Hi all, Does anyone have any info on the current status on development of the tire model? We all know S397 have been working extensively with Pirelli to improve the tires. AFAIK this has resulted in tires of different design. I wonder what they learned from this in terms of required changes to the underlying physics. There has been the well-known exploit of very low tire pressures. The recently released Porsche cup car is, AFIAK, the first S397 car since long to have standard tire pressures above minimum. A minimum I think set higher for previous cars to prevent this exploit. From testing I feel the drawbacks of lower tire pressures are more evident with this cup car, but am not sure. Does anyone have more info on the current status of this issue and the general development of the tire model?
Language precision is desired here. Pretty certain the tire physics haven't changed in a couple years, but the parameters used to arrive at the current GT3/GTE tire model have changed as more information has become available. And changes in the physics have been minor, adding a couple parameters to support behavior on grass and/or supporting larger lookup tables.
It should be a trade-off between increased grip due to a larger footprint but at the expense of increased heat build-up as the low pressure tire moves more. Eventually the heat build up should be enough to damage the tire.
The allowed pressure range is small enough so that the difference in temperatures shouldn't be drastic. More grip more wear, that's it. Anyway, I wanted to know what OP thought the drawbacks are. Maybe he thinks there's something else.
I feel it's slightly more difficult to keep temperatures under control doing a longer stint with lowest pressures. But it's hard to tell under the dynamic circumstances we're driving in.
Less pressure means more grip, less slip and as the direct result less slip caused heat so it's never simply to know whats right
some time ago (years?) was stated what the code fore tire blow was in the simulation but not used; who knows if that code maybe implemented in the future as a consequence of using low tire pressure over an extended stint. also, lower pressure should imply more drag, and more grad equal to more power needed to move the car and more fuel consumption; again hampering longer stints... for your standard sprint races MAY not be long enough to be punished for using lower pressure
The problem is, none of the modern sims have developed the "failure modes" that might occur as a penalty for running too low tire pressures that happen in the real world. I worked for Cooper Tires for a while, not doing tire design or engineering or suchlike, but I did get chances to talk to their engineers. That was during the Firestone Ford Explorer (aka Exploder) tire failure time, so I was asking them why Firestones tires were failing while theirs were not. In that case, it was all to do with the tire "shoulder" - where the tread and sidewall meet. The Firestone tires had incredible heat build-up in that area, which caused it to fail, and the tread delaminated from the rest of the carcas as a result. Those sorts of failures were affecting Pirellis F1 tires a few years ago, so they were asking teams to run 20psi or more where in the past they'd run in the teens. The extra pressure helps support the carcas so it doesn't do so much work and hence build heat in that area. In NASCAR, running pressures too low can result in the tire "bead" melting, so they'd run blowers on that part of the wheel. These are the sorts of mechanisms that we could do with having built into all tire models. iRacing don't have these either, and suffer the same issues.
You're asking that the pressure range is allowed to go into the zone where the tire doesn't work as intended. I guess tire manufacturers wouldn't like that. It would also be probably impossible to simulate correctly because I don't think there's test data in that non-optimal working pressure range. If the manufacturer is telling you the minimum recommended pressure, why would you ignore it? I don't get why would we want to let the tires use pressures that aren't recommended and that would make them behave in unrealistic ways. Don't you know how hard it is already to simulate a tire in real time only in the recommended pressure range and under optimal conditions?
Racers are like that. Sometimes they find something that works (until it doesn't), something that gives them an edge.
