DIY wheel alignment

[nattyphysicist]

I use the string method all the time. Tie the string to the towing loop at the back and wrap it around the rear tire, intersecting the center of the wheel, and up to the front tire. Then slowly approach the front tire (also intersecting the wheel center). You have to look to see if the string hits the rear or forward edge of the tire first. If it hits the rear edge first, then you have a toe in condition and vice versa. This assumes that the rear tire track width is the same as the front.

I guess the idea with setting static toe in is that the wheels will toe out when the suspension travels. Is this still true with a lowered suspension?

[FestYboy]

I use the string method all the time. Tie the string to the towing loop at the back and wrap it around the rear tire, intersecting the center of the wheel, and up to the front tire. Then slowly approach the front tire (also intersecting the wheel center). You have to look to see if the string hits the rear or forward edge of the tire first. If it hits the rear edge first, then you have a toe in condition and vice versa. This assumes that the rear tire track width is the same as the front.

I guess the idea with setting static toe in is that the wheels will toe out when the suspension travels. Is this still true with a lowered suspension?

there's only one problem with that theory: you're assuming that the rear is square with the body, and that the rear tires are toed in properly.

the best way to get an alignment is to find someone with a Hunter (newer laser and paddle design) and the willingness to shim the rear properly. Hunters use .00 degrees of accuracy. the one i use at my shop is so finicky that a slight breeze will change the measurements by as much as .07 degrees. sometimes it drives me mad!

to answer the question, as the car goes into jounce (down) there will be a toe in contition, and as it rebounds (up) there will be a toe out. now, if you were to lower the car enough to cause the inner tierods to be parallel with the ground, both jounce and rebound would cause toe out.

[nattyphysicist]

there's only one problem with that theory: you're assuming that the rear is square with the body, and that the rear tires are toed in properly.

the best way to get an alignment is to find someone with a Hunter (newer laser and paddle design) and the willingness to shim the rear properly. Hunters use .00 degrees of accuracy. the one i use at my shop is so finicky that a slight breeze will change the measurements by as much as .07 degrees. sometimes it drives me mad!

to answer the question, as the car goes into jounce (down) there will be a toe in contition, and as it rebounds (up) there will be a toe out. now, if you were to lower the car enough to cause the inner tierods to be parallel with the ground, both jounce and rebound would cause toe out.

When I lowered the car, it resulted in static toe out. I think that's why others here have said to make the static toe in. At the stock suspension height, jounce will cause toe out on the Festiva.

You've given the key to understanding this whole thing: the angle of the tie rods wrt to the ground. I guess the ideal case is that they are angled so the inner joint is higher than the outer? That way jounce will cause toe in?

Shouldn't the rear toe be set to zero? It's a trailing arm, so there will be no toe change with jounce. Anyone know what the stock rear toe is set to?

[FestYboy]

total rear toe is around .12-.20* or at least it should be. i'm not accounting for thrust angle in this.

about the toe in/out condition durring suspention travel, i was assuming tie rod angle to ground = 0 in relation to the ground (parallel) at ride height. you are correct in stating that lowering a stock festiva will result in a toe out condition. lowering further, or going into jounce will further this condition (not a good thing). a possible way to aleviate (sp) this would be to flip the outer end upside down so there is less initial angle on the inner rod. NOTE: this is assuming the inner rod is at an upward angle at ride height, and flipping the outer end would result in a more nutral angle.

[nattyphysicist]

total rear toe is around .12-.20* or at least it should be. i'm not accounting for thrust angle in this.

about the toe in/out condition durring suspention travel, i was assuming tie rod angle to ground = 0 in relation to the ground (parallel) at ride height. you are correct in stating that lowering a stock festiva will result in a toe out condition. lowering further, or going into jounce will further this condition (not a good thing). a possible way to aleviate (sp) this would be to flip the outer end upside down so there is less initial angle on the inner rod. NOTE: this is assuming the inner rod is at an upward angle at ride height, and flipping the outer end would result in a more nutral angle.

Yes, that assumption is correct. I looked at the tie rods on the weekend and they are angled up toward the wheels. I like the idea of flipping the outer ends to the other side of the knuckle mount. Is there a taper at that connection?

I don't understand why toe in would be a good thing for the rear. Is it something to do with the torsion beam and the way it acts under load?

Thanks for the insight on all this. I should have thought about these things before I lowered the car.

[Levitan]

I just had Levistiva aligned about 3 weeks ago. I used the opportunity to ask the alignment guy about toe in and toe out. He said rear wheeled car's toe is set slightly in so as to allow straightness when speed is reached. Front wheel cars are set slightly toed out and get straight when speed is reached. That's what he said.
As far as rear wheels, I had one wheel that was toed in just a smidge. He said if we had a long enough and sturdy enough pry bar, we could bend it out a bit. We didn't but it will be fine. I did have to use a 1 1/2 degree camber bolt purchased off of eBay to correct the camber on the right front. All I know it sure handles waaaaay better!

[FestYboy]

well actually, toe in/out is a factor of manufacture design, and not of drivetrain type. mid 90s taurus' like to be toed OUT about .07* whereas our cars call for .07* toe IN, and both are FWD cars. MOST vehicals call for a slight toe IN to recenter the wheel after turning and to stablize at speed. rear toe is for the same reason and i can't think of any car that calls for toe out in the rear (subsequently: rear toe out can cause the car to feel very squirly).

there IS a taper to the steering arm of the knuckle, and that would have to be removed and a straight shank rod end placed on the inner tie rod so that it could be flipped. there's another solution to this: drill out the taper, replace the outer end with a spherical bearing type end and attach with a bolt and nut.

[Arnie]

And all due respect to factory specs, but I only use those as a guide to see if anything is bent. I always align my cars to how I want them to handle. Am i understeering? Need more neg camber up front. Am i experiencing snap lift throttle oversteer? More neg camber in rear. Do i want faster turn in? A smidgen more toe out up front. More rear rotation? More toe out in the rear.

How much camber you'll need will best be determined by tire temps and lap times. If you are going solely on tire wear concerns, take a look at your current tire wear, see if you are getting more outside edge wear, inside edge wear or is it even? depending on your driving habits on that current alignment can give you a clue as to what you need to do. I find that my camber adjustment depends on how i'm driving at the time. Sometimes i go through phases of aggressive driving where i need more front end grip and i dial in more more neg camber up front. usually around -1.5 degrees. 1mm toe out. I'll get perfectly even tire wear. then i find myself driving like a grandmother and those same alignment specs give me inside tire wear. so i realign my car with maybe -.75 or -1 degree of neg camber and zero toe. Grandma mode gives me even tire wear when driving in grandma mode. Start driving aggressively again and i will see my sidewalls and outer edges wearing. You get my point. On the whole, zero toe up front will give you the most even tire wear. Like i said, in side or outside tire wear will depend on how much neg camber you run and how aggressive you drive.

I do all my toe alignments at home using two 3 foot shelving boards and a tape measure. I set both boards up against the wheels, holding them up against the wheels with a buddy or with jackstands and a sandbag. I measure the distance between the front wheels at the rear of the board then the front of the board. If the front measurement is larger than the rear i have toe out. Subtract the two measurement to find out exactly how much toe out or toe in you have. Split the difference and adjust the tie rod that much on each side to get zero toe. Or whatever amount you want to have. Camber can be measured either by using a camber guage from someone like Smart alignment or using math. You can also measure thrust angle using boards on the back and front and using a laser up against a tape measure in the front. but since we have no toe adjustment in the rear, nor camber, rear adjustments are pretty irrelevant.

A perfectly even floor is key and since most garages are not level i've found its possible to create a level section where you are aligning your car if you build up the surface of one wheel using linoleum flooring squares. You'll need to get a a straight edge like bar stock and put a level on it. Stretch it across the front of the car. place the squares underneath the low end until its level. Once its level use that same amount of squares in the same spot underneath the front wheel of the car. Then you'll know that spot is level.

[bbqsauce]

I hope someone is still treading this thread. I've got a 91 Festiva that has the front & rear struts and shocks from an Aspire just not the whole setup. I've got a set of American Racing Outlaw rims w/ 185/75/13's and I am eating up the outside tread on both front tires. Can I set my own alignment so as not to eat my tires.

[rcottle]

If you read this whole post and know if your wear is caused by camber or toe. Then Yes you can probably fix it. If not sure - I would take the car to an alignment shop. You know those guys that charge outrageous prices for that 10 minutes on that $50k machine which takes years to pay for. I would try to find an alignment shop with a tech that really understands alignments. There are those ones that just do toe and the adjustments that say they are adjustable. Then there are the ones that believe and will spend the time to make it all correct. Thats me but i do very few alignments these days. I need to get shims for the rear of mine. If you have any specific questions ley me know I will try and help...

[festivaWES]

Just jack the car up and measure center-to-center tread on the front and back. I always toe mine in at 1/8 inch. Just because your tires are wearing irregular doesn't always mean it is the alignment. Blown struts/shocks, worn wheel bearings, non-balanced wheels could all be factors.

[ejp2fast]

I did have to use a 1 1/2 degree camber bolt purchased off of eBay to correct the camber on the right front.

Thus far in the thread, Toe in and Toe out has been very clear on how to do it and the results. Camber though is still a little foggy on how to correct. In Levitan's post he mentioned the 1.5* camber bolt. Can someone please clarify this and explain a little more about it? Thanks.

[ejp2fast]

Whats the difference between camber bolts and camber wedges? rockauto has both..

[Mike McKown]

I thought the wheels were toed out on my car. It drove like it.

I put a carpenter's square against the front and rear of the tire sidewall, marked the floor at that point then drew a line between the two. Same thing for the other side. Then I measured the distance between the the two lines, front and rear. I had about 1/4" of toe out. Dont' know how it got there or why as I can't find anything loose.

I turned the tie rods a half round each to lengthen them. The car drives MUCH better now. I haven't re-measured yet but it looks like somewhere around zero toe. I could physically see the quarter inch toe-out before I adjusted on it by standing in front of the car but I measured it just to confirm.

[ejp2fast]

here is another link using the string-around-the-car method:

http://www.c-speedracing.com/howto/alignment/alignment.php

anybody use this type of method?