Wheel Spin and Brake Fade Balance Issues

[mrfuzzy]

Well said Madrias. I get what you guys are saying and I had to sit down and really mull this over in my mind. Perhaps I am looking at this the wrong way. I guess when I think about it I get hung up on what the different stats mean, which unfortunately the abstract nature of them isn't helping. So we have drivability, which I assume means how the car handles under normal everyday driving. Then we have sportiness, which I assume means how the car handles on the edge or under extreme stress, like what you might experience on a track. Now if that is true, why is wheelspin and brake fade a factor in the calculation of drivability? Wheel spin is what happens under pedal to the metal drop the clutch acceleration, which no one would do in routine driving. Brake fade happens when you stomp the pedal as hard as you can, stop as fast as possible conditions, which no one does in routine driving. So, I can see why gearbox setup and overall braking distance would matter to drivability, but not wheelspin and brake fade. I think having wheelspin effect two stats, both drivability and sportiness is where the imbalance may lay. A 10% penalty to just sportiness I can live with, it makes perfect sense, but a 10% penalty to both drivability and sportiness seems a bit steep. I can see where maybe wheelspin effecting drivability can be linked to bad weather handling, but perhaps an actual inclement weather stat would be a better way of handling that. Taking into account maybe a combination of the offroad stat (snowy conditions) and wheelspin (water and ice) and also the fact that bad weather is an occasional event so maybe not weighed as heavily.

[RobtheFiend]

IIRC the maximum grip from a tire is when it is moving 25-30% faster than the tarmac.

[Madrias]

Mrfuzzy, you raised a good point regarding the things people wouldn't do in routine driving. However, there's that unpredictability factor in real world driving. Sometimes someone passes you on the highway, then nearly cuts the front of your car off to go up the exit. Sometimes you're hauling a heavy trailer down a hill with a ridiculously low speed limit, making you ride the brakes down the hill. Sometimes the guy driving the truck behind you keeps nodding off and threatening to drive into the back of your car. Each of these little things adds up, and if you can't rely 100% on your brakes to stop you or rely 100% on your car to put the power to the road and go, then the car should suffer a penalty. If you're stopped at an intersection and suddenly have someone barreling down on the back of your car in a huge dump truck, blaring the horn because his brakes have given up, would you rather be in the car that can put 100% of the power to the pavement, or the car that can only put 90% of the power to the pavement, and that 10% is going to be spinning the tires, making smoke and noise, and not going anywhere? If you're going down a hill, hauling a trailer, and someone in an insanely expensive luxury car brake-checks you, would you rather be in the car that can guarantee you will stop, or the car that has mild brake fade increasing the stopping distances?

On the flip side, for sportiness, would you rather have the car that has 300 horsepower at the wheels and can put 100% of that to the ground at all times, or the car that has 300 horsepower at the wheels and occasionally breaks the tires loose in first and second gear? Would you rather have the car that can make a full lap of the race track and still stop like it did when it was cold, or the car that loses braking efficiency halfway around the track and takes half a mile to stop from 60 miles an hour after crossing the finish line?

Now, to help eliminate brake fade, very small amounts of more aggressive brake pads can help. You might not lose too much, in fact, might gain some drivability and sportiness by adding more aggressive pads. Just use enough to wipe out the brake fade. Try different amounts of front and rear pad types to see which one gets rid of the fade while minimizing damage to the remaining stats.

To help eliminate wheel spin, spacing, top speed, and differential can make a big difference. Tire compound can make a difference, a point or two of increased tire quality might help, wider tires might help, adjusting sidewall thickness (bigger/smaller tire diameter, bigger/smaller wheel diameter) can help, possibly changing your rim material (I've found I get less wheel spin using steel rims than I do when using alloy, for example) and adjusting your downforce can also help with wheel spin. These are all the options I've found so far, but I'm far from an expert.

Either way, I agree that the penalties can be a bit severe, but so are the circumstances in which these items can come into effect. I'm surprised, honestly, that brake fade or wheel spin doesn't also affect Safety.

[Killrob]

Safety is "How safe is the car when it crashes."
Drivability is "How easy the car is to drive/handle. How good is the car at avoiding crashes."

[Madrias]

Good point, Killrob. That also explains brake fade and wheel spin affecting drivability. Wheel spin harms the ease at which the car can be handled, and brake fade makes the car more likely to crash.

[Packbat]

One of the things that occurred to me when I was trying to design my own contest was that the in-game stats are very well suited to describing consumer impressions of a new car. People should perceive active safety - drivability - as an essential component of automotive safety, but when a large part of the popularity of SUVs was that they were seen as safer in spite of their drivability issues, you have to separate the former from the latter to model correctly. I personally think a fancy little high-revving four-cylinder engine is a lot cooler than a big simple V8 making the same power, but that just means I care more about Sportiness than Prestige. Even things like Reliability being a single, arbitrary number make sense - the customer is working off stuff like Consumer Reports testing, and doesn't know the Mean Time To Failure of any of the components.

[TrackpadUser]

The main area where some balancing of wheel-spin might be required is with lower powered cars.

I have two examples based on cars I owned, both end up getting around 20% wheel-spin, even though both of those only get some wheel spin at the very beginning of the first gear IRL.

The first one is a Geo Metro, with a 75hp engine, 155 medium compound tires, a first gear that red-lines at around 50 and a second gear that red-lines at around 80.

http://i.imgur.com/WkcZ4Aw.png

The second one is a slightly less accurate Chevy Aveo, with around 95hp, 185 medium compound tires and slightly longer gearing than the real life car.

http://i.imgur.com/99OTHoh.png

The penalty to drive ability ends up at around -5%, which is definitively non-negligible, especially if we consider that its going to be a big factor in the demographics that usually buy those types of cars.

[Killrob]

That is an interesting observation, TrackpadUser. This probably has more to do with how tires are balanced currently. Shit tires need more longitudinal grip and less lateral grip (i.e. more sane skidpad values). It is balanced that way currently to make track times reasonable, but as soon as we have Martin's new track calculations in the game we will be able to rebalance the tires without making track times ridiculous!

[07CobaltGirl]

I think there are some issues with AWD vs. RWD in the game.

AWD essentially eliminates ALL wheel spin on my cars. I just built a reasonable V8 using the modern coupe (looks like a Corvette sorta) with good balance for a F/R car (53/47). Using the same motor, a 5.0L, tuned to 425hp/375tq, an AWD 6 speed has ~6% wheelspin, while a RWD has ~64% wheelspin. The car is around 1250 kilos, so somewhat lightweight, but not extremely so. With the AWD, you lose usability for 1st gear, while with the RWD setup you lose 1st-3rd gear. I know V8's tend to spin tires easily, but not THIS easily, and AWD magically makes it all go away? I just think the difference between the two should not be so dramatic. In fact, the magical AWD reduced the much more powerful 6.0L (499hp/445tq) V8 from 68% to 10% in the same car, at around 1350 kilos. Granted, the bigger engine upset the car balance to 56/44, which is expected.

Both of these cars are using 245/40-18 tires. Sure, I could throw some beefy 335's on all four corners, but this is not a realistic solution for a moderately powered car. This kind of tire is reserved for supercar power-to-weight, which I am nowhere near.

With both cars, changing gearing for the RWD setup made only minimal improvements to wheelspin. Best I could gain was 45% wheelspin with the 5.0L car. Thoughts?

[TrackpadUser]

400hp is definitively not moderately powered That's the kind of power output you get with an LS2.

As for the RWD vs AWD, it might need some rebalancing, but AWD truly is somewhat OP IRL.

You are pretty much doubling the amount of surface you are transiting the power to.

[Leonardo9613]

Just to make it absolutely clear, a Corvette Stingray, which was your basis, it seems, uses 285/35 R19 rear tires and 245 fronts. Also, RWD cars with more than 250 hp or so, usually have wider tires on the rear.

[nialloftara]

Well look at the last gen dodge charger, it's ~340hp 5.7 hemi could smoke tire in regular r/t trim but when you bumped up to r/t awd the tire spin pretty much disappeared.

[07CobaltGirl]

400hp is definitively not moderately powered That's the kind of power output you get with an LS2.

As for the RWD vs AWD, it might need some rebalancing, but AWD truly is somewhat OP IRL.

You are pretty much doubling the amount of surface you are transiting the power to.

Well, my argument is it needs rebalancing. The 6.0L in the second example actually was an LS2, with 499hp. The 5.0L was a modernized L99 (305) with 425hp. The car was being built for the MRCSR Time Trials, but since it also will not seem to save beyond the initial build-through, it was scrapped.

[Killrob]

There will be rebalancing of tire grip, that is the only thing that can and will be rebalanced as the rest is pure physics. If you don't like physics that is not the problem of the game.

[gt1cooper]

My Infiniti M35s has 245/45/r18 high performance all seasons on it. Being all season, I assume this should be equivalent to a fairly high quality mid level tire? I made it +9 quality, which is likely a little over optimistic.

Unless it's running on standing water, it will never wheelspin in second gear. If what you say is true, this should lead to 0% wheelspin penalty, since no wheelspin occurs in gear 2+, and this is by no means what results in game. This is with an accurate 303 hp VQ35HR, a 7 speed with first gear ending at low 30 mph's and second at just over 55. It gives me a 36.2% wheelspin, in a 3800 pound car with an lsd, an automatic transmission with fairly long gear ratios, with a rear multilink setup that should keep all the tire on the ground. I don't believe that that is the way the penalty occurs then.

However, if I look at the graph, that is fairly accurate. As soon as second gear comes around, the car stops wheelspinning. I don't mind having a wheelspin penalty in this car, in the rain it deserves it, spinning in second easily. But it most certainly is not based upon gear 2+, in normal conditions, when no wheelspin at all occurs in that range, and there is a reasonable gap between the tire grip and the engine output.

Also, with traction control it has a -3% penalty to drivability, but I could stomp it in any gear at any speed and not have any wheelspin occur. The only way to have anything happen is to have it in first or second gear, turning around a hard corner, with a lot of water on the ground, and to floor it. In which case, the rear end will rotate a little bit before coming back into line.