SimHQ.com - Motorsports Zone - Feature: Sim Racing Tips - Getting the Most Out of Your Virtual Racing Hobby

In Part I we discussed how to set up your PC workstation for sim racing. In Part II we'll look at how to tweak your racing wheel, the game's controller options and driving aids for a good session of sim racing.

Controller Calibration & Linearity

Ensure your pedals and wheel are calibrated properly before each driving session. You can do that with the calibration test tool in Windows (Control Panel/Game Controllers/Properties/Test), or with the calibration check tool in the games. There's no guarantee that your wheel and pedals will be properly calibrated for a race session. And without the proper calibration, any cal problems could be masked, making you think you're just having a bad day. No sense in needlessly adding frustration to your hobby, so always calibrate before you race, and verify that calibration's accuracy before taking to the track.

Sometimes the controller may have a built-in calibration problem in the software or hardware. Back in 2003, Logitech MOMO Racing FF owners were having all sorts of problems with mis-calibration of their accelerator pedals, which resulted in full throttle input giving as little as 80% throttle in-game. Many at the time thought the problem was bad potentiometers (RSC's "is it a lemon?" forum thread) and many a MOMO was returned under warranty for replacement, only to have the problem return in the replacement item. Others dared to void their warranty, crack open their pedals and manually clean the pots, often only to do permanent harm to them.

After only a few months of regular but gentle use, I too started having accelerator calibration problems. The throttle would work fine for the first half hour of driving, and then my lap times would substantially slow. A recheck of throttle calibration showed I was getting less than full throttle response with full throttle input. I did some troubleshooting on my rig, and some research online, as well as contacting Logitech. I didn't believe it was an issue of bad pots because of the way the problem manifested itself. Suspecting something more, in the short term I simply elected to "short calibrate" my pedals in Papyrus game controller GUI (telling the game that 80% pedal travel = 100% in-game throttle) while I awaited an 'official' cure from Logitech.

As it turned out, the problem was one of the auto-calibration software in the Wingman GUI, not hardware. A simple beta fix from the Logitech Wingman Team, when applied to the Wingman controller software was all that was needed to address the problem, and provide a permanent fix.

Controller Rates

One of our members also had a problem with his ACT Labs pedals. Over time, he saw his racing performance slowly deteriorate. Was he getting "un-good" at racing? : No, but his pedal springs were going bad, causing bad inputs as he drove. As he puts it:

"When I first started sim racing, right away I went out and order some Act-Labs pedals. They seemed fine at first, but as I kept getting more seat time I notice that I could never quite get the same max speeds I was seeing with the replays and telemetry files I studied.

"I always (seemed to have) problems with my accelerator — at 100% throttle input the calibration indicator would flutter. I could dial the flutter out but it was a sign of something deeper. My brake pedal was the opposite: it would mysteriously register a 10% in-game input with no physical input by me. When I blipped the pedal the brake pressure would go down to zero, but sometimes when I checked the calibration indicator I would see a touch of red (so, this driver was "dragging the brake" without even knowing it).

"When the PCC mod (for rFactor) came out (a friend of mine and I) decided we were going to focus on one mod and one track to get to the same level as the AI at 100%. To make a long story short, I opened my Act-Lab pedals and found out that both the brake and accelerator springs attached to the potentiometer were soft. Nothing I could do then and there would resolve the problem. So, I pulled out my cheap pedals (I have a Logitech Driving Force Pro now) and wow I can really push hard — except I now have to unlearn my "muscle memory" as I can now brake later and steer far better with the accelerator, feathering the gas around corners".

So the moral to these two tales is to always check the calibration and response of your controller before you race, and perhaps even after a driving session. If you start to see problems, investigate them thoroughly and work with the manufacturer's tech support staff on possible remedies. Don't be surprised if they don't know what to do at first — you might be the first one to report the problem. And always do your research and troubleshooting before working on a solution. The "obvious" answer isn't always the right one.

With modern race sims and race controllers, there's more to good controller input and response than just calibrating. There's also the question of axis linearity, also referred to as "digital steering rate" in ISI sims. Since the total rotation angle on FF racing wheels and throw of the pedals varies by product, and sim drivers have varied tastes, there are an infinite number of "optimum" linearity settings for wheels and pedals. Therefore, most hard core racing sims offer the ability to adjust the linearity or response curve of their controllers. The same is true of flight simulations and joystick axis sensitivity.

In basic terms, linearity refers to how a given angular input to the racing wheel produces an angular response to the virtual steering system in the game. A totally linear wheel setup will result in a 1 for 1 matching of angles — i.e., turn the FF wheel 5 degrees and get a 5 degree response on the virtual wheel in the 'car'. As you raise the linearity setting, angular changes in the virtual car will lag behind what's being done to the wheel — at first. But as the angle of the FF wheel increases, the virtual steering system responds with ever-increasing inputs until, at the steering lock, both angles again match. Increased linearity can improve straight line stability as you make minor corrections to your racing line, but as you enter corners the results can be counterintuitive, with the car suddenly starting to overturn in a corner, or spin out even though you only moved the wheel a fraction of an inch in the turn. That's because while a minor movement off top-dead-center on the wheel might make for a 1 degrees steering input in the game, as you approach the steering lock a minor movement of the wheel might cause a 7 degree change in the steering input in-game.

So, you might think that the answer is to set all games' linearity settings to 100% or total linearity, right? Well, not really. The real answer is "it depends." It depends on the game, and your tastes. I always suggest that you start with the default level of linearity in a game/wheel combo, and try it out. If things aren't working for you, try a different setting until you find one that works for you. But keep in mind that over time, your tastes and driving style may change. As an example, when I first entered into the sim racing hobby with GPL, I had a Saitek R100 wheel. Cheap and simple, I liked how it reacted — especially for $29. But in GPL I needed to severely scale back the linearity on that wheel to get the proper response from the cars. Three years later I purchased a Logitech MOMO Racing FF, and found that that wheel needed almost 100% linearity to drive GPL properly. My style hadn't changed, but the wheel's input to the game had. And while 100% linearity worked for me in GPL and NR2003, it doesn't work for me in GTR or rFactor. There I need just a touch of nonlinear response to get the right 'feel' for my tastes.

Controller Linearity in NASCAR Racing 2003 Season

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