Enforcement of MotoGP minimum tire pressure rule

[02redhawk]

Just read this. Hoping it isn't true. In MotoGP, the front tire must have a minimum tire pressure of 1.9 bars, while the rear tire must have a minimum tire pressure of 1.7 bars. If a MotoGP rider does not adhere to the set tire pressure bars, they are considered breaking the rules. Furthermore, the temperature can affect tire pressure.

As a controls system engineer this BS drives me crazy. Talk about unintended consequences. Teams will get penalized for readings dropping above or below due to conditions beyond their control.

[tls25rs]

As it is a minimum pressure it would be pretty difficult to get a lower measurement then what the team put in the tire unless they were running on some type of cooled surface or the tire pressure was initially set and measured in a warmer environment then it would be used in. Anything a team/rider do to a tire during use should theoretically only add pressure. I would hope this would be set and tested "cold" with some type of control as to what the definition of "cold" is.

I believe similar rules are in place in Formula 1 without much drama.

[csmutty]

Why would this be a thing? Lower tire pressure will cause faster wear. Is it a safety based rule?

[R7]

I thought nitrogen was used in tires rather than air to control pressure changes between hot/cold?

[02redhawk]

Lower tire pressure (assuming the rider and bike can deal with it) "may" give better grip. Flirting with the max pressure is a sure way to hit the tarmac. The pressures are read directly by the sanctioning body. One can imagine stepping below the low threshold if you start at the lower limit and run through a few wet patches or cloud covered areas of the track.

[JettaJayGLS]

From my understanding, minimum tire pressures was always a rule. It just wasn't enforced. Further, there was not a unified measuring device, which offered another way to cheat the readings by using your own device.
Ducati were the largest breakers of this rule.
I believe it is safety oriented. But clearly whatever they were doing all season wasn't unsafe.

To me, the proper fix is regulating aero and ride height devices. The combo is causing incredibly noisy and dangerous air behind riders, causing front tires to overheat, causing them to want to run lower pressures.
Overheating front tire was a major problem all season for all manufacturers, and is a major proponent of letting someone just ride away at the front.

On the other hand....this is one more technical challenged to overcome and racing challenge that riders need to overcome. So I'm sort of for it.

But still. Aero and ride height are whats driving us back to a procession.

But still. The racing was awesome all last season barring a few boring races.

[MattR302]

I thought nitrogen was used in tires rather than air to control pressure changes between hot/cold?

Even with nitrogen, the ideal gas law still applies:
PV=RT
Pressure * Volume = gas constant * Temperature
Since the gas constant is fixed and the tire volume is basically fixed, as temperature goes up, pressure goes up.
Nitrogen is slightly better due to other factors; the first couple paragraphs here explain it well:
https://www.getnitrogen.org/sub.php?view=nascar

There’s no way that the pressures would drop below the off-track “cold” temperatures. Even if with a cool/wet track, the friction is going to heat it up well above the off-track temperature.

[Jim]

1.9 bars 27.5 PSI in the front tire.
1.4 bars is 20.3 PSI in the rear tire.

that's much lower than you'd want off the track.
you're making a complaint about something that shouldn't even happen

[02redhawk]

Interesting commentary from teams/riders why they running such low pressure at the start to begin with. I hadn't even considered the effect the wings and aero were having on pressure. I was thinking more the heat/grip relationship at the low end of the readings. As others above noted the low pressure readings likely won't be an issue assuming they don't penalize from the start. https://www.youtube.com/watch?v=nXaq1b3pzd4