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'Random' Front End Crash Possible Fix?! v2

Started by Manu, June 17, 2020, 12:51:53 PM

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Hawk

Quote from: Vini on June 19, 2020, 01:47:30 PMChassis flex has always influenced bike handling in GPB very positively. Sadly, a lot of mods are way too stiff.


Quote from: HornetMaX on June 19, 2020, 11:56:49 AMSide note: I think Victoria is a good test track. It has a bit of everything. Not sure why Vini crusades against it :)
Because I have ridden plenty of bikes there that seemed to be good but then revealed themselves to be absolute shite on more technical tracks. Victoria lacks slow corners, bumps, quick direction changes and hard braking. You only have all those long corners where you basically have enough time to get any bike to turn nicely.
The track is simply not bike dependent at all, that's partially why real MotoGP races are always so exciting there.

+1 Vini

Totally agree with your deductions about testing and track testing for bikeMOD devs, at least to get the bike handling well initially. ;)

Hawk

Quote from: h106frp on June 18, 2020, 10:16:08 PMI have been going through the usual re-tuning of a bike using Victoria and I have developed a bit of a new theory on what occurs at the bottom of Lukey Height/MG. After noticing the problem only ever occurs when entering the turn with high lean (you can always blast through it any old how when you pick it up after a drop) I wondered about chassis flex and damping, theory being that as the bike has a high lean angle we lose damping and travel from the suspension units and become dependant on the mechanical flex and damping - much in line witrh Vinis comments about the bikes being overly 'stiff' but maybe with a slightly different perspective.

With the newer inertia calcs it appears we have a bit more range to play with in the damping and chassis stiffness ranges and it does improve the situation very noticeably if you can add a bit of flex and damping to the chassis. It might be worth you trying and comparing it to what you obtain from tyre adjustments.

If you remember the problems bikes used to have on Silverstone entering that right hand rising bend as you exit from under the bridge, the front end always used to wash-out? Well that issue was fixed with correct chassis-flex settings if you remember mate? ;)

HornetMaX

Quote from: h106frp on June 19, 2020, 01:22:51 PMAfter a bit of reading that is apparently the perceived wisdom on chassis flex and why super stiff chassis is a bad idea for bikes, as you lean the bike over the 'bumps' still occur vertically but the suspension can only translate the vector of travel so the displacement is less than it would be for upright, as the displacement in the damper rod movement is less the damping contributed is equally less effective so we become dependant on the lost motion in the chassis construction to contribute some of the damping.
This is absoluely true, even if it is probably worth to remember that the travel you get from a non-rigid chassis is way smaller than what you get from suspensions (so yeah, it helps a bit, but it's not something that can absorbe bumps). The thing I'm not convinced about is that it helps/solves the problem we have in GPB on turns with camber and slope changes. Or at, best, why it does it.

Quote from: Vini on June 19, 2020, 01:47:30 PM
Quote from: HornetMaX on June 19, 2020, 11:56:49 AMSide note: I think Victoria is a good test track. It has a bit of everything. Not sure why Vini crusades against it :)
Because I have ridden plenty of bikes there that seemed to be good but then revealed themselves to be absolute shite on more technical tracks. Victoria lacks slow corners, bumps, quick direction changes and hard braking. You only have all those long corners where you basically have enough time to get any bike to turn nicely.
The track is simply not bike dependent at all, that's partially why real MotoGP races are always so exciting there.
Well, Victoria has:
  • A fast straight
  • Plenty of fast turns, including a high-speed direction change
  • Sort of a hard braking
  • Some not-so-fast turns
  • Some bit of slope changes
And, of course, it's the track GPB comes with.

So yeah, suggesting modders to stop testing their mods on Victoria is not a good idea in my book.
If you're suggesting for modders to also test on other tracks, then yes, that could be OK.
You should probably name the track you thinks are relevant.

Vini

Quote from: HornetMaX on June 20, 2020, 01:15:17 PMSo yeah, suggesting modders to stop testing their mods on Victoria is not a good idea in my book.
If you're suggesting for modders to also test on other tracks, then yes, that could be OK.
You should probably name the track you thinks are relevant.
Sure, they can also keep testing at Victoria, it's just that those results are pretty unimportant compared to more technical tracks.
Almost any track I can think of is better for testing than Victoria.

Some examples: Valencia, COTA, Mugello, Sepang, Aragon

Myst1cPrun3

If we're going for test tracks, then the real world test tracks are probably gonna be the best choices.

After all they test there for a reason...  ;)

Catalunya/Montmelo has pretty much everything, and Jerez is good to. Sepang has a wide variation, and cheste/Valencia is good for low speed handling and testing traction.


Victoria and Assen 2005 should be the best tracks to use, as they are (in theory) the most optimised for the sim being official content.

h106frp

With the latest updates is anyone else noticed the return of the 'old' problem of the rider 'just giving up' and dropping the bike in turns?

Vini

June 20, 2020, 07:00:40 PM #21 Last Edit: June 20, 2020, 07:05:41 PM by Vini
Yeah, while the rear feels nicer the front has lost stability.

@Mystic: I agree. There is a reason PI is not a real MotoGP test track...

Stout Johnson

Quote from: h106frp on June 18, 2020, 10:16:08 PM[...] After a bit of reading that is apparently the perceived wisdom on chassis flex and why super stiff chassis is a bad idea for bikes, as you lean the bike over the 'bumps' still occur vertically but the suspension can only translate the vector of travel so the displacement is less than it would be for upright, as the displacement in the damper rod movement is less the damping contributed is equally less effective so we become dependant on the lost motion in the chassis construction to contribute some of the damping.

Obviously anybodys guess if this is how its applied in GPB!

I totally agree. Chassis flex is very important, especially during high lean angles, as the suspension is almost non-effective anymore.
https://motodna.net/flex-or-not-flex/
https://www.cycleworld.com/2015/10/16/motogp-racing-chassis-flex-and-stability-are-key-to-winning-races/

If the suspension is acting as irl, then chassis flex should be similarly important as it is in real life. Piboso could probably bring light into this matter.

Another important factor is the tires acting as a sort of suspension.

So essentially, you have front and rear suspension, chassis and also front and rear tire acting as suspension-like entities and therefore possibly affecting grip level. Not sure how that is reflected in GPB?


Quote from: Vini on June 19, 2020, 01:04:04 AMOn a side note, you guys really need to stop testing bikes at Victoria. The simple, sweeping layout masks almost all handling issues of bikes.
Similarily, aids (including TC/AW) should be turned off when testing physics and high direct lean values should be used, as this too avoids "fake stability".
Totally agree with all here, escpecially the part on direct lean.

Quote from: Vini on June 19, 2020, 01:04:04 AMThe track is simply not bike dependent at all, that's partially why real MotoGP races are always so exciting there.
On Victoria the only turns worth testing are lucky heights (to some degree) and especially the right tigh turn afterwards (turn 10). Some info can also be obtained by accelerating through "Stoner Corner" (turn 3). All the other parts are really not giving much information.
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