Arma Reforger Dev Report #24 — Powertrain Rewrite, Full Racing Wheel Support & The Rally DLC

Arma Reforger's Dev Report #24, published on September 22, 2026, is almost entirely about vehicles — and the headline is that the entire powertrain simulation has been rewritten from scratch for Update 1.9. Steering, suspension, differentials, clutch, engine behaviour, force feedback and even the dust on your paintwork are all part of the story.

If you drive, race or run milsim convoys in Reforger, this is the dev report to read.

The full report comes from Bohemia Interactive — read Dev Report #24 on the Arma Reforger site.

📋 Where Development Stands

• 1.8 shipped across all platforms, and work continued on community feedback and the systems 1.8 introduced or changed.
• 1.8.0.13 followed with stability, gameplay, vehicle and modding fixes — including Far Hide, helicopter damage, vehicle behaviour, server performance, and several crashes and scripting issues.
• 1.9 is on Experimental, with further fixes to AI visibility through vegetation, plus ongoing work on stability, replication, server browser usability, Conflict balancing and supply handling.
• Experimental is being used to iterate quickly on larger changes, particularly vehicle handling and input controls.

⚙️ Powertrain Simulation, Rewritten From Scratch

All powertrain components — engine, clutch, differential and wheels — have been resimulated from scratch, while keeping backward compatibility with the previous implementation.

The reason is a bug that drivers will recognise: incorrect torque flow from wheels to engine made the engine RPM shoot to redline — a weak zone on most diesel engines — so trucks in particular became painfully slow on hills or couldn't move at all. Bohemia had patched around it in 1.7 and 1.8 by expanding the engine power zone on the M923A1 and Ural, which then made them too powerful on flat ground. The rewrite fixes the underlying problems: incorrect torque flow, slipping parts, and torque appearing out of nowhere.

Two more powertrain changes:

• The Pacejka tire model can now be tuned per vehicle, giving each vehicle its own tire friction behaviour — and a tire can behave differently on-road versus off-road.
• Inter-axle differentials (IADs) replace the old "torque share" split. Previously a three-axle truck with one axle in the air wasted 33% of its torque and often couldn't move; IADs distribute torque based on traction instead, which makes trucks and APCs notably stronger on uneven ground.

🛞 Wheels, Steering & Suspension

• Wheel, steering and suspension axes can be defined independently. Until now the wheel axis was always perpendicular and the three axes were identical; separating them allows proper simulation of Caster, Camber, Toe and SAI, plus steering torque feedback that wasn't possible before. One visible side effect: steering a stationary vehicle can dip one side up or down — wheel jacking.
• Ackermann steering is now simulated. The outer wheel turns less than the inner wheel, which removes the excessive friction that used to slow vehicles dramatically through corners.
• Driverless vehicles now steer themselves. With steering torque simulated, vehicles without a driver (or with an unconscious or dead one) will steer as they move — a car on a slope steers into the slope. Bohemia's own advice: always engage the handbrake before leaving the vehicle.
• ABS braking is supported — not used by vanilla vehicles yet, but available to modders.

🔧 Clutch & Engine

• The clutch is simulated properly now. Under the old system it was almost always slipping and only served to disconnect the engine. It can now transfer torque to and from the engine and stall the engine — so in manual cars, leaving the vehicle without putting it in neutral (on Partial/None driving assistance) will stall it, with a small jolt.
• The engine is simulated while stalled or off. Previously a powered-down vehicle could roll freely in gear with no resistance; now engine compression slows it significantly, so a car left in 1st or Reverse without the handbrake may not move at all — or only very slowly.

🎨 Visual Effects

• Dust and mud accumulate based on environment, and vehicles can be cleaned by rain or by wading through water. Drive through water, then onto dusty terrain, and you'll get muddy instead.
• Skid marks are supported for slipping vehicles — plus "static" skid marks without slipping on dirty or muddy ground. Not enabled for every vehicle for performance reasons, but scenario designers and modders can turn it on.
• Tire smoke and burnout: when tires slip fast enough to get hot from friction, they start to smoke.

🎮 Input & Controls

• Full racing wheel, pedal and shifter support, including clutch, with realistic force feedback taken from the simulation itself rather than vendor-specific effects. FFB is currently driven by steering torque, clutch slip, gear grind, engine vibration and suspension vibration.
• Shifter behaviour follows the Driving Assistance Mode: Full means shifters do nothing; Partial drives everything like an automatic (R/N/D only); None lets manual-transmission cars use the stick fully. To use the clutch you need None assistance, the Manual clutch gameplay option, and a bound clutch action — and the car itself must have a manual transmission. Release the clutch badly and you'll feel a strong gear-grind through the wheel.
• Mouse steering gives mouse-and-keyboard players an analog option, with tweakable steering speed.
• Unified steering speed across devices. Analog controls used to steer instantly, which gave controller users an unfair edge and could flip vehicles at speed. Every vehicle now has its own maximum steering speed based on physical characteristics, and releasing the controls no longer snaps the wheel back instantly — it uses natural centering to avoid sudden wheel slip.
• Faster reverse-to-drive shifting: holding the Gear Shift Up key (E / left stick up) selects 1st gear (manual, None assistance) or Drive (automatic or Partial assistance); holding Shift Down selects Reverse. Keys are rebindable under Game options → Controls → Vehicle.

🏁 The Rally DLC

Bohemia also revealed the upcoming Arma Reforger Rally DLC, which fits naturally alongside all this vehicle work. The reveal took place during Rally Point Praha with community members and creators in the Czech Republic. The DLC is available to wishlist on Steam and on Xbox.

🖥️ What This Means For Your Server

• 1.9 will change how vehicles drive on your server — expect the shift. A convoy or motorpool-focused community will feel the powertrain, Ackermann steering and steering-speed changes immediately. It's a large improvement, but it is a different feel, and worth announcing rather than letting drivers assume something is broken.
• Driverless vehicles becoming self-steering is a real admin consideration. Rollaway vehicles that now steer into slopes are a genuine hazard around bases and airfields. If your server has rules about parking, this is the moment to enforce the handbrake habit.
• Mods that touch vehicle scripts will need a pass. Combined with the 1.9 modding changes (see below), vehicle-related mods are the highest-risk category on this update. Test them on Experimental before your next campaign night.
• Plan your 1.9 update window now. While 1.9 sits on Experimental, keep your live server on the stable build; once it releases, schedule the update with a backup so a mid-campaign surprise is recoverable.
• Racing wheel support makes racing nights more viable. With proper FFB, pedals and clutch on top of the Rally DLC, communities that run driving events have a much more credible setup than keyboard-only — a nice community event format if your server is looking for one.

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Conclusion

Dev Report #24 is the most vehicle-focused update Reforger has had: a ground-up powertrain rewrite that finally fixes the truck torque bug, per-vehicle Pacejka tire tuning with on-road/off-road behaviour, independent wheel/steering/suspension axes enabling caster, camber, toe and SAI plus steering torque feedback, Ackermann steering, self-steering driverless vehicles, inter-axle differentials, a properly simulated clutch that can stall and an engine that resists movement when off, plus dust, mud, skid marks and tire smoke. On top of that: full racing wheel and force feedback support, mouse steering, unified steering speed, and the upcoming Rally DLC.

Read the complete report from Bohemia: Dev Report #24.