Zero FFB during understeer in modern Formulas

Just a quick question, is FBB cutting out in an understeering formula car (F138 and later, but also Tatuus) a bug, a feature or a wheel setup problem? To test you turn in at speed to create understeer, and then turn in some more. At the "turn in some more" stage, the wheel becomes completely empty, no FFB at all - but only in aforementioned cars, other cars (even older F1 Lotus 98T fro example) do continue to give FFB feedback even as you increase the steering input through the understeer.

My wheel is G29 and FFB is working great otherwise.

 

Are you using the enhanced understeer effect? Thats likely what it does at high settings. I dont use the effect at all and dont have this issue with my past logitech wheelsor current DD wheel.

 

I keep using understeer effect on and off. For some car it is believable more with understeer effect to me.

In order to understand this, I think, we should know how much caster does cars have, and if they have powersteering. One guy in reddit wrote that cars with no powersteering are usually going really light on steering when tires completely slips. This makes sense, especially if car would have little or no caster (mechanical trail), so drop of pneumatic trail would be much more noticeable then.

This is random pic I google, but makes sense to me.


Maybe Lotus 98 is going light even with enhanced understeer being off, but it is very likely that you have it on. This being said you do something wrong with Lotus 98 or its setup if you make it understeer Commit to those little slides, it is fun how it grips up because of downforce when you just slightly lift off the throttle.

 

Sorry for abandoning the thread for a couple of days - RL and all that...
Luckily for this discussion, we don't have to reply on subjective reports of feel but can simply analyse what the grey FFB bar in the pedals app is doing.

Here is a video of F138 understeer with zero or near enough FFB, the grey FFB bar drops to near zero and subjectively it feels like its steering rack snaps off once the front begins slipping.


Here is 250GTO (no powersteering) doing the same thing and it has plenty of FFB right through, grey bar fluctuates at around 30%+. Thus. this

does not seem to apply here. The FFB is lightER than during the initial turn in, but it does not go to near zero.


Enhanced understeer effect is off in both cases.

 

Out of curiosity, do you own RSS Formula Hybrid? Is it the the difference in scrub radius again? Without decent scrub radius AC doesn't provide any slipping feedback which might be realistic but makes me not like some cars.

 

I don't have RSS Formula, no
Which other cars in AC have "indecent" scrub radius?

 

Tire flex can give some scrub I think, or take away. But would scrub radius be significant when understeering ?


Scrub radius is more about responses when traveling straight, or relatively straight. Roughness and bumps of road, braking, tramlining, perhaps effort at the turning in moment...



I think I have to find from where those pictures are taken out, this picture of prewar car is totally forcing me.

Edit... off topic, but just for the record these are by Erik Zapletal, it seems that he was writing for Racecar Engineering magazine ! Now thats a magazine I would like to read.

A little example I just found: https://hpdedriver.files.wordpress.com/2010/02/trailbrake.pdf

 

Nice magazine

I finally did try the RSS Hybrid and understeer has plenty of FFB there, just like in normal AC cars. This is good as I thought maybe FFB limpness is related to 360deg steering lock of modern formulas, but now its clear that the steering lock is irrelevant.



So what now? The question is still the same: is the formulas' steering wheel going limp during understeer a feature or a bug?
Is there any evidence that steering wheels in modern formula cars (with their particular scrub radii, weird suspensions etc) go completely weightless when understeering?

 

I think you should post it in physics bugs/issues forum. You probably will get no issue without explanation, or explanation will be no mechanical trail or something like that.

 

Will do just that. The name of the topic is not correct by the way as I've tested all the formula cars again and it is only the F138 and 2004 that show this FFB drop. SF15, SF70 (as well as Lotus Exos, 98T, MacLaren MP4-12C GT3) are completely fine. Tatuus FA1 is kinda midway between the two - FFB is not absent like in F138 and 2004, but it is less pronounced than the other cars in AC.

PS Done : https://www.assettocorsa.net/forum/i...ng-understeer-on-ferrari-2004-and-f138.49407/