adding toe, how it affects steering/front end?

[concretejungle]

Thought i would throw this out there, but recently i have noticed a lot more wandering on the road with my rig. More so then usual. So i figured i had something loose, maybe wheel bearing, maybe trunion, tie rods worn out, 4 bolts holding steering arms on knuckle.....

It was only further noticed when i jumped behind a friend's 80 series last friday and drove it for a while. I notice how much tighter his steering was and how straight his truck drove.

my truck has j springs up front with slee blue bushings pressed in using landtank's template. No vibs at speed. I have a ARB bull bar with a t-max 12,500 lbs winch.

Yesterday i decided to mess around and see what was loose. So i put the front on jack stands and perform the checks as Landtank has pointed out in a thread some time ago.

First, checked tightness at the 3 and 9 oclock positions. Tight.

Next, 6 and 12 positions. Tight

Checked the four bolts on the bottom of the knuckle. Tight.

i then lowered the truck and put the frame on stands so the front end could sag. I tried to push the axle side to side in an attempt to test the bushings in the panhard. Pretty solid.

So i'm thinking WTF is the deal here. Then i remembered someone saying that with larger tires, adding a little more toe-in helped handleing. So i added just a little more toe. What i noticed was my rig still wandered a bit, but not as much. Also, the front end felt much tighter. As if i had done an axle job or something.

just thought i would put this out there. I did not eliminate all my wander, so i'm still a bit stumped on that. But i reduced it. I figure it's almost time for a rebuild anyway, so a front axle job, new rod ends, new panhard should really do the trick.

['74 UA FJ]

More toe in will increase tire wear. FYI.

I remember nate having a similar issue and he fixed it by tightening a screw on the worm gear or something. Let me see if I can find that thread.

http://forum.ih8mud.com/80-series-te...-softness.html

[FirstToy]

I agree.
My toe was eyeballed after i replaced my tie/relay rods and I finally got the alignment done professionally. It made a big difference in handling and felt much more "set in" instead of darty handling. It is really nice after a simple professional alignment.

[concretejungle]

Originally Posted by '74 UA FJ

More toe in will increase tire wear. FYI.

I remember nate having a similar issue and he fixed it by tightening a screw on the worm gear or something. Let me see if I can find that thread.

http://forum.ih8mud.com/80-series-te...-softness.html

You are talking about the adjustment on the steering box aren't you? Yes, i have thought about that, BUT, when i did that last (almost 4 years ago) my power steering developed leaks and has been leaking/moaning/groaning ever since.

Unfortunately, i think i'm about to need to spend some serious money on the 80's steering system.

['74 UA FJ]

I don't see how taking up the slack in the steering box would cause a leak. Perhaps just a coincidence?

Power steering systems are prone to leak with age.

[landtank]

I'm sure you are aware of the fact that you're under in caster with that setup and the fact that you have 37s on it only increases the problem.

For checking the rubber bushings I usually use small pry bars right next to the bushing and really work them over. It takes a lot of force to get near what they are seeing from a moving truck. Also, since I've seen you wheel first hand Slee's blue bushings might have cracked similar to the OME yellow ones on trucks that see a lot of twist. You might have to drop the arms to see that.

[Tools R Us]

"Professional" alignment on an 80 equals set toe. Yes they can tell you about other things that are out of spec, but none are adjustable. There are two ways to measure it, degree angle, this requires a machine and toe measurement, with a tape measure or bar. Toe if done correctly and carefully can be set just as accurately with a measuring tape as a high dollar machine.

Like most alignment specs, toe measurement is affected by bigger tires, the factory spec (0 - .16") is for ~30" tires, measured ~15" from hub center. With larger tires, if measured where it's normally measured, at the tread center line, the spec will need to be adjusted. Degree angle is unaffected by the tires, so if you adjust a set of 30" tires at .16" it will be ~4 degrees of toe, with 37" tires it will be somewhat less. I will leave the correction factor math to someone who cares about that stuff.

A general rule of thumb is; larger tires need more toe and less caster, to net a comfortable drive. Most bias ply tires require less/no caster, standard truck radials in the middle and stiff, heavy load carrying truck radials need the most.

IIRC I set it at ~.125" and went to a deserted long straight section of highway. Drove at highway speed, sawed the wheel back and forth a few times, got a good "feel" for how it drove. Pulled over cranked in some toe and repeated until I found the spot where it was "right" for me. The factory specs are great and will probably net close to the best setup for a soccer mom in a stock rig. My junk is no longer that rig and prefer it's set to be comfortable for me.

Excessive toe can cause higher tire wear and drag, but will take a pretty big number to get there. If I had to guess, I would say mine is probably in the ~7/32" range with the 37's?

[landtank]

Where are you getting the info that bias ply tires want zero caster. I did alignments back when everything was bias ply and not once did I see specs requiring zero caster. The one thing we did see is with the advent of steel belted tires and their lower rolling resistance it was recommended to set toe to the minimum spec which was often zero toe.

I set my toe with a tape measure and adjust toe just enough to know that I'm toed in and nothing more.

[concretejungle]

right now, i have not measured how much toe in i have. I do know that the steering is much tighter and it tracks better. I plan to take just a little out tomorrow, drive for the day, and continue this process until i know "what's good and what's bad" for my driving style. After that, i will take it to an alignment shop to see exactly where i ended up.

[Tools R Us]

Originally Posted by landtank

Where are you getting the info that bias ply tires want zero caster. I did alignments back when everything was bias ply and not once did I see specs requiring zero caster. ...

Had to dig out an old Service Manual;

1968 Olds 88
caster 0 deg to -1 deg

1965 Cadillac, except 75 Series
caster -1/2 deg to -1 1/2 deg

1968 Buick Skylark
caster 0 deg to -1 deg

1963 Chevy Bel Air, Impala
caster -1/2 deg to +1/2 deg

1966-68 Dodge Monaco, Polara, Coronet
W/O Power Steering; caster -1 deg to 0 deg
W/ Power Steering; caster +1/4 deg to +1 1/4 deg

1965 Ford Galaxie
caster -1/2 deg to +1/2 deg

1964 Mercury Monterey
caster -1 deg to +1 deg

I can go on, but got tired of typing.

It was mainly on the huge tuna boats. They got away with it for two main reasons; The bias tires deflected more, causing more drag, return to center and they wanted them to have as light as possible steering on their "sofas on wheels". Yes, if you put radials on them, without changing the caster, they were evil to drive, herding sheep!

[motoloco]

Pretty simple to diagnose, Have someone get in and steer the truck while you check EVERY part on the frontend, then set your toe about 1/8" in (radial tires tend to want to pull apart slightly at speed) IF it still has sloppy steering or "follows the road" its your caster.

[Tools R Us]

Originally Posted by landtank

...
I set my toe with a tape measure and adjust toe just enough to know that I'm toed in and nothing more.

Glad that it works for you, but it may not be the best setting for all rigs, mods and driving styles? Have you tried other toe settings to see how they effect your rig?

[landtank]

Originally Posted by Tools R Us

Glad that it works for you, but it may not be the best setting for all rigs, mods and driving styles? Have you tried other toe settings to see how they effect your rig?

The truck drove like crap with the OME bushings in with the factory toe setting. I then worked out the caster with plates which is when I set the toe to near zero. The overall improvement over what I had before was so drastic I left it alone.

I had another member drive the truck and he felt it handled better than his T100. Maybe it could be better but it really drives great.

[IdahoDoug]

I wouldn't be afraid of a bit extra toe in, and when I bought the 97 a few years ago I had an alignment shop do just that because it wandered a bit compared to the 93. I have the numbers around somewhere but IIRC it was at the max toe in setting of the spec'd range. It took about 50% of the wandering out, but is nowhere near as rock stable as the 93 which I've had since new.

Having said that, the tendancy to wander is extraordinarily sensitive to tire type, tire pressure and of course to wheel offsets that are not at factory. Radials don't tend to steer away from each other, they go straight down the road better than a bias ply and like any tire they will respond to castor, camber, and toe in. A tire's tendancy to steer itself is a very bad thing and mfrs do not build them to do that - pure urban legend.

If you've accounted for the lift's effect on caster, I'd not be afraid to dial in more toe in though the above suggestion of 1/8 inch difference from back of rim to front of rim would be huge - too much IMO. You'll also notice a bit crisper steering response with added toe in.

DougM

[-Spike-]

1/8" front to back too much? Wow, I always set it between 1/8" and 1/4".

-Spike

['74 UA FJ]

Originally Posted by Tools R Us

Most bias ply tires require less/no caster, standard truck radials in the middle and stiff, heavy load carrying truck radials need the most.

Are you certain that you don't mean "camber" and not "caster". Try driving a truck with 35 inch bias ply swampers and zero caster and get back to me on that statement.

[peepers]

Originally Posted by concretejungle

You are talking about the adjustment on the steering box aren't you? Yes, i have thought about that, BUT, when i did that last (almost 4 years ago) my power steering developed leaks and has been leaking/moaning/groaning ever since.

Unfortunately, i think i'm about to need to spend some serious money on the 80's steering system.

FWIW, I just replaced my drag link with OEM ends and a Slee HD tube and the tie rod with OEM and and an OEM bar. My steering box was blown so I replaced that with a "working" used one and I still have the lack of tightness you are describing.

What's my point? Rule out absolutely every else before you dump all that money on the steering parts. I had loose bolts under there from when I did the Slee 4" lift. The rear bolts on the castor plates were loose and the front panhard bolt was loose. check them all... I have to go under and do it again, they have me worried.

[knorrena]

Good info guys. I am currently in the process of changing out my tie rod ends, and if that does not help, I was planning on putting in new bushings too.

I hope that the following is not considered a hijack, but I was also inspecting my rag bushing. I can grab the firewall side of my steering and easily flop it around. The dust seal is worn out too. I have read a number of posts that state that the rag bushing floppiness does not contribute to vague steering, but I find this nearly impossible to believe. Have you looked at yours ConcreteJungle?

Karl

[concretejungle]

Originally Posted by knorrena

Have you looked at yours ConcreteJungle?

Karl

I have not. Actually, i'm not even sure what it is? I'll have to give it a look-up this evening in the FSM.

['74 UA FJ]

Originally Posted by concretejungle

I have not. Actually, i'm not even sure what it is? I'll have to give it a look-up this evening in the FSM.

Typical rag joint:

[concretejungle]

never seen that before. Is it located in the steering linkage from the steering wheel to the steering box? anyone have a pic of this in the system?

[Tools R Us]

Originally Posted by '74 UA FJ

Are you certain that you don't mean "camber" and not "caster".

Those are caster specs.

Originally Posted by '74 UA FJ

Try driving a truck with 35 inch bias ply swampers and zero caster and get back to me on that statement.

Exactly my point, Swampers are relatively stiffly constructed tires and will need a different setup that a lesser, softer bias ply. A setup that drives great with say a load range C Geolander, probably isn't going to be the best if load range E BFG's are swapped on to it.

I run two sets of tires, both load range D. With the Nitto 295's my setup works to my liking, if anything slightly heavy in the caster effect. With the Coopers 37's it's very similar at low speed, around town, at high speed it has much more caster effect than I prefer.

It maybe because they are a hybrid bias/radial construction or because the larger tires put the contact patch center further behind the turning center. In the end it doesn't matter they are different tires. When I switch full time to the 37's will make a new set of arms that reduce the caster, this will also give a better driveshaft angle.

[Tools R Us]

Originally Posted by concretejungle

never seen that before. Is it located in the steering linkage from the steering wheel to the steering box? anyone have a pic of this in the system?

It's between the pedals under the dash, if worn it can contribute to steering wheel play. To test rock the steering wheel back and forth with the motor off, there should be no play in the rag joint or the u-joints.

[Tools R Us]

Originally Posted by IdahoDoug

...
If you've accounted for the lift's effect on caster, I'd not be afraid to dial in more toe in though the above suggestion of 1/8 inch difference from back of rim to front of rim would be huge - too much IMO. You'll also notice a bit crisper steering response with added toe in.

DougM

Originally Posted by -Spike-

1/8" front to back too much? Wow, I always set it between 1/8" and 1/4".

-Spike

Doug is talking about measuring at the rim, it's possible to do it that way, but I have never see anyone do it. The factory spec is at the tread center (for a ~30" tire) and all specs that I have seen are for tire OD measurement. Using a tire OD spec and measuring/setting it at the rim would make for about double the degrees of toe.