Lvangundy

I've lowered two cars of my own and noticed that doing so makes the steering heavier as the ride height drops. I'm also wondering if this assists in premature wear/failure on the power steering system.

Why does this occur? My only guess is that as the higher the control arms are sitting (the lower the car) while the wheels are straight, it's becomes harder for the steering system push the controls down (or the chassis up) while rotating the wheels. Notice how the height changes during certain points in the rotation of the wheel from left to right? I don't know if I'm wording this correctly, but it's the only concept that comes to mind.

mmarshall

Several reasons...you hit on one of them above. Other contributing factors are:

(1) The fact that lowering the car usually means using wider lower-profile tires than stock. These wider tires put a larger footprint on the road, more grip and friction, more resistance in the steering column, and therefore a greater effort required to turn the wheel. The actual response to the steering with this type of tire, though, is quicker.

(2) A lower ride height, especially with front air dams and extended rocker panels, lessens the amount of air flowing under the car, therefore the amount of lifting force that the car's body produces under motion. Less lift means, in effect, more downforce and more gravity effect forcing the tires down on the road.....therefore more steering effort required to turn them.

(3) Less suspension travel on a vehicle with lower ride height, meaning that as the springs and shocks compress more fully in the same radius turn, more of the steering feel, effort , and resistance involved in actually steering the wheels in the turn will be transmitted through the suspension and steering hardware into the driver's hands.

(4) With the lower ride height, more effort in the steering will also be required for the driver to overcome the effects of what is called " bump steer "...the tendency of sharp bumps in mid-turn to throw the car's nose off course....this, of course, in a car without a stability system where the electronics do all the work..

Lvangundy

Those reasons make me second guess lowering a car *hoping* for performance gains. If an IS300 at stock height can outrun a GS on a road coarse, why lower a GS to try to achieve the same result?

I could only see potential handling gains with control arms designed for a lower ride height. I'm far from knowledgeable in suspension design, but I would guess different control arms would be more fitting.

I remember reading a track time test on Tirerack( etc..) with a BMW 3-series and different spring heights. At the lowest drop, maybe 2.5", the car barely gained any time on the track. There are so many OTHER factors there though.

Addition - With all those factors you listed above, I'm betting that more strain on the power steering system could eventually wear out the pump or bushings/knicukes (? ) MUCH faster.

RA40

iTrader: (6)

By lowering it alters the geometry of the components so steering feels different. You can adjust the caster angle so that turn-in is compensated to some degree. I forget which way makes it feel heavier and which way it feels lighter...??

mmarshall

Positive caster ( with the wheel assemblies leaning toward the front ot the car ) will generally increase steering effort. Here is a site that explains it more fully:
http://www.tirerack.com/tires/tirete...e.jsp?techid=4

RON430

Two reasons to lower. One I put in the "chrome it if it don't go" category and the other is performance related.

So numero uno is to reduce or eliminate the wheel to fender gap that so many people have found so objectionable. I put this in the beauty category.

Numero two is to lower the center of gravity. I wouldn't want to get in to aero considerations unless you only drive on the autobahn. Aero effects under 50 mph are not going to affect lap times very much. The underside of modern cars can be quite good but the amount of extra downforce you get something like a GS with reducing the body to tarmac distance is not going to be a lot. Spoilers do wonderful things but not for free. Down force at speed comes with drag.

So all things being considered what happens to lap times reducing the center of gravity a bit? About what tire rack found. And of course once you lower and get all that image of speed, you also get to provide endless amusement value for people watching you attempt to scale speed bumps or go up steep driveways. Lowering can be useful or not, especially on street cars. And a lower that might look and seem fine when you take pictures of it in front of your gf house is another mattter when you take her and her parents out to dinner and get high centered on a speed bump. Been there done most of this.

I found out where you could and couldn't put mufflers on a lowered 69 Z28 by ripping the exhaust off going over some railroad tracks. Personally I think there are quite a few other places to improve lap times without lowering. And as you found out, the designers design for a certain ride height and when you take it upon yourself to alter it you are now the suspension engineer. But there is also nothing wrong with deciding you don't like the mod and undoing it. Been there and done that too.

Lexy GS430

i have lowered three cars already, and for som reason lowered car steering feel better everytime, i have no problem.