How many turns of the tie rod to set toe in?

[roccaas]

Currently running 7/16 toe in. OUCH.

Is there a ratio of turns to take 6/16 +/- 1/32 out of the front end?

[RonC]

http://www.abarnyard.com/workshop/align.htm

http://www.wheel-a-matic.com/page6.html

[Patrick L.]

Its just trial and error for me. The 'A' is easy, it won't take long.

[TDO]

Each turn will give you .083 so you need to go 3/8 inch so 4.5 turns will put you real close

[Tom Wesenberg]

It also depends on where the tie rods fall in line with the line for the toe in.

They would have to both follow the same line for the turns to be a direct relationship to toe in.

[Joe K]

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Originally Posted by Patrick L.

Its just trial and error for me. The 'A' is easy, it won't take long.

Isn't this what the Stanley Rule & level "folding rule" (with extension) is made for?

Here's a Lufkin - Stanley apparently stopped making these years ago.



Joe K

[roccaas]

Originally Posted by TDO

Each turn will give you .083 so you need to go 3/8 inch so 4.5 turns will put you real close

Thanks. Took 4.25 turns to bring it to 1/16".

[sphanna]

TDO: Am I correct to assume that there are 24 Threads per inch on the tie rod? I don't know, I just thought that was what calculated to at .083. When you toe in at the front, you toe out at the back so do you have to use 1/2 of the distance you need to correct?

[Patrick L.]

Wow, 4 turns. That must be some kind of record. I'd recommend checking it again sometime this summer just for the heck of it. Not necessarily because of the 4 turns, just for the heck of it.

[TDO]

Originally Posted by sphanna

TDO: Am I correct to assume that there are 24 Threads per inch on the tie rod? I don't know, I just thought that was what calculated to at .083. When you toe in at the front, you toe out at the back so do you have to use 1/2 of the distance you need to correct?

There is 24 threads per inch . 1/24 comes out to .0416 When you turn the tie rod One side is right hand threads and one side is left hand threads so that means your turning both tires at the same time , so you double the .0416 , that gives you the .0832, I just rounded it off to .083. If your tires are setting perfectly straight , and you turn the tie rod one turn you bring the tires in at the front .083. (1/16 is .062) you can go +1/32 which is a total of 3/32 (.093) so your .083 would still be with in your tolerance.
If you need to bring the front of the tires out ward than turn the tie rod the other way, and the formula will still be the same. I not very good at explaining things , Just remember, how much you move the front of the tires the back of the tires will be the same amount in the opposite direction.

[Tom Wesenberg]

For sure you want to double check the toe in. When you move the front of the tires in, you move the rear of the tires out at the same time. So are we now quadrupling the movement per turn of the tie rod?

[TDO]

Tom, I agree that you should always double check the toe in. But the way I see it , is how far the front of the tires are pointing in ward is the measurement of the toe in.
And in the model A it is 1/16 + or - 1/32. although the rear of the tires are moving out ward at the same time is an absolute. and has nothing to do with the measurement of the toe in.

[sphanna]

TDO, I have never thought of this the way you described. If I am understanding you correctly. I always thought the difference between the front and rear should be 1/16 +/-. The way I think you stated it you would have a toe in of 1/16 +/- from axel to front. and another 1/16 +/- from axel to rear for a total of 1/8 +/-. I still think it should be the difference from rear to front.

[MVal]

All the calculations re the tie rod threads and turns are fine but not of any value as I see it. This is because any measurement at the tie rods is only maybe 1/2 or less of the distance out to the tire sidewall. So a measurement at the tie rod of say 1/2" is in actuality 1" at the sidewall (or more). Be easy on yourself and forget about everything except the measurement at the tire sidewall--or was my Geometry 1 all wrong?

[TDO]

[QUOTE=sphanna;858496]TDO, I have never thought of this the way you described. If I am understanding you correctly. I always thought the difference between the front and rear should be 1/16 +/-. The way I think you stated it you would have a toe in of 1/16 +/- from axel to front. and another 1/16 +/- from axel to rear for a total of 1/8 +/-. I still think it should be the difference from rear to front.[/QUO

You are right , there will be a difference of 1/16 +or- 1/32 from the rear to the front ,I do have a hard time explaining myself at times. Getting it out of my head to the pen in my hand.

[Don/WI]

Here is information for calculating the number of revolutions of the tie-rod to acquire the desired “toe-in”. This is quite lengthy, but it should leave no questions unanswered. (Am I dreaming??)
First is some required information.
The thread on the tie-rod is 11/16-24 which calculates to a pitch of 0.04166” (24/1 = 0.0416666). Since there are two threads turning, one on each end of the tie-rod and one being right-hand thread while the other is left-hand thread, the total movement of the tie-rod is 0.083” as has been stated by a number of people. To move the front of the tires together, the tie-rod must be rotated CCW as viewed from the driver’s side (left side). Obviously, to move the front of the tires apart, the tie rod must be rotated CW.
The centerline of the Tie-Rod is 5.375” (= Y) behind the front axle. According to information gathered from the “Coker Tire” website, the diameter of a 19” Model “A” tire is 29.8” (14.9” radius = X1). The diameter for a 21” Model “A” tire is 30.75” (15.375” radius = X2).
The ratio of the movement between the tires, measured from the center of one tire to the center of the other, in line with the axle with the movement of the tie-rod is calculated thus: X/Y
In the case of a 19” tire, the movement is 14.9/5.375 = 2.772
In the case of a 21” tire, the movement is 15.375/5.375 = 2.860
To calculate the amount to move the tie-rod, use this formula for a 19” wheel:
Desired change = D D/2.772= amount to move tie-rod
To calculate the amount to move the tie-rod, use this formula for a 21” wheel:
Desired change = D D/2.86 = amount to move tie-rod
Using “roccaas” original question as to how much to rotate the tie-rod to move the tires 3/8” closer, here is the answer.
Desired change = 0.375”
(19” tire) 0.375/2.772 = 0.135” (21” tire) 0.375/2.86 = 0.131”
These dimensions are the linear distance to move the tie-rod. The rotational distance is a ratio of one rotation = 0.083 to the change required.
0.135/0.083 = 1.626 rotations
This can also be expressed as one (1) complete rotation (360 degrees) plus 0.626 x 360 = 225 degrees if you have a means to measure this. If you have read thru all of this, I thank you for your patience. Don/WI

ps: If the tire had no toe-in, the tie-rod should be turned CW 98 degrees (linear distance of 0.023") to obtain 1/16" toe-in.

[larrys40]

Not to dampen everyone's hard work on calculations as I find it incredible that you have it nailed down so close... but the accurate method is to use a toe in gauge..... plain & simple. I know that's easier said than done.. .but then, they are out there... or you can make one. Not sure how you can be accurate screwing in both sides at the same time all the way out, and in counting turns to hope you get correct toe in within a 32nd......

Admittedly I use an original duby guage... but also used an older aluminum tubular toe in gauge up to a few years ago that accomplished the mission. Maybe I need to go into making these things! Would you buy them?
Larry S

[Mitch//pa]

a duby gauge can be purchased for under 100 buckaroos

[larrys40]

Mitch,
I know... I have said that before that they have been around in a limited supply... not sure why all the unreliable home built attempts when good steering and the cost of tires is on the line. It would be an item for the local clubs to purchase for use.
I see the company who supplies them has a couple of different sizes.
Larry

[Mitch//pa]

larry
yes i agree they are readily available ..this is on amazon