i know that zero toe all around is the recommended spec for the evo, but i havent seen any explanations as to why this is the best spec. the service manual agrees that the front toe should be 0, but the service manual calls for +3 on the rears. can anyone explain the reasoning behind zero toe all around?

 

+3 on the rear? That's insane - can you check again?

Here's some good info an Alignments and Toe:
http://www.tirerack.com/tires/tirete....jsp?techid=4&

Toe is how the tire sits in relation to the centerline of the vehicle. Meaning if you have toe, the tire isn't rolling straight, it's actually being forced to roll against itself as the car is steered straight. This is where your odd tire wear issues - not to mention odd handling are introduced.

Toe can be manipulated to help a car turn at the track. Some people run anywhere from 1/64" to 1/8" of toe to help force the car to turn. But it's at the cost of increased tire wear.

 

Everyone always says get Zero Toe all the way around, which is great for tire wear but makes the car wander a bit on the freeway or track in the semi lines. I usually like a C-hair of positive toe (toe in) in the front and a C-hair of negative toe (toe out) in the rear. Might make the turning response a tad slower but gives better straight-line stability. But I don't autoX or anything so I don't really need super turn-in ability. My thought anyway.

 

It is application specific and also driver preference. I usually recommend zero toe or a very slight amount for most people as it covers all the bases and is generally a good compromise between stability, response, and tire wear. It can definitely help for auto-x. At the track its up to you....some like it, some don't. Many people in my experience end up with similar times, but it just takes a bit more effort and may not be as consistent. Not always the case though.

- Andrew

 

x2 my last set of tires wore out pretty fast so I changed it to Zero Toe. The car wanders a bit but it's better than spending 1k on tires every 6-8 months.

 

I think OP means 3mm, not inches. The manual says up to 3mm toe-in on the rear is within spec.

 

http://i85.photobucket.com/albums/k6...rearcamber.jpg



Car tracking is a lot of factors beyond toe (conicity of the tire, road variation...). I ran zero toe on my car, DD/AX/HPDE. Got fantastic life on most tires for what I did to that car.

 

sorry, shouldve clarified, service manual says +3mm for the rear, or 0.12", which is basically 1/8".

 

One reason for running something different than 0 is to keep the toe angle always positive or always negative. The change over from pos to neg can make a car a bit twitchy which can be felt on the freeway with how it pulls different based on if you're accelerating or decelerating (with a 0* toe setting). Generally though, we run a ton of camber and to get the best wear we don't want any toe out. Toe in up front hurts turn in so we pick the best compromise of running 0*.

For autocross I always dial in a little extra toe out and set it back to 0* after the event. Its a fairly noticeable feeling in turn in when I forget to do it.

 

for one thing, if you want to "force" better turn-in you would get alittle front toe-out, not the rear(at a cost of straight-line stability); its the reason why autoX setups have alil toe out. rear toe-in is for stability, but zeroing it out wouldnt make turn-in significantly worse.

also you have to remember , stock suspension settings are always leaned heavily towards safety then all out handling. factory specs must account for a wide range of driver abilities, this is same reason why tire psi specs are so damn low. soon as you take any hard turn, tires set to oem specs often will roll its edges. so when it comes oem specs for tire psi, alignment specs etc, they always have safety margin factored in.

 

To clarify, I meant I toe out the front not the rear . Rear is set 0* during the summer and a touch of toe in in the winter.

 

it should be 0 toe in front and 1/16 toe in, in the rear.

the slight toe in, in the rear gives you more confidence attacking a high speed corner, and stabilizes the car at high speeds.

the Evo's rear suspension toes out under compression.

 

so why does toe eat up the tires? is this something specific to us?

 

here's my before/after specs on an '11 with 30 miles on it.... the drive home was noticeably improved

edit: just noticed I posted in the 1-9 forum, oops

 

As you see from the report above the rear is .04-.2 and the front is essentially 0 as you stated. From my personal experience when I purchased my IX it had 8 miles on it. I did nothing but drive it around and after 12K miles the inside of my tires were worn down to the belts.

When I went for the alignment what I saw was the car from the factory was so far off the specs it ate my tires. This may be why people are advising to get toe corrected quickly. With the factory settings seen in the sheet above I have not experienced excessive tire wear issues.