How Wheelbase Force Feedback Is Tuned: Kerbs, Road Feel and Steering Weight

Force feedback is tuned at three stages: the simulation decides which forces reach the steering, the wheelbase decides how quickly and how faithfully its motor reproduces them, and your settings rebalance the result. Steering weight, kerbs and road feel reach your hands mixed into one torque at the rim, and differ mainly in how fast they change. Steering weight builds and fades over fractions of a second, a kerb arrives as a sharp jolt or a rapid run of ridges, and road feel is fine, fast texture. Tuning means letting each through at a strength you can read, without one hiding another.

Where Do Kerbs, Road Feel and Steering Weight Come From?

A physics-based simulation computes the torque at the steering from its tyre and suspension model. It recalculates the forces on the front wheels many times a second and turns them, through the virtual steering rack, into a torque request.

Steering weight comes from the front tyres pushing back through the steering: their self-aligning torque, plus extra leverage from the caster angle. How that weight reports the grip limit is covered in Self-Aligning Torque Explained: How Force Feedback Tells You the Grip Limit.

Road feel comes from the modelled track surface acting through the tyres and suspension, plus the vibration of a sliding tyre. Some simulations build their tracks from laser scans, so cracks, patches and undulations in the asphalt exist as geometry the tyre model rolls over.

A kerb strike comes from the tyre climbing the kerb's modelled profile. The sudden change in the forces on that tyre spikes the steering torque, followed by rhythmic pulses if the kerb is serrated. Because the kerb's modelled shape drives the force, changing that shape changes the feel. In 2025, iRacing softened the profile of its rumble strips to reduce the audible noise they produced through its force feedback.

On top of that physics torque, some simulations add optional cues: a kerb effect that fires even on flat kerbs; road, slip or understeer effects; engine and ABS vibration. The physics torque and most added cues reach the wheelbase mixed into one torque signal, alongside effects such as spring and damping that react to the wheel's own movement.

Some simulations also send a separate vibration channel. iRacing's Wheel LFE, supported on every MOZA wheelbase, plays effects such as rumble strips, road texture and wheel slip through the wheelbase motor. Some wheelbases, such as the MOZA R16 Ultra, add a layer of their own from the game's telemetry: gear-shift, engine and ABS vibrations for supported titles.

How Do Kerbs, Road Feel and Steering Weight Differ at the Wheel?

The clearest way to tell them apart is how fast they change, measured in hertz (Hz), the number of back-and-forth cycles per second. Slow changes are low frequencies, rapid ones high frequencies.

Steering weight is slow. Through a long, fast corner it builds at turn-in, then holds. Even sawing at the wheel, a driver manages only about four or five back-and-forth movements a second. In a University of Limerick lab study of one sim wheel, force feedback and steering moved the wheel mostly below 5 Hz, while its added vibration layer moved it mainly at 25 to 30 Hz.

Road texture is much faster. In real cars, steering-wheel vibration can reach up to 300 Hz over some surfaces. Telling one surface from another by touch alone needs vibration above roughly 40 to 60 Hz.

Kerbs have no fixed frequency. The faster you cross the ridges and the closer they are, the higher the buzz, since its frequency is the number of ridges hit per second. A serrated exit kerb clipped slowly out of a hairpin gives separate thumps; crossed flat out through a fast chicane, it becomes a continuous buzz.

Your hands read slow and fast changes differently: slow forces as resistance you push against, fast ones as vibration in the skin. Small changes also slip past. Depending on how fast and how strong a vibration already is, its strength has to change by 20 to 58 percent before you notice. A small nudge to a vibration setting can therefore go unfelt.

How often the game sends its force matters too. A game that updates its force feedback 60 times a second can carry nothing faster than 30 Hz, half its update rate. iRacing's 360 Hz mode, also supported across MOZA's wheelbases, packs more torque values into each update, letting faster detail through.

How Is a Wheelbase's Response Tuned?

Inside the wheelbase, the electronics and a control algorithm turn the game's request into torque at the shaft. Engineers check that response in two ways. First, how it handles a sudden hit such as a kerb: how quickly the force arrives, whether it overshoots and wobbles before settling, and whether the same kerb gives the same force every lap. Second, how faithfully it passes on everything from slow steering weight to fast texture. To check, engineers feed the base test signals from slow to fast and measure how much of each gets through, and how late (gain and phase, in engineering terms).

The filters that clean up the signal cannot do both jobs perfectly, so tuning is a compromise, and smoothing shows what that compromise costs. Smoothing removes harshness and noise, but it adds delay and rounds off sharp edges, so the jolt of a tall kerb becomes a soft push. In iRacing, more smoothing even makes the wheel more likely to oscillate, because the delay it adds makes the force lag behind the wheel's movement. Interpolation is a different kind of smoothing. It fills in between successive torque values to remove the steps from one update to the next, as MOZA's Force Feedback Interpolation does.

The approach behind NexGen Force U1 (the MOZA R16 Ultra's force feedback algorithm) is to measure how the base handles sudden hits and changes from slow to fast, then shape that response and filter out unwanted, irregular vibration. The algorithm is tuned so self-aligning torque stays smooth and consistent, road-surface detail feels fine and distinct without clutter, and kerbs land as clearly defined impacts of more consistent strength. Professional circuit, rally and esports drivers fed into that tuning across several racing titles.

What Do Force Feedback Settings Change?

Strength and Clipping

Overall strength scales the game's whole force feedback signal at once and cannot raise the wheelbase's maximum. When the requested torque passes the top of the range, in the simulation's output or at the wheelbase, the peaks are cut off: that is clipping. Under a heavy load in a fast corner, the road texture riding on that load goes flat. Lower the strength where the clipping happens, or earlier in the chain, because turning the wheelbase down cannot undo clipping that has already happened in the game's output. How much torque headroom it takes to stay clear of clipping is covered in Peak vs Sustained Torque: What Direct Drive Wheelbase Ratings Actually Mean. As a starting point on a MOZA wheelbase, keep the base's force feedback strength at 100 percent and, in games that use a percentage, lower the in-game force feedback to around 80 percent to help prevent clipping. That advice is about where to cut, not how heavy the wheel should feel.

Nor does more force automatically make you faster. A 2026 study by the same University of Limerick team found that 59 experienced sim racers lapped faster with mid-intensity force feedback than with high intensity or none. The wheel's added vibration brought no lap-time benefit, even though the racers preferred having it.

Response Curve

A response curve maps the game's output to the wheelbase's output; in MOZA Pit House, it is the Base FFB Curve. A linear curve passes the game's forces through in proportion and is the usual reference on a direct drive wheelbase. A non-linear curve favours one part of the range over another. Lifting small forces makes faint detail easier to feel but squeezes the strongest forces closer together, while easing them does the opposite.

Damping, Friction and Inertia

Left to itself, a direct drive wheel can oscillate when you loosen your grip, or feel light and twitchy. Damping resists how fast the wheel turns, inertia resists changes in that speed, and friction resists the movement itself. All three react to how the wheel moves, not to what the tyres are doing. Damping and friction calm oscillation. Inertia imitates the mass of a steering column, and friction also imitates the drag of a rack without power steering. Too much of any of them makes the wheel heavy and lifeless and blunts fast detail.

In Pit House, they appear as Natural Damping, Natural Friction and Natural Inertia. Games can send spring, damping, friction and inertia effects of their own, and MOZA's game force feedback decoupling lets you adjust those separately from the rest of the game's signal. Speed-dependent Damping raises damping as the car's speed rises and lowers it as speed falls: more stability at high speed, more agility at low speed.

Equalizer

An equalizer raises or lowers frequency bands like a sound equalizer. Low bands carry steering weight and load transfer, while higher bands carry texture and, depending on speed, kerbs. Where each band starts and ends varies between simulations and wheelbases. Raising every band equally comes close to raising overall strength, and an equalizer can only reshape what the simulation sends. The frequency scale of MOZA's FFB Effect Equalizer carries kerb markers for 80, 160 and 240 km/h, in rising order: the faster the crossing, the higher the frequency. If a kerb buzz is too fast for the game's force feedback updates, a higher-rate mode, such as the 360 Hz mode, or a separate vibration channel, such as Wheel LFE, can still bring it to the rim.

Presets make a quicker start than a flat equalizer. With NexGen Force U1, three road-feel intensity presets run from a softer feel with more controlled vibration to a sharper, more direct one, and you can fine-tune each one frequency by frequency, on an equalizer with more adjustable points. Choosing a preset locks nothing. Friction, damping, inertia and the equalizer stay adjustable, and U1 widens the friction and damping ranges.

How Should You Tune Your Own Force Feedback?

Work in this order:

• Start from a known baseline: either a preset, or a linear curve with a flat equalizer and little in-game smoothing.

• Match the rotation of the wheel to the car's steering, or let the simulation set it, since a mismatch changes the steering ratio and so the weight you feel.

• Set the strength so your heaviest corner stays below clipping.

• Shape the weight next with the curve, then kerbs and texture on the equalizer, and re-check clipping, since boosted bands add to the peaks.

• Add damping in small steps, only until oscillation stops.

• Change one setting at a time, in steps big enough to feel, on the same car and corner.

• Keep a profile for each car or simulation.

Information, Not Force

Steering weight, kerbs and road feel are three layers of one signal, from slow load to sharp edges and fine texture. The aim is information, not force. When the balance is right, the hardware fades into the background: the wheel is heavy enough to lean on, calm on a straight, and sharp enough to let you read the kerbs.