zoomx2
zoomx2 Reader
8/7/09 10:39 a.m.

Yesterday I finished my spring and shock install on my Miata and now it needs an alignment before Sundays auto-x. My 2 local alignment shops are booked for a week and the munkees at my local Tires Plus were'nt sure what I meant when I asked if they would set the numbers to my specs (Lanny #'s), plus they wouldn't let me sit in the car or add ballast while they did it. So since I would rather screw it up than pay them to screw it up, how do I do it? I've read up some on a string alignment procedure but thought I would ask the experts first before I took a wrench to my car. Background: New tie rods, ball joints, Racing Beat springs, Koni STR-T shocks. The car is definetly lower than before. Right now the car pulls slightly to the right and if I hit a bump it jerks to the right pretty good. It also wants to step out in the back end more than before.

Appreciate any help.

BTW, highly reccomend the Koni's for street driving. As far as auto-x we'll see Sunday......

White_and_Nerdy
White_and_Nerdy New Reader
8/7/09 11:50 a.m.

I'm curious about DIY alignments as well (I've tried it before and destroyed tires afterward ), and will also be interested in what you think of the STR-Ts after Sunday. My understanding is they're basically Koni yellows on full soft. I had adjustable Konis on my last Miata and loved them, but my budget is practically nothing this time around. Shocks will help, and so far the STR-T is my top choice. More data, pro or con, will help me decide further.

Good luck!

peter
peter New Reader
8/7/09 12:01 p.m.

I've read and understood the string alignment procedures, but I'd love to hear from people how they level the car and get it high enough to slide under to turn the cams.

neon4891
neon4891 SuperDork
8/7/09 1:14 p.m.

my new issue of car crack has a good alignment article. But I'm not sure when the Oct. issue will be on news stands

amg_rx7
amg_rx7 Reader
8/7/09 2:18 p.m.

Hmm... I think GRM did an article on DIY alignment sometime ago. I think they also reviewed "Smart Strings".

Jensenman
Jensenman SuperDork
8/7/09 4:20 p.m.

Excessive toe in or out is what wrecks tires, camber just moves the wear area on the tire. Camber is, however, very important to equalize the load and wear across the tire. Ask Toyman about running slicks with insufficient camber.

deadskunk covered the high points for a quickie alignment. About camber: run over to Lowe's and get one of those angle finders, like this:

and use that against the rim to check the camber. Make sure the car is on a level floor, use a 4 foot level for checking the floor. If it's not level, pieces of Masonite hardboard can be stacked for the car to rolled onto.

The levels bungeed to the tires will get you started, be sure to check both front and rear. Once the toe is set (I'd recommend zero toe in the rear and about 1/16" toe out on the front to start), use a string to make sure the front and rear are in line with each other. If they aren't, adjust as necessary. This will get you in the ballpark for the weekend.

Once the weekend is done, you need to find the centerline of the car to be able to do a really good alignment. You'll need 4 plumb bobs, a way of making reference marks (masking tape and pencils will work) and a way of striking straight lines (a chalk line will work). Once the centerline is found, alignment is simple. Marking it permanently means you only have to go through that part of the process once.

Jack up the car and remove all 4 wheels.Now look at the front subframe mounting points and hang a plumb bob from each of these points. (Don't use control arm bolts as these move when adjusting the camber.) Mark each of these points on the floor. Then run diagonal lines between the marks, you'll now have a point at the center of the front subframe.

Now repeat the process at the rear of the car. You will now have 2 marks centered lengthwise under the car, these are your centerline reference point. You'll need to make a line on the floor the full length of the car, use the chalk line for this.

Use a plumb bob at the front of the car hanging from the front center of the subframe aligned with your centerline on the floor, make a mark on the subframe where the string crosses it. I used a hacksaw to make a notch. Now repeat this process at the rear and you now have a set of permanent centerline marks on the vehicle, unless you wreck it or replace a subframe.

To set front/rear toe after this has been completed: put all 4 wheels back on, then check the camber measurements and adjust as needed. (I'd get some toe plates. Much simpler.) You will need to hang plumb bobs from your previously made center marks on the subframes, mark those points on the floor and then mark a straight line on the floor again. A chalk line will work but it's hard to see if you are dead on the line. I used to have 2 pieces of aluminum strap 1/8" x 2" riveted together (it was about 16 feet long) which I slid under the center of the car, aligned one side of it with the plumb bobs and then held it down with weights. I could then feel when the tape measure touched the aluminum, a good tactile reference point. Check your toe from this center line, the measurements will need to be the same on each side for the wheels to be in line with the car centerline.

If you run, say, 1/16" toe out the front toe measurement will be 1/32" per side greater at the front of the tire than at the rear of the tire.

zoomx2
zoomx2 Reader
8/7/09 4:36 p.m.

Thanks for all the info so far. That's a whole lot of text there Jensen, thanks for spending the time typing that.

I have a angle finder like that, I think that it has a % of error +/- 1degree though, still accurate enough for camber? Will a digital one be better?

As far as toe, part of the problem is since the car is so low I cannot measure the tires at the 3 and 9 o'clock positions as recommended in most instructions. Will using a level strapped to the tire still be accurate for toe-in if the level is only up about a 1/3 of the way up the wheel allowing me to get a tape measure underneath still?

Jensenman
Jensenman SuperDork
8/7/09 6:00 p.m.

You gonna do a billy3 and count my words?

+/- 1 degree will get you in the ballpark. FWIW, on Miata stuff I've messed with in the past 1.5 degrees negative seems to be a good starting point.

Digital would be better, but those are pricey. There's one that was sold by Solotime (now SPS) that is marked in 1/8 degree increments and I have found it to be pretty darn accurate. It's now sold by Toyhead Auto (no affiliation of any kind on my part!) http://www.toyheadauto.com/CasterCamberGauge.html Heck of it is, mine was $39.95.

If there is anything other than zero toe unfortunately the toe measurement will change as you go lower and that difference will be dependent on how tall the tires are. I'd use toe plates and start at zero toe. As you get used to toe plates you'll be able to extrapolate a bit, i.e. 1/8" at the bottom will be ~ 1/16" at the 3/9 point you mention. You could also drop plumb bobs from the 3/9 points for accuracy but speaking from experience that is a PITA. The damn things go to swingin' if you breathe on them hard.

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