Three brands, three trademarks, one idea. Logitech calls it TrueForce. Fanatec calls it FullForce. MOZA calls it Wheel LFE. iRacing, which has to make all of them work in the same sim, calls the category Wheel Low Frequency Effects — WLFE.

They aren't identical implementations, but they solve the same problem. I've had all three running on my rig, and the most useful thing I can tell you is that none of them are force feedback in the sense you already understand. They sit on top of it.

The problem they all solve

Traditional PC force feedback goes through DirectInput. That pipe was designed a long time ago for a very different class of device, and it's slow. Fine for the big stuff — self-aligning torque, weight transfer, the load building through a long corner. Useless for anything fast.

iRacing states the limitation plainly in its 2025 Season 3 release notes. Describing Fanatec's FullForce support, the notes say it "allows you to send tactile vibrations to the wheel like engine vibrations, that would normally be too high of a frequency to send across the normal DirectInput Force Feedback api."

That's the whole thing. Engine harmonics, kerb texture, the flutter of a tyre starting to give up — those live at frequencies the standard pipe can't carry. So each manufacturer built a private channel between the game and the base, running alongside the normal FFB signal rather than replacing it.

Logitech got there first. TrueForce launched with the G923 on 5 August 2020, and Logitech's description hasn't changed much since: two kinds of feedback in sync — kinesthetic (the big forces from weight shifts and cornering) and vibrotactile (high-frequency detail pulled from audio and in-game physics), processed in the wheel 4,000 times a second at 1 ms latency.

Fanatec's version arrived much later and is framed differently. FANATEC describes FullForce as "a new force feedback protocol" built for "the instant response and zero backlash of direct drive systems," fusing high-fidelity vibration cues into the core force feedback signal.

MOZA didn't bother with a marketing name. It adopted iRacing's terminology and calls it Wheel LFE.

The tell: iRacing's config section is called [TrueForce]

Here's the detail that settles the "are these the same thing?" argument better than any spec sheet.

To fine-tune these effects in iRacing by hand you open Documents\iRacing\app.ini and look for the [TrueForce] section. Not [FullForce]. Not [WheelLFE]. iRacing's own notes tell Fanatec owners to tune FullForce there, and MOZA's support article sends MOZA owners to the same section.

iRacing implemented Logitech's concept first, named the config block after it, then routed every subsequent manufacturer through the same plumbing. If you've been searching app.ini for "FullForce" and finding nothing, that's why.

The release notes are explicit about the umbrella too: "FullForce is part of our Wheel Low Frequency Effects (WLFE) and is similar to Logitech's TrueForce system."

This is not the same as 360 Hz FFB

This is the confusion I see most, and it costs people hours of pointless troubleshooting.

360 Hz mode replaces the 60 Hz DirectInput stream with a faster direct feed of the same force feedback signal. WLFE adds a different signal — vibration content — on top. One raises the update rate of forces you already had; the other sends you something you never had.

The proof is in the same 2025 Season 3 notes, where iRacing added four manufacturer APIs at once and gave them different things:

  • Asetek — 360 Hz force feedback. No WLFE mention.
  • VRS — 360 Hz force feedback. No WLFE mention.
  • Fanatec — FullForce haptic effects. No 360 Hz.
  • MOZA — Wheel LFE haptics and 360 Hz mode.

Four vendors, three combinations, one build. If they were the same feature iRacing wouldn't have written them up separately. Note too what Fanatec did not get: Fanatec owners regularly assume they have 360 Hz in iRacing, and by iRacing's own notes they don't. I covered the update-rate half of this story in the iRacing 360Hz FFB mode guide — read that if your complaint is latency or notchiness rather than buzzing.

Which wheels actually have it

Logitech (TRUEFORCE) — G923, PRO Racing Wheel and the RS50 System. Logitech works with developers through a proprietary SDK, so each title implements it differently and the feel genuinely varies game to game. Logitech also makes the fair point that on Xbox, TrueForce's direct connection unlocks things like RPM lights and full button mapping that are otherwise restricted. That's one of the real dividing lines in the entry range — see G29 vs G923 and the G923 review.

Fanatec (FullForce) — direct drive only. It launched on ClubSport DD and ClubSport DD+, is on Podium DD (2026), and was added to CSL DD and Gran Turismo DD Pro through a free firmware update. Fanatec lists iRacing, Gran Turismo 7, Project Motor Racing and Assetto Corsa EVO as supporting titles. Overall strength is set in the Fanatec tuning menu, shown as FUL on most wheel displays.

MOZA (Wheel LFE) — MOZA states that all its bases support 360 Hz and Wheel LFE, with base firmware ≥ 1.2.5.5 and Pit House ≥ 1.3.1.50, both enabled by default. Firmware is handled in the software, which I walk through in the MOZA Pit House settings guide. One caution: MOZA's page dates the change to "iRacing 6.10 updated version." That's MOZA's naming — iRacing versions its builds by date, so don't go looking for a 6.10.

Why your wheel started buzzing

This is why most people arrive at this topic. You updated, you drove, and your base now makes a fine, constant, slightly nasty vibration on the straights. That's almost certainly the engine channel of WLFE, not a fault — MOZA's support FAQ opens with the exact question, why the wheelbase vibrates at high frequency and makes abnormal noises after the iRacing update, and answers it with the 360 Hz and Wheel LFE support.

Fix it in this order:

  1. Use the in-game sliders first. MOZA says the effect can be reduced or disabled directly in the in-game settings interface, and Fanatec publishes per-channel recommendations for the same screen. In current builds those controls sit on iRacing's Force Feedback and Haptics page — see the FFB and Haptics settings page guide if you can't find them.
  2. Turn Engine and Road Texture down before anything else. Both are continuous rather than event-based. Fanatec makes this point itself: because those two channels are always running, they mask everything else.
  3. Only then edit app.ini. The [TrueForce] block gives per-effect dB trims — car body acceleration, drive shaft, engine RPM, gear change, rev limit, road texture, rumble strip, wheel slip.
  4. Don't max everything. Fanatec warns that running all sliders at maximum tends to clip the output and can reduce fidelity. A saturated channel stops carrying information.

If the buzz comes with oscillation or a wheel that won't settle, that's a damping and inertia problem, not a haptics one — start from the iRacing wheel and FFB settings baseline instead.

The defaults are not tuned for your base — and the manufacturers disagree

This is worth publishing rather than smoothing over, because it tells you how seriously to take any "recommended" number you find.

MOZA's support article reproduces iRacing's app.ini defaults: engine RPM −9 dB, gear change +3 dB, rumble strip −3 dB, wheel slip +6 dB, and car body acceleration, drive shaft, rev limit and road texture all at 0 dB.

Fanatec, for the same game and the same sliders, recommends: main volume 0 dB, car body impact 0, engine 0, gear change +10, rev limiter +10, rumble strip +10, wheel slip +10, road texture −25.

Not small differences. Fanatec wants the engine channel nine decibels louder than iRacing's default, road texture twenty-five quieter, every event-based effect at +10. Both sets are official, for the same title.

Neither is wrong, and that's the point — a hard-mounted direct drive base transmitting vibration through an aluminium frame needs a different balance from a wheel clamped to a desk. Start from whichever matches your hardware, then trust your hands.

My honest take

WLFE is simultaneously the most oversold and the most genuinely useful feature in modern sim racing hardware.

Oversold, because it will not make you faster. Nothing in the vibration channel tells you something the main force feedback signal can't, if that signal is set up properly. Nobody ever found half a second in a rumble strip effect.

Useful, because it makes long stints less tiring and easier to read. Rev-limiter feedback through your palms means you're not staring at a shift light, and wheel-slip texture gives an earlier cue that the rears are going than yaw alone does.

What it is not is a reason to replace a wheel base. If you're shopping, the four-brand comparison and the direct drive explainer will serve you better than any haptics feature list. Motor, encoder and mounting decide how a base feels. WLFE decides how it decorates.

FAQ

Are TrueForce, FullForce and Wheel LFE the same thing?

Different implementations, same concept, and iRacing groups all of them under Wheel Low Frequency Effects. Its release notes describe FullForce as "part of our Wheel Low Frequency Effects (WLFE)" and "similar to Logitech's TrueForce system." All three are tuned from the [TrueForce] section of app.ini.

Is Wheel LFE the same as 360 Hz force feedback?

No. 360 Hz raises the update rate of the existing force feedback signal. WLFE adds a separate vibration signal on top. iRacing's 2025 Season 3 build gave Asetek and VRS 360 Hz only, Fanatec FullForce only, and MOZA both — the clearest evidence they're independent features.

Why is my wheel buzzing after an iRacing update?

Almost certainly the engine channel of WLFE, which iRacing enables by default on supported bases. Turn Engine and Road Texture down first in the in-game Force Feedback and Haptics settings.

Does Fanatec have 360 Hz FFB in iRacing?

Not according to iRacing's own release notes. The 2025 Season 3 build gave the Fanatec API FullForce haptics; 360 Hz went to Asetek, VRS and MOZA in that same build. For tuning a Fanatec base, start at Fanatec iRacing FFB settings.

Which Fanatec wheels support FullForce?

Direct drive only: ClubSport DD, ClubSport DD+, Podium DD (2026), plus CSL DD and Gran Turismo DD Pro via a free firmware update. Belt and gear-driven Fanatec wheels don't get it — one of several reasons direct drive costs what it does, which I break down in why direct drive wheels are expensive.

Can I turn it off completely?

Yes. Use the in-game toggle, or disable the manufacturer API in app.ini under [Force Feedback] — loadFanatecAPI=0, loadMozaAPI=0, loadAsetekAPI=0 and loadVRSAPI=0 are the switches iRacing documents. Disabling the API also removes anything else it provides, including 360 Hz mode on bases that have it.