I hear the Q5 senses when a roof rack is installed(dot sensors in rails) and somehow adjusts for the centre of gravity/weight. Can someone explain this, what realy happens? Thanks

 

I pulled this from Audi's UK website.ESP with roof rack detection
The roof rack detection comprises a sensor that has a direct connection to the ESP control unit.
When the roof bars are fitted to the roof of the Audi Q5, a signal is generated which causes the adjustment of handling-related parameters to the change in the height of the vehicle’s centre of gravity (when loaded).
Consequently, the ESP is able to respond effectively even with the maximum permitted roof load of 100 kilograms; when there is no load on the roof, the vehicle's dynamic handling potential can be harnessed to the full.

https://www.audi.co.uk/glossary/e/es...detection.html

Nice to see another Q5 owner from ON, here on the forum.

 

Correct, the roof rack basically dumbs down the ESP and then uses a default assumption there must be a max roof load. If you look at the front roof rail on the (US/Continental Europe) driver's side, you will see a third protruding peg where it locks into the inside of the rail. That is where it picks up that the roof bars are attached. Even though Audi sedans and my recent Golf add all have specifically prescribed rack attachment points and markings (and on the Golf, a peg), none of them modify ESP settings AFAIK. I usually leave the rack off, but on or off I don't really notice a real world difference. On the other hand, no matter how its equipped or modded, it ain't going to be up to a performance sedan in the corners and sweepers.

 

Agreed, i notice zero difference with the roof rack installed or not (unless there is actually a heavy load in top). I tend to leave mine on for no other reason then laziness. I will how ever remove them when I take longer highway trips as the wind noise at 70ish km/h plus is pretty annoying.

 

Audi-UK, or I, seem to have a reading comprehension problem. As best I'd been told, if you put the front rack on the roof, that tells the ECS system "There may be another 100 (200?) pounds all the way above the center of gravity on this 4400# truck, expect it to roll over sooner, start braking the wheels sooner on turns to prevent that from happening, go to Defcon 2 just in case."

Except, the Audi-UK web site seems to say that although putting the rack in tells the ESC to be more something...it also says that putting the rook in won't prevent you from getting the usual performance.

"ESP with roof rack detection

The roof rack detection comprises a sensor that has a direct connection to the ESP control unit.

When the roof bars are fitted to the roof of the Audi Q5, a signal is generated which causes the adjustment of handling-related parameters to the change in the height of the vehicle’s centre of gravity (when loaded).

Consequently, the ESP is able to respond effectively even with the maximum permitted roof load of 100 kilograms; when there is no load on the roof, the vehicle's dynamic handling potential can be harnessed to the full.*
nt Our Code of Conduct © Audi United Kingdom 2018 All rights reserved "

*My emphasis,not theirs.

It can't be both ways...unless the roof rack is just telling the ESC system "If you think you are needed, don't hesitate!"

In practical driving I've never felt a difference. But then again, the ESC system doesn't know about me and the fifty pounds of "stuff" I've got loaded in the car...Or maybe that's 1000# worth of heavy passengers and their masonry collections? Damned effective system though. It kept me from becoming Oreo filling one day.

 

Thanks for all the info. It however sounds more like a advertising gimmick rather than a significant performance enhancement.

 

Advertising gimmick? Can, that can't be. Audi is just full of superlative feats of superior German high technology and engineering, which inferior competitors try to dismiss as meaningless and unimportant. There is no gimmickery at Audi, and despite the repeated rumor, nothing in the car (like the headlight switch pointlessly installed in such a way that the driver's knee can and will shut the automatic headlights from time to time) is the product of some malcontented engineer who is still pissed over losing WW2. So they say.