Just Ordered '06 - Is Front Air Suspension the key to the 4.8 smoother ride?

Juanted · #1 11-20-2005, 11:37 PM

You'll soon find out that I have no useful feedback to give, and well, that will continue with this response. I just wanted to welcome you to the board and congratulate you on your purchase. Post some pics.

We do have a bunch of great, knowledgeable folks here, though. I am certain your question will be answered soon.

Juan

z356 · #2 11-21-2005, 12:02 AM

Will post photos as soon as it arrives. Target date is Christmas. Color combination is Kalahari with Truffle Brown interior. Just about every option. MSRP is $65,750. My deal was $2,000 over invoice. Will only need to add a set of 18" wheels (probably replica 87s from Lakeshore) with Pirelli Scorpion Ice and Snows 255/55/18s. I am also considering the Dunlops M2s in 265/55/18, seen as an alternative X5 size at Tirerack website. Any feedback on these possible Winter tire choices would also be appreciated. Travel often between homes in Reno and Carmel (CA), so need good balance for snow, rain and dry road use on tires for winter months.

LVR · #3 11-21-2005, 03:24 AM

I have both an X5 with Sports suspension and a 4.8 with the air suspension. The 4.8 absorbs bumps and corners like a sports car with little body roll in comparison to the sports.

The first thing that is noticeable is that the 4.8 is lower with a wider stance.

As you said, the wheels are larger with lower profile tyres. Wheel size is important as this can affect the scrub radius (difference between the wheel centreline and the ball joint centre line) which relates to how positive the feedback is through the steering wheel. It also affects the cornering through the lateral forces absorbed by the tyre (sidewalls).

Track width resists the 'overturning inertia' when cornering, so it follows that a wider track will help the cornering.

Over bumps the initial shock transferred through the body is vastly lower, but I think this is partly due to the geometry of the suspension (eg damping rates) as much as the air suspension.

Around a corner the suspension is actively working different in my understanding. I think it has more to do with tyres, ride height (roll centre) spring settings, camber, caster and wider stance (Track width = lateral force) and then there is the electronic levelling side, which moves the roll centre during cornering by applying a 'jacking force' .... and is a whole world of confusion.......

The bump steer is vastly different. When you hit a bump mid corner in the sports (depending on the speed) it will require correction to your steering line whereas the 4.8 barely registers it. This is quite often due to the steering system geometry.

I think you would have to look into the specs of the steering, type of springs, geometry settings including camber (bump steer giveaway), caster, toe in/out settings to really answer your question.

That said, any upgrade of your suspension by the factory should require sympathetic settings to suit so it's all good.....

Cheers

z356 · #4 11-21-2005, 04:16 AM

Thanks for the post, LVR. Does your 4.4 Sport has Front Air Suspension? My research on the subject of 4.4 vs 4.8 reveals that there is some confusion on this point. Some have posted that a 4.8 and a 4.4 Sport with AHR (Adjustable Ride Height or front air suspension) have basically the same "sport" suspension. Is this true or not? Some, like you, are certain that they are totally different. Some have said that there is a ride height difference in 4.4 AHR vehicle vs a 4.4 non-AHR vehicle. That a 4.4 AHR is lower, per factory specs, than a non-AHR 4.4. Nothing to do with adjustable ride control function which returns the height to a factory setting at some speed; just that this default "normal" factory height setting is lower than the setting for a normal front coil spring & shock X5. Also that a 4.4 AHR sits a bit lower to the ground, like the 4.8. Is this true? Remember I am talking about a post-'04 4.4 Sport with AHR, not an earlier pre-'04 X5 with AHR. There must be many of you that have tackled this issue, I am sure. What is the secret to the 4.8 ride quality? Have you guys in this forum reached a consensus as to whether there is a real, quantifiable difference in the suspensions of a 4.8 and a current 4.4 Sport with AHR, other than the stock 20 inch wheels in the former? That is what I am trying to nail down. You might have a point in your technical explanation. I just want to see if other owners of 4.8 or 4.4 Sport {with front air suspension} in this forum agree, or not, with this theory. My hope is that, at this late date in the development of the E53 X5, there is a definite answer to my question based on the actual & collective experiences of our members in their understanding the fundamental suspension dynamics of their vehicles.

jditom · #5 11-21-2005, 01:41 PM

Quote:

Originally Posted by z356

Will post photos as soon as it arrives. Target date is Christmas. Color combination is Kalahari with Truffle Brown interior. Just about every option. MSRP is $65,750. My deal was $2,000 over invoice. Will only need to add a set of 18" wheels (probably replica 87s from Lakeshore) with Pirelli Scorpion Ice and Snows 255/55/18s. I am also considering the Dunlops M2s in 265/55/18, seen as an alternative X5 size at Tirerack website. Any feedback on these possible Winter tire choices would also be appreciated. Travel often between homes in Reno and Carmel (CA), so need good balance for snow, rain and dry road use on tires for winter months.

Here is my choice for snows!
Congrates on the X5. I also switched from an Audi!

snow tires

blondboinsd · #6 11-21-2005, 02:20 PM

Hey I have your combo (khalahari with truffle) its a rare color combo and a special order, you'll LOVE it, as for air suspension, my last x5 had it before i totaled it, then this one doesn't, just self-leveling rear suspension, I don't really notice the difference.

z356 · #7 11-21-2005, 04:21 PM

The BMW public website doesn't allow certain colors and interiors to be built that pose really no problem for the factory. Stratus and Truffle is also a great color combination, but the website will not allow you to build it. But it is available from the factory without any problem once the dealer inputs it via Priority One. The most bizarre thing is the way that BMW hides its Servotronic option from the 3.0 and 4.4 customers. It is not listed in its official X5 brochure or website. Porsche makes a big deal of this option on its Cayenne brochure, yet BMW is mysteriously silent on it, other than to say its standard on the 4.8. It only comes up in the dealer's Priority One website for ordering (option 216). Equally, the Adjustable Hight Ride is not explained very well anywhere, their brochure or their website. It makes a big deal of the adjustability of height, but does not mention or emphasize the superior ride quality or cornering it provides because of its front air suspension, nor explains why it requires the Sport Pkg to order it. I have my suspicion for their reasons in being so vague, but its all speculative.

GRAHD3 · #8 11-21-2005, 05:47 PM

Quote:

Originally Posted by z356

Will post photos as soon as it arrives. Target date is Christmas. Color combination is Kalahari with Truffle Brown interior. Just about every option. MSRP is $65,750. My deal was $2,000 over invoice. Will only need to add a set of 18" wheels (probably replica 87s from Lakeshore) with Pirelli Scorpion Ice and Snows 255/55/18s. I am also considering the Dunlops M2s in 265/55/18, seen as an alternative X5 size at Tirerack website. Any feedback on these possible Winter tire choices would also be appreciated. Travel often between homes in Reno and Carmel (CA), so need good balance for snow, rain and dry road use on tires for winter months.

I ordered the same setup as you describe above along with Adjustable Ride Height, Servotronic, Sirus radio and tow capability, but I got the Alpine White with Truffle interior. You should be really happy with this setup! Overall, I find the ride and handling amazing. I wish I was back in California to drive mine...

Anyway, before I bought, I drove a 4.8is comparing it with the 4.4i sport. It was a tough decision. I felt the 4.8is sort of scrubbed the tires around tight corners and I'm not sure why. The 19's I have are almost a wide, but I don't notice the effect. To me the most notible difference is in braking and acceleration. What I did learn is that the servotronic on the 4.8is really makes a difference getting around tight spots with the wide tires, so I made sure to get this option.

z356 · #9 11-21-2005, 08:21 PM

Yes, the ride between Carmel and Reno-Tahoe is pretty incredible, except for the boring inland part on Hway 5, between Santa Nella and Sacramento. In general, we are blessed with beautiful highways in our Northern California & Northern Nevada area. It takes five hours between homes in our 745i and the latter shines on the curvy parts of 80 as you get up in the mountains or the Pacheco Pass closer to Carmel. I am hopeful that the X5 4.4 with front air suspension will be equally fun. I use the adaptive cruise control quite a bit. It is a wonderful technology which we will probably see in the next X5. I also can not wait to have Head Up Display, probably also in the upcoming new model. Does your AHR optioned 4.4 seem to sit lower than a regular X5?

GRAHD3 · #10 11-22-2005, 12:21 PM

Quote:

Originally Posted by z356

Yes, the ride between Carmel and Reno-Tahoe is pretty incredible, except for the boring inland part on Hway 5, between Santa Nella and Sacramento. In general, we are blessed with beautiful highways in our Northern California & Northern Nevada area. It takes five hours between homes in our 745i and the latter shines on the curvy parts of 80 as you get up in the mountains or the Pacheco Pass closer to Carmel. I am hopeful that the X5 4.4 with front air suspension will be equally fun. I use the adaptive cruise control quite a bit. It is a wonderful technology which we will probably see in the next X5. I also can not wait to have Head Up Display, probably also in the upcoming new model. Does your AHR optioned 4.4 seem to sit lower than a regular X5?

It doesn't appear the AHR option sits any lower unless it's put in low setting. The 19s make it look like its lower than it is. On rough roads and bumpy roads the suspension performs extremely well, even on bumps in corners. In eastern PA, we have very narrow, tight curvy roads with lots of blind corners often with negative camber (essentially 300 year old dirt roads covered in asphalt). The 4.4 eats up these roads with little body roll. I test drove a 745i and a 530i on the same road as the 4.4, and the similarities in handling were amazing. The 745i seemed to adapt to the undulating surface the best, the the 4.4 was very close to the 530i; it sold me on the 4.4 as my first BMW. On open hiway, the 4.4 is smooth as glass & very quiet. Overall, I couldn't be more happy. I can hardly wait until my trailer arrives so I see how that works out.