Braking telemetry during F1 broadcasts

[rfs]

This is something that has bugged me every time I see a race or an onboard shot. They often have throttle and brake indicators on the screen, but the brake meter is always either totally full or completely empty. Why is this?

[Jersey Tom]

Throttle is easy to scale, it's known that it will be 0-100%. Brake pressure on the other hand can be... whatever. Easier to do with an on/off switch and display.

[Hangaku]

Throttle is easy to scale, it's known that it will be 0-100%. Brake pressure on the other hand can be... whatever. Easier to do with an on/off switch and display.

I don't understand this vague "explanation" at all.

It's a valid question - the brake is still being applied somewhere between zero and one hundred percent, so why isn't it being shown as this?

[Pandamasque]

I don't understand this either. I'm pretty sure the teams have precise braking pressure data available to them in real time.

[Jersey Tom]

The brakes are not 0 to 100%. What would be 100%?

Brake telemetry is measured in line pressure. Depending on the corner, the driver, the car, the master cylinders... could be in the hundreds or thousands of psi. There's no hard limit like there is on the throttle.

Easier to treat it as on/off.

[andrew]

Does the acceleration not go on the volume?

Braking would be nigh on impossible for the TV broadcasters without tapping into the teams telemetry.

[beelsebob]

Does the acceleration not go on the volume?

Braking would be nigh on impossible for the TV broadcasters without tapping into the teams telemetry.

To be honest, given the inaccuracy of guessing rev based on audio when there's so many other cars about the place, I'd guess they have a (likely limited) feed of team telemetry.

[Mystery Steve]

Throttle is easy to scale, it's known that it will be 0-100%. Brake pressure on the other hand can be... whatever. Easier to do with an on/off switch and display.

I don't understand this vague "explanation" at all.

It's a valid question - the brake is still being applied somewhere between zero and one hundred percent, so why isn't it being shown as this?

Well, something that is 'vague' to one person can be deemed 'concise' by another. To say what JTom said, but in more words:

What is 100% of brake application? The upper threshold is only dependent on how hard you can push the pedal; the measurement is force-based. The throttle, on the other hand, has a clearly defined stopping point; this measurement is position-based.

Hypothetically, you may be able to back out a calculation of the maximum line pressure if you knew what the line pressure would be based on the master cylinder size, the brake pedal mechanical ratio, and the maximum (arbitrary) force that the driver can possibly apply, but that value wouldn't have any intrinsic meaning. If two cars have different master cylinders and brake pedal setups, they could hypothetically generate the same braking force at the tire while requiring different inputs from the two drivers. On the contrary, wide open throttle essentially means the same thing regardless of which car is being driven.

[Hangaku]

Throttle is easy to scale, it's known that it will be 0-100%. Brake pressure on the other hand can be... whatever. Easier to do with an on/off switch and display.

I don't understand this vague "explanation" at all.

It's a valid question - the brake is still being applied somewhere between zero and one hundred percent, so why isn't it being shown as this?

Well, something that is 'vague' to one person can be deemed 'concise' by another. To say what JTom said, but in more words:

What is 100% of brake application? The upper threshold is only dependent on how hard you can push the pedal; the measurement is force-based. The throttle, on the other hand, has a clearly defined stopping point; this measurement is position-based.

Hypothetically, you may be able to back out a calculation of the maximum line pressure if you knew what the line pressure would be based on the master cylinder size, the brake pedal mechanical ratio, and the maximum (arbitrary) force that the driver can possibly apply, but that value wouldn't have any intrinsic meaning. If two cars have different master cylinders and brake pedal setups, they could hypothetically generate the same braking force at the tire while requiring different inputs from the two drivers. On the contrary, wide open throttle essentially means the same thing regardless of which car is being driven.

Sure I understand all of this, but brake pressure for each car has to be measured somehow, if it's with bars of pressure or bars of chocolate it doesn't matter, it's still a certain percentage of the maximum achievable pressure. Sure, that's a variable, but you would expect it to be available to the guys that do the race overlays.

[beelsebob]

the maximum achievable pressure

Such a value doesn't exist, as explained above.

[Hangaku]

the maximum achievable pressure

Such a value doesn't exist, as explained above.

It's not limitless. Don't be silly.

The difference is, different cars will have different values. It doesn't mean they can't be normalized to a percentage.

[beelsebob]

the maximum achievable pressure

Such a value doesn't exist, as explained above.

It's not limitless. Don't be silly.

The difference is, different cars will have different values. It doesn't mean they can't be normalized to a percentage.

It's limited by only the strength of the driver's leg... Given that there's no rule capping how strong a human can be, it is effectively limitless. The only thing you could possibly do is make assumptions about how strong a driver could possibly be, but you're likely to be very wrong. It was recently shown for example that one driver (who shall go unnamed to save flames) was exerting 1.5 times the preasure on the break pedal than his team mate (who shall also go unnamed).

[Richard]

Why not % based on pedal travel? Yes 100% would be notional, drivers might actually push to 110% in some cases, but the graphic would show 100%. However, it would enable us to differentiate between a light dab and pedal to the floor.

[Jersey Tom]

I'd want nothing to do with installing extra BS weight on my car with some linear pot on the brake pedal, purely for the pleasure of a handful of TV viewers.

Beyond that, what if different cars have different pedal travel? One chassis might take 2mm for "max" realistic brake travel at a given circuit, another car might be 4mm. Might be 3mm and 6mm the next race.

Beyond THAT, pedal travel on a proper racing car should, IMO, be VERY short. As short as possible. Would be harder to get consistent measurements based on position rather than force.

Not like a production car where it can just go to the floor and that's that.

[mep]

I'd want nothing to do with installing extra BS weight on my car with some linear pot on the brake pedal, purely for the pleasure of a handful of TV viewers.

One thing you should never forget. Those TV viewers are the only reason you can do what you are doing because that's where the money actually comes from.