Alignment change with lowering

Canada Kev · 06-25-2012, 09:13 PM

If I adjusted the torsion bars to lower the front end of my car about 1/4 inch, in what way would my alignment change?

Currently, it sits pretty low, but it does have raised spindles so my A-arms are angled slightly downward. With it a bit lower, they would likely still be below level, and for sure not angled up. How would my alignment change? Camber would be affected, but how much? More negative, I presume? How about toe - more toe in?

I recently had an alignment and corner balance, but the front was set too high (my fault). I don't want to get it aligned again right now if I don't have to. I'd just turn the adjusters an equal amount to get the quarter inch. Or maybe I'll just live with the height where it is...

Any thoughts?

Tidybuoy · 06-25-2012, 09:40 PM

I was told by my alignment guy that the slightest change in ride height will affect tow. This is becaue the angle of the tie-rods will change and either push out or pull in as the angle straightens or leans more.

michael lang · michael lang's Garage

That and also the balance of the car because the center of gravity has just changed. I'd say unless you jump in with both feet, you should just leave well enough alone.

Elombard · 06-26-2012, 03:51 AM

Yah youl will mess up your CB a little,

When you lower the car the outboard end of the tie rod (attached to the wheel hub) stays in the same location. the in board end of the tie rod will go down with the chassis (its attached to the rack). As the chassis comes down it pushes the tie rod outer end outward. When the outer tie rod end goes out it causes the rear of the tire to go out and the front to go in - so it causes a toe in condition....

Unless you are really low then it does the opposite as it pulls the rear of the tire back in when the tie rod goes past horizontal.

Its like the hypotenuse of a triangle....not sure that helps.

As the hypotenuse gets more level the base has to get longer or the triangle wont close....nah that does not help :-)

Canada Kev · 06-26-2012, 06:27 AM

Would the corner balance get messed up if I'm lowering both sides the same number of turns on the adjusters? If that's the case, I'm not going to do it, just too much hassle. However, if it's just the alignment, especially the toe that would need attention, I could just set up some strings to measure and fix it up. I'm not adversed to getting a bit more camber up front - I'm only at about - half a degree, now.

Elombard · 06-26-2012, 06:41 AM

Yes, as you lower the front (assuming both sides lower the same amount) the weight of the car shifts forward and weight comes off the rear. It is probably a small amount, might not be a big deal...might be a positive thing? maybe some one who has done a bunch of them will chime in.

I "think" the right - left CB is more important than the front rear on our cars...I dont think you can change the front - rear as much overall....I am speaking out of my comfort zone - might need an expert opinion.

mnez · 06-26-2012, 09:29 AM

You will not mess up the corners weights by lowering both fronts by the same amount. Dropping the front 1/4" may shift some weight from the back to the front, but I suspect it is insignificant.

It is worth having your guy put it back on the alignment rack and readjusting the toe. Out of spec toe will ruin your tires fairly quickly - something that often gets blamed on negative camber.

Canada Kev · 06-26-2012, 10:01 AM

Yeah, I would just take it back to my guy, but the shop is in another city far, far away. The people I've dealt with here in the past have proven, uhh, less than stellar. There is one other shop I might look at, but perhaps I'll try the strings myself first.

Another thing I've noticed, the car drops a quarter inch when I fill the tank from empty to full. What will this do to my alignment and tire wear? I know you should have about a half tank when you get alignment/CB work done. So I would suspect that 1/8 inch height difference either way won't do much bad stuff.

It's also pretty amazing what almost 200 pounds up front does to the ride quality.

Elombard · 10:25 AM

You could try taking a straight edge and drawing a line on the floor next to and along the front tires (front to rear)(3 or 4 feet) then carefully reach under and turn the adjustment a couple of turns to the height you want. Then put the straight edge back and see if the line orientation has changed...

What ever you do put the gas in the tank and roughly the equivalent of your weight in the drivers seat - makes a big difference in where everything lines up.

Note: when you have heavier T bars the ride ht does not move around so much with the weights changing - which can be nice.

Also Note, going down on ride height with the adjusters is probably OK with the cars weight on them, I hear its best to take the weight off when adjusting the front ride heights though, but that will not allow you to use the quick and dirty check above, you will need to do the full monty on the alignment and settle the car first etc. if you take the weight off. raising the ride ht with the weight on could cause the adjuster to strip or break.

Canada Kev · 06-26-2012, 10:55 AM

Yeah, I HAVE larger TBs - 21 or 22 mm, I think. Still, 200 lbs up front will make a difference.

I'll give this a go, and ill check the toe before and after. It's easy to switch back if it gets too out of hand. But not for a few days - long weekend coming up and I want to go do stuff.

Chuck Moreland · 06-26-2012, 09:56 PM

Lowering the front causes the camber to become more negative, and more toe out.

Front ride height can change 1/4 inch between full and empty fuel tanks. Compound that with passenger weight and luggage changes.....

For a racecar, yes 1/4 makes a meaningful impact on alignment. For a street car, not a big deal.

Lowering the front has no meaningful impact on corner balance, provided both sides are changed exactly the same.

Canada Kev · 06-26-2012, 10:37 PM

Thanks, Chuck.

T77911S · 06-27-2012, 04:15 AM

camber is your big concern. you already have the ideal setup with raised spindles. that is done, as you already know, to keep the lower control arm at an angle that was intended by porsche to increase neg camber when turning. lowering the car eliminates or reduces that suspension design and can cause bigger problems that are usually fixed be reducing suspension movement, which reduces grip in bumpy turns.
if you want to lower to make it handle better, you may lose more than you will gain. if you want to lower for looks, go for it.
after lowering it, you may need to look into raising the steering rack to reduce bump steer.

Canada Kev · 06-27-2012, 06:02 AM

I just recently had the whole car raised 3/4 of an inch, as I thought it was too low. I should have given the shop fender height measurements instead of just telling them the height I wanted it raised. Really, this is more for looks, as it handled pretty good before and does so now, too. However, in my opinion, the front is a touch too high in relation to the rear - about 3/4 inches higher. To get it where I want it, it's a whole lot easier to lower the front a bit than raise the rear the same amount. Maybe I should just try to find a local place to raise the rear that quarter of an inch and do an alignment to make everything copacetic. Right now I have fender heights of 25.25 FR and 24.5 RR, or very close to that.

T77911S · 06-27-2012, 06:31 AM

camber is your big concern. you already have the ideal setup with raised spindles. that is done, as you already know, to keep the lower control arm at an angle that was intended by porsche to increase neg camber when turning. lowering the car eliminates or reduces that suspension design and can cause bigger problems that are usually fixed be reducing suspension movement, which reduces grip in bumpy turns.
if you want to lower to make it handle better, you may lose more than you will gain. if you want to lower for looks, go for it.
after lowering it, you may need to look into raising the steering rack to reduce bump steer.