Alignment and tires for Birkin

[pethier]

I have a 4:00 appointment tomorrow with thealignmentguy.com to swap tires and set the front alignment on my Birkin. Lucky me that there was a cancelation. He was all booked up in the week before our first double-autocross weekend. 

 

I assume that a live-axle Birkin has no rear-alignment adjustability. 

 

The front camber is adjustable via a system I have not come across before.  I intend to shoot for the same area as my non-adjustable Caterham has.

 

The tires I am going to put on are takeoff Yoko A052 205-15 from a friend who is a national champion.  I was a bit disappointed that the bolt circles on the Caterham and Birklin are different.  The wheels on this Birkin are 7x15.

 

Well, I'm off to measure the camber on the Caterham.

[pethier]

In my shop, getting a perfect reading on each camber is iffy.  Since the front camber on the Caterham is not adjustable anyway, I figured i could just check the total negative camber for both sides and divide by two.  I zeroed the electronic gizmo that measures angles on the RF wheel.  Then I brought the gizmo to the other side and read the difference.  Bang on 5 degrees.  Therefore, I surmised that Caterham were probably shooting for 2.5 degrees of negative camber.

 

Got the front of the Birkin set to 2.5 degrees negative camber and zero toe.  The caster is not adjustable, and measures 8 degrees.  Dogtracking does not appear to be a problem:  The thrust angle is -0.02 degrees.

 

I'm not ready to buy new tires for these 7" wheels.  I have 8" wheels for the Caterham, which will be a faster car when it's finished.  I got the secondhand Yoko A052 205-15 tires mounted.  These don't seem to have any flange-side voids, unlike the Prisoner wheels and the 8" wheels I have for the Caterham.

 

If the weather cooperates, I'll take it around the cones this weekend.  It appears that I can adjust the front swaybar without crawling on my belly like a reptile.  

Edited 8 hours ago by pethier