does this alignment look o.k? The tech was confused regarding the rear toe adjustment according to Pfadt's recommendations. I have a sneaking suspicion the rear has toe out for some reason.

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Virtually all commercial alignment racks use positive (+) for toe-in and negative (-) for toe-out, and that is the normal convention (positive toe is toe-in and negative toe is toe-out). Pfadt's published recommendations use negative values for toe-in. Looking at your sheet that you posted, I would bet that the car has toe-out in the rear.

 

with acrace

Here's a link to Pfadt's alignment sheet:

http://www.pfadtracing.com/blog/wp-c...-9.12.2011.pdf


When you gave the sheet to your alignment tech, if you didn't highlight the part on the Pfadt sheet at the top about "Negative toe measurements indicate toe-in", then your alignment guy probably used the industry-wide convention of negative (-) meaning toe-out.

If you do actually have toe-out for the rear, you definitely want to get it aligned again - you DO NOT want toe-out for the rear. A little toe-in will help keep the car settled during acceleration out of turns.

BTW, although Pfadt's specs have zero or a very slight toe-in up front, many track hounds like a slight toe-out up front for a crisper turn-in. So....it looks like you have essentially zero toe up front, which is fine for street or track - especially high-speed tracks with long straights. If you're doing very twisty tracks with lots of tight corners, a little toe-out up front might be appropriate.

Bob

 

I agree, the tech asked me to come back to the shop and we had a conversation regarding the rear toe. He advised me the same thing that negative toe on Pfadts recommendation sheet equates to toe out. I advised him I was positive it has to have toe in in the rear. We went back and forth for a minute and I told him 100% toe in...I just hope that he actually set it up that way as the colors are confusing. Negative is in green for the camber but the red seems to be positive. Very confusing...But if ACRACE is correct then it really means it does have toe in in the rear as commercial racks indicate toe in positive terms...I think the color red is whats messing with me....My first track day is coming up soon so I hope it is correct. I'd hate it if a bad alignment spoiled me weekend

 

Doesn't it seem ODD that only Pfadts recommendation sheet is completely opposite of the remainder of the world ????

 

It does seem odd, I know the tech races an rx-7 so I'm sure he knows the rear would be squirmy with toe out under braking and corner entry. That's why he called me to the back of the shop to confirm what was written on Pfadts spec sheet. He advised me he set it up with toe in and to disregard the colors. I trust him, as he aligned my Audi S4 for the track and it handled great. I guess I'll soon find out at the track I suppose.

 

looks to me like you have very little toe out up front and more toe out in back.

C5Z loves toe out in front about 1/8" total and toe in in rear about 1/8" total. It will wander on street and eat tires on street but be an animal on track.

 

Hey guys can you comment on my rear toe situation - this is a C6Z - I also gave my shop the pfadt settings, did they setup my rear toe incorrectly - it shoes -1.4mm for rear .

 

He may be OK. The sheet is a little hard to read but I don't see any negative signs in front of his rear toe settings. The red color is the machine indicating the setting is out of tolerance. What is interesting is the machine's Specified Range it is all negative toe.

I think you may be OK. As I mentioned above I don't see any minus signs in front of those rear toe numbers. I would go back and ask the mechanic what the red color means though. I think by stating emphatically that you wanted rear toe in and he knew that toe in should be set that you got what you wanted. He knew the signs were wrong and called to get you to confirm you wanted toe in. To avoid confusion I always supplement my instructions with a note whether I want toe in or toe out along with the numbers.

If you look up the definition on the web toe in is somewhat more accepted as being a positive number but it isn't standardized and you might find machines that do it exactly like Pfadt's sheet does.
That is another reason why I always spell out Toe In or Toe Out.

Based on my experience you have the wrong rear toe setting. The numbers are negative which is generally accepted to be toe out. However, you first need to check with the mechanic and find out how the machine treats toe in Vs toe out. If it truly is toe out then you need to get it changed to toe in. You will probably have to pay for the change since your sheet had the wrong info. Your mechanic wasn't as sharp as the other mechanic. The other thing you should ask him is what in the hell does .7 mm mean? The toe is spec'd in degrees. How does .7 mm relate to degrees? The Chevy dealer I used to go to used a BMW Kinematics alignment machine and it gave readings in inches (in.). When I was watching the mechanic do my alignment I asked him what that meant he said he didn't know, he just used the readouts as degrees. He said he never noticed it before. I never got a bad alignment from him and he did a lot of BMW/Chevy/Corvette alignments on a weekly basis. But you do need to ask what is going on so you can make sure you are communicating with the other person. Remember, Communication is an Un-Natural Act.

Bill

 

Thanks Bill!! I will check with my alignment guy..

 

This is all pretty interesting. I'm curious how many different types of alignment racks read in degrees or inches and how a "commercial" rack indicates positive or negative values. If ACRACE is correct that commercial racks dictate positive toe in negative values then it really makes people wonder exactly what is going on. The technician even mentioned he hasn't seen anything being measured in inches in quite some time.

 

Probably virtually none of the modern alignment racks or types of devices measure "distance" - probably almost all measure "degrees".

However....those of us that do our own alignments almost all use measurements in inches or millimeters. Take a look at forum member David Farmer's great DIY alignment info:

http://dl.dropboxusercontent.com/u/1634366/align.pdf


Scroll down to the toe measurement part and you can see that he is measuring the distance between the front of the left and right tires, and then the rear of the tires - the difference is the TOTAL toe. In his example less distance between the front of the tires than the distance between the rear of the tires is toe-in.

Also, here's a link to using Hardbar's toe plates:

http://hardbarusa.com/uploads/image/...%20rev1(1).pdf


Some of us may also use the string method - strings down the side of the car (well...just outside of the side of the car, and parallel to the string on the other side). In that type of measurement you measure the distance on one side of the car from the string to the front of the tire and then from the string to the rear of the tire, and the difference is the toe-in or toe-out for just that side. If the front is 1/8" closer to the string than the rear you have 1/8" toe-out for that side. If the other side is 1/8" toe out as well, then you have 1/4" TOTAL toe-out.

If you have 1/4" total toe, then each side is 1/8". 1/8" is approx 3mm if you're measuring metric.

You can do the trig, but depending on the distance between the points you're measuring (the distance between the points you're using for the front and rear of the tire/wheel, say 20" to 24") 1/8" of toe on one side is around 0.3 to 0.37 degrees.

It's really very easy to do your own alignments, and you can be very accurate.

Bob