Hello everybody, I have a problem when driving my KTM X-Bow in Raceroom. The handling does not correspond to reality, because the rear wheels do not lock at high speeds, no matter how hard I press the brake pedal. I have also already turned the brake balance as far back as possible. Again, the rear wheels do not lock at the moment I press the brake fully. I can tell by the videos of the training and the view where you can see a rear tire. When wheels lock, it is always the front wheels, but never the rear wheels. For driving I use the following configuration: Windows 7 Fanatec ClubSport steering wheel BMW GT2 Fanatec ClubSport Wheel Base V2.5 Fanatec ClubSport Pedals V3 I also varied with the maximum braking force in Raceroom and also tried different settings when calibrating the pedals, but unfortunately I still can't get the rear axle to lock up. I also tried this with another pedal set (Thrustmaster F1 Force Feedback) and the same problem occurred here as well. Furthermore, I already had the game checked for errors in Steam. There was no mistake. I also completely uninstalled and re-downloaded the game once. This has not solved the problem either. Hence my question: If the problem occurs only with me or also with someone else. If it occurs to more people, is there a bug that support could fix or is there another solution to the problem?
Just tried for a while and your observation seems to stick. I can't block the rear wheels either, not even with BB completely to the rear. Just to be sure I moved the BB completely to the front to see if something was reversed: clearly more braking power to the front, no locking of the rear (which would obviously be as suspected). So yeah, +1 for the non locking rears. Edit: see post #5 for a different experience: augmented brake power from 90 to 100% and then the rears lock easier when BB is moved to the rear.
A little nuance to my previous post: I had brake power set to 90% in the car setup. At 100% the rears block indeed when the BB is moved to the rear.
Interesting question. I'm not sure that this is a problem, given that locking rear wheels is most undesirable in the real world. It's usually the result of a badly set up car, knackered tyres, or something the driver is doing wrong such as not matching revs on a downshift. I've spent countless days trying to dial rear lockups out of real cars. It's a real pain. I'll go through it now and give reasons as to why it may be very hard/impossible to lock the rear wheels at speed with the KTM. Before I do, I will say that I didn't make the physics for the KTM X-Bow. They are very good though, and I can easily access all the behind-the-scenes numbers. So, let's begin... The rear brakes are 25% less powerful than the fronts Full rear brake bias is still only 70%. So 30% of you braking energy is still going to the front. The car has quite a reasonable amount of downforce, so the rear tyres are being pushed quite hard into the ground at speed Weight distribution is very rearward - 63% in fact. Again, that means the rear tyres are really being worked hard all the time, even under heavy braking. The centre of gravity is very low, so weight transfer off the rear tyres under heavy braking isn't that great. Ie. rear tyres remain well loaded Inertia of the spinning assembly at the rear (wheel, tyre, brake disc, drive shafts) is quite high, so it will take a lot of energy to stop it quickly, more than the braking force can provide.
With the extreme settings I just want to determine if there is a problem in the game physics or not. No matter how the weight distribution and the brake balance are, it should be possible with enough force on the pedal to make ALL wheels lock at any time (this is a typical Test for Formula Student cars). In reality, this is a simple mechanical system. The more you press the brake pedal, the higher the pressure on the brake cylinder and thus on the hydraulics. This pressure is transmitted to the brake pistons via the brake line. There the pressure is then transferred to the brake and its brake pads. The higher the brake pressure, the greater the braking force at the brake disc and the corresponding deceleration. It's a linear system. If the braking force is too high, the wheels lock. There is no limit to the braking force (unless a component breaks). Asked the other way round: What mechanical reason is there that you can't get ALL wheels to lock with enough force on the brake pedal? You are right that it is more difficult to lock the rear axle in a vehicle with a lot of weight on the rear axle. In reality, all I have to do is press the brake pedal a little harder until it blocks. I don't care how much braking force you exactly need for this. The problem is that the rear wheels do not lock at HIGH speed. I have already set 100% in Raceroom. I have also adjusted my pedals so that I can lock the front wheels with approx. 50 kg force on the brake pedal. The pedals work up to 90 kg. That means I could generate almost twice as much braking power. This should also allow the rear wheels to lock at HIGH speed (especially with 70% rear balance). Inertia of the spinning assembly at the rear: - Wheels, tire, brake disc: more or less the same as on the front axle-->no appreciably higher inertia on the rear axle than on the front axle - Drive shaft and gearbox: Small diameter, relatively low speed. At high speed the gear has slightly higher moments of inertia, but due to the low rotating mass --> relatively low moment of inertia. - Motor: Speed dependent. At high speed the engine speed is about as high as at low speed because you shift down (you always try to be in the upper speed range) --> no appreciable difference between low and high speed
Doesnt that video Andy posted above show the rear wheels locking? So, it's certainly possible to get the rears to lock, even if that is unlikely under normal driving for the reasons Alex mentioned above.
I think you need to do some reading (or measuring) on the force needed to operate the V3 pedals. The brake has a loadcell that works up to 90 kg, correct so far... but there is NO WAY you need to push that amount of force to activate the brake pedal at full force. IIRC I measured the force on my (ex) V3's at 17kg (or was it 21kg ?) with the hydraulic damper installed and set to highest resistance. My actual HEUSINKVELD Pro pedal needs up to 55kg and the HE Ultimates that I am waiting for atm need a max of 136 kg. Just saying...
Well, to begin with you can't talk about forces applied to a pedal and expect it to be transferred directly into the brake system in a simulated car in the same way as it would happy in a real braking system. Whether the pedals your racing with need 100N or 25N to register 'full braking' makes no difference to the in-game calculations; when the brakes are fully on all the game sees is a "1". The force required to attain that is irrelevant as it uses the same sliding scale whether it's a keyboard button, mouse scroll or pedal press. The way I work to calculate braking forces in game now is to plot out the complete brake system. Pedal pressure, pedal ratio, master cylinder size, brake caliper piston area, braking radius, braking friction coefficient, etc. Thus braking force is calculated to match a given pedal force and is not a direct result of it. Now as I said, I wasn't involved in the creation of the KTM physics, so I can't comment much on the numbers with just a glance. Peak torque may look a little on the low side to me though. If you're looking to determine if there is a problem in the game physics or not try the Formula RaceRoom Junior, and you'll find all the answers you need.
If I understood that correctly, Raceroom has a maximum braking force (the value 1). Below this value 1 (e.g. at 10% brake pedal pressure) brake pedal pressure behaves exactly linear to braking force (in Raceroom). If the brake pedal pressure is further increased (e.g. 40%), the front wheels lock. If the brake pedal pressure is further increased (e.g. 50%), the rear wheels only lock at low speed. If the brake pedal pressure is then even further increased (e.g. 60%), the rear wheels lock in reality at low and high speed (due to downforce). Since the factor for maximum braking force in Raceroom is limited to 1, that’s the highest it can get. This means that the rear wheels can only lock at low speed but not at high speed (due to downforce). Am I getting this right? Is there a possibility to increase the value 1 to for example 1.1?
My Problem is at HIGH speed! I have now uploaded videos where you can see a braking manoeuvre at HIGH speed. In the range of 100-200 km/h there is clearly no blocking of the rear (and front!) axle with full braking power. Therefor i tried to get in touch with the test driver and beta-tester "Christian Ebner". Maybe I'll get some feedback from him. Video complete vehicle: Video rear left tire: Video front left tire: Setup setting (max. rear brake force; min. downforce): Additional there ist another Problem. When the car is more or less standing still(end of video) ~1 km/h. The Wheels locked, but the car is still moving with ~1 km/h. But this doesn´t matter when your driving on track.
I was looking at this car the other day & I think it has too much downforce, which would explain your problems. Now I know I've seen wind tunnel data for one of these, but I can't find it again..
There is a downforce of about 200 kg at 200 km/h for the X-Bow RR: https://www.ktm.com/fr/x-bow/x-bow-rr/aerodynamics-bodywork With 810 kg vehicle weight + driver+ fuel <= 1000 kg --> The downforce is ~ 20% of the total weight. So the driver can push the brake pedal 20% harder and can decelerate 20% faster (lateral acceleration up to 2 g with slicks) Is there any difference in driving physics between the "normal" Raceroom version and the "Event version" where you dont need any online connection? As i know the event version does not get forced updates, because they need no online connection. One difference is in the eventversion you can shift up without lifting the throttle. In the "normal" version you can´t do that without getting a lose of performance (this update came some weeks ago). I talked with a person who uses the event version on a simulator called "upracer" for the "Super Racer" in germany. It is a competition to get from simulator into a real KTM X-Bow. He told me they can lock the tires (front an rear)! Is there a possibility in the event version to increase the braking force? Or are there generally more setting options in the "event version" than in the "normal" version?