Let's Talk Track Tires - 2023 Edition
03-14-2023, 12:04 PM
#136
Rennlist Member
I run 305 rears and don't have any rubbing issues. I've run 255/305 Re71r and I've run 255 re71rs with 305 660's. Would prefer 265/305 if they had them, but have had no issues running 255 with 305 rears. I can always play with sway bars, air pressures, and dampers until I get it like I want it.
03-14-2023, 04:27 PM
#137
@paffinity I heard R7 run wide for their nominal size.
I'm running the wing at a pretty low AOA to have efficient downforce & not totally ruin the balance without installing the gigantic splitter. Shouldn't be enough additional DF to cause issues, esp at a max airspeed of ~130 mph (if I have a decent headwind at H2R), but regardless, I expect to be able to exercise the suspension travel until bumps without rubbing, and I'm def not hitting bump stops unless I try the 'right' line thru T3, which I never do.
That said, I am wearing my underbody aero some, so I should prob check the car's rake and height. Its rake & height is whatever it came with from the factory, minus ~3/8" or so due to the smaller tire radius, but given the variance of factory alignment, I should probably expect variance in factory height settings. Also, guess I should try installing the splitter, crank up the wing a little, and explore some larger DF, at least within what's reasonable for factory springs.
I'm running the wing at a pretty low AOA to have efficient downforce & not totally ruin the balance without installing the gigantic splitter. Shouldn't be enough additional DF to cause issues, esp at a max airspeed of ~130 mph (if I have a decent headwind at H2R), but regardless, I expect to be able to exercise the suspension travel until bumps without rubbing, and I'm def not hitting bump stops unless I try the 'right' line thru T3, which I never do.
That said, I am wearing my underbody aero some, so I should prob check the car's rake and height. Its rake & height is whatever it came with from the factory, minus ~3/8" or so due to the smaller tire radius, but given the variance of factory alignment, I should probably expect variance in factory height settings. Also, guess I should try installing the splitter, crank up the wing a little, and explore some larger DF, at least within what's reasonable for factory springs.
03-14-2023, 04:31 PM
#138
Stock ride height with -2.5 camber. Stock struts with 100 N/m springs. Forgelines 19x11 wheels. I do have to run a 5 mm spacer to clear the TPC rear toe link. I forget right now what toe I'm running.
03-14-2023, 07:07 PM
#139
By running a 305/30 on 19" wheels you could be losing 0.5" in diameter. That could aid with clearance.
My OEM Dunlops on the 4RS at -2.4 camber slightly rub under full compression...I think I lost a couple MM when increasing camber via shims.
Have the Immocars rear camber plates on hand for installation next weekend.
03-14-2023, 07:27 PM
#140
By running a 305/30 on 19" wheels you could be losing 0.5" in diameter. That could aid with clearance.
My OEM Dunlops on the 4RS at -2.4 camber slightly rub under full compression...I think I lost a couple MM when increasing camber via shims.
Have the Immocars rear camber plates on hand for installation next weekend.
My OEM Dunlops on the 4RS at -2.4 camber slightly rub under full compression...I think I lost a couple MM when increasing camber via shims.
Have the Immocars rear camber plates on hand for installation next weekend.
03-14-2023, 07:59 PM
#141
03-14-2023, 08:03 PM
#142
03-14-2023, 08:13 PM
#143
I don't think the caster will solve the problem....by using toe IN the rear half of the tire is sticking out a bit more.
Once I get the Immocar camber plates on the car the problem will be solved as I can take off most of the shims and tuck that tire in...just like int he front.
Once I get the Immocar camber plates on the car the problem will be solved as I can take off most of the shims and tuck that tire in...just like int he front.
03-14-2023, 08:29 PM
#144
I don't think the caster will solve the problem....by using toe IN the rear half of the tire is sticking out a bit more.
Once I get the Immocar camber plates on the car the problem will be solved as I can take off most of the shims and tuck that tire in...just like int he front.
Once I get the Immocar camber plates on the car the problem will be solved as I can take off most of the shims and tuck that tire in...just like int he front.
03-14-2023, 09:24 PM
#145
By running a 305/30 on 19" wheels you could be losing 0.5" in diameter. That could aid with clearance.
My OEM Dunlops on the 4RS at -2.4 camber slightly rub under full compression...I think I lost a couple MM when increasing camber via shims.
Have the Immocars rear camber plates on hand for installation next weekend.
My OEM Dunlops on the 4RS at -2.4 camber slightly rub under full compression...I think I lost a couple MM when increasing camber via shims.
Have the Immocars rear camber plates on hand for installation next weekend.
03-14-2023, 09:35 PM
#146
03-14-2023, 11:18 PM
#147
Burning Brakes
The 265/305-19 combo lowers the tires height from 27.0 to 26.3 or .7 inches or 18 mm or 9mm lower off the rim. That is a fair amount of extra height to allow for a wider tire. I just checked mine for marks after cleaning the wheel wells throughly before last weekends track activities. Backs looked good and there was a bit of rub on the front right. That can be adjusted for with taking out a few mm of shim and canting the shock tower in a bit more to compensate or raising the height by 2mm (one turn on the shock collar). Zero marks on the tires. I do have camber plates.
03-15-2023, 08:21 AM
#148
^
I believe the issue being discussed here is rubbing on the rear, not on the front. Some have experienced it on GT4s but with the added track width on the GT4RS it looks like it is more of an issue than before.
I believe the issue being discussed here is rubbing on the rear, not on the front. Some have experienced it on GT4s but with the added track width on the GT4RS it looks like it is more of an issue than before.
03-15-2023, 09:30 AM
#149
Burning Brakes
Has anyone done or seen any testing of the new "Bridgestone Potenza Race"? This is the OE tire developed for the Huracan STO. They are a 200TW rated "Streetable Track & Competition tire". They come in only 2 sizes currently but will fit our factory 20" wheels - 245/30/20 (not ideal) and 305/30/20.
https://www.tirerack.com/tires/bridgestone-potenza-race
EDIT - Wow. Tirerack.com absolutely refuses to let me link directly to the product page. You may have to search for it...
Anyway I think this could be an interesting one for us to watch as
1) the Huracan STO is also a mid engine RWD track-focused car with weight and weight balance similar to a GT4
2) Bridgestone has a great recent history of developing well-rounded high performance 200TW street tires that do well enough both in the cold and hot.
3) the Potenza Race, while not cheap, are about the same price as our OE tires.
4) The Potenza Race shows in stock and available on TR, unlike many of our other tire options that would fit our OE wheels
EDIT 2 - Bridgestone Press Release on these tires from 2021 Press Release Details (bridgestoneamericas.com)
"... the tire’s tread is lined with the colors of Italy’s il Tricolore – a nod to the fact that both the tire and vehicle have been designed in Italy – and features Lamborghini’s distinctive markings." il Tricolore?!? OK now I really want to try these on my GT4 once I burn up my current comp street tires.
Huracan STO wheels are the same dimensions as the GT4/GT4 RS - 20x8.5 front and 20x11 rear. Also note, these Bridgestone Potenza Race tires are the optional hi-perf tires for the STO. Otherwise the STO comes standard with Bridgestone Potenza Sports.
https://www.tirerack.com/tires/bridgestone-potenza-race
EDIT - Wow. Tirerack.com absolutely refuses to let me link directly to the product page. You may have to search for it...
Anyway I think this could be an interesting one for us to watch as
1) the Huracan STO is also a mid engine RWD track-focused car with weight and weight balance similar to a GT4
2) Bridgestone has a great recent history of developing well-rounded high performance 200TW street tires that do well enough both in the cold and hot.
3) the Potenza Race, while not cheap, are about the same price as our OE tires.
4) The Potenza Race shows in stock and available on TR, unlike many of our other tire options that would fit our OE wheels
EDIT 2 - Bridgestone Press Release on these tires from 2021 Press Release Details (bridgestoneamericas.com)
"... the tire’s tread is lined with the colors of Italy’s il Tricolore – a nod to the fact that both the tire and vehicle have been designed in Italy – and features Lamborghini’s distinctive markings." il Tricolore?!? OK now I really want to try these on my GT4 once I burn up my current comp street tires.
Huracan STO wheels are the same dimensions as the GT4/GT4 RS - 20x8.5 front and 20x11 rear. Also note, these Bridgestone Potenza Race tires are the optional hi-perf tires for the STO. Otherwise the STO comes standard with Bridgestone Potenza Sports.
Last edited by 0-Day; 03-16-2023 at 04:40 PM.
