FFB clipping: causes, detection, and prevention

Clipping is when the sim demands more force than your wheelbase can output, so the peaks get flattened to the wheel’s maximum. Once a force maxes out, every stronger force on top of it reads as the same heavy, constant pull. You lose the detail that lived in those peaks: the front washing into understeer, weight transfer through a corner, kerb texture, all of it merges into one numb block. The fix is a single setting rule: set base strength to 100% and lower the in-game gain, not the other way around.

What clipping actually is

Your wheelbase has a signal ceiling. On an 8Nm base that ceiling is 8Nm; on a 15Nm base it’s 15Nm. The sim continuously calculates a force and asks the base to reproduce it. When that calculated force exceeds the ceiling, the base can’t go higher, so the waveform’s peaks square off at the top. Everything above the line collapses into one value.

The audio analogy is exact: it’s like maxing an amp into a speaker that’s too small. The peaks distort and you hear mush instead of dynamics. A photography version works too. A weak wheel is a low-dynamic-range camera; crank the exposure (gain) and you blow out the highlights. The information in those highlights is gone, not just loud.

What clipping feels like

Heavy but dead. The wheel feels strong and effortful, yet you stop getting information out of it. The classic tell is mid-corner: you load the front, the tires start to let go, and the wheel should lighten to tell you. Instead it stays pinned at full force, so you can’t feel the front let go and you carry too much speed into the understeer. Kerbs and bumps that should spike above the cornering load instead feel the same as the load. If you got your first rig and the FFB feels powerful but vague, that vagueness is usually clipping.

How to detect it in each sim

There’s no universal gain number that’s safe. Each sim measures and exposes clipping differently, and the same setting that’s clean in one car will clip in another.

iRacing

Turn on the built-in Force Meter: Options > Interface > On-Screen Displays > System Meters, enable the steering force bar. The bar tracks demanded wheel force and rises with speed, steering angle, and bumps. Green is fine; when the bar hits full and goes orange, you’re clipping. The cleanest tool is the auto Strength button, documented in iRacing’s Controller Setup and Calibration guide: drive a few laps so the sim gathers force data, then hit auto in the garage. It sets Strength to the highest value that does not clip. Set Strength above that and you reintroduce clipping. Also set wheel force (added in the December 2018 build) to your wheel’s true max torque, e.g. 25Nm for a Simucube 2 Pro, so the slider can’t oversaturate the base and auto won’t overload a weaker one.

ACC

The pedal/input bars are bottom-right. Under the throttle (green) and brake (red) bars is a grey FF bar, which is FFB output. When that grey bar fills completely, you’re clipping. The goal is that it should not fill from normal cornering alone, only momentarily on big kerbs or bumps. For automatic control, the FFBClip app adjusts gain live so output never exceeds what the wheel can produce. On strong bases in AC and ACC, around 50% gain is often the practical clip-free ceiling.

AMS2 / Automobilista

There’s no clean built-in clipping bar by default. The community reads clipping through SimHub dash gauges. Note that the clipping formula differs per sim, so an rFactor 2 SimHub bar won’t map correctly to AMS2. Gain usually lives in the 80–100 range to drive weaker bases hard, so watch the bar carefully there.

rFactor 2 / LMU

The in-game FFB telemetry bar flashes red when output clips. rFactor 2 also exposes FFB output to SimHub if you want a dedicated gauge.

The one setting rule that fixes it

Set wheelbase strength to 100% (or to the wheel’s true Nm via iRacing’s wheel force), then lower the in-game gain until the peaks stop clipping.

This order matters. Wheelbase strength at 100% with in-game gain capped gives you the maximum torque the base can deliver without clipping, while preserving headroom for spikes. The reverse — base at 50%, in-game gain at 100% — still clips, because the in-game signal is already saturated before the base ever scales it down. It also runs the base hot: at 100% in-game gain you’re almost always asking for full torque, so a Moza R9 will heat up and start dropping force to protect itself. Run the software at 100% and in-game at roughly 65–80%, and both the clipping and the overheating go away.

Does more Nm fix clipping?

More torque buys headroom, not immunity. A 15Nm base can be set to clip exactly like a 5Nm one. What more Nm gives you is dynamic range: you can keep all the detail at a force level that still feels strong, instead of choosing between weak FFB and clipping. On a weak base that choice is real — turn it up and it clips, turn it down and the whole signal goes faint.

The numbers people land on: around 15Nm is a common sweet spot for strong feel plus clip-free headroom. 8Nm is plenty to make your arms sore, but it clips sooner in high-load situations: formula cars, fast corners, and big kerb strikes. So “is 12Nm enough for formula cars at Spa?” depends on the car and track — 12Nm will be cleaner than 8Nm there, but you still tune per car. The same gain that’s clean in a GT3 will clip in a heavy formula car.

A clip-free starting point

1. Set base/driver strength to 100%, or set iRacing wheel force to your wheel’s max Nm.
2. Turn on the clipping meter for your sim (Force Meter, ACC FF bar, SimHub gauge).
3. Drive a representative lap in the car you’ll race.
4. Watch the meter through the heaviest corner and over the biggest kerb.
5. Lower in-game gain until the peaks stop pinning at full during normal cornering.
6. Leave a little headroom so only the biggest kerbs spike to the top.

Then repeat per car and per track. Tune it once globally and you’ll either clip in the heavy cars or run weak in the light ones. See FFB strength and gain for base-by-base starting values, per-base tuning for the actual Fanatec, Moza, and Simagic settings tables, and pedals if you’re chasing consistency on the brake side too.