I noticed a thing....

"GE90man" (ge90man) 06/29/2016 at 12:18 • Filed to: None

0

25

on the new Porsche Panamera, the front brake calipers are mounted toward the front of the wheel as opposed to the rear of the wheel. so my question is, does this pose any advantages/disadvantages of where the brake caliper is positioned? I’ve really only seen rear mounted brakes on sportier cars, while front mounted ones are usually on cheaper cars, more regular cars if you know what I mean. (camry and all the other beige cars) in fact, the panamera is one of the only sporty cars with front mounted brakes. werid.

mounted toward the front of the wheel as opposed to the 911's brakes, which are mounted toward to the rear

Sam > GE90man 06/29/2016 at 12:24

0

It’s reversed on both ends -

BvdV - The Dutch Engineer > GE90man 06/29/2016 at 12:24

2

I think it is mostly a factor of where it fits due to the geometry of the steering knuckle, and also the way in which cooling ducts can be pointed at them. In the 911, there is enough space to route the cooling ducts to caliper at the rear, though in the Panamera there is an engine in the way.

GE90man > BvdV - The Dutch Engineer 06/29/2016 at 12:25

1

I’ve seen other front engine sports cars with rear mounted brakes, in fact, I think only the panamera has front mounted ones, my initial thought was that the position might be to cool the brakes, but that makes sense too

aberson Bresident of the FullyAssed Committe > GE90man 06/29/2016 at 12:26

3

It’s a german thing, you wouldn’t understand.

FromCanadaWithLove > GE90man 06/29/2016 at 12:26

1

Good catch. Isn’t that worse for cooling? I don’t really know much about brakes.

jariten1781 > GE90man 06/29/2016 at 12:26

0

I've seen people argue that mounting towards the center mitigates front end diving. I don't buy it, but it's regularly argued. The other, minor, benefit it brings is the centralization of mass.

GE90man > FromCanadaWithLove 06/29/2016 at 12:27

0

that was my thought too, I initially thought all the sportier cars had their brakes rear mounted for better cooling

HammerheadFistpunch > GE90man 06/29/2016 at 12:28

3

Generally speaking if you can you want to put them inbetween the wheelbase for weight reasons, but as BvdV mentioned, there are also packaging concerns. It doesn’t affect the overall clamping ability of the caliper either way.

MontegoMan562 is a Capri RS Owner > FromCanadaWithLove 06/29/2016 at 12:28

2

Lesson 1: Brakes are installed to stop the car.

ChooChooMotherFudger > GE90man 06/29/2016 at 12:29

2

I did a bunch of research into this designing my schools FSAE car’s brakes.
Long story short:
Don’t matter where they are for braking effectiveness.

Slightly longer story:
It does matter for cooling, CG, Moment of Inertia, brake beading, and packaging.

OPPOsaurus WRX > GE90man 06/29/2016 at 12:30

1

i’m with you, i’ve always wondered in caliper placement has any effect on anything

Snuze: Needs another Swede > GE90man 06/29/2016 at 12:32

1

I had this discussion once before in here and someone much smarter than me explained it all has to do with getting the proper ackermann steering geometry.

https://en.wikipedia.org/wiki/Ackermann…

JDIGGS > GE90man 06/29/2016 at 12:39

0

Thought it helped with weight distro.

this looks like it hurts and that is already front heavy, makes you wonder if it was done for cost instead of performance.

RamblinRover Luxury-Yacht > GE90man 06/29/2016 at 12:42

2

For reasons related to suspension geometry and stresses under compression/tension, it is slightly better to have the tie rod ahead of the center line of the wheel instead of behind. This is harder to package with a center of rotation for the spindle positioned for more neutral handling like most modern cars, and due to Ackermann geometry means the point at which the tie rod connects is even further out toward the wheel if it’s in front. Putting the brakes on the same side as the tie rod isn’t easily done in that case. I will bet you that the new Panamera has trailing instead of leading pittman arms.

Smallbear wants a modern Syclone, local Maple Leafs spammer > GE90man 06/29/2016 at 12:48

0

SOOOOOO much better than the original Panamera. Still looks like a 4-door 911, but thankfully they blended the roof this time instead of just cutting a 911 in half and adding a bit in the middle.

JQJ213- Now With An Extra Cylinder! > GE90man 06/29/2016 at 12:50

0

My C30 has the brakes in the same place

Therefore: My C30 = Panamera

GE90man > Smallbear wants a modern Syclone, local Maple Leafs spammer 06/29/2016 at 12:50

2

this doesn’t look like a four door, like you said, it looks like a 911 that’s slightly longer, which is probably the best thing, now imagine if they make a gt3 RS version of this

Ash78, voting early and often > GE90man 06/29/2016 at 13:00

0

Lots of detailed discussion, but I’m thinking they just mounted the (giant) caliper carriers wherever they would least interfere with the rest of the suspension geometry and the steering arms. Being front-engined, that probably means it's pretty cramped under there and the rear half of the wheel is probably dedicated to tie rods and control arms. /speculating

BREADwagon > GE90man 06/29/2016 at 13:10

4

There is a nuanced benefit for brakes being mounted behind the axle, and it has nothing to do with braking, and everything to do with steering.

The brake caliper supports tend to be opposite of the steering rack linkage since they both take up space on the knuckle. The ideal layout is having a steering rack that impinges in front of the axle centerline (pushing the brake caliper to the rear), otherwise known as ‘front steer’. There’s a few reasons for this, but it basically boils down to steering precision and steering dynamics, where a front mounted steering axle is preferable.

However, since front wheel/AWD cars tend to have very cramped engine bays, routing the steering column ahead of the axle line is sometimes impossible. In these cases, the rack has to be put to the rear of the axle. This also requires a steeper steering column since it has less distance to drop to the axle, necessitating Ujoints with greater angles....which also reduces steering accuracy.

So a rule of thumb is, a rear mounted caliper infers a front mounted rack which is the preferable location for steering accuracy.

Michael > GE90man 06/29/2016 at 13:12

1

Sports cars generally have the front calipers rear mounted, and the rear calipers front mounted, which reduces the polar moment of inertia (heavy things at the middle of the car is better than heavy things at the outside edges of the car). Makes the car like changing direction better, because it takes less energy to start the car turning, and to stop turning.

Michael > Michael 06/29/2016 at 13:13

0

Milky > GE90man 06/29/2016 at 13:43

1

Your brakes aren’t cool unless they hang low.

JRapp: now as good as new again > GE90man 06/29/2016 at 14:38

2

The front brakes being forward of the axle makes the steering lighter and twitchier, where as the front brakes mounted rear of the axle makes the car track straighter more easily under acceleration. The effect may be very minute though, and is probably compensated for with the power steering and all that. Just from a purey physics standpoint, a trailing weight wants to stay trailing, where as a leading weight will also want to be trailing, if that makes sense.

And it doesn’t have much beyond that to do with weight distribution for body-roll or lean/squat and whatnot, because it’s unsprung weight, and not directly attached to the body.

TheNeonDriver - Now with More BMW! > GE90man 06/29/2016 at 17:24

1

Most likely due to packaging constraints with an engine in the way of the steering rack. Not an issue with a rear engined 911, you can stick the brakes wherever you want.

I had to look it up, my old Neon had the brakes in front of the axle (due to there being an engine in the way in the front of the axle), while my 335i has the brakes behind the front axle (xdrive) because the engine is tucked back against the firewall (and all the other reasons people have mentioned).

bob and john > GE90man 06/29/2016 at 18:06

1

The position of the brake is mainly dictated by where the fucking thing will fit lol. Those are friggen MASSIVE calipers, and steering, suspension, and the possible inclusion of AWD (and thus, drive shafts) all must be avoided by the brake in any position

Cooling and what not comes after