I am measuring about .5" @ 13'. Is this too much toe in?
~JH
Quote from: Jonny Hotnuts on July 07, 2010, 08:29:33 AM
I am measuring about .5" @ 13'. Is this too much toe in?
~JH
Jonny...most toe end is measured from front to back of tires we run about 1/8 inch. What are you measuring?
JL222
way to much...... take yer car to an alignment shop.... it probably wont fit the racks as my liner wont either but put it on the ground next to the rack and use their computer stuff.... for yer car shoot for an 1/8th..... my liner is 1/16th
kr
With wheels and rotors off I measured the distance between the tdc of the hub face.
With a magnetic laser snapped to the hub face I mark a point on a wall 13' (parrallel to the hubs) and mark a point on the wall for each hub reading dead level on the laser.
(The wheel hubs have a large section the laser fits dead flush with the hub.)
I measure 25" between the hub faces.
@ 13' the points are 25.5 (*the laser head is .5 off the base so 1" must be subtracted from the total).
This makes 24.5"
Because the number is less then means the alignment is toe in 1/2 inch @ 13'.
This is how I do my alignments.....Is this crazy.....seems to work good.
(*an alignment shop is not an option)
I will try to get the toe to 1/8 or less.
~JH
I set Hooley's Studebaker 2 years ago at 1/8" toe in just prior to Speedweek. It is a Mustang II style front end. The first pass, which was a turn out, he was all over the track trying to drive straight. We checked our specification from the original alignment and it had been set at 1/8" out. I reset the toe to the original setting even though it makes no sense. The car now goes straight with no unusual handling problems. I do not know why, as this is the oposite that I think it should be. Maybe someone knows the answer. All I know is that it works, so we are leaving it alone.
John
JH. google (toe in alignment) you will learn a lot there.
Jonny...1/8 toe on our car is the difference between the middle of both the front and back of the tires measured at center of hub. The tires are 24'' at 4' out it would be 1/4''....8'-1/2''....16'-1''
It would be better if you could get the exact centerline of your chassis to measure to and use two lazers or straight edges
JL222
This is what my toe alignment stuff looks like. I can send you a larger picture if you PM me an email address. It is something that I copied from a set like this that I borrowed while we were on the salt. It is two pieces of heavy sheet metal bent in a 90 degree bend with each side about 6 inches and about 18 inches long. A 3/4" square stick of wood is attached at the top so that it will lay up against the sidewall of the tires. There are slots near the bottom to hook and read the two tape measures. You take measurements in front and behind the tires. If you want 1/8" toe in, you will want 1/8" less at the front than at the back. Hooley says that the reason we set up his Studebaker with toe out is that at speed the down force (lower ride height) on the car makes the toe change and this setting makes his right. I know that sometimes toe will change with the ride height of a car,(independant suspension) so this makes sense to me.
John
The change in toe as the car changes ride height is the dreaded "bump steer". It can normally be adjusted out to a great extent on a conventional independent front end.
When you grab the two tapes to do the measuring hook them both over the same object, side by side, and pull them out to approximately the same length that you're going to measure. You'd be surprised how often they differ and by how much.
The only other thing I noticed with the setup shown is that the slots are toward the bottom. If you move them to toward the top, when you pull them tight the tops of the angles will clear the bulge at the bottom of the tire and give you a more accurate reading.
I've found most of these thing out the hard way while setting up road race and oval cars. Hopefully it'll save others from going at things the long way round. :-D :-D
Pete
Quote from: Peter Jack on July 07, 2010, 03:12:29 PM
The only other thing I noticed with the setup shown is that the slots are toward the bottom. If you move them to toward the top, when you pull them tight the tops of the angles will clear the bulge at the bottom of the tire and give you a more accurate reading.
The strip of wood along the top edge makes the jig catch the sidewall of the tire front and rear. I have noticed, as you have also, that almost all tires bulge at the bottom no matter how much air they have in them. By making the jig rest against the sidewall higher up on the tire you eliminate this problem of the jig rocking.
Most all independent suspensions have minor amounts of bump steer. When this becomes a larger change, it becomes a problem. Ideally you do not want any bump steer but in real life sometimes you have put up with small amounts. At speed the Studebaker is nearly on it's suspension stops and the toe is probably where it needs to be. If you were driving on the street this change might be a problem.
John
JHN,
If your measurements are right you have about .038" toe in per foot or about .076" difference front to back on a 24 inch tire. More than 1/16 and less than 1/8, pretty close to ideal.
Jim
If you do a Google search on FWD it states several places that you should run a little toe out to compensate for the tires towing in under acceleration. My car has no suspension but does have some clearance to take up in the moving parts that may effect the toe under acceleration. Any profound thoughts on the subject would be appreciated. Terry Nish told me they run about 1/16th toe out and they are RWD so maybe its on a case by case experimental basis?
Thanks Jim.
Basically, looks like I am measuring .5" toe in on a 156" (*13') tire.
Without using lasers it would be almost impossible to measure toe accurately to .076" on a 24" tire.
Because my front end is ridged there will be no changes in toe from down force or bumps and I could see where any suspension system could cause minute changes in toe.
Is there any problems with running zero toe on a ridged front end?
~JH
On a beam axle or rigid like you have, toe out is to be avoided to keep the steering from either wandering or feel like it is. A minimum amount of toe in prevents the inevitable play in the system from resulting in toe out.
Sorry WZJ. My old eyes didn't detect the strip of wood. Whatever or however you guys are doing you must be doing it pretty close to right because the results are there. :cheers: :cheers:
Pete
This is why I like Carroll Smiths books as he explains stuff like this, and one reason against avoiding toe out is if a gust of wind hits the side of the car in toe out the car will turn against the gust which is upsetting, with toe in it moves with the wind, or just moves over, as passenger cars are designed to do. He also explains all about bump steer and how much is acceptable.
JL222
Jonny
at 13 feet from your axle center line 13/16in will give you the same setting as Jl222's(1/8in on a 24 in tire)
I didn't see anywhere on here about how I learned to set toe in/out on a car from a friend of mine who raced atlantic cars. He put a jackstand at all 4 corners and tied some nylon snap-line to each stand from front to back. He then slid the stands where the back ones were behind the tires but the string was almost against the tires, raised or lowered the stand so the string was in the middle of the tire. Now with the other stands past the front wheels and also adjusted so the string is in the middle (up and down) pull the string tight and slide it out or to the center until the string is perfectly parallel with the back wheel (use a steel ruler and preferably another person cuz its easier) and when both sides are done, you have a poor man' laser! Take your ruler to the front and make your settings off the string which is square with the back wheels! Hope this makes sense. He also said run toe out as toe in would cause the car to dart. Just another idea to throw in the ring...