Braking regulation change - "asymmetric braking torques for a given axle is forbidden"

[clownfish]

FIA confirms technical regulation update

An intriguing change made on the technical side has been to Article 11.1.2, related to braking systems.

“The brake system must be designed so that within each circuit, the forces applied to the brake pads are the same magnitude and act as opposing pairs on a given brake disc,” says the unchanged text before the new wording is confirmed with the following sentence: “Any system or mechanism which can produce systematically or intentionally, asymmetric braking torques for a given axle is forbidden.”

This tightening of the wording doesn’t suggest a team has already engaged such a system, but the governing body has spotted a potential loophole in the wording of the regulation.

This may have been due to an audit of its own rules, or could have been pointed out by a team that may have spotted a grey area in the regulations and sought clarification.

https://www.planetf1.com/news/fia-sign- ... -2024-wmsc

[Just_a_fan]

The addition of the new wording would suggest to me that either:

1. a team has been found to be using differential braking, or

2. a team has asked whether a system they want to use is legal,

and the FIA want to kill it off before it starts an arms race.

[bluechris]

Which team suddenly lost speed? (except Ferrari... or not?)

[LetHimTrough]

Which team suddenly lost speed? (except Ferrari... or not?)

Ferrari lost time because of bouncing, that we all could see "live". I dont think it is Ferrari, but who knows.

[Sergej]

Which team suddenly lost speed? (except Ferrari... or not?)

or

Which team suddenly gained speed?

[clownfish]

The addition of the new wording would suggest to me that either:

1. a team has been found to be using differential braking, or

2. a team has asked whether a system they want to use is legal,

and the FIA want to kill it off before it starts an arms race.

Also implies that a team has an idea to work around the existing 'brake steer' regulations that banned the Mclaren system?

Maybe Red Bull's brake failure the other week attracted somebody's intrigue

[chrisc90]

Will be interesting to see if there is any change after the summer break. A lot of teams we could all pass comment for and against. Lost time. Gained time. Retirements etc.

On a side note could you not use the ERS to give a similar effect with diff settings and recovery on one side of the rear wheels?

[bluechris]

Will be interesting to see if there is any change after the summer break. A lot of teams we could all pass comment for and against. Lost time. Gained time. Retirements etc.

On a side note could you not use the ERS to give a similar effect with diff settings and recovery on one side of the rear wheels?

For this to work, you need to get the steering input electronically or with any other way and i think this is forbidden.

[Farnborough]

Will be interesting to see if there is any change after the summer break. A lot of teams we could all pass comment for and against. Lost time. Gained time. Retirements etc.

On a side note could you not use the ERS to give a similar effect with diff settings and recovery on one side of the rear wheels?

I believe that's possible anyway, and without much in the way of direct control.

With the regen through transmission blending with bbw, then this "braking" effort passes through the diff to the gearbox, crank and arrives at generator. The tyres are restrained through this path accordingly and within recovery capacity etc.

If the diff is opened (less locking) at corner entry, commonly this is true to facilitate turn in response, then the braking is distributed unevenly across the rear shafts.

With the car "leaning" on the outside wheel to turn, with enhanced traction, then the inside radius wheel will be retarded more, notionally rotating backwards in comparison to the fully loaded opposite wheel.

Anyone that's worked on a transmission braked vehicle is familiar with this principle. The rear drive shaft is restrained by the Park brake to hold the vehicle on many arrangement of that type. If you have it parked on a slope, then jack one rear wheel it will roll away with the diff not now in equally loaded state.
Here's the good detail, that lifted wheel will now rotate backwards to demonstrate this principle.

In F1 application, if the diff is opened at corner entry, then high degree of recovery is imposed, this will differentially "brake" the inside rear wheel.

Further, if driver is to pull late and aggressive downshift into turn rotation regime, then that too is enacted through the diff to accomplish the same.

Action of the friction disc brakes will pull it back to parity though with their balanced hydraulic activity.

[Tommy Cookers]

.... If the diff is opened (less locking) at corner entry, commonly this is true to facilitate turn in response, then the braking is distributed unevenly across the rear shafts.

With the car "leaning" on the outside wheel to turn, with enhanced traction, then the inside radius wheel will be retarded more, notionally rotating backwards in comparison to the fully loaded opposite wheel.

In F1 application, if the diff is opened at corner entry, then high degree of recovery is imposed, this will differentially "brake" the inside rear wheel.

I have been waiting 12 years for this - and now I'm not ready !
fwiw my gut feeling is ....
the quoted above explanation is conflating ie confusing work done with force

an open diff is a force equaliser - regardless of source it won't support unequal wheel forces
that's why we have open diffs

[Holm86]

Verstappens rear brake got destroyed during the Melbourne GP, a few weeks ago somebody mentioned that something was found on the Red Bulls that FIA asked them to remove, their pace has been worse since, now this, ofc it's only speculation but my bet is that it's red bull

[Farnborough]

.... If the diff is opened (less locking) at corner entry, commonly this is true to facilitate turn in response, then the braking is distributed unevenly across the rear shafts.

With the car "leaning" on the outside wheel to turn, with enhanced traction, then the inside radius wheel will be retarded more, notionally rotating backwards in comparison to the fully loaded opposite wheel.

In F1 application, if the diff is opened at corner entry, then high degree of recovery is imposed, this will differentially "brake" the inside rear wheel.

I have been waiting 12 years for this - and now I'm not ready !
fwiw my gut feeling is ....
the quoted above explanation is conflating ie confusing work done with force

an open diff is a force equaliser - regardless of source it won't support unequal wheel forces
that's why we have open diffs

Yes agree with tbat, but at sum total of the three routes in this case, proportion dependent on the "traction " for want of a better word, in each of the shaft (input /restraint, both tyres at potentially unequal load given chassis track interaction) it's effectively the inverse of asking a straight open diff to accept full load, only to have one driven wheel then go up in smoke, needs "limitations" to cope with unequal traction events in that case.

Relative traction of the two tyres being the control in this case.

Similar to "pinching" an inside radius front brake as chassis load transfers across in dynamic through cornering.

Particularly interesting, as it was shown so clearly, these current cars across entry curb in places like variants alta chicane at Imola, you could see clear air under most of them on inside rear wheel. Exaggerated circumstances, but clear visual non the less.

[Just_a_fan]

Will be interesting to see if there is any change after the summer break. A lot of teams we could all pass comment for and against. Lost time. Gained time. Retirements etc.

On a side note could you not use the ERS to give a similar effect with diff settings and recovery on one side of the rear wheels?

The diff is adjustable, by the driver using the steering wheel switches, for entry and mid corner (and also high speed, it seems). But that is just a "at this switch setting you will do this" type approach. In order to do what you're suggesting (an active response in real time), there would have to be feedback and steering angle information fed in to the system. That is not allowed.

[chrisc90]

It would also only really be there for those drivers that prefer to do a little bit of trail braking into the corners.

So, it could be interesting to look back at which drivers typically decide to do that style of cornering/braking. My mind refers back to a post made about the hairpin at Canada that was quite well discussed by a member on here. I cant remember the exact specifics without going back and digging the post up, but sure it was Max that was taking a different line in the corner.

Would such a style of driving/cornering ( I think Max has had that style in this whole G-effect era?) be helped or hindered by such a asymmetric braking system?

[Farnborough]

Really, really hard on the brakes generally dictates a straight type approach just to keep the chassis flat in preventing early locking as downforce comes off during speed reduction.

I thought, through general discussion on here and elsewhere, that MV is early onto brakes with a more gentle phase at that point, certainly in comparison to CP. Perhaps there's more concise detail in trace on here that I recall ?

My interpretation of that, is that he's running a more "adaptive" curve down into the slowest peak at chosen apex.

MV seems to be very detailed in rotating the car during that brake phase, possibly living with a more lively rear grip fine line to accommodate that aspect.