rough riding

[eds2003bmw]

Hey folks! I own a 2003 x5 which I bought last year And I've just about had it with the rough suspension,its very bumpy. A friend suggested I replace the rear bags with springs but he said it would also lower the height of the vehicle. are these comfortable,I mean, more than the factory bags? Is there any way I can have the dealer adjust the bag pressure making them more confortable? I have on the vehicle 19 inch chrome bmw rims and low profile tires, the manufacturer asks for two different sizes of tires on the vehicle's front and rear. please ,anything helps.

[TwinTurboGTR]

Tires absorb some of the impact, so having low profiles automatically reduces ride comfort, not a lot, but it is noticable. You could change out to springs, but doing that is only done looking into the future i.e not having to deal with a sagging ass every few years because of air leaking out of the bags. Will springs make it more comfortable? Hard to say, some people say yes and some say no. If you have a set of factory wheels, (255/55/18) slap them on and check for ride comfort. As for a way to adjust air pressure, the computer handles that mess, adjusting pressure for ultimate precision. Air too low - pump inflates bag. Also, I am not a expert. Wait for JCL, Weasel, kill crap to answer. They should have a more definitive answer.

[o. l. t.]

And I've just about had it with the rough suspension,its very bumpy

The truck rides excellent with proper tires. You made the issue, not the suspension. The truck was built and tuned to work together properly. If you are going to change the dynamics, you must change all of them instead of blaming the truck. Airbags are not the issue here, as they ride spectacular. The natural camber of the truck makes you ride on the very inside of the wheel and tire so you are literally riding on the stiff inner sidewall of the tire and not much anything else. You can find a way to remove all the camber from the suspension and it will not handle for anything, or put a tire on with proper sidewall.

[Jordo]

Originally Posted by o. l. t.

The truck rides excellent with proper tires. You made the issue, not the suspension. The truck was built and tuned to work together properly. If you are going to change the dynamics, you must change all of them instead of blaming the truck. Airbags are not the issue here, as they ride spectacular. The natural camber of the truck makes you ride on the very inside of the wheel and tire so you are literally riding on the stiff inner sidewall of the tire and not much anything else. You can find a way to remove all the camber from the suspension and it will not handle for anything, or put a tire on with proper sidewall.

Lets talk about this.
As I agree that a thinner side wall on a tire will transfer jolts to the driver better then a tire with a tall side wall. I think we can all agree on that. Then to add that the very common excessive camber caused by the rear upper control arm's bushing wareing out can causing the wheels to ride on the stiffest part of the tire, amplifys this bumpy condition. (we are still on the same page)

But you had mentioned that if all of the Camber was taken away completely, it wouldnt handle for chit. This confuses me. From what I know, (and I will add my 4 wheel chassis set up has only been for dirt surface race cars/4 wheelers) I disagree.

I am not picking a fight here, I just wanna pick your mind and learn a little. I'm not saying I'm right your wrong, just my experiance didnt show that a wheel sitting square on the ground will cause undesirable handeling trates.

Your thoughts......

(sorry my spelling sux)

[nom3rcy]

Originally Posted by Jordo

Lets talk about this.
As I agree that a thinner side wall on a tire will transfer jolts to the driver better then a tire with a tall side wall. I think we can all agree on that. Then to add that the very common excessive camber caused by the rear upper control arm's bushing wareing out can causing the wheels to ride on the stiffest part of the tire, amplifys this bumpy condition. (we are still on the same page)

But you had mentioned that if all of the Camber was taken away completely, it wouldnt handle for chit. This confuses me. From what I know, (and I will add my 4 wheel chassis set up has only been for dirt surface race cars/4 wheelers) I disagree.

I am not picking a fight here, I just wanna pick your mind and learn a little. I'm not saying I'm right your wrong, just my experiance didnt show that a wheel sitting square on the ground will cause undesirable handeling trates.

Your thoughts......

(sorry my spelling sux)

When the X5 is cornering, as with any vehicle, body roll causes the tires to lean over along with the car.

Negative camber basically compensates for this by allowing the outside tires to be perpendicular with the road surface during high-g cornering.

The inside tires droop to become closer to perpendicular with the ground as well.

Setting the camber to zero when static (going straight) won't necessarily impact handling unless you are driving past 60-70% of the car's limits.

[o. l. t.]

Originally Posted by Jordo

But you had mentioned that if all of the Camber was taken away completely, it wouldnt handle for chit. This confuses me. From what I know, (and I will add my 4 wheel chassis set up has only been for dirt surface race cars/4 wheelers) I disagree.

Your race cars are not 7 feet tall 2 ton SAV's on asphalt. This monster can really benefit from camber. Zero camber on this truck will push at any speed in turns. I live on a mountain and every turn is great thanks to the setup this truck has with negative camber. Not only does it push from rolling the sidewall when you have zero camber, it severely reduces surface contact. This truck is not a tiny car, you don't have to drive it's balls off to see benefits of negative camber. Inertia is what matters and mass makes all the difference. Anyone who says you do is not bothering to take its size and weight into account, which make it drive completely different from a 1500lb aluminum go kart.

As well, due to the truck going into POSITIVE camber over any bumps or inconsistencies that cause the truck to unload the suspension, even as it goes down the freeway at 70 mph, will cause wandering and instability.

[Jordo]

Originally Posted by o. l. t.

Your race cars are not 7 feet tall 2 ton SAV's on asphalt. This monster can really benefit from camber. Zero camber on this truck will push at any speed in turns. I live on a mountain and every turn is great thanks to the setup this truck has with negative camber. Not only does it push from rolling the sidewall when you have zero camber, it severely reduces surface contact. This truck is not a tiny car, you don't have to drive it's balls off to see benefits of negative camber. Inertia is what matters and mass makes all the difference. Anyone who says you do is not bothering to take its size and weight into account, which make it drive completely different from a 1500lb aluminum go kart.

As well, due to the truck going into POSITIVE camber over any bumps or inconsistencies that cause the truck to unload the suspension, even as it goes down the freeway at 70 mph, will cause wandering and instability.

Interesting. What your saying does make sence. But what I'm having a hard time understanding is the wheels ability to "change it's camber"
In a turn as you used as an example.

So hear me out and let me know you think....

Visualize our X5 from behind it with no body on it. Now let's visualize the rear suspension and wheel. We see the control arms, air bag system AND axle.
And let's not forget we have some serious camber on that wheel.
Now in your mind, keeping the chassis level (parallel) with the ground, let's go ahead and lift the rear wheel simulating a bump. The camber that it had WILL maintain the same amount through out the suspension stroke.

And from how I understand what your telling me the camber (in my words) "flatten out" as the suspension stroke compresses.

For the camber to flatten out you would need a pivot point on the control arms to move right and left to give you varying amounts of camber. (like what the adj. do for an alignment)

Am I communicating my self? In order for the wheel to sit flat on the road when it's deep in the stroke would require the rising rate to be variable. And that is not on our X5's.

Maybe a better example would be a car that was lowered, excessively. With no alignment correction. That wheel would look similar to what we have. The FIXED pivot points prevent the wheel from changing is camber. Am I making any sence as to how I'm visualizing this?

Granted 99% of my work is dirt related, and is usually motocross bikes and quads, but I still feel the wheel does. It have the ability to adj. Mid stroke.

Let me know what your thinking. Maybe I am misunderstanding what your describing.

Thanks for your time.

[o. l. t.]

You answered your own question already. Lowering (or raising) a car changes it's camber showing that camber does indeed change as the suspension does. Your problem is that you are looking for this mechanical action to take place when it is simple geometry. That's where there are upper AND lower control arms. Their offset determines the amount of camber change happens. It is the vertical equivalent of bump steer.

[01X5Guy]

How many miles on the struts? Possibly struts are gone so your getting no dampening making the ride really bouncy? This is my case right now.. just thought I'd ask.

[jst2878]

might just need rear shocks. they can be worn out