Alignment question regarding toe.

I changed the steering rack on the e30 the other day and wanted to align it. So I took some string and went at it.

The question is, if I want a total of 1/8th toe out, what would the difference in measurement be on a 15" wheel (I am actually measuring at the lip which is 16").

I got it to 1/32" per side more on the front than the rear of the wheel. By my calculations that is more than 1/8 toe out, but not sure.

Any ideas?

I set it by outside of tire to the outside of the opposite tire. Subtract accordingly for toe in or toe out. If theres an easier method than two straight edges and a tape measurw, I ain't found it.

Dusterbd13 wrote: I set it by outside of tire to the outside of the opposite tire. Subtract accordingly for toe in or toe out. If theres an easier method than two straight edges and a tape measurw, I ain't found it.

Yeah, thats basically what I am doing. I just don't know how much more show I measure on the front in order to achieve 1/8th deg toe out total.

By my calculations it would have to be around 1/64ths more on the front. Is that correct?

The number obviously has to change depending on the diameter of the wheel.

1/8".

1/8th of a degree? total or per side?

Triangle:

|\

|_\

| - adjacent

_ - opposite

\ - hypotenuse

SOH CAH TOA - sine = opp/hyp, cosine = adj/hyp, tangent = opp/adj

Your adjacent is 1/2 the wheel, or 7.5 inches. you are looking for opposite.

Tangent (1/8) = x/7.5

x = 7.5 * Tan(1/8)

x = .0163 inches or about 1/62nd of an inch.

Yup. Id actually shoot for zero toe on a street car.

I always use inches, never degrees.

rcutclif wrote: 1/8th of a degree? total or per side? Triangle: |\ |_\ | - adjacent _ - opposite \ - hypotenuse SOH CAH TOA - sine = opp/hyp, cosine = adj/hyp, tangent = opp/adj Your adjacent is 1/2 the wheel, or 7.5 inches. you are looking for opposite. Tangent (1/8) = x/7.5 x = 7.5 * Tan(1/8) x = .0163 inches or about 1/62nd of an inch.

1/8th total.

Ok, my math was correct then. I have 1/32nd now, will get it to 1/64th per side and be done with it.

Dusterbd13 wrote: Yup. Id actually shoot for zero toe on a street car. I always use inches, never degrees.

Yeah, I had zero before. I want to try a little toe out, I can always bring it back to zero if I don't like it. But after driving it a couple of miles as it is now, I think 1/8 will work just right.

Thanks.

good luck … I'd think that that much toe out will eat some tires pretty quickly

0 toe in my 924 and there is no feel to the steering. Put just a hint of toe in t it and it "feels" much better.

On a side note when I took the race alignment out of my car and put it back to stock the MPG's went up by about 15 percent or so.

wbjones wrote: good luck … I'd think that that much toe out will eat some tires pretty quickly

Why "good luck"?

I drive the car only 2-3000 miles/year tops if that; so what does pretty quickly mean? I bet they last no less than 6k miles.

If they wear out, I go and buy more ... its not like they are not making them anymore.

When talking in distance its just the difference between the front and rear measurement. if you want 1/8" out you set it so the front/leading measurement is 1/8 wider. If you want it in degrees you just draw up the triangle and do the trig.

You want a toe? I can get you a toe, believe me. There are ways, Dude. You don't wanna know about it, believe me.

plance1 wrote: You want a toe? I can get you a toe, believe me. There are ways, Dude. You don't wanna know about it, believe me.

Lol ... Only 1/8th though ... Can you do 1/8th

Slippery wrote:

wbjones wrote: good luck … I'd think that that much toe out will eat some tires pretty quickly

Why "good luck"? I drive the car only 2-3000 miles/year tops if that; so what does pretty quickly mean? I bet they last no less than 6k miles. If they wear out, I go and buy more ... its not like they are not making them anymore.

glad you're ok with that …. 6k miles for a set of tires would leave most folk a bit unhappy

Slippery wrote:

plance1 wrote: You want a toe? I can get you a toe, believe me. There are ways, Dude. You don't wanna know about it, believe me.

Lol ... Only 1/8th though ... Can you do 1/8th

with the toe set to zero (and hopefully with the steering wheel set the way you want it) then add 1/16" toe out to one side (leaving the other alone for the time being)

then go to the 2nd side and add the same 1/16" toe out to that side … total toe out is then 1/8"

I use toe plates and 2 tape measures

Toe setting would depend on some design features and useage too.

FWD? Front steer? Rear Steer? Wheelbase? Surface (skating or glued down)? Distance between turns and sharpness of turns?

You don't want something darty at high speeds with long straights and high traction.

FWD wants some toe out. (goes in under power)

Rear steer is very sensitive to toe out. (goes out under braking)

Etc. What it actually measures to is not really relevant as it is somewhat dynamic on a street car. Adjust for the feel you want, then measure it so you can repeat it if stuff changes.

Relative to a couple statements above, I found the 0 toe worked best on my ZX2SR.