DIY Toe adjustment and Tire RR

[benfrogg]

Two things;

I had an alignment done last summer. Everything checked out to 0 afterward. However, camber was way off (1.8degrees) because someone had cut the stock front springs to lower it.
I replaced the front struts with junkyard ones I had in the garage. The ride highth was restored, but the alignment shop cautioned me that this was likely to change toe as well as camber.

I used the backyard method tonight, to get a rough idea of what we are looking at. I bungied a 2' level to the tire face in the center at the widest point. I centered the steering wheel. I raised the front end of the vehicle off the ground. I used a standard tape measure to measure the distance to the other front tire to my other 2' level that I held in the same position. This gave me reference point that should be reasonably close to the same on each tire/wheel. Now, I'm aware there are variations in tires from side to side, so I'm guessing my accuracy is probably within a margin of error of 1/8th inch or so.

The difference between the two measurements was 3/4" of an inch. (toe IN) This seems excessive. Assuming that I was able to toe on of the tie rods out so that the tire moved 3/8" of an inch or less, I should be closer to zero, right?
I made an adjustment and got the two numbers within 1/8" of each other. The toe is still slightly in, according to my measurements.

Question 1, how effective is my procedure?
Question 2, shouldn't toe be zero or even slightly out because accelerating a FWD car will pull them in?
Question 3, how much effect would 3/4" have on toe in angle? (not a math wiz here)

I'm aware that alignments are done with the weight of the vehicle on the axles. My method is impossible this way because I can no longer measure in the center of the wheel at it's widest point.

The car drives no differently around town that I can tell so far. I've got a few known hills that I coast from 45mph up to about 62mph by the bottom during EOC. If these hills change dramatically, I can infer results from this low tech testing.

Yes, I could (and will likely have to) go to the alignment shop and pay $75 to have it done again. I'm just trying to keep the expenses low at the moment.




Okay, onto part duex:
I've got two new sumitomo htrt4 tires I just put on. They handle very well at high psi's (running mine at 52, considering increasing to 55). They also have pretty good snow traction for an all season.

The rears are Pirelli P3000's. They are a 75k tire and were on the car when I got it. The web says that pirelli says they are LRR. Forums and this post:
http://www.gassavers.org/showthread....=pirelli+p3000 (about a california study on RR) say that these tires are really bad for RR. In other words, they could be effecting FE negatively).

The questions are:
How bad are these tires for RR?
The tread is at about 1/3 or less left right now. I'm going to have to replace them this summer for a sticker, I think. I'm gonna have dad order me up some for my birthday so I dont have to pay for them.
Will it be worth it to swap them out before they are bald because of the LRR argument? (cost benefit analysis of 3-6 months [1200miles a month] ) I usually run tires to the bitter end because in the summer handling isn't compromised too bad and you save some money/resources by keeping them on until wear bars have been showing a while.

Thanks for the input.
B

[theholycow]

Regarding the rear tires...

I don't think RR will ever win against not buying new tires. Keep rolling the old ones. Worn tires have better RR than new tires anyway, for whatever that's worth.

[GasSavers_Erik]

I believe that the toe will usually change when you raise the front end of the vehicle.

Here's my method for checking toe (similar to yours except weight is on the car and I measure the tread distance) I admit that this method also cannot measure the wheels at their widest point:

1. Park the car on a very flat surface (cement) with the steering wheel perfectly straight.
2. Place a stick pin or sewing needle in the rear facing side of each front tire tread as high up as you can and still be able to make a straight line between them without hitting the car underbody.
3. Use a tape measure and record the exact distance between the base of the pins- you will likely need a friend to hold the tape against the pin on one side as they bend easily. Hint- it will be more accurate if you use an arbitrary mark on the tape (like the 10" mark) rather than trying to use the "hook" on that end of the tape
4. Leave the pins where they are and roll the car forward (push it) with the steering wheel still straight until the pins are as high as possible on the front facing side of the tires with no underbody interference.
5.Repeat the measuring step.

If you usually carry a bunch of stuff in the car, then it would be even better to check the toe with the car loaded up.

[theholycow]

Some front-end alignment ideas here:
http://www.gassavers.org/showthread.php?t=1144

I think I remember a similar method using 2x4s instead of lasers.

[benfrogg]

Thanks-
Those are some good ideas on alignment. I'm going to measure it on the ground today and see what I'm looking at. Still, 3/4" seems excessive even if it was to come out some when the vehicle is lowered. I'm sure I can get it closer to what it needs to be.

Any idea what 3/4" of toe in could do for FE? I would imagine it is not helping!

HC-
Yeah, I'm going to sit on these tires a while longer. I probably wont go all the way to full bald like I did on the fronts, but I'll get past the wear bars.
B

[benfrogg]

I also just found an incredible tire website here:
http://www.barrystiretech.com/
You can spend an afternoon reading about tires here. There is an extraordinary amount of great info.
This particular link is great for RR and FE:
http://www.barrystiretech.com/rrandfe.html

If it isn't already, perhaps HC might want to put this into his Meta-sig. It's pretty good stuff.
B

[theholycow]

I love that site and I'm pretty sure it's in there, or at least in one of my posts (linked in there) on tires.

[benfrogg]

On the ground using my method, I was 1/8th" out. So, I can infer that I was rolling likely 3/16" to 1/2" toe in before. I corrected the to out condition to 0, but a hair to the toe in side.

I'll note my hills on my trip tonight, if the traffic is light.

HC-
I didn't see it in your meta last time I looked. It might be buried in another thread link or something.
Thanks!
B

[theholycow]

Found it, it's in the tire pressure thread linked directly in my sig.

Some day I should re-do all of that stuff, condense it and clean it up. In the past few years I've learned to be much less verbose.

[Ford Man]

Most cars still run just a slight toe in, I'm not sure just how much but just watch the wear on your tires and if they go to wearing on the inside you have too much toe out and if they wear on the outside you have too much toe in. I think about 1/16-1/8" is usually about the recommended toe in.