Setting for After-Market Adjustable Rear Camber Arm?
 

I've noticed there is a lot of talk about adjustable rear camber arms for Mazda 3's, but I can't find any recommendation for a setting. Should I just set this to 0 degrees? Or would I want something a little bit in the negative for better performance?

Also, if I adjust the camber, will I need to adjust the toe-in?

Thank you.

look around on the forum
https://www.mazda3club.com/3rd-gen-protege-mazdaspeed-p5-mp3-26/stock-camber-adjustment-2997/

I remember someone saying they had theirs set @ 1 deg, and thats where ive put mine. you will need to adjust the toe in, spec says (0.040" per foot) which works well for me.
Adjust yours & see how you like the handling, change it around til you're satisfied.

Did you get an alignment after you adjusted the camber? Why or why not?

I aligned it myself.
Camber to ~0.7 deg was my final reading for front and rear using a digital angle gauge.
I then adjusted the toe in to ~0.040" per foot by clamping a 4' level to each wheel and measuring to the door sills on the car. I wish there was a more accurate way to do it at home, but it's cheap, all the parts are under $80 which is what an alignment would cost. And I get to tweak things, see how it feels, and tweak it again with added time but no added cost.

You can get sort of close by eyeballing down the side of the car to the tire edge, though since there is a slightly different position side to side from the suspension not being perfect - that way of doing it is only sort of close.
You can also run a string between the tires, or use a tape measure from front to rear on the tires, but it's not as repeatable as measurements off the rims.

Good luck. & ask away if you have other questions.

Are you talking about rear camber? Just want to make sure we're talking about the same thing.

I installed SPC adjustable rear camber arms over the weekend. I'm hesitant to take it to a shop for an alignment because I don't think they'll have any idea on how to properly adjust the camber.....maybe I'm wrong. It was confusing to figure out myself when I was playing around with the adjustments while off the vehicle; I can't imagine trying to adjust while on the vehicle.

When I google "Digital Angle Gauge", this comes up:
Is this similar to what you used?

You said you aligned it to, "~0.7 deg". Is that positive or negative? Usually I think of the tilde as meaning "approximately"...is that what you meant?

How do you adjust the toe-in on the rear wheels?

Sorry for so many questions, thanks.

they will probably align it per the manufacturer spec, which is what the cars came with, that eats tires... if they adjust it at all that is.

And the measurement is negative - whatever it is where the top is narrower than the bottom /\
And yes approximately was used only since I wasn't working on level ground and there's some error in the digital angle finder... so there is a bit of error, but within a tenth or two.
The angle gauge you linked is basically the same as what I got - mine was a harbor freight special :)
I measured the camber assuming the brake rotors were square to the axle.
And the toe is in, front narrower than the rear. Toe in is adjusted by the lower rear arm, the bolt at the middle part of the rear subframe is an offset bolt, so you turn it and it'll move the rear of the tire in and out with respect to the front.

Questions aren't a problem :)

I ended up having to re-do the adjustment on my rear camber arms because I adjusted them wrong the first time. So, I did it right and bought one of those angle gauge from harbour freight. My adjustments showed around -0.9 degrees of camber on each side. I didn't really want to mess around with toe in on the back so I brought it in for an alignment anyways and gave them instructions to set the rear camber at -0.5 degrees. As it turns out my measurements were pretty close; one side was set to -0.8 degrees and the other was set to -0.9 degrees. Somehow I think that's the only thing he did. I don't think they adjusted toe in at all.

I was looking at the hidden hitch you installed and i was wondering if you had to get rid of any styrofoam in you bumper. I was looking at my bumper behind the license plate and it looks like I'd have to cut out a piece of the styrofoam to get at the piece for welding. What did you use to cut out the piece behind your license plate? How come you went with that option instead of the over-the-counter Hidden Hitch? Is it because of the hang down of the Hidden Hitch (i.e. hangs low to the ground and maybe scrapes on driveways, etc.)?

Good to hear that the angle was accurate, good verification for the tool. If toe in wasn't adjusted the rear could float around or at least wear the tires unevenly.
They should have provided, or you can ask for - the printout from the machine saying what all the measurements were.

As for the hitch, I didn't need to cut off any foam, there were 2 pieces with a gap in the middle as I recall. There's a chance I did cut some or left a piece off, but I don't think that was needed. I did cut a piece of the bumper to weld the hitch in though, mostly to line up with the licence plate height wise, not to avoid foam.
I did that option for a couple reasons...
1: I like to do it myself
2: the hidden hitch hanging from under the bumper is not hidden (bad naming)
3: I had time and ability, so why spend a hundred on a hitch when I can spend like $20 in parts.
4: the car isn't rated for towing, so if there is no need for extra weight & strength of the "official" hitch for anything i'll be towing.

Yeah, the harbour freight angle gauge worked good. The only trick I used was that I cut a piece of square steel bar exactly 17" (the size of the rim) and lightly clamped it to the rim, then put the angle gauge on the steel bar. I tried putting the gauge on the brake rotor, but I couldn't see the display numbers. I also zeroed the gauge on the ground just behind the tire to account for any slant in my driveway.

I did get a print-out of my alignment specs:

Rear Left
Actual: 1/16in
Before: 1/16in
(Specified Range -1/32in to 1/8in)

Rear Right
Rear Left
Actual: 1/16in
Before: 3/32in
(Specified Range -1/32in to 1/8in)

Rear Total Toe
Actual:1/8in
Before: 5/32in
(Specified Range -3/32in to 9/32in)

So, maybe they did adjust the toe. I was thinking about asking them to set the rear toe to zero, but I couldn't find any reliable info (on the internets) to suggest that was a good idea. What do you think of 1/16in toe?

As for the hitch, I'm thinking about doing something similar but easier. There's two 1/4" holes in the bumper that would work to secure a metal plate with a hitch welded on. I'd have to poke a hole in the plastic just below the license plate. I think that would work for my purpose, which is to use it for a bike rack; I have a hatchback and the only other options are to take off the rear spoiler (above the back window) for trunk rack or put on a roof rack, neither of which seem like good options to me.

More random questions:

Have you ever thought about tech for deer avoidance? I was reading up on the hornet deer whistle, but I really doubt that it works.

(Assuming you live in a relevant climate) What kind of snow tires do you use? What about snow chains? Have you ever looked in to snow chain alternatives?

The alignment spec is in the book, though that specified range looks correct, I recall it was from slightly negative to a little more positive - which matches the negative 1/32 to pos 1/8 The 1/16 toe should be fine, see if it starts leaving a pattern on the tire tread as a double check. Rotate the tires or any little tread pattern will start to be magnified.

For the hitch, bolting something on should work, though I was worried about torque on the bumper since it's boltes on to the frame with a thinner piece of steel. Then again bicycles shouldn't be too heavy for issues.

Deer avoidance = keep an eye out and have good brakes... I also think an exhaust leak helps :)
I'm in NY and wasn't happy with some BFG traction T/A's, though they worked great on a maxima I had - though that was an auto and i've got a manual. Could be that or the weight difference. I'm probably going to get general altimax arctic tires this winter.

If you have any other questions, please send a PM or open another thread / post - as this is drifting off topic :)

correction / update... I pulled the bumper off for painting recently, and I did cut a section of the foam out. just enough to fit the hitch with some wiggle room around it - which is where the trailer connector rests when not in use :)