Tires ... again!

[guillermo968]

So I've been wondering for most sports cars which tires are the best to represent grip real counterparts would get?

 

[llNovall]

Comfort hards = Summer high performance or all season ultra high performance

Comfort mediums = Summer/ ultra high performance radials. Ex: bfg gforce sport or gdyr eagle f1 gs

Comfort Softs = Summer/ max performance radials. Ex: michelin ps2 or pirrelli pzero or Goodyear eagle f1 supercar

Sport hards = Summer/ extreme performance radials. Ex: bridgestone potenza re11 or kuhmo ecsta xs or nitto nt05

Sport Mediums = Summer/ Track and Competition DOT radials. Ex: michelin pilot ps cup zp or pirelli pzero corsa

Sport Soft = Grooved racing slick. Ex: Hoosier R6

Off my observation and research thru motortrend (factory tire refernce) and tirerack ( tire specs), this above seems to be consistent when referencing stock tires to stock cars.

 

[MOTORTRENDmitch]

Comfort hards = Summer high performance or all season ultra high performance

Comfort mediums = Summer/ ultra high performance radials. Ex: bfg gforce sport or gdyr eagle f1 gs

Comfort Softs = Summer/ max performance radials. Ex: michelin ps2 or pirrelli pzero or Goodyear eagle f1 supercar

Sport hards = Summer/ extreme performance radials. Ex: bridgestone potenza re11 or kuhmo ecsta xs or nitto nt05

Sport Mediums = Summer/ Track and Competition DOT radials. Ex: michelin pilot ps cup zp or pirelli pzero corsa

Sport Soft = Grooved racing slick. Ex: Hoosier R6

Off my observation and research thru motortrend (factory tire refernce) and tirerack ( tire specs), this above seems to be consistent when referencing stock tires to stock cars.

Everyone quote this guy in ANY future discussion about tires in GT5. 👍 Great post. Totally agree.

 

[Denilson]

Here's a good read when it comes to tires in GT5.

I've uploaded a spreadsheet with the recommended tires to Google Docs:

GT5 Stock Tire Recommendations


*************

In an effort to figure out what is going on with GT5's tire models and which tires should go on which cars, I decided to do some skidpad testing. I used the 2010 Camaro SS and the Corvette ZR1, since I'm familiar with those cars and actual data is readily available.

We don't have an actual 200' skidpad to calculate lateral g force with in GT5, but what we do have is a g "meter" and a datalog. For the values I came up with, I created a delineated scale and taped it under the HUD g-force bar graph, and also used a scale against the datalog graph during replays as verification. The measurements were taken on the widest part of the TGTT, by turning a continuous steady-speed circle after warming the tires. Lateral g force was recorded up to the point where the car started to skid and could no longer hold the established circle. I also ran laps "on the edge" to verify the numbers, and repeated all the tests twice. (Note that I rounded the numbers to the nearest .05, due to my screen resolution).

My setup is a racing simulator chassis with a G25 wheel, and a Sony 50" HDTV. I ran each test with no aids and a manual tranny in "bumper" cam. (I hate that inaccurate view name ).

First up was the Camaro, with comfort hard (CH) tires. I performed the test on each tire type, trying to be as consistent as possible. I only tested comfort and sport tires; once I got to the racing compounds the grip started getting ridiculous, and was beyond what I wanted to test with this setup.

Here are the numbers (Notice that each softer tire compound increases lateral acceleration by approximately .05g):

CH - .85
CM - .90
CS - .95
SH - 1.00
SM - 1.10
SS - 1.15

The real-life Camaro SS scores a 0.87 on R&T's skidpad test. So it would appear that CM tires would be closest to stock for the Camaro, based on lateral acceleration. (I'm going to the next higher number, just because ).

Now for the 'vette numbers:

CH - .85
CM - .90
CS - .95
SH - 1.05
SM - 1.10
SS - 1.15

Virtually identical as far as the lateral acceleration numbers for each tire type. The real-life ZR1 scores a 1.10 on R&T's skidpad, so it would appear that SM tires would be the best stock equivalents for it.

Note: Just for reference, RH lateral g values were around 1.25, and RS were around 1.35 with the ZR1.

Here's where it starts getting weird. The real-life Camaro comes equipped with Pirelli P Zero tires, and the ZR1 comes with Michelin Pilot Sport PS2 ZP tires. According to TireRack.com data sheets, both of these tires have identical speed rating (186+mph), tread wear (220), and traction rating (AA).

The only thing I can come up with to explain the unexpected test numbers is that the size of the contact patch is not figured into GT5's tire equations. In other words, to duplicate accurate lateral acceleration numbers for the ZR1, you have to use a softer tire compound to make up for the larger contact patch on the real-life car. (The 'vette has considerably more rubber on the road than the Camaro, especially in the rear).

So far it looks like each car would have to be tested independently to come up with the best GT5 tire type to simulate real life. I plan on doing some more as time permits, but it will be a slow process. First up will probably be one of the Ferrari's that come with the Pirelli P Zero's (599 I think?), so that we have a side-by-side comparison.

Thoughts?

*************

For those that are late to the party and want a quick summary:

My testing so far has revealed that the 9 tire types (CH, CM, CS, SH, SM, SS, RH, RM, RS) in GT5 form what appears to be a simple grip multiplier, with each tire type adding approximately .06g of lateral grip. The only thing that changes is where the scale starts for various cars. (i.e. for the ZR1, CH = .85g and for the '71 Cuda, CH = .80g). It also appears that the width of the tire is not being considered in the grip equations; for any specific tire type, the '02 Mini Cooper has the same amount of lateral grip as the '09 Corvette ZR1! And as softer tires are equipped, the amount of grip increases equally for both cars.

The implications of this are that in order to get close to IRL grip performance (based on lateral acceleration anyway), you have to equip different cars with different tires. As an example, just throwing sport mediums on all performance sports cars means nothing. One car may need CM tires to reproduce IRL performance numbers, while a very similar car may require SH tires.

Here are my "recommendations" for the cars I've tested so far (take it for what it's worth and do with it what will you will ).

Edit: See link at top

In short terms, it says that you can't say that this or that tire is supposed to simulate this or that.
The tire model is a simple grip multiplyer.
So the tires of choice in GT5 should match the real life skid pad numbers and nothing else.
In some cases, the Pirelli PZero Corsa could be a SH, and in other cases perhaps SS. It all comes down to what the car of choice can pull later G-force wise in real life, and from that, match it with the best suited tire GT5 has to offer.

But I do agree that one can somewhat categorize the tires. But the above text is what you should use to get it as close as possible. 👍

 

[MOTORTRENDmitch]

The main problem with GT5 rubber, I find at least.. Is the fact that the Lateral/side to side grip is to much for the tire grade, but the forward bite is to low.. Obviously that is a super simplified description and if I weren't so tired at the moment I would go much further in depth with it..

But that's what I feel toward tires.

 

[eran0004]

Comparing tyres in GT5 to real world tyres is a bit like comparing soy-beef to real beef. It's not really the same thing. The generic tyres of GT5 is more than anything else simply a matter of difficulty level and should be regarded as such.

 

[VBR]

The tyre grip levels have changed overall, & on individual cars after certain updates, so calan's findings are not as accurate as they were initially. Best thing to do is find as many lateral g ratings for any given car, work out the average, then perform your own lateral g test on the track you wish to run it on. Make sure you are using ratings for sustained lateral g, as on a 200ft skidpad, otherwise you'll get a false positive.

 

[Denilson]

The tyre grip levels have changed overall, & on individual cars after certain updates, so calan's findings are not as accurate as they were initially. Best thing to do is find as many lateral g ratings for any given car, work out the average, then perform your own lateral g test on the track you wish to run it on. Make sure you are using ratings for sustained lateral g, as on a 200ft skidpad, otherwise you'll get a false positive.

True. But the method he use to find the right tire is still the way to go.
The tire compounds are still simple grip multiplyers which make any effort to specify SM's as this real life tire, or CH's as that real life tire as incorrect as previously.