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The Importance of Toe-in or Toe-out

76K views 63 replies 27 participants last post by  RELLIKPIR 
#1 · (Edited)
There has been quite a few questions about alignment lately. Alignment is most affected when a car is lowered. The more it is lowered, the more impact occurs. In general, camber and toe are the main settings that are impacted. Since camber is discussed so frequently, we all pretty much know what it is and the problems it can cause. The impacts of toe (whether toe in or out) are not nearly discussed as much. You've heard me indicate many times that excessive camber combined with too much toe can be the death to tires. This remains true. But we rarely discuss the impacts of toe in or toe out so I'm going to give this issue a shot. I will do it as simple as possible and hope not to offend any engineers.

Toe-in is when both tires on the same axle (front or rear) point toward a line drawn through the axis (center) of the car. Toe-out is when the tires point away from the centerline of the car. The amount of toe measured is tenths of a degree or hundredths of an inch. It's minute measurements that have major impacts!! Zero toe means the tires are perfectly parallel to the centerline of the car. In a perfect world, with perfectly flat roads, and the ability to have rigid suspensions, zero toe on the front and rear would be the ideal. But because we have crowned roads and enjoy nice compliant rides (meaning movement in the suspension) zero toe would lead to a car that tends to wander (wants to roll off the road in the direction of slope). To correct this, toe adjustment was built into cars. Caster is also an integral component of directional stability but we'll save that for a later discussion.

A Focus and almost all front wheel drive cars have TOE-OUT in the front. This is reflected by "negative" numbers on the alignment specs (TOE-IN are the "positive" numerals). Why toe out on the front? Its simple physics. As the tires pull themselves forward (aka torque) they pull themselves into the desired toe-in position. In essence it's a self compensating. Once at a consistent speed the resulting front toe ends up being a tiny bit inward. Just enough to allow that directional stability that is needed. If the toe is set to far out it never gets to the proper amount of toe-in when the car is moving. What are the downsides besides bad handling....tire wear. Too much "toe-out" causes inside edge tire wear (toe-in causes the outside edges of the tire to wear). Combine it with camber and it only amplifies the problem. Another thing to consider, the alignment specs were determined using factory bushings. When you install harder bushings, the wheels may not be able to pull themselves fully back into the desired toe-in position. Watch yours tires carefully for wear after installing bushings and be prepared to reduce the amount of initial toe-out if wear is occurring.

The rear of the Focus is just the opposite. Since the rear wheels have no power to them and they are not able to pull themselves into the correct or needed toe-in angles, it must be set with some initial toe-in. The ever going debate is how much toe-in. While Ford provides some specs we have learned that the rear tires are very temperamental to too much toe especially when combined with a lot of rear camber (even if its within the allowable spec range). In simple terms, you want to reduce toe-in if you want to increase camber. My philosophy is to run the minimum allowable rear toe-in to avoid wear problems.

What about toe out in the rear? First, Ford specs don't allow it. This should only be used for autocross and the track and not the street. It will make the car react very quickly to any steering input. Stability is drastically affected and 100% driver concentration is required if rear toe-out is used. A sneeze can literally cause you to change lanes. If you intend to use it for motorsports events, use VERY small initial toe-out adjustments until you understand the full impacts of the adjustment. And please don't use the freeway for testing as these changes are amplified by speed.
 
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#4 ·
Nice explantion of Toe in /out

Thanks
 
#5 ·
So the tow is always changing? with speed and different amounts of torque to the front wheels? If you're going down the road at 60 mph and you let off the gas then the front tow will go negative so the car will wander slightly?
 
#7 ·
Theoretically yes. But remember, these are very very small changes and the condition of then suspension will be the determining factor. A car with sloppy bushings, tie rods, ball joints, etc would be far more noticeable than a new car. If you were to drive an identical model 2000 focus with 100+K miles vs a 2005 focus with 25K miles stock suspensions you'd notice different handling characteristics based on plain ol wear and tear.
 
#6 ·
could we discuss the implications of running toe in at slightly less than the recommended spec?

I think it would be fine, a little more touchy handling-wise, but imo it can only help things with respect to tire wear. especially when you put a lot of weight in the car.
 
#12 ·
there is a company called longacre they make race car set-upproducts that can easily be used for any car. well here are their toe plates

http://www.hrpworld.com/index.cfm?form_prod_id=12,10,363_185&action=product

they also make camber and caster gauges, scales, and all sorts of set-up stuff. with about 200 bucks you can get everything you need to set-up your car and align it to your own specs or accuratly set-up your car for the track or street. pays for itself on your second alignment. its pretty cool and not very hard to do, we set up a freind of mines spec miata in around 45mins and niether of us had ever done it before, im pretty sure if we did it again we could do it in about 20 mins. if you are a DIY kinda guy i recomend it. just read your manual and figure out exactly how to adjust everthing! good luck

Matt
 
#17 ·
ok so check it, iv had this problem for about a year. iv been through 3 sets of very expensive tires and and its just the rears, they all have the same wearing problem, they all get bad flat spots and the car will shake horribly between about 55 and 70 then it smooths out iv had 3 alignments and im willing to try for 1 more before i put my stock springs back on.........by the way i have the sportlines and 17's and 16's both of which have had 3 sets of tires.

im a flight nurse in a different city and have to drive 27 miles one way to the hospital and i need my ride to be smooth and still keep my bad ass low look, if i have to i will trade for the prokit

thanks to all
knox (RN)
 
#19 ·
Can you be more specific about what you're calling a flat spot? Are you referring to a completeley bald area such as the edge of the tire. Is it in only one area of the tire (localized), is it a series of cupped like bad areas around the tire? Can you post any of the printouts from your alignments as those numbers could be very helpful.
 
#20 ·
well lets see how to describe my tire with a flat spot...kinds looks like a d lol like its just in one spot on the rear tires and its all the way accross the tire so its like u run ur hand around the tire and its like full tread half tread bald slick half tread full tread in that order, i dont have a printout of the alignment specs but i know im still towed out in the rear and im at a -camber, the front wears fine just normal.

but if i had to say the flat spot runs the width of the tire and about 20% around then the tire looks fine
 
#22 ·
A toe and/ or camber problem would cause, more or less, even wear around the entire circumference of the tire and localized to the inside or outside tread edge. If the tire was out of balance or if the shocks were bad, the wear could get wider or more pronounced in localized areas. A bad shock causes a cupping pattern around the circumference of the tread.

That said, and I'm taking a guess here, I think your problem is with the tires themselves. You either flat spotted them by locking up the brakes (only takes once) or the internal belts are separating (not as uncommon as it sounds). Either can cause the kind of wear you described. If the tires are relatively new I'd go back to the dealer for a tire inspection. Separating belts (aka de-lamination) can be determined by a visual inspection of both the inside and outside of the tire and is a warranty issue in most cases. Anyway, it sounds like you need to have them replaced.
 
#24 ·
ok i put it up on the lift and found that the flat spots are def. on the inside of the rear tires and they look really choppy, its only one spot on each tire but it looks like someone took a meat cleaver and just hacked it up, thanks for the help

knox
 
#25 ·
Castor, Camber And Toe-in/out

I was getting a little unsure what all these terms meant, particularly the CASTOR - so I did some digging on the internet and cut & pasted and added some notes to these diagrams: Hope this helps other like me! Seems like a small pic - if someone tells me how I will try and get a bigger pic posted. I think if you click the thumbnail you get a larger view.
 

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#29 ·
Just found and installed some camber plates. I'm a newb at autocross, but after some research they seemed like a good idea. I love the results..i'm set at -1.7 degrees front and -.8 rear. The handling improved signifigantly in the corners, but it is a little touchier on the highway. 3k miles later and no noticable difference in tire wear. They are basically just a steel plate that mounts to the top of your strut mount. You have to remove the mounting bolts from the upper strut plate and use the included bolts to mount the adjustable plate to the strut mount and car. Fun mod for autoxing, and pretty cheap if you DIY. Not a project for unexperienced though...compressed coil springs are no joke. Was gonna do the rear, but decided to go to the H&R coil kit first.
 
#30 ·
I've noticed on my 05 that the drivers rear is getting a lean to it. I checked over the bearing's and they seem good there's no play to it so what should I be looking at this thread has me intriged. Iam doing upgrades as things get worn and after reading alot of everyones post ( which by the way thanks to all ) I wondering where to be looking @ for the next mod so does anyone have any suggestionsfor me. I think I posted this in the right section and please feel free to backhand me if its not. Thanks again to any help thats offered because I will try it.
 
#31 ·
I have an 03 Focus SVT that I'm tired of buying tires for.
My problem, and I can't imagine I'm the only one with this problem, is excessive inside tire wear front & rear.
How can I fix this when the camber is fixed front & rear.
Is there something after market available.
After about 20K miles on new tires, I start getting alot of tire noise from the insides wearing.
 
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