7 replies to this topic

[mariner]

Once upon a time inboard barkes , rear and front , were very popular due to the percieved benefits of lower unsprung weight and the opportunity to fit bigger brakes than the wheel size would otherwise allow.

MB used inboard fronts on the W196, Citroen used them on the DS and SM ( with underbody cooling ducts) and they were a key part of the Lotus 72 concept.

They seem to have dropped out of road use due to bigger rims allowing bigger discs, the general growth in weight helping (?) ride and the oil leak problems on rear ones.

In racing the advent of massive downforce raised sprung " weight" versus unsprung, so much any unsprung weight benefits were lost. Also inboard fronts made everybody nervous due to the high engineering quality required for safety.

As far as I can see there is no specific ban on inboard brakes , it just talks about "one brake per wheel" - a bit vague.

Why might inboard brakes have any benefit in todays F1?

Well, there is a lot of work going on for better aero flow through the wheels , no wheel mounted front brakes might give more aero opportunites, today even tiny aero gains seem valuable.. Not having to pump hot brake air out to the side of the car, as now, might cut drag

Having a nice, rotating vented disc requiring cooling air must be huge downforce opportunity whatever the regs say about ducting. The air has to come from somewhere and go somewhere so, whilst it might get banned after one season some clever rule reading could give the car " on board air pumps" within the rules.

Just a thought as F1 design is so stuck now - if it did work there is one last advantage - other teams couldn't copy it quicka s so much redesign of the tub etc. would be needed. Also with the modern levels of F1 enginnering the old safety worries needn't apply

Edited by mariner, 07 April 2013 - 17:08.

[Ross Stonefeld]

Where would an inboard front brake go?

I think on the rear some teams are running them inboard.

[Kalmake]

As far as I understand the rules, you can have inboard brakes, but might have a hard time cooling them.

11.4 Air ducts:
Air ducts around the front and rear brakes will be considered part of the braking system and shall not protrude beyond:
- a plane parallel to the ground situated at a distance of 160mm above the horizontal centre line of the wheel;
- a plane parallel to the ground situated at a distance of 160mm below the horizontal centre line of the wheel;
- a vertical plane parallel to the inner face of the wheel rim and displaced from it by 120mm toward the car centre line.

Edited by Kalmake, 07 April 2013 - 19:34.

[Tony Matthews]

Where would an inboard front brake go?

Historically, cars with inboard front suspension have had much wider tubs/chassis at the front, I don't think any designer would want to sacrifice the narrow tub for the sake of inboard brakes.

[bigleagueslider]

Inboard brakes provided less direct driver feedback due to the torsional wind-up created in the driveshaft between the wheel and brake caliper.

[mariner]

Tony, remember the Lotus 77, inboard front discs and very narrow nose, not the best advert for inboard fronts but certainly narrow!

I am not sure that inboard brakse have less feel due to the driveshafts, any torsional frequency would be above the driver sensitviity range I think.

My main reason for bringing up inboard brakes is the current problem with making the Pirelli tyres last very long. The drivers are complaining that they are driving at 8/10ths to preserve tyres so there is no real racing going on.

Tyes are black art beyond me but , historically, heat destroys tyres so inboard brakes might just help tyre management with the current " wear out to excite the fans" approach.

[Lee Nicolle]

Personally I can see no benefit of an inboard front brake. The driveshafts defeat any benefit. Wheras on the rear they make sense as the driveshafts have to be there already. So the true unsprung weight should be a benefit and cooling should be easier. Aero?
Though I have not looked at a modern F1 car, the closest is a F3! Or a 5000.
I am surprised that more modern sports cars and silhouette touring cars do not use them on the rear. They all seem to be outboard.
On a road car though outboard is good. As anyone who has ever serviced a Jag will attest!

[MatsNorway]

http://forums.autosp...=inboard brakes

Please correct me if any of this is wrong.

Short version is that its not likely just because of the weight issues given by it.

Long version:

Arguments can be made about brake dics in the rear would distrupt airflow to the diffuser and beam wing.

And as mentioned there is issues with flex in driveshafts giving a different and likely a undesired feeling for the drivers.

Then the mass you save from the brake discs goes away when you add a big driveshaft.

In addition you get aero penalties due to the big pipe sticking out in the air. You could cover it like they do now but it does still provide some turbulence and resistance.

Edited by MatsNorway, 08 April 2013 - 08:45.