Why does a solid front axle need some toe in?
 

After finishing my front end, i was at a well known alignment shop that does alot of lifted trucks getting my alignment checked, i asked the guy about having a little toe in, he said no you want a solid axle at zero, so i started thinking about it and it makes sense to be at zero. So my question is, why would a solid axle, with all tight components have any toe out under power? Ive read so many posts that say u must have 1/16 toe in but nobody explains why, what is going to allow the tires to tow out on a solid axle? Thx

That guy is wrong, never go there again, you should have toe in. Toe in prevents wander and increases steering response by keeping the tie rods in tension. The caster wants to pull the wheels straight, by having the tie rods keep them just in of straight they stay in tension. This prevents wander in the grooves of the road, and makes the steering much more responsive to small inputs of the steering wheel.

You don't need much toe, just enough. For new components basically the smallest amount you can adjust in and still be sure there is some(1/16" when measured at the tire), but if components are more worn lean for more. A great test is to feel for feathering. Feathering is a condition of tire wear that happens when the tires are wearing in one direction more then the other. To check for it run your hand across the top of the tire and pay attention to how the corners of the tread feel. If the corners grab your hand in one direction more then the other that is feathering. So if you have to much toe in the tire tread will grab your hand more sliding out then sliding in.

I have a favorite, simple, free, and quite accurate method for measuring toe that you may like to try.

Start by putting the truck on a level hard surface that you can push the truck front to back a few feet on. Then place a pin, like a clothes pin in a tread lug in the center highest part of the tire. In the same spot on each tire and level with each other. Roll the truck back but of course not far enough to run over the pin, then forward until the pin is at a spot directly forward that you can measure under the leaf springs between the pins. Note this measurement then roll back until you almost roll over the pins then forward as far as possible and still be able to measure between the pins in the back. Note this number, adjust, and repeat.

You always want to measure after rolling forward to maintain forward conditions. Measuring with the pins maintains the exact same spot and removes any variation in the tires.

1/16th is a good general number, tight components and low profile tires might lend to a condition where you may want to shoot for less. Large tires and worn components means more toe.

very good and simple explanation.
i set toe at 1/16 to 1/8 on every vehicle that leaves here after front end work to go to the alignment shop.
on straight axle vehicles if they tell the shop i did the work, they tell the owner to go home and save their money, they don't need an alignment.
i usually send the shop 30-40 vehicles a year for alignment, and they know my work.
i normally get caster/camber close enough that it can be run for a couple of weeks without and tire damage too.

The other MASSIVE reason you need some toe is "death wobble", (if you've ever experienced it you never want to again), don't let anyone tell you you don't need some toe. No matter if it's a dana 30, 44, KP 60, or ball joint 60. You will thank everyone who suggests toe for this reason. I usually set it @ 1/4" and use my hand held pyro to monitor tire heat, then back it off to 1/8" or 1/16" depending on wear...

Death wobble is a hell of a thing, I've had my fair share. But IDK about toe as a cause or solution. That hasn't been my experience but I might have to look into it more.

Mine will death wobble a little still when I hit a pot hole or something with the inside front tire on a slight turn. Might have something to do with the designed toe out on turns removing my set toe.

However logic tells me that too much toe is very likely to contribute to death wobble. The wobble is a series of rhythmic turns in, having it toed in to me would tend to make this worse.

Thx for the responses, i have a better understanding now so i guess a little toe in is good. My front end has all new bushings and steering components, theres no freeplay anywhere and i can do 75 on the freeway and the truck drives straight, no wobble at all with holes or bumps, i didnt even put the steering stabilizer back on, seems like thats just a band aid.

My follow up question is, knowing im at zero now, if i do a half turn on the adjuster sleeve, bringing the toe in, would that get me in the ballpark of between zero and 1/16? Using a tape measure always pisses me off cause i cant see it, reminds me how old im getting, but i will if i have to, im just more of a work on and learn on my own type of person. Thx again.

Sure, half turn should be about right, just pay attention to how it drives and the tires wear, that will tell you what you need to know.

Ok thx ill give that a try, time to start lookin at the rear end leafs and shackles.

I will tell you if your set-up is prone to DW and you throw some toe at it it will go away if your in spec on all other aspects.. I've played with this on several d60 equipped trucks with very positive results. Tire wear, pressure, and steel belt integrity will also perpetuate a condition prone to DW..
I'll add that at least on d60 GM trucks being within 5 degrees positive caster is where you wanna be which can be negitivly affected by going to a shackle reversal or RSK as we know it. Typically your positive caster is increased w a RSK but if your not paying attention or doing a custom one it can bite ya.. The closer you get to neutral or negative the worse it is.. The topic is a classic and very opinionated to say the least...

hey dude
I don't follow on getting second measurement at back...

"then roll back until you almost roll over the pins then forward as far as possible and still be able to measure between the pins in the back. Note this number, adjust, and repeat."


if you roll forward as far as possible, that sentence places pins at front...

I believe he was stating to:
- Start by putting the truck on a level hard surface that you can push the truck front to back a few feet on.
- Then place a pin, like a clothes pin in a tread lug in the center highest part of the tire. In the same spot on each tire and level with each other.
- Roll the truck back but of course not far enough to run over the pin, then forward until the pin is at a spot directly forward that you can measure under the leaf springs between the pins.
- Note this measurement then roll back until you almost roll over the pins
- Then forward as far as possible and still be able to measure between the pins in the back.
- HERE: When you roll back to almost running them over, you roll back forward because you want your measurements to always be after forward momentum. You only roll it forward far enough to get a reading at the back, not fully forward.
- Note this number, adjust, and repeat.

that seems like a lot of work for nothing.
i measure inside of tire to inside of tire other side 12 inches up front and rear. i then set the front at 1/16 to 1/8 inch less that rear.

Agreed, was just explaining the steps of the previous post.

Your way is much closer to what I have always done and had pretty good luck.