General OEM feedback

[Asdrael]

Not sure if the 250 and 450 have the same rear tire, but they shouldnt.

All OEM bikes have the same tyres. Actually, a good test to know if something comes from the engine side is to ride the Huskies. Strictly the same geometry, except 1kg more and center of gravity a few cm lower for the 450f. And why shouldn't they have the rear tyre? Because of the width? I'm not sure how we can get that in the tyre file. It might be a small change in springrate and grip, but I think there is still more to do currently with bikes and tyres overall that starting to divide things. Plus, not sure we want to keep up with all that shit :p (Edit: just double checked, the current geo rear tyre "width" is the same as default with r = 55mm. Which is a 450f rear width, a current classical mod on 250f bikes).

I will investigate on the 450f engine and run some tests. I might have went overboard increasing both inertia and braking torque. It might take a few days as I have a busy week, so if the 450 really feels like poop for some of you... well ride the 250 

The good news is that in the meanwhile, we seem to have found "the" value to change in the tyres to allow for a more controllable rear without increasing traction (actually, a net loss in grip giving a better and somewhat faster bike).

[HornetMaX]

And why shouldn't they have the rear tyre? Because of the width? I'm not sure how we can get that in the tyre file.

Tyre width is easy to put in game, you need to play with the parameters Radius, TorusRadius and Width. Width is an angle in fact, half-angle of the tyre profile (assumed circular).



For the rest (tyre properties difference between 250 and 450) you're on your own

P.S.
Not sure, maybe you were all already ware of that I'm being Cpt.Obvious here ... but I'll take the risk

[Asdrael]

Thanks Max, I had it figured out but it never hurts to have confirmation. The difference between 250f and 450f is a slightly broader tyre for 450f, which is often compensated by people mounting a 450f rear on a 250f. I think the "width" stays the same but the Torys Radius is slightly bigger (2.15" vs 1.9").

imo, let's see how good we can make "a" tyre work, then we'll think about making "tyres" work. I have some ideas with different brand and models giving different properties but we are still far off. Or, are we...

[HornetMaX]

^ That and well.......we need selectable tyres as it is a pain in ass right now having to duplicate things

Isn't that already doable ?
It would be enough to add all Piboso's standard tyres to your tyre set and name them accordingly (like Pib soft, Pib med, ... Geo Soft, Geo med, ...).

So in geo_p_mx.cfg you can probably refrence PiBoSo's tyres and you're done.

Not tried and not ideal, but it should work no?

[Asdrael]

I haven't tried, but I m pretty sure we can expand the selection to more than 4. The thing is tho, you don't want to mix PiBoSo tyres with geo's because of the wet vs dry grip thing.

But in theory we could have thinner, hardpack, pure sand tyres etc already. I just don't think the base we currently have is good enough to start adding this kind of variety (sorry geo).

[Asdrael]

Ok so rolling out a general update on all 450f OEM. All engine braking torque back to MSM values (~20% lower).

The reason is, the rear sometimes decided to just buzz off and go its own way when braking / cornering at low speeds. There was no bringing it back. Apparently, I went overboard when increasing both inertia and engine braking (actually I increased engine braking first, then inertia, and never tried inertia increase without engine braking increase. My bad!). I suppose it put the rear wheel in slide mode and there was not enough lateral grip to bring it back. Changing the grip was no option (as the 250f work well and more grip made the 450f wheelie land).

I think the 450s is now lacking a bit of engine braking, but at least you can push them and not break your controller when you get random spins out. Feedback welcome, it's one of the last part remaining where it's completly subjective and I have no real data to work with.

[loinen]

I'm a 450f MSM rider since first betas and here is my unpretentious opinion after 2 serious rides on OEM 450 bikes (husky mostly and few others). I was confused with OEMs on first try - they felt more random to me, less predictable but having more grip while sliding the rear end, whipping also seemed a bit different - dunno why, maybe weight or dynamics was the reason. Wasn't be able to be stable making consistent laps and scrubs without falling. After some practice and playing with setups I feel fine but still unsure about my stability with them. I cant say whether OEMs are worse or better than standard, they are really different, maybe more agressive or something, MSM feels little 'softer' to me in terms of character. Maybe I'm wrong, too fixed on MSM still and need to get used. I'll tell more later, with new experience.

[HornetMaX]

Width is an angle in fact, half-angle of the tyre profile.

Hmm.......then why do default Rear Tyres have a width (angle) of 75 and front 85??

Seems backwards

If you check the torus radius too you'll probably find the width (in mm) to be bigger at the rear (can't check now, don't have the files at hand).

Width[mm] = TorusRadius[mm] * 2 * sin(Width[angle])

[Asdrael]

Thanks Loinen for the feedback. 450 OEM are a bit more tractor-ish and less forgiving than the MSM, which comes from a mix of engine, chassis and weight differences. The main problem is that the geometry and weight distribution gave those more grip, but not always interacting in a good way with the engine as it was - and not with scrubbing for sure. I think the update rolled out yesterday on the 450 OEM removes a bit of that tractor feeling in a good way, and there might be another update very soon of the tyres that fixes the remaining problems.


So about tyres - MX tyres are broader but flatter on the rear than the front (even disregarding nipples orientation). That's why "width" as defined in the tyre files is lower on the rear - what you'd actually call width is indeed larger, but to get it you need to use Max's formula. 75 and 85 seem about right but it's tough to say and measure, once again given the orientation of the nipples. If my calculations are somewhat ok, the tyres we have now are more or less the right shape (I say more or less because I'm not sure how the orientation of the pattern and its thickness is taken into account - and not sure if MXB values for tyres are on the tyre or on the nipple surface).

I'd say that once the values we have found to have a dramatic effect on the tyre are set, we can start looking into the other stuff. Not sure if worth though, because thinner tyres are mostly made to fit into ruts better and dig differently in looser surfaces, and terrain deformation for grip is actually not taken into account (afaik).

[Paradox28]

I kind of like the feeling of the Yamaha with the engine braking more than now.  Seems like before I could rail berms and now it wants to pull over the berm more.  As always, I'm not a super pro rider so thats feedback from a maybe slightly above average rider.  The same weird spinouts I would get frustrated with before happen now and I only attribute it to a severely rutted out track with a lack of grip in certain turns. 

[Asdrael]

I kind of like the feeling of the Yamaha with the engine braking more than now...

Thanks for this. Engine braking changes are supposed to go hand in hand with a tyre update coming "soon" (TM) to have their full effect. I still think it's slightly better now but I agree - it does feel overpowering a bit when directly switching because of how the rear tries to push the front (for a lack of better explanation), and now rolling the throttle lets the engine a bit more lose. Land of compromises here :/ (also, the Yamaha was the bike with the least issues with engine braking due to its power curve).

[Bj Slice]

Hey asd, I notice that the rmz 450 2016 oem's clutch and brake cables are getting rusty overtime as opposed to just getting dirty, including the tank vent and the tank cap. Also, the crf450 2017 OEM is not getting dirty at all even after 5 laps or so. Are thiese known? thanks!

[Paradox28]

I wish we had some of that engine braking back

[Asdrael]

Hey asd, I notice that the rmz 450 2016 oem's clutch and brake cables are getting rusty overtime as opposed to just getting dirty, including the tank vent and the tank cap. Also, the crf450 2017 OEM is not getting dirty at all even after 5 laps or so. Are thiese known? thanks!

I have done the dirt maps, they are done by the model builder. But yes, the RMZ is weird and the CRF stays clean for now - until someone comes up with updated dirt maps.

I wish we had some of that engine braking back

Me too (somehow). But it just doesn't work that well now, the rear gets really unpredictable :/

[Asdrael]

Tiny bit of a bump. If anyone has more feedback (especially now with the surface specific geo tyres), I'll take it. Might have some time soon to have another look into OEM bikes.