jsi

Ok, when I had the alignment done last time i sorta got into a little argument with the alignment guy. He said that from his experience different wheels/offsets/tires change nothing in final alignment. For some reason, I was allways under the impression to the contrary. Anyways, we aligned the car with the crap 175-70-13 on stock steelies i use to get the car to/from track. My race tires are 205-60-13s on 13x8 ET25 wheels. Anybody here actually checked alignment after swapping wheels/tires?

He did agree that the weight can affect alignment. We checked and with my fatass 250+lbs in the car, the front camber on both sides increased by 0.1. No change in toe or rear alignment. Was already late getting to the event, so we did not bother checking with the race wheels on.

Mr Hammond

Sounds like you were under the wrong impression.

Targa250R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">Ok, when I had the alignment done last time i sorta got into a little argument with the alignment guy. He said that from his experience different wheels/offsets/tires change nothing in final alignment. For some reason, I was allways under the impression to the contrary.</TD></TR></TABLE>
Why would the wheels change the alignment? The alignment should be the same regardless of what wheels are bolted to the hub.

Tire wear can affect alignment, but on a race car this shouldn't be a huge concern.

I personally believe he is right.

turbohappy

If they had a significantly different outside diameter it would change the alignment. As could width/offset potentially. Even tire pressure will affect alignment. These all can affect camber, which affects toe on our suspensions. Usually not enough to worry about though.

Targa250R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbohappy &raquo;</TD></TR><TR><TD CLASS="quote">If they had a significantly different outside diameter it would change the alignment. As could width/offset potentially.</TD></TR></TABLE>
I don't understand; how? What does the wheel have to do with the suspension? How would it affect camber?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Even tire pressure will affect alignment. These all can affect camber, which affects toe on our suspensions. Usually not enough to worry about though.</TD></TR></TABLE>
This I can understand and agree with - but the difference would be so insignificant that it wouldn't really matter. I bet you can change the alignment by the same amount as you're tightening everything up afterwards.

duh blacksheep

i dont see how changing wheels/tires would change alignment either. alignments are done by angles in degrees.

jsi

Well my original reasoning was that a really soft, high profile all-season tire like a 175-70-13 on a narrow rim would have a different stance than a stiff, relatively wide race tire on a fat rim (the 205-60-13 Z211 on a 13x8 is easily wider than most 225 street tires). Also, given the much wider track with the 13x8s may have an impact as well, with the changed scrub radius and all. Maybe in theory it should, but in practice the difference maybe negligeable.

Targa250R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">Well my original reasoning was that a really soft, high profile all-season tire like a 175-70-13 on a narrow rim would have a different stance than a stiff, relatively wide race tire on a fat rim (the 205-60-13 Z211 on a 13x8 is easily wider than most 225 street tires). Also, given the much wider track with the 13x8s may have an impact as well, with the changed scrub radius and all. Maybe in theory it should, but in practice the difference maybe negligeable.</TD></TR></TABLE>
The Hunter alignment machine we have at work measures the alignment using heads that you attach onto each wheel rim. This would factor the tires out of the equation, wouldn't it?