F1technical.net

izzy wrote: ↑

19 Jun 2019, 23:48

bigger discs would improve braking control by needing less force, i saw 175kg quoted recently for current F1 pedal force! When you're near maximum effort it's harder to modulate muscle contraction, and of course that's exactly what they have to do as the downforce fades away with the car slowing.

That'll be another driver differentiator gone then. Some drivers excel on the brakes - Hamilton and Ricciardo to name but two - and making it easier just moves driver skill toward the average. That way leads to even more boring racing.

I don't know enough to make an educated guess, so I'll make some uneducated observations.
I never knew anything about drivers needing 175kg of force to brake, but if they do, perhaps the added weight of bigger discs wouldn't make up for the reduced braking force needed. At the rear, for example, they just use brake by wire, and though I'm not sure if they use it for the front, I would guess that if they wanted a lighter pedal they would've made it long ago already.

But let's say they're limited by the size of the discs and bigger wheels would allow for a lighter pedal. I don't see why that would reduce the skill factor. From my simracing experience braking is much more about feel than it is about force, maybe if all of this is true and they get lighter pedals that can even increase the skill factor.

But like I said, I don't know about any of this, so this is all guessing.

Pretty sure pedal pressure is entirely driver preference. I read an article a while back from Brembo where an engineer was discussing how each driver had their own master cylinder setup to give the feel they wanted. Some drivers had less than 100kg of force, some much more.

I don't know if it's still the case, but F1 braking performance used to be pedal force limited in the first part of the braking zone due to dimensional limits on the braking components in the rules. This meant that at high speed with lots of downforce, the drivers could not lock the wheels because the braking system was under dimensioned.

Just_a_fan wrote: ↑

20 Jun 2019, 00:50

That'll be another driver differentiator gone then. Some drivers excel on the brakes - Hamilton and Ricciardo to name but two - and making it easier just moves driver skill toward the average. That way leads to even more boring racing.

Yes but is leg strength a good differentiator? Do we want beefy guys like Lance to have an advantage over small guys like Ant or Fernando? Women generally have only about 60% of make leg strength, so if there's ever going to be a woman in F1 that means basically Serena! Is that what you want? Be honest

i mean they have power steering, and the only reason they don't have power brakes is the anti-locking thing. So if they can take the pure strength more out of the equation i think they ought to, personally

Maritimer wrote: ↑

20 Jun 2019, 02:20

Pretty sure pedal pressure is entirely driver preference. I read an article a while back from Brembo where an engineer was discussing how each driver had their own master cylinder setup to give the feel they wanted. Some drivers had less than 100kg of force, some much more.

I searched on this and Brembo do an article on each circuit and for China this year they're now saying 284kg on the pedal! They just give one figure for all the cars so i don't think it can vary that much. Also it's about double what it used to be in 2016 (132kg). Of course it'll be with the leg nearly straight and with the g of the car helping, but Martin Brundle last year said that trying the Mercedes he couldn't apply enough force to the pedal.

Tim.Wright wrote: ↑

20 Jun 2019, 10:31

I don't know if it's still the case, but F1 braking performance used to be pedal force limited in the first part of the braking zone due to dimensional limits on the braking components in the rules. This meant that at high speed with lots of downforce, the drivers could not lock the wheels because the braking system was under dimensioned.

Yes this is my understanding too. The pads need running clearance from the discs and they compress a tiny bit, everything stretches a tiny bit with the huge pressures like 12+ bar and so there's a limit how big you can make the ratio between the master cylinder and the calipers and that initial braking with like 5 tonnes of downforce it's almost impossible to lock them, with the skinny 11" discs

How much of that +280kg of brake force is generated by G-forces of braking itself?

280 kg is quite impossible with one leg, lap after lap. I think there was a mixup somewhere with pounds vs kilograms... But I read that it was somewhere around 115-135 kg. G forces from braking do work on the pedal, but you still have to stand on it with your foot/leg, even or especially when your body triples in weight when you push it

Is the force required at the peddle not a result of the leverage to the hydraulic piston?
To reduce the pressure required to produce the same at the caliper, have more leverage by increasing the lever length or re positioning the fulcrum.
I know there is not room for much movement but a belcrank could surly overcome that?

Master cylinder diameter plays a large role in the amount of force at the pedal.

strad wrote: ↑

20 Jul 2019, 19:39

Master cylinder diameter plays a large role in the amount of force at the pedal.

But is the master cyl piston(s) not calculated to give the required pressure on the actuator? (where regen is not used)
to get the same 'effort' it has to be bigger or travel further, which needs more movement

But is the master cyl piston(s) not calculated to give the required pressure on the actuator?

Yes it is but you can change that ratio, master cylinder to wheel cylinder, to create a pressure you find suitable.

NL_Fer wrote: ↑

19 Jul 2019, 21:53

How much of that +280kg of brake force is generated by G-forces of braking itself?

A portion of the drivers lower body weight multiplied by the braking acceleration makes it through to the pedal as extra load.

Tim.Wright wrote: ↑

21 Jul 2019, 11:02

NL_Fer wrote: ↑

19 Jul 2019, 21:53

How much of that +280kg of brake force is generated by G-forces of braking itself?

A portion of the drivers lower body weight multiplied by the braking acceleration makes it through to the pedal as extra load.

What we could say it a "heavy foot"

I read somewhere that the size of the master cilinder and leverage is regulated, as is the ban on powered brakes. That is why we still see (slight) difference in braking between drivers, raw power with the ability to come of the pedal gradually if downforce drops.

I remember training for single seater brakes with a scale up the wall, pushing it with my left leg, sitting with my feet up against the wall, up to 100kg+ and within a second or two bringing it back to 70 kg. It was hellish