I'll start with some of the tyre comparisons between GTS and GT7. Beginning at high altitude and looking at raw lap times for the same between GTS and GT7, on the same 2015 BRZ at Laguna Seca using the same lobby settings.
Tyre - GTS ------- GT7
CH - 1'55.213 - 1'54.191
CM - 1'53.239 - 1'49.494
CS - 1'48.535 - 1'45.323
SH - 1'46.190 - 1'43.213
SM - 1'44.925 - 1'41.380
SS - NO DATA - 1'39.706
RH - NO DATA - 1'36.869
Compared to GTSport, each tyre compound has increased grip and ultimate lap pace. CS is faster than SH used to be on the same car, and SH are faster than SM used to be. I suspect they are as fast as SS was in GTSport, but my data at Laguna stopped at SM because that was already way into silly amounts of grip for the stock car. Data I have from other experiments show that SH in GT7 is as fast as SS was in GTSport, and that SM are just as fast as RH was in GTSport. It seems like the further up the compound list we go, the bigger the jumps. CH and CM may only be one compound softer, but by SM and SS they're two compounds softer than they used to be.
For comparison to real life, the all time
lap record in 86cup for a stock class 2013-16 BRZ/FRS at Laguna is 1'48.633. Now, it is important to note that a stock class 86cup car is allowed larger wheels than stock, up to 8" wide, as well as increased camber, and big brake kits with larger calipers and rotors. So the cars should, in theory, have more grip than our stock versions and be a tick faster on any given tyre. The spec tyre that 86cup uses in stock class is the
GT Radial SX2. It's a 200 treadwear, street legal track oriented tyre. It is a mid level tyre in the
Extreme Performance Summer category for tyres, usually a couple of seconds slower than the fastest 200tw like the
Yokohama A052 and Bridgestone
Potenza RE71RS. These are all track tyres designed to be 'street legal' to drive to and from the track. The fastest lap I can find of any 2013-16 FRS/BRZ running those top tier 200tw tyres like the Yokohama and Bridgestone RE71 is 1'46.334, and that car has a header and a number of other power adding modifications as well. Looking at the raw lap times alone, I would wager that even CS tyres are likely faster than any lap that any stock FRS/BRZ has ever run at Laguna on any tyre.
Even the 86cup lap record for unlimited class, which is 700hp LS swaps and/or superchargers and full race tyres and crazy aero is 1'36.904. (iirc it's a supercharged car that holds the record.)
Now, there is more to it than lap times. In order to determine truly whether the tyre have more grip or not, I needed to look at the cornering speeds; entry speeds, and minimum/apex speeds. This is where those track maps with all the speeds at various points on the track come in. As a comparison, I'll use T8 at Streets of Willow as an example, as it is a fairly long sustained turn on camber that the car remains loaded up and makes a great indicator of overall grip. In parenthesis are the overall lap times for comparison as well.
Game/Compound(Lap Time) - T8 Entry speed - T8 Minimum/apex speed
GTSport CS(1'27.283) ---------------78 ----------------------- 41
GTSport SH(1'25.557) -------------- 79------------------------45
GT7 CM(1'27.778) -------------------76 ----------------------- 43
GT7 CS(1'25.925) -------------------76 ----------------------- 45
GT7 SH(1'23.533) ------------------ 79 ----------------------- 47
As you can tell, overall grip is up an entire compound. CS has a lower entry speed and can still maintain the same minimum speeds as SH used to, which shows that the car is scrubbing less, in other words the car isn't working nearly as hard to get to the apex and make the turn. It is easier to run just as fast of a lap time on a compound harder tyre than in GTSport. For real life comparison, the 86cup lap record at Streets of Willow in stock class is 1'29.352. The lap record on a street class first gen FRS/BRZ 2013-2015 is 1'25.915. That is with a header, exhaust, intake, tune, wide wheels, weight removal, etc. Those cars are about 250-255hp and 2600lbs on Yokohama A052s, the fastest of the 'street' tyres. The apex speed in T8 in that car was 43mph, for comparison.
In summary, as relevant to a production car(as noted in the background info above, racing specials with super high downforce aside,) the most comparable tyres in GT7 compared to their real life counterparts are as follows;
CH: OE Performance Summer or
Ultra High Performance All Season Tyres like the Michelin Pilot Sport AS, Conti Extreme Contact DWS
<Then there is a pretty big jump>
CM: Low-Mid Level
Extreme Performance Summer Tyres like the
stock 86cup spec racing tyre and Michelin Pilot Sport Cup 2
CS: Top Tier super200tw
Extreme Performance Summer category tyres designed specifically for track use like the
A052 and
RE71RS
SH: DOT Radial
Competition Only Race Tyres like the
Yokohama A055 and corn-fed baddie
Hoosier R7
SM: Full
Bias ply racing slicks
SS: Magical Faerie Dust tyres
RH and Above: lolwut
Anyway, in conclusion the tyre options have not only gotten a compound or two stickier and faster going from GTS to GT7, but the names of the tyre options themselves are somewhat mislabeled. By the time you are into the lower end of "sports" tyres in the game you are well into "racing" tyres in real life. Pretty much the same as GT5 above.
😭