Tire wear problem.

[Casa de Mesa]

Here is a link to the Google drive of the spreadsheet:

https://drive.google.com/file/d/1hwyWheyWjVDbzJymMKMi2ReF64TQx2kD/view?usp=sharing

This is the spreadsheet I use for alignments. First tab. I take this to the car with my laptop when I'm doing an alignment and plug these numbers in. I typically have a goal of what I want the alignment to be, so I figure out these numbers ahead of time. You can see that I've played with the numbers a bit over time - there are a couple of "scenarios" for toe at the bottom of the first tabbed worksheet.

My car currently does NOT have the ability adjust caster, so that's missing in this version. I have another version on a back up drive somewhere with that included (it was 7.1 degrees). But if you can measure camber, you can measure caster - just Google it.

Here I Googled it. This is a great article on DIY alignments. Smart Strings referenced in this article is what I use too (as said above). This is geared more toward a track car, but you will get the gist.

In this file, I also included a lot of other info I keep on it that I've collected over the years. I removed several tabs with personal info, car maintenance history, etc. When you use this, you have to float over the cells to see the formulas.

PLEASE use at your own risk - I created this for me and me only. If a formula doesn't look accurate in this file, there is a chance it's not. So double check my math. It's worked for me, but as the saying goes, your mileage may vary.

[Casa de Mesa]

I appreciate the comprehensive response!

1. Good point, I may have to do what you’re suggesting, I just took 1 measurement at the centre of the centre cap and used that as my baseline.

I actually biffed on this slightly. You want to measure just ABOVE and BELOW where the center cap goes on the wheel. This will rule out very small differences in toe. Still not perfect, but it's how I had to do it on the M3.

EDIT: Just corrected my other post explaining this.

5. I think this could be a big contributing factor. We bounced the car up and down but did not roll back and forth. I definitely feel your pain on this, because even after just bouncing a bit the string was no longer where it was supposed to be relative to the car, and we had to re-adjust the jack stands multiple times. I’m going to re-align next weekend and roll back and forth instead of just bouncing.

Try rolling it. It will make a difference because you'll relieve pressure you just put into the suspension by twisting something that moves something else (e.g., a tie rod).

7 & 8. A bit of forewarning here, with respect to adjustments my car is basically stock (hey, I’m a student on a budget here lol). So the only additional adjustment I have aside from stock is the front camber plates, which allow for camber and limited caster adjust. I also didn’t disconnect the sway bars because I’m basically stock… not sure if I should still do so?

I raced an entire season chasing down a really weird understeer/oversteer issue. Turned out to be a bent sway bar due to some really close racing with a tree. Thought I fixed everything after said tree encounter... Your suspension is probably not tweaked like mine was, but disconnecting the sway bar will eliminate a variable. Super easy to disconnect and reconnect so...

11. Yeah I just eyeballed the steering wheel but it wasn’t locked and I suspect that was also a contributing factor. A steering lock is on order which will be here by next weekend. Though I still question the effectiveness with the steering guibo being present, a bunch of other (like Japanese) cars just have 1 u-joint and that’s it. I just feel that the steering guibo can really makes things inconsistent

That guibo probably is not affecting your alignment measurements. Rest easy on that one! Now wheel feedback and road feel... I'll give you that.

Lastly, another question - assuming you have camber plates, how often do you do an alignment when switching camber settings? My fairy-tale thoughts prior to my first DIY alignment experience was that I'd have a street & track camber setting, and that toe (which would still change with camber) would stay more or less consistent.

I don't know exactly how much toe changes with camber, aside from the fact that it toes out. But just as an example, say my street/track settings were below:

Changing camber will affect tow. Depends on the suspension geometry as to by how much, but I never understood that "drive to the track then dial in negative camber, when it's time to go home, put it positive camber back into it". Not pointing the finger at you - this just seems like a colossal pain in the arse for a car that gets itself there (i.e., is not trailered to the track)

[timmo]

Changing camber will affect tow. Depends on the suspension geometry as to by how much, but I never understood that "drive to the track then dial in negative camber, when it's time to go home, put it positive camber back into it". Not pointing the finger at you - this just seems like a colossal pain in the arse for a car that gets itself there (i.e., is not trailered to the track)

I was planning on swapping to my track tires at home, using them to get to/at/from the track, then swapping back to my street tires. While the car is jacked up both before and after each event, I might as well slide the camber plates over, as I don't want to be running such high amounts of camber and have inner tire wear on my street set. I understand that toe changes with camber - I'd set toe to be ever so slightly in for street, so it would be toe-out for track. What I'm trying to gather is if others have had toe being inconsistent with sliding camber plates, or if it was also a fault of my alignment? Say, I'd set toe to be 1 mm out at -2.7 deg camber. Then go to -1.0 deg camber for street, then back to -2.7 deg camber and toe is now 3 mm in.

The reasoning and based off what has happened with my DIY alignment so far seems to point at my alignment given my issues, I just want to be sure that if I were to slide the plates back and forth, that toe would stay consistent with my 2 street/track setups, and wouldn't "drift" out of spec to something, say like 3 or 4 mm toe in, and prematurely wear out my tires.

And if it does turn out that you cannot rely on the camber plates to maintain a consistent toe between the 2 setups, I may have to "set and forget" and run 1 setup on both street and track that I won't touch.

[timmo]

Starting to think there may be something else in play here, perhaps my positively-camber worn street tires? Even disregarding the 2 camber settings I wanted to run, I verified that front camber and toe left and right were symmetric with what were basically Smart Strings, yet I still have a slight pull to the left and a steering wheel 5-10 deg left. Gonna swap on my brand-new RS4s to all 4 corners and see if the pull is still present.

[Casa de Mesa]

Hey timmo - ahh, I get it. Totally see your logic. I would think that if your camber plates are truly just camber plates (not camber & caster), then sliding the camber between spots wouldn't screw up anything else. Everything on the car is a fixed point once locked down.

Regarding the worn tire, that could be the source of your pull. Especially if it's a wider tire.

Lastly... Is that a Radical next to your car? An SR3? Never driven one, have always wanted to. They are sick cars!

[pawa_k2001]

Should get around to doing the alignment this weekend. Everything was setup with a 360 laser, digital gauge and a mm measuring stick. Each individual ramp is level and all 4 are level to each other.

Before alignment, I will raise the ride height to 14" front and 13.5" rear, adjust out the pre-load on sway bar and also re-corner balance the M3 with my weight in it.(with swaybars disconnected)

[Casa de Mesa]

Nice setup up... wow. You've gone fully on fancy!!

That AccuLevel is what comes with the Smart Strings if I'm not mistaken? Regardless - super nice setup.👌👊

[pawa_k2001]

I am trying to self justify the purchase. 🤣

I went with Longacre Digital C/C Gauge w AccuLevel. The Acculevel slides out so you can use it elsewhere by itself.

[timmo]

OP I'm so jealous... 🤑🤑🤑 how much did all that equipment come to? I'm sure it'll pay off in the long run, and you can endlessly tinker with your setup and never have to visit an alignment rack ever again

Hey timmo - ahh, I get it. Totally see your logic. I would think that if your camber plates are truly just camber plates (not camber & caster), then sliding the camber between spots wouldn't screw up anything else. Everything on the car is a fixed point once locked down.

Regarding the worn tire, that could be the source of your pull. Especially if it's a wider tire.

Lastly... Is that a Radical next to your car? An SR3? Never driven one, have always wanted to. They are sick cars!

Yeah, the GC plates re-use the 3 nuts, you just loosen and slide it back and forth. The slots are a bit wider than the slots in the strut tower for up to 3/4 degree caster adjust, so as long as I keep them pushed all the way back it should be consistent. That's good to hear - once I fix my pull I may try to experiment with them and some point, kinda a PITA to set up and re-align with just jack stands.

Yup I think that's an SR3, my friend was helping one of the guys at Radical Canada set up a CRX for Time Attack, so they (kindly) let me use their equipment after. Man, referencing the strings off the car instead of jack stands on the ground is such a luxury!

[Casa de Mesa]

Yup I think that's an SR3, my friend was helping one of the guys at Radical Canada set up a CRX for Time Attack, so they (kindly) let me use their equipment after. Man, referencing the strings off the car instead of jack stands on the ground is such a luxury!

Yeah, once you get the strings that mount to the car and allow you to roll it and not have to setup the box again... game changer. Also when you figure out where & how it mounts to your car, you can make small markings on the various couplings, pipes, etc. with a sharpie and so tear down and setup becomes super quick. Save the measurements off the wheels hub for the next alignment and it will make setting up the box much faster too.

Those Radicals... so stupid fast. I did this Open Track Challenge event back in 2003. NASA used to host it on the west coast. It was like the Car & Driver One Lap of America, but 7 racetracks in 7 days and they'd basically add up your best track times at each track. Lowest overall time per class won. They had various street and race classes. A Radical swept the event. That was my intro to them and have wanted one ever since.

[Albino09]

Timmo, I haven't seen this discussed yet so I'll ask:
- What size front tires are you running? Wider than stock?
- When do you notice the steering wheel pull? On the highway in the left lane? On backroad 2-lanes? In parking lots?

I had my alignment set with 235 fronts to 0 toe, a change from a mild toe-in, and immediately noticed my car started following road crowns (Especially in the left lane of the highways where I spend most of my time). I had the alignment verified more than once, and my suspension is fully stock with new bushings and koni yellows, camber pins pulled.

[pawa_k2001]

OP I'm so jealous... 🤑🤑🤑 how much did all that equipment come to? I'm sure it'll pay off in the long run, and you can endlessly tinker with your setup and never have to visit an alignment rack ever again

Just over $4k. Bought a pyrometer also so I can setup the M3 based on data, not peoples recommendation.

[timmo]

Timmo, I haven't seen this discussed yet so I'll ask:
- What size front tires are you running? Wider than stock?
- When do you notice the steering wheel pull? On the highway in the left lane? On backroad 2-lanes? In parking lots?

I had my alignment set with 235 fronts to 0 toe, a change from a mild toe-in, and immediately noticed my car started following road crowns (Especially in the left lane of the highways where I spend most of my time). I had the alignment verified more than once, and my suspension is fully stock with new bushings and koni yellows, camber pins pulled.

Stock is 225 wide, I'm running 245s for both my street and track setup. My street setup is heavily worn on the outside, so I thought that would contribute to it. Swapped on my brand-new track setup and it's still the same. I thought it could be due to the curvature along the width of the road, but it was still happening no matter what lane I was in, either on a major suburban road or on the highway.

What was happening was that dead-centre was slightly left, but I also had a slight pull to the left. So just said screw it and decided to shimmy both tie rods over the same # of turns to see what would happen. I managed to get it such that my steering is now pretty straight. However the pull is still present, though it does not seem to be as bad as it was before.

At this point I might have to bite the bullet and get on a rack.

[pawa_k2001]

Took a day off to setup and do the alignment. First I raised the M3 by 9mm, then I corner balance it with myself in it and 5/8ths tank of fuel.

Alignment did not show anything out of spec.

Old requested alignment:
-2.8" front camber, -1,9" rear camber
0.10 toe-in front, 0.30 toe-in rear

What I found:
-2.7" front camber, -1.7" rear camber
0.19 toe-in front, 0.29 toe-in rear

My final settings:
-2.7" front camber, -1.7" rear camber
0.05 toe-out front, 0.29 toe-in rear

I looked at both control arms and tie rods, control arm position is still good, it has a slight angle down. The tie rod is a problem, it has a slight angle up. I used a plum line to see what happens to toe on 1 5/8ths" compression, I get 6mm toe-in.

Is there any street safe bump-steer kits? I may try to build something myself since all I find are exposed heim joints. Even a 20mm kit would really help.

[pawa_k2001]

Did some testing tonight and caught the sunset.

(out, middle, in)
FL: 122-121-125
FR: 120-120-127
RR: 127-136-135
RL: 127-140-134

Front went from 35 to 39psi. (Started at 36psi and went to 41psi, brought down to 38psi on previous runs I did a couple of hours earlier)

Rear went from 34 to 38psi. (Started at 36psi and went to 41psi, brought down to 38psi on previous runs I did a couple of hours earlier)