 2 laps to be sure but lap 10 was really the end for these tyres. If we use lap 10 as benchmark for pitting, I was ahead of the Racing Medium tyre by 8.4 seconds, and 18.9 seconds ahead of the Hard tyre run.
The medium tyres. As you'd expect, not a grippy or fast as the Softs, but their consistency in feel and predictability makes them the surprise tyre of the session for me. They quickly get up to temperature and their optimum operating window between lap 2 and 5 at this circuit. Performance then gradually tails off for approx 6 laps, and then a more pronounced performance loss begins. But... Unlike the softs, this phase didn't catch me by surprise. Degradation felt linear and so I could push the car on the limit with confidence from start to finish, which is reflected in the smooth lap time curve. Around lap 15/16, the grip started falling off more aggresively (around 5 - 10% again) and a couple of extra laps took them down the cliff. If we use lap 16 as the benchmark for pitting, I was 11.1 seconds ahead of the Hard Tyre compound run. However, from lap 9 until lap 14, the medium tyres offer only a very small amount of extra pace over the hard compounds. From lap 14 to lap 16, the hard tyres match the pace of the medium tyres, and from lap 17 the hard tyres are a full 2+ seconds faster per lap.
Racing hard tyres. These took a little longer to get temperature into them and get into the optimum window, between laps 3 and 7. They're a good few seconds slower than the other compounds around this period. Trying to push a bit more from them I slipped on lap 6, hence the blip. Until around lap 20 though, I just kept on crunching the laps in without any surprises. Degradation felt linear, and I felt I had to make hardly any adjustments to my braking and turn in points for a full 20 laps. Around lap 21 I had a sudden wake up call with oversteer, followed by a sudden increase in braking distances. They just about hung on for another 2 laps by being less aggressive on the gas pedal for similar lap times, but then it all got a bit too much and down the cliff they went, again at around the 5 - 10% mark.
Conclusions.
Over a 10 lap race, who wouldn't take the soft tyres? Get used to the flashy nature of them coming in and out of their optimum window, and you've a very predictable and fast set of boots for a sprint race. A little tyre management might be necessary to do the full 10 laps comfortably, but your competitors will likely need to do the same. In a longer race of 20 laps of more, you've got some maths to do to work out the performance gains of softs against the time lost to pitstops.
The medium tyres are ones to watch at the races, where their performance might change compared to these tests I've done on my own. Drafting will extend both their pace and their life (I think?). These are the tyres that have me scratching my head the most about long race strategies. You kind of know where you're at with Softs and Hards, but these could shake the order right up. Interestingly though, they only have any significant advantage over the hard compound until around lap 9. You'll have opened up a gap to the racing hard tyres, but it's nip and tuck in lap times between them from there.
The hard tyres. The driver with these is driving his own race. The opportunity to slipstream will come back to him later in the race for any pace he loses at the start, and he's just going to keep on truckin' right past the soft and medium tyre pitstop windows. Will they do a full 30 laps? In the right hands perhaps, but the option to jump so many cars at pit stops and then splash and dash a set of softs or mediums for the final stint... So many permutations, and as valid a choice for race day as the other tyres.
I think this is an awesome update from Polyphony Digital. How this is going to play out on race day, I think we'll just have to see. On paper, it looks like the order is going to be well shaken up, but in reality who knows? Perhaps one compound will quickly establish itself as supreme for most race distances? Also, under race conditions with slipstreaming (which is still too much PD!) and defensive driving coming in to play, and of course the effects of sitting in the pack, race incidents etc... the data above in no way dictates how things are going to play out. Race craft, skill, and a little bit of luck will always be necessary. This is a real quality update in my opinion!! Kudos PD!
Of course, just for a little extra context. At Laguna Seca, it takes the PS3 48 seconds to put you through a pitstop, from the moment it takes over at pit entry to the moment you get given control back at pit exit. In total, the cost of a pitstop is between 27 and 29 seconds at this circuit.
