"Slammed" the X5

[X5SND]

Originally Posted by 525iT_Feen

Did you drive 400 miles on egg shells? You would certainly be hitting the bump stops up front. At this height, the rolling edges of your rear bags are going to be nicely mashing into the top face of the wheel carrier in which the bag sits.

For those who want to lower thier X safely: once you go beyond the factory "access" height, start seriously considering removing the ping tanks (aka accumulators). This will limit the amount of compressible volume for each corner, making the bag react faster (eliminating the bouncy/mushy ride often associated with extreme drops), but still maintain a comfortable ride for everyday driving.

[TiAgX5]

Living/driving in FL and TX (even putting over 100k miles on my '94 Viper, dropped 1.5 inches with stock shock/spring rates) I have never bottomed out.

I ordered the KW Var3 coilover set for my X last week (spring rates and high speed damping almost identical to the OE setup), planning on a 2.5 inch drop. In the years driving my X I have never come close to bottoming because BMW designed the X to operate on much rougher roads then I drive. For my application there is absolutly no "downside" to the drop. If I lived in a local with severe potholes I would never lower due to the fact that going with higher spring rates and/or firmer shock damping actually DECREASES roadholding/performance on rough roads. The "fix" for keeping the suspension from bottoming actually hinders performance on those very road you are driving. This is a textbook example of modding like Martha Stewart (looks) and not like Colin Chapman (performance).

[bigwave2255]

i have no experience with air bag suspension but i do with lowered coils, and i can say that the ride quality will be more dependant on the spring manafacturer than how low the car is ( excluding cars riding on there bump stops)

my experience as stated earlier is that eibach lowered springs have dramatically improved the quality of my cars ride, replacing the front struts has been the icing on the cake.

for me it has turned a hard ridding car into a comfortable ride that now also handles far better than stock.

so in my view its not the lowering that causes trouble or causes the car to be unsafe, its how its done.

[525iT_Feen]

Originally Posted by X5SND

Did you drive 400 miles on egg shells? You would certainly be hitting the bump stops up front. At this height, the rolling edges of your rear bags are going to be nicely mashing into the top face of the wheel carrier in which the bag sits.

For those who want to lower thier X safely: once you go beyond the factory "access" height, start seriously considering removing the ping tanks (aka accumulators). This will limit the amount of compressible volume for each corner, making the bag react faster (eliminating the bouncy/mushy ride often associated with extreme drops), but still maintain a comfortable ride for everyday driving.

The car rode like absolute ass like this and definitely wasn't safe for the lively hood of the suspension. I had no choice because I was running around like a mad man (in NY) Sunday morning and had to go to Manhattan for hotel check out at 12. By the time I got back on the road to go home my friend had left his shop so I rode it out. I didn't drive it today to avoid damage and raised it at a different friends shop right after work. The front doesn't seem to really be an issue but the rear is a visual 2 inches higher then in that picture and the car now drives great. Most of my experience with lowered cars comes from trial and error and this one is no different. I drive on shit roads in Boston everyday and the bit i've driven today (after raising the car) hasn't bottomed out anything.

Removing the accumulators doesn't seem that difficult. Is there much to it? Pros and cons? I was admiring your build earlier. Seems like you've done alot of cool stuff.

[X5SND]

Originally Posted by 525iT_Feen

The car rode like absolute ass like this and definitely wasn't safe for the lively hood of the suspension. I had no choice because I was running around like a mad man (in NY) Sunday morning and had to go to Manhattan for hotel check out at 12. By the time I got back on the road to go home my friend had left his shop so I rode it out. I didn't drive it today to avoid damage and raised it at a different friends shop right after work. The front doesn't seem to really be an issue but the rear is a visual 2 inches higher then in that picture and the car now drives great. Most of my experience with lowered cars comes from trial and error and this one is no different. I drive on shit roads in Boston everyday and the bit i've driven today (after raising the car) hasn't bottomed out anything.

Removing the accumulators doesn't seem that difficult. Is there much to it? Pros and cons? I was admiring your build earlier. Seems like you've done alot of cool stuff.

Its been a while since I've studied all parts the diagrams.... Since I did a complete to-air conversion the only thing my set up shares with the factory system is the bags and struts. The rears are an easy fix, pull the springs out, stick them in a vise up-side down; and very carefully with a bit of grease on a 1/4"NPT (if I recall correctly) tap, tap out the inside of the inlet. You'll be able to use a standard DOT push in fitting after that. The problems you're going to run into is with the lines....I won't be able to help you much on that as I used 1/4" DOT air brake line (I think BMW used 3/16" for the air lines). I don't see it being an overly complex task provide you have access to all the proper tools and skills needed.

As far as pros and cons go.....I'll bring in Skyline's previous statement about the generally accepted path of the need to increase spring rate because of decreasing suspension travel. Removing the ping tanks when you lower the truck is sort of the same idea....but still preserves the ride quality because of an air springs slightly different characteristics. As far as pros & cons though; I would list it as more of a necessity to not backyard botch an X....

You mention you drive on rough roads....our roads up here are pretty grotesque as well. Take a look at the pic below, this is my truck in the "low" setting. You can go about a maximum of maybe another 1/4" before the factory bags rub on the wheel carrier with daily driving....but IMO thats REALLY pushing it.



Hope this helps.

[4.8isX5]

X5snd, thanks for all the good info. You mentioned in your other post on how low 525s was sitting in the rear and the bag would be rubbing on the "carrier" i dont think this is an issue in the front though right? And i think im safe in the rear cause my rear height is probably close to what you have in your pic right above this, but my front is lower.

[525iT_Feen]

Originally Posted by 4.8isX5

X5snd, thanks for all the good info. You mentioned in your other post on how low 525s was sitting in the rear and the bag would be rubbing on the "carrier" i dont think this is an issue in the front though right? And i think im safe in the rear cause my rear height is probably close to what you have in your pic right above this, but my front is lower.

Yea thanks alot for the info XFsnd!

After last night i'm just about a 1/4 inch lower then you in back but quite a bit lower in front. I will be removing the wheels tomorrow night to do the spacers and will inspect. When you switched to management what made you keep the rear bags and not switch to a UAS Aero sport or similar aftermarket performance bag?

[TiAgX5]

Originally Posted by bigwave2255

......so in my view its not the lowering that causes trouble or causes the car to be unsafe, its how its done.

That about says it all!

[X5SND]

Originally Posted by 4.8isX5

X5snd, thanks for all the good info. You mentioned in your other post on how low 525s was sitting in the rear and the bag would be rubbing on the "carrier" i dont think this is an issue in the front though right? And i think im safe in the rear cause my rear height is probably close to what you have in your pic right above this, but my front is lower.

The fronts use air struts....so they wont be subject to the same issues as the rear. HOWEVER, that doesn't mean you wont have other clearance issues....
I would be willing to bet you have rub marks on the top of the fender liner from bottoming out.
Here's an exercise for you: Air out the front, and put a chalk like on the tire where the bottom of the fender comes to rest. Now air it back up to your ride height. This is the maximum amount of compression travel you have before you smack the absolute minimum....you may be surprised at what you find.

Originally Posted by 525iT_Feen

Yea thanks alot for the info XFsnd!

After last night i'm just about a 1/4 inch lower then you in back but quite a bit lower in front. I will be removing the wheels tomorrow night to do the spacers and will inspect. When you switched to management what made you keep the rear bags and not switch to a UAS Aero sport or similar aftermarket performance bag?

Essentially with aftermarket universal bags, whether they're rolling lobe, single, double or even triple convoluted designs.....have to many unknowns. What do I mean by that? Well for starters, there's the ride that they produce, which is dependent on things like material, # of ply's, suspension geometry and the pressure range they are designed to operate in. Secondly is the mounting issue---you need to find a bag with the right dimensions for the range of heights the X operates in but also contains the proper mounting points. Things get even more tricky when you move to the struts up front, as your options are even more limited.

When I was planning my system out, I only intended to go about an inch lower than the factory ride height of a 4.8is----just enough to even out the wheel gap for daily driving. I have the ability to lay it right out like you see in my sig, but it isn't drivable like that----strictly a photoshoot/parking height.

I looked into many (and probably just about all) air suspension "kits" that were available for the X. The airrunner kit was what I wanted to go with, but they wanted $4100 for just the struts and bags, and also would not warranty them if something went wrong with them because I wasn't buying their "complete" setup (I already had my valves, controller and compressor by that point). I would group universal air in with the stuff from airbagit.com and the lot....not exacltly quality stuff. If you want to do a true "performance upgrade" either go with the airrunner kit or contact the guys over at ride tech and have them fab up a set of Shockwave select's.

So I suppose to answer your question as to why I chose to stick with the BMW bags and struts....because it would do what I wanted, give me a ride I was familiar with, keep the install relatively simple.....and all the while being relatively reasonable in price (for a student lol).

Just one last point before I sign off here....
Guys, I don't mean to harangue you about this kind of stuff, but things like checking clearances after you play with the suspension is one of the first things you should be doing....just looking at the pictures that have been posted, shows that there is a ton of oversight/inexperience on your behalf. When things start to break (and they will if you keep driving around smacking bump stops all day)....don't be surprised if you receive more than a few "I told you so's". Please, if you don't know....ask! That's what we're here for!

[525iT_Feen]

Originally Posted by X5SND

Just one last point before I sign off here....
Guys, I don't mean to harangue you about this kind of stuff, but things like checking clearances after you play with the suspension is one of the first things you should be doing....just looking at the pictures that have been posted, shows that there is a ton of oversight/inexperience on your behalf. When things start to break (and they will if you keep driving around smacking bump stops all day)....don't be surprised if you receive more than a few "I told you so's". Please, if you don't know....ask! That's what we're here for!

I don't feel like i'm being harangued. I've dealt with quite a bit of aftermarket air but its always been switching a car from shock and spring to air (mostly VW/Audi) never something with already existing factory air suspension. If I didn't feel you know what you were talking about I'd just ignore your advice but I posted because you seem to know quite a bit about it.

I don't necessarily agree with you that an aftermarket rear bag couldn't be matched up and made to work BETTER then what is back there now but I have no proof because I haven't begun to look into it much and have no evidence to disprove your theory. I've used Aerosports which is on the cheaper end with no major issues but see your point about matching it up to the X's suspension ride.

I can however tell you that I have yet to bottom the front struts out. I've driven the car 500 miles now and while I agree 100% about the rear (which is why its raised almost to your height now - might even be the same height) the front doesn't seem to be as much of an issue. I had it up last night and saw no markings on the liner or bag and I know all to well what riding on bump stops feels like which I'm not.

I'll take another look tomorrow night when I throw it up to do the spacers and if i see any markings like what your mentioning I'll definitely raise it up and just order v3s.

Either way I'm not offended I enjoy informative posts. Its the internet so getting called an idiot by someone who doesn't know me never really affected me much. I take what I need for context and ignore the rest. Thanks for the info.