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Can I lower front end without messing up my alignment?

Posted By: Gusteve

Can I lower front end without messing up my alignment? - 06/26/10 08:16 PM

Hey all,

I rebuilt the front and rear suspension on my 68 charger. I added shackles to the rear to give it a decent rake. When I took the car in for an alignment, they adjusted the front end height to match the rear. I suppose they did this to get the best alignment. After a few months, I don't think I like the look, and want to lower the front end at least an inch, maybe two.

Is any adjustment at all going to screw up my alignment? Or how far can I go? I've hardly been able to drive the car at all since I bought it, and if I'm lucky this year, I'll put maybe 100 miles on it, if I can get it drivable enough. So its not like I'm going to toast the front tires in that amount of time if the alignment is off.

Will it handle funky if I lower it? Or should I just drop it down and not worry about it?

Last question - will it be easier to adjust it if if I jack the car up? Or will that not really matter since I'm lowering it, not raising it?

Thanks!
Posted By: WILD BILL

Re: Can I lower front end without messing up my alignment? - 06/26/10 08:42 PM

Changing the ride height will have an impact on the alignment angles. How much is hard to say.

Will it hurt your tires till you get it back on the rack? Again hard to say but probably minimal if any in only 100 miles.

My suggestion would be get it back on the alignment rack and have them set it where you want it and align from there.

I do it for my customers all the time.
Posted By: SNK-EYZ

Re: Can I lower front end without messing up my alignment? - 06/26/10 09:46 PM

Quote:

Changing the ride height will have an impact on the alignment angles. How much is hard to say.

Will it hurt your tires till you get it back on the rack? Again hard to say but probably minimal if any in only 100 miles.

My suggestion would be get it back on the alignment rack and have them set it where you want it and align from there.

I do it for my customers all the time.





Posted By: Neil

Re: Can I lower front end without messing up my alignment? - 06/26/10 10:18 PM

You can lower it down a little at home, but if you get to where the top of the tires start to lean in towards the car then it's time to see the alignment guy.

Another thing to watch out for is the underside of the upper control arms will start hitting the rubber bump stops on the fender apron. You can trim the rubber bumpers a little with a hacksaw or cut off wheel to gain a little more clearance.
Posted By: Wedgeman

Re: Can I lower front end without messing up my alignment? - 06/26/10 11:54 PM

I would say do not lower the front more than 1/2 in-3/4in at most, otherwise you will have to reset camber because it will feel like each wheel will go in their own outward direction

Dan
Posted By: Todd

Re: Can I lower front end without messing up my alignment? - 06/27/10 12:19 AM

Everything will change. Even if you lower 1/2" ever angle changes. Lower it down where you want it then take it to the alignment shop. At least a couple of miles to get the suspension settled before getting aligned.
Posted By: Wedgeman

Re: Can I lower front end without messing up my alignment? - 06/27/10 01:57 AM

It is true ! going by the book it will alter everything.

Dan
Posted By: pishta

Re: Can I lower front end without messing up my alignme - 06/27/10 03:35 AM

Yeah, even the slightest rear raising or front lowering will alter caster, taking out a little. When you do this, you can correcdt it a little by buying offset bushings for the upper A arms. By making the rear bushing offest toward the frame and the front bushing offset toward the tire, you effectively move the upper ball joint toward the rear, regaining lost caster. This helps the wheels return to straight after a turn and have higher speed stability. Camber is the tilting of the wheel inward or outward from the cars centerline. Lowered VW's have ridiculous negative camber on the rear IRS suspensions, looking like the tires centerline would intersect about 10 feet above the car. Generally, when you cranks the torsion bars down to lower the front, you dont alter the caster too much, if at all making them a little more negative. This will actually help steering but will wear out tires faster.
Posted By: Leadfoot

Re: Can I lower front end without messing up my alignme - 06/27/10 03:44 AM

Once you raise it or lower the front end too much the angle increase or decrease of the upper arm may cause the camber to fall outside the limits of your cams.
Raising will cause the camber to go negative lowering it will cause the caster to go positive.
About 1-1/2 inches away from factory specs will render you unalignable regardless of which way you go.
If you raise the back end your caster will go towards the negative side. They may have had to raise the front to compensate for your shackles.
Posted By: Kern Dog

Re: Can I lower front end without messing up my alignme - 06/28/10 06:45 AM

Some of what I have read here sounds like theory instead of experience. Lowering the car WILL affect caster.Anyone with experience with front end tech knows that. The toe setting will not change. The suspension was designed in an effort to minimize toe changes during full travel of the suspension. The camber going a little negative wont increase tire wear nearly as fast as incorrect toe settings. On a longer wheelbase car like the Charger, the alignment changes will be less dramatic than on a 108" Cuda or Duster.
A true, old timer alignment guy should be the one that can answer this question with certainty, but the guys that knew these cars when they were new are probably all out of the business by now. Good Luck.
Posted By: Mr T2U

Re: Can I lower front end without messing up my alignme - 06/28/10 12:03 PM

lowering the car should not change the toe as posted before.
it will increase the neg CAMBER, tilt of the tire. to much will wear the inside edge of your tire.
it will remove positive CASTER and add neg, angle of the upper ball joint to lower ball joint. positive caster aids in high speed stability. neg caster will make your steering wheel feel weird and the car will wander in the lane by it's self. think of a wheel on a shopping cart, this is a example of neg caster. this shouldn't add to tire wear much.
Posted By: JAKE68

Re: Can I lower front end without messing up my alignme - 06/28/10 02:01 PM

Please do yourself a favor and get it realigned. Changing the height changes almost everthing. Including toe. Hense bump steer. The up and down motion has a big efect on toe. That is why it takes some heating and bending to get rid of toe change when we do race car front ends.
Posted By: HealthServices

Re: Can I lower front end without messing up my alignme - 06/28/10 04:24 PM

boy, I think some of us should not talk about things when we are not sure if we have the correct answer.

Please at the very least check and adjust toe. It is the most tire wearing adjustment if off. You are basically scrubbing the tires when you have the toe off.

For those who think change in ride height does not change toe, according to test done by Hotchkis toe can change as much as 1 inch during the up and down travel of the suspension!

Although this video is about bump steer it basically tells you the toe is in a different spot depending on where the suspension (ride height) is.

http://www.youtube.com/watch?v=VzxPWrdPlt0
Posted By: Todd

Re: Can I lower front end without messing up my alignme - 06/28/10 05:38 PM

Maybe they don't understand bump steer?Ride height always gets ajusted first then camber/caster then toe.
Posted By: 1969RR

Re: Can I lower front end without messing up my alignme - 06/28/10 06:04 PM

X2! Ride height will affect camber and toe! Camber changes toe, toe does not affect camber. That is why you set toe last!! 1" change in rear ride height can change front caster approx 1 degree. Please, check alignment any time you adjust ride height!! Jeff
Posted By: Kern Dog

Re: Can I lower front end without messing up my alignme - 06/28/10 08:29 PM

Okay... If I am wrong, I apologize. I am aware of what bump steer is, but I didn't think that one to 1 1/2 inches below stock would be enough to make a difference. ONE full inch of toe change in full sweep? Is that the work of damaged components or REALLY sloppy tolerances? I have had a few worn out suspensions that had alot of toe change, but it seems that a rebuilt suspension with straight tie rod sleeves and drag link should be no more that 1/4 to 3/8 of an inch of bump steer.
Posted By: ledft79

Re: Can I lower front end without messing up my alignme - 06/29/10 03:06 AM

I do about 1,000 alignments a year, and been doing them many years. If you drop the front end, you WILL change camber, caster, and toe. The front end travel will change everything. If you just change the rear height, caster will change the most, but, you are still transfering weight to or from the front end, and that will change camber and toe some. If you raise or drop your front end half an inch without aligning it, I'll bet you don't get 10,000 miles out of your 50,000 mile tires. That's just my estimate, I've never put any mileage on one after altering the height.

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Posted By: Mr T2U

Re: Can I lower front end without messing up my alignme - 06/29/10 12:10 PM

if you significantly drop the front end, over 1/2". you will drastically change the front end geometry. and you should have the front end re aligned.
i dropped the front end on my 72 road runner 3/8" without really changing the toe, caster, or camber, out of specifications. if i remember correctly the camber is a little over 1/2* neg camber from almost 0*, 3* pos caster from 3 3/8 , and between 1/16" to 1/8" toe in from 1/16".
i get more tire wear from excessive pos caster than from the toe.
i dropped the suspension 1 1/2" - 2" from stock before i lowered it another 3/8".
after i dropped the front end i checked the alignment and didn't change a thing. i have driven this car over 15K miles and the tires still look like new. the tires are pirelli p-zero 17". i have to check the exact size, metric equivalent of a G 70, but they were take off tires off a 07 mustang gt.

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Posted By: Mr T2U

Re: Can I lower front end without messing up my alignme - 06/29/10 12:19 PM

yes it's low but i do have some ground clearance.
those are 4" collectors and the rocker is about 4 1/2" off the ground. the header flange is about 1 1/2" off the ground.
all of the dirt is from driving the car 400 miles to the show and not really washing it. i just gave it a quick wipe down from the body line up.

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