Log in

View Full Version : Large metal weights at swinging off rear chassis rails


rusty
11th April 2010, 09:36 PM
Crawling under my D3 today I noticed that there are heavy metal weights that hang over the rear of each chassis rail. They swing fore and aft, look to be about 10 - 12 kg each, and seem to be in a cast U shape. They are shaped to follow the departure angle and are partially hidden by the rear bumper.

Anybody know why there are there? Why add another 25 kg to an already heavy vehicle?

Can you take them off - and if you did what would be the effect?
stig0000
11th April 2010, 09:57 PM
i wouldent touch them,, they are there for a reason,, and that is harmonics thru the chassis,,, there is allso shocky type looking thinks round the place on d3s and sports and thats to help as well,

so all they do is make your ride all nice and confy and quite,,:D

and i guess whats 20kg off a 2.6t car enyway;)
ADMIRAL
11th April 2010, 10:09 PM
NVH- and Stig is correct. They would not waste the time & energy to design and fit them if they did not serve a useful purpose.
Neil P
12th April 2010, 11:42 AM
.. heavy metal weights that hang over the rear of each chassis rail ..

Originally there was going to be one in each corner , but cost cutting of the run-away development expense
saw the fronts cancelled ....... never to be reconsidered.
Forest
12th April 2010, 08:39 PM
Do remove them - if you would like to feel sea sick every time you drive in the vehicle!!!:o Remove them and you will decrease the smooth ride, and probably have a whole lot of people being car sick.
Celtoid
25th October 2010, 12:35 PM
I only noticed these on the weekend.....not that I've actually been under my D4 very often. I'd had to reverse back out of a steep rut as I was leaning pretty heavily over to one side and was scared of trashing the side of the D4 as it was pretty wet and slippery. I just couldn't get any forward or sideways traction with my crappy tyres and each time I moved forward the lean increased. As I backed out I nudged the back bumper at the side of the car, so I had a gecko underneath to make sure all was well.

Everything was fine but I'd never noticed the weights before.
rmp
25th October 2010, 05:44 PM
Do not mess with the weights. They are the car's testicles. Removing them will turn it into a Freelander.
Celtoid
25th October 2010, 08:02 PM
Do not mess with the weights. They are the car's testicles. Removing them will turn it into a Freelander.

Funny you should say that Robert....that's exactly what they reminded me of.....LOL!!!

The other thing I noticed when poking around back there and in the engine bay is the disappointingly poor finish on the wiring looms. There are literally very fine wires....I recon 18 gauge and less, completely exposed under the car...masses of them. You'd think LR would have tried harder to cover them up and protect them.

I'm not sure what is supposed to/can be fitted in front of the battery bay in the D4....but there are just looms hanging...with the same incomplete conduiting......Fine wires exposed to the elements.

Not good at all.
sniegy
25th October 2010, 08:14 PM
I'm not sure what is supposed to/can be fitted in front of the battery bay in the D4....but there are just looms hanging...with the same incomplete conduiting......Fine wires exposed to the elements.

Not good at all.
Fuel Burning Heater. Cold Climate only.
rick130
25th October 2010, 09:41 PM
i wouldent touch them,, they are there for a reason,, and that is harmonics thru the chassis,,, there is allso shocky type looking thinks round the place on d3s and sports and thats to help as well,

so all they do is make your ride all nice and confy and quite,,:D

and i guess whats 20kg off a 2.6t car enyway;)


NVH- and Stig is correct. They would not waste the time & energy to design and fit them if they did not serve a useful purpose.

yep, the technical term is 'mass damper', and they are on most all modern cars in some way, shape or form to cancel out a harmonic at a specific frequency.

Tuned mass damper - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Tuned_mass_damper.gif" class="image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Tuned_mass_damper.gif/200px-Tuned_mass_damper.gif"@@AMEPARAM@@commons/thumb/0/07/Tuned_mass_damper.gif/200px-Tuned_mass_damper.gif

Even F1 cars were using a sprung mass damper a few years back to enhance front end grip.

http://img127.imageshack.us/img127/8503/damper0019pz6ni.jpg (http://img127.imageshack.us/i/damper0019pz6ni.jpg/)
Celtoid
26th October 2010, 03:28 PM
Ah, the Blackhawk Helo has things called Bifilars near the rotor hub at the root of each blade. I guess they are doing a similar thing. They sit loose and 'wobble' as the main rotor turns.