Front Wheels Toe Out?

[George7941]

Soon after I bought my Sierra (2006 1500 2WD long bed reg cab 75k km 46k mi), I checked the toe on the front wheels with a string and two jack stands. I was surprised to find a bit of toe-out (1/16in total), so I turned the driver side tie rod 3/4 turn for a bit of toe-in.

I just noticed both front tires have extra wear on the outside ribs, indicating too much toe-in. So I just reset the toe back to the factory setting and the string again indicated toe-out.

I have the GM factory service manual and it specs positive toe (toe-in) for the front wheels. I am fairly confident of the accuracy of the string method, at least as far as indicating whether the wheels are toed in or out.

What gives?

 

[Chris142]

What do the jackstands do?

 

[mkIIIman089]

You can't use the string method unless the 2 sides are exactly parallel and centered side to side by making sure the front hubs and rear hubs are spaced equally (F and R can be differrent, as long as the LR and RR match, same for the front).

(It is impossible with only 2 jack stands and one string)

 

[jaj]

You turned them too far. One or two flats on the tie rod will probably give you about 1/16 of an inch. The 3/4 turn cranked them in further than you wanted.

Originally Posted By: George7941
Soon after I bought my Sierra (2006 1500 2WD long bed reg cab 75k km 46k mi), I checked the toe on the front wheels with a string and two jack stands. I was surprised to find a bit of toe-out (1/16in total), so I turned the driver side tie rod 3/4 turn for a bit of toe-in.

I just noticed both front tires have extra wear on the outside ribs, indicating too much toe-in. So I just reset the toe back to the factory setting and the string again indicated toe-out.

I have the GM factory service manual and it specs positive toe (toe-in) for the front wheels. I am fairly confident of the accuracy of the string method, at least as far as indicating whether the wheels are toed in or out.

What gives?

 

[Rix]

If you put it on jack stands, with the wheels in the air, or the suspension even partially unloaded, your toe will change.
Outside edge wear is toe in, the math adds up.

 

[grease_monkey]

Originally Posted By: jaj
You turned them too far. One or two flats on the tie rod will probably give you about 1/16 of an inch. The 3/4 turn cranked them in further than you wanted.

Originally Posted By: George7941
Soon after I bought my Sierra (2006 1500 2WD long bed reg cab 75k km 46k mi), I checked the toe on the front wheels with a string and two jack stands. I was surprised to find a bit of toe-out (1/16in total), so I turned the driver side tie rod 3/4 turn for a bit of toe-in.

I just noticed both front tires have extra wear on the outside ribs, indicating too much toe-in. So I just reset the toe back to the factory setting and the string again indicated toe-out.

I have the GM factory service manual and it specs positive toe (toe-in) for the front wheels. I am fairly confident of the accuracy of the string method, at least as far as indicating whether the wheels are toed in or out.

What gives?
+ 1. I have been an alignment tech on heavy over the road trucks for over 5 years, and for the first 2.5 we used a tape measure and for the last 2.5 we used a hunter computer based set up. You'd be amazed at how un acurate a measuring tape is at setting the toe. You might want to consider taking it to a reputable alignment shop because if the camber is out it too can cause the same wear pattern on your tires. Hope this helps.
O

 

[fsskier]

First, put the jack stands back in the garage, set the alignment with weight on the car and proper suspension geometry.

Factory toe in specs are a guesstimate that allows your tires to be aligned properly when traveling at speed. SO, RWD vehicles get Toe in, FWD vehicles get toe out.

If you want them perfect, first, find a flat parking lot, stribe mark you tires unless you are sure your tread grooves are very straight. Then (RWD) with the vehicle in gear and idling ahead, bring the vehicle to a gentle stop with the brakes, and do NOT allow it to roll back. This preloads the front end suspension parts (to simulate normal drag at highway speeds) , now do your measuring. If you adjust anything, back up, bring it back to a stop and remeasure.

With FWD, bring it to a stop with the emergency brake, leaving the vehicle in gear and the front tires pulling. This also preloads the suspension to simulate highway travel and normal use, now measure everything and adjust if necessary. Of course, back up and do it again if you adjusted things. In both cases you should set the toe in to 0!!

Someone at the factory spent hours doing this and provided numbers to the service industry for their alignment machines, so that they can adjust the toe in - or out - quickly, but the goal is the same.... perfect alignment under normal conditions.

Using the above methods are a little more time consuming, but very accurate and cheap..... and has given me tire life up to 100,000 miles.

 

[ProfPS]

I'd back the driver's side tie rod out 1/2-5/8 of a turn close to the original setting; very little turn of a tie rode moves the toe a lot. A quick toe check is drive forward on a flat surface and turn the wheel and stop; you have to drive/roll while turning and not just turn the wheel while stopped. I'd turn to the right to expose the driver's tie rod adjustment. Take a look at the bulge of the tire touching the ground in relation to the rim. If the bulge of the tire is on the inside the toe is out, if the buldge is on the outside then the toe is in. You want a slight toe in. After making a slight adjustment drive/roll a little farther and recheck. Final check is driving on the road: When stopping the steering wheel shouldn't turn if your brakes are okay and the car shouldn't drift when driving straight [depending on the crown of the road and the lane you are in].

 

[bkbenjy]

You need to bring that truck to a shop with an alignment lift and alignment equipment. You will never get it accurate with the wheels off the ground. Not to mention there is adjustable camber on this vehicle. If the camber reading is off the front toe reading will be off. The same applies with rear toe. The string method is not an accurate test. There is a reason shop's spend thousands of dollars on alignment equipment

 

[George7941]

"Jack Stands" seems to have muddied the waters! The jackstands were just anchor points for the string, the truck was in its normal loaded position on the flat concrete in a garage.


"You can't use the string method unless the 2 sides are exactly parallel and centered side to side by making sure the front hubs and rear hubs are spaced equally (F and R can be different, as long as the LR and RR match, same for the front)."
It never even occurred to me that the axle widths could be different, I just assumed they were the same. That said, on a mainstream vehicle like a GM full size truck, isn't it likely the axle widths are the same?


" A quick toe check is drive forward on a flat surface and turn the wheel and stop; you have to drive/roll while turning and not just turn the wheel while stopped. I'd turn to the right to expose the driver's tie rod adjustment. Take a look at the bulge of the tire touching the ground in relation to the rim. If the bulge of the tire is on the inside the toe is out, if the buldge is on the outside then the toe is in."
This test would only be valid if the steering geometry was perfect and there was no tire scrub at all during turning. Would not manufacturing limitations preclude the engineers from designing in perfect steering geometry? And thinking about it further, why turn the wheels? Would just rolling straight ahead and coming to a gentle stop not produce the same bulge, if there is toe in or toe out?

I probably turned the adjustment too far. Anyway, it is back to factory setting. And I have learned my lesson about turning the adjustment just one or two flats. I will monitor tire wear for a few months and then decide on my course of action, which might include taking it to an alignment shop. It brings up another question. Do slight errors in toe necessarily show up in tire wear patterns?

 

[meep]

i think a better method might be measuring front and rear edge rim-to-rim and doing the trig to determine the math. It will take careful measuring.

The track width can vary on any vehicle-- you'd be surprised to see how many mainstream vehicles have slightly, and I mean slightly different track width. add in some bushing wear, and a solid rear axle will sit differently than a rubber-suspended IFS.

Toe WILL change in a turn. sometimes it's because of cheap/compromised design. Some amount is actually preferred since the front wheels travel in different arcs during a turn.

also keep in mind that any cornering forces always beat up the outside edges of a tire, especially in larger vehicles that sit up higher on taller rubber.

M

 

[fsskier]

I agree totally with the above posters...the "superaccurate" home method that I described above assumes that you measure the stribe mark on the front and the back of the front tires each time.

This method only adjusts the toe in, caster and camber gauges and equipment for home use are also available. When I first started working as crew on formula cars I found that many of the cars were meticulously aligned using what some might describe as "home methods". Toe in of course is the primary contributor to long tire life.

 

[George7941]

Thanks, fsskier, I am going to try your "superaccurate" method next and see if a tape measure yields different results vs string.

 

[eljefino]

Originally Posted By: fsskier
First, put the jack stands back in the garage, set the alignment with weight on the car and proper suspension geometry.

Factory toe in specs are a guesstimate that allows your tires to be aligned properly when traveling at speed. SO, RWD vehicles get Toe in, FWD vehicles get toe out.

If you want them perfect, first, find a flat parking lot, stribe mark you tires unless you are sure your tread grooves are very straight. Then (RWD) with the vehicle in gear and idling ahead, bring the vehicle to a gentle stop with the brakes, and do NOT allow it to roll back. This preloads the front end suspension parts (to simulate normal drag at highway speeds) , now do your measuring. If you adjust anything, back up, bring it back to a stop and remeasure.

With FWD, bring it to a stop with the emergency brake, leaving the vehicle in gear and the front tires pulling. This also preloads the suspension to simulate highway travel and normal use, now measure everything and adjust if necessary. Of course, back up and do it again if you adjusted things. In both cases you should set the toe in to 0!!

Someone at the factory spent hours doing this and provided numbers to the service industry for their alignment machines, so that they can adjust the toe in - or out - quickly, but the goal is the same.... perfect alignment under normal conditions.

Using the above methods are a little more time consuming, but very accurate and cheap..... and has given me tire life up to 100,000 miles.


I'm not to argue with your success measured in tire wear, but if the factory wanted, say, two degrees of toe under load, and spec'd the control arm bushing deflection, they'd be able to come up with a "service measurement" with unloaded wheels on frictionless turntables. Was just reading on JHZR2's special w123 benz procedure with preloading bar... Those engineers must expect more of their service depts than most brands.

It *would* be a good exercise to see how much deflection you're getting, which could be of academic interest.

 

[fsskier]

Originally Posted By: eljefino

I'm not to argue with your success measured in tire wear, but if the factory wanted, say, two degrees of toe under load, and spec'd the control arm bushing deflection, they'd be able to come up with a "service measurement" with unloaded wheels on frictionless turntables. Was just reading on JHZR2's special w123 benz procedure with preloading bar... Those engineers must expect more of their service depts than most brands.

It *would* be a good exercise to see how much deflection you're getting, which could be of academic interest.


The factory spec is a service measurement, provided to shops so that technicians can achieve relatively accurate alignment while sitting still on nearly frictionless plates- without a preload. Again that is why FWD cars are given toe-out, and RWD cars are given toe in... to hopefully achieve correct alignment (neither toe in or toe out) under loaded conditions. The preload method eliminates the guess factor, kind of like sighting in a rifle. You can guess that aiming 18 inches high will give you an accurate hit at 450 yards, but repeatedly patterning your shots will give you a slightly different answer, but both are attempting the same result:
perfect alignment under normal driving conditions

 

[eljefino]

But if the rack & pinion were in front of the front axle, a FWD would toe out, as the control arm bushings gave way, but the rack held firm.

Though truth be told I can't think of a car set up this way. RWD loves putting the rack or box & track bar in front of the axle as there's a longitudinal engine's oil sump behind it.

I should look up how the LH dodge intrepid with its longitudinal engine does it. My BIL had one and it held the road great, even as the rest of the car was kind of a turkey.

 

[fsskier]

Doggone, my keyboard has gone crazy, I just have to write a good alignment story. In the early 1970's my neighbor bought a brand new mini-motor home, called a Transvan, with a Dodge Chassis.

Friday they drove 200 miles to retrieve a child from summer camp, returned and packed until late at night, got up Saturday morning for the BIG VACATION.... their neighbor (me) walked over to look at the new vehicle and pointed out that tire cords were showing on the front tires!! The tread was scrubbed totally off. They made frantic calls to their dealer (Saturday of a 3 day weekend, Monday off) who said "Maybe next Wednesday we can get you in"!!

By then, I had measured the front alignment (home method of course) and determined that the Dodge had over 3 inches of toe in!!! I took pictures, then started adjusting - at first he was reluctant since "machines are needed" but faced with the prospect of giving up the vacation he relented and I set things accurately, he proceeded to Sears - they had tires for it and installed them at closing time. He kept the old "brand new" tires of course and the Dodge dealer did pay the Sears bill eventually. The tires aligned with the tape measure lasted for years and years....maybe 1,000 times longer than the "factory alignment" LOL.

 

[fsskier]

Originally Posted By: eljefino
But if the rack & pinion were in front of the front axle, a FWD would toe out, as the control arm bushings gave way, but the rack held firm.

Though truth be told I can't think of a car set up this way. RWD loves putting the rack or box & track bar in front of the axle as there's a longitudinal engine's oil sump behind it.

I should look up how the LH dodge intrepid with its longitudinal engine does it. My BIL had one and it held the road great, even as the rest of the car was kind of a turkey.


The rack in front, or rear, it makes no difference. The preload takes out the variables, you are no longer guesstimating. You preload a FWD car with the front tires pulling, a RWD car with the front tires exhibiting rolling resistance.

A $40 front end alignment is still a fair deal for those uncomfortable with mechanical work - except for the chain tire stores that want to sell you $800 worth of unneeded front end parts each time!

Remember "60 Minutes" taking a car to 5 chain tire stores in a row.... each time spraying the new parts with mud to "hide the new", each store then replaced the same parts since they were "dangerously worn!!

 

[IndyIan]

You can't generally say though that FWD cars will always have toe out with acceleration. Longer tie rods than A-arms will result in toe in when on the gas, with the tie rods behind the ball joint.
Every time I mess with the front camber on my cars I just use a tape measure to get the toe reasonably close and the car drives fine with no unusual tire wear. Good enough for me.

 

[mechtech2]

Toe can be accurately set with string, tape, or a home made measuring device.
It is easy.
Then, if necessary, center your steering wheel by adjusting one side in, and the other out. Common sense.

But why your wear patterns? What about camber? That could be out.
And who knows how much your 3/4 turn achieved? That is a LOT of toe in!