Front End Alignment Clarification

[GlennC]

I have one of the very early kits. I've been driving the car with just a rough front end alignment. Things have settled enough to to do final alignment. I've read many posts on the subject & I want to make sure I understand things correctly. After setting the toe I adjusted the front tubular control arm (the one used to adjust caster) to the recommended 15.25" & the rear (or lower) control arm (the one used to adjust camber) to 18.5" to serve as my base points. With the control arms set to these dimensions the front control arm has plenty of Heim Joint thread showing. The rear control is out of any available adjustment or bottomed out. I have approximately 1.5 degree of negative camber on both front wheels. I haven't checked the caster yet. Since I have an early kit I assume since I'm out of rear control arm adjustment I need to shorten the rear control arm tube threaded end, adjustment nut female end & the clevis male end approximately 1/2" each in order to achieve enough adjustment to get to the .5 degree of negative camber. What I'm still somewhat confused about is that some posts mention shortening the front control arm but others don't say mention anything about shortening.

My questions are:

Am I understanding the procedure correctly?

Is the trimming of 1/2" off of the rear control arm pieces the standard?

Does the front control arm need to be trimmed?

Thanks,

Glenn

[33fromSD]

I have a Gen2 so there was no cutting needed, but just to set your expectations, there is not a specific adjustment for Caster only or Camber only. Turning the front or the rear bars or both at the same time on the control arms will impact Caster, Camber & tow at the same time believe it or not.

Aligning these 33s takes some time & a whole lot a patience, and it also takes small tweak at a time with a lot of rechecking. I would also suggest rolling the car back and forth about 3-5 feet too prior to remeasuring to help settle the latest adjustment.

I tend to leave toe until the very end since adjusting the tie rods for toe has no affect on Camber and Caster but Camber & Caster adjustments will affect toe.

Jim

[RoadRacer]

Hey Glenn,

I’d set rough toe to zero before starting because I’ve seen cars with 2” toe and it does get in the way

I’d recommend forgetting the measurements but I suppose they may work to get you close. But I’d be very suspicious of them. As Jim says it’s an iterative process. Measure what you have - camber and caster - and then make small adjustments to see the changes… then sneak up on it

Jim is right that both arms change camber and caster but in different ways. Here’s the cheat sheet:

- shortening front lower control arm REDUCES camber and ADDS caster.
- lengthening the rear lower control arm ADDS camber AND caster
- Finally adjust toe using tie-rods

Carefully note the words above.. I wrote this down long ago and it may only be true when you’re close to aligned.. once you’ve done dozens of alignments you’ll realize it’s easy to measure wrong and start go in the wrong direction sometimes!

And start with the factory recommended settings:

total toe in 1/16" (0.0625), camber -0.5º, caster 3-4º (manual) 6-7º (power)

[edwardb]

I didn't have any trouble getting the front end alignment to specs with my truck build. Same front suspension. As already stated, the three specs interact with each other. Pretty dramatically at first when you're making large changes. But mainly I want to stress you don't have to cut anything. Don't do it. I think the threads where you're seeing builders cut parts are for the Roadster and Coupe to achieve additional caster with power steering setups. Other than the spindles, completely different suspension parts.

[Mastertech5]

Just one comment on roadracers comment in regard to camber. Adjusting the front and rear arms will change camber positive or negative depending where your starting from. You need to balance between caster and camber and recheck both after each adjustment. A more accurate description would be that shortening either front or rear LCA will increase camber and lengthening either will decrease camber. Toe should always be done last. We would adjust caster with 1/2 a degree more positive on the right and about a 1/4 of a degree more positive camber on the same side to compensate for road crown. This can cause a slight drift left if you drive in the fast lane on some highways.

[Bob Cowan]

With the control arms set to these dimensions the front control arm has plenty of Heim Joint thread showing.

How much is "plenty"? If it's too far out, you'll run out of threads and it will literally fall apart while driving. That's a bad thing.