Using Threshold Braking to Gain Important Lap Time with mBooster

At a recent race event at Brands Hatch, I watched as two identical GT cars approached the tight 180-degree corner at turn 2. The first car locked up, running out wide and losing position. The second? A perfectly timed brake with a controlled, decisive move to win the apex and exit the corner ahead.

In sim racing, your brake calibration means everything. Getting extra hints, like enough pedal feel to know that your tyres are using all of their available grip, is a phenomenon usually only reserved for real-world drivers.

Image: GT World Challenge

If you’ve ever wondered why you can’t quite match the pace of those alien-fast drivers despite having similar hardware, the answer might be hiding in plain sight: your brake pedal settings.

While many sim racers obsess over steering settings and force feedback, braking remains the most misunderstood and improperly configured aspect of most setups.

Today, we’re going to take a look at one of mBooster’s most useful settings, the Threshold setting. In short, you can set “Threshold” to peak at a point just before your tyres are going to lock. This gives you a haptic signal to tell you you’re at the maximum available grip level your tyres can provide. This maximises braking efficiency and gives you the extra feedback you need to make sure you’re not leaving any lap time on the table.

mBooster’s effects settings in Pit House

What is Threshold Braking?

Before diving into calibration techniques, let’s understand what we’re trying to achieve: maximum braking efficiency at the threshold.

The “Threshold” occurs at the point where your tyres are delivering maximum deceleration without locking. In this state, the tyres are slightly “under-rotating” – turning slower than they would if they were freely rolling, but not fully locked. This subtle state is where maximum braking performance lives.

Image: thesportsrush

In a real car, drivers develop sensitivity to this threshold through physical cues:

• Weight transfer sensation through the seat
• Vibrations through the brake pedal
• Steering wheel feedback changes
• Auditory cues (noise!) from the tyres

In sim racing, we’re working with a significant handicap – many of these sensations are reduced or absent altogether. This becomes especially problematic in closed-cockpit cars where visual cues are limited.

Why Default Pedal Settings Make Threshold Braking Nearly Impossible

A load cell brake pedal measures force rather than position – theoretically perfect for threshold braking. Yet most sim racers with high-end pedals still struggle with consistent braking. Why?

The answer lies in a fundamental calibration problem: By default, your maximum physical pressure on the pedal (100% force) maps directly to 100% brake force in the sim.

This means you must consistently find and maintain the exact pressure point (let’s say 80% of your maximum push) that brings the front tyres to the threshold. The margin for error is tiny – press just 2% harder and you’re probably going to lock up your tyres.

As James Baldwin, professional esports driver and Le Mans winner noted: “The biggest mistake I see even in professional sim racers is running default brake calibration. It’s like trying to walk a tightrope with no safety net.”

Moza CRP 2 Pedals (source)

The Solution: Strategic Brake Force Capping

The previous best practice solution was to cap your maximum brake output in your configuration software so that 100% of your physical pedal travel produces less than 100% brake force in-game.

For example, if you calibrate your system so that maximum pedal pressure only registers as 80% in-game, you’ve now created a buffer zone. You can push your brake pedal to its physical limit without overshooting the threshold braking point.

The trick is to cap the maximum brake pressure setting at the point just before your tyres would normally lock.

Setting a brake threshold yields a few important benefits:

1. Consistency: You can hit maximum braking with confidence, knowing you won’t lock up

2. Control: The effective range for modulation becomes wider

3. Confidence: Braking later becomes far less risky

Image source: Reddit

Threshold braking with mBooster

Now we understand what threshold braking is, we can look at how this applies to mBooster.

Image: simracingcockpit.gg

Rather than setting a notional “maximum” force setting in Pit House, you can continue with your usual force settings and use the Threshold settings instead:

Brake threshold settings highlighted

“Trigger input level” is the key setting here. Put simply, it is set to trigger a haptic vibration based on pedal pressure. As you can see in my screenshot, it triggers at 58%, which is precisely where my F4 tyres begin to under-rotate under braking.

So, at 58% of brake pressure, I experience a vibration. This tells me I’m at the limit of useful brake pressure – essentially telling me I have maximum braking applied.

Naturally, all cars (and many tracks) are different, so it makes sense to make a setup for each of your favourite cars, and possibly tracks, depending on how advanced you are. 

How to set the Threshold in Pit House

The best method to set the threshold (for me) is as follows.

1. Run a test session in your car at the circuit you plan to race
2. Do a few laps on medium fuel to get your tyres warm and your brake points set
3. At a brake critical part of the track (a big stop for a hairpin, for example) use enough brake pressure to slightly lock your front tyres (you can see this easily in an open cockpit or for a GT car you’ll need to listen to the tyre noise)
4. Remember your brake position. I hold my foot at the point where the tyres locked, switch to Pit House and set the threshold to match the % brake pressure that you’re holding with your brake leg
5. Return to the track, do a few laps with this setting and decide if it needs another change

Image: The Sim Racing Den

Once you’re familiar with the process of setting the threshold, you’ll need to turn some laps to fully acclimatise to the meaning of this information. I find there’s enough scope to modulate the brake pressure inside the threshold depending on factors like brake pressure, conditions, fuel load and so on. 

The key thing that the threshold gives you is quick access to the approximate maximum brake pressure, so that you rely less on pure muscle memory alone. Ultimately, a real-world brake system will have a very particular feel under braking, and now you have the same information.

Happy racing!