Tire wear problem.

[Tbonem3]

Lots of negative camber by itself won't cause wear like that. Its the negative camber AND toe. Toe causes the tire to scrub and generates heat which results in more wear. If you add camber, you get more heat and wear on the inner edge of the tire vs it being spread across a wider section with less negative camber.

The toe is out. Doesn't take much at -3 negative camber.

I said the same in post #7, but they don't want to believe it.

[Casa de Mesa]

I said the same in post #7, but they don't want to believe it.

Agree with both of you. What I don't understand in the outside edge. I've corded plenty of tires, but seeing two edges like that... it's odd.

[Tbonem3]

I run pretty aggressive toe out and neg camber, and my fronts are also starting to cord just like that. I'll upload a pic.

[Casa de Mesa]

I run pretty aggressive toe out and neg camber, and my fronts are also starting to cord just like that. I'll upload a pic.

What pressures are you running?

[Tbonem3]

31 cold F 34 cold R

[timmo]

I run pretty aggressive toe out and neg camber, and my fronts are also starting to cord just like that. I'll upload a pic.

How much camber and toe, and how much mileage on those tires?

[Tbonem3]

I've made manual adjustments, so not perfectly sure. Alignment is due when I move to 235/265 mpsc2 soon. Something like -3, toe no idea, but significant enough to see visually. 4 year old tires, 11k miles. For half those miles, the alignment was not this aggressive.

Thinking about it a little more, my case actually demonstrates what I was saying about toe being the problem. i didn't see the accelerated wear until I went from neutral toe to toe out. I always had significant camber.

[Casa de Mesa]

I've made manual adjustments, so not perfectly sure. Alignment is due when I move to 235/265 mpsc2 soon. Something like -3, toe no idea, but significant enough to see visually. 4 year old tires, 11k miles. For half those miles, the alignment was not this aggressive.

Thinking about it a little more, my case actually demonstrates what I was saying about toe being the problem. i didn't see the accelerated wear until I went from neutral toe to toe out. I always had significant camber.

So I'm harping on this not because I enjoying being a troll on forums, but because the OP's tire wear is weird. I'm genuinely interested in what the root cause is.

Your wear looks like it's mainly on the inside and if you're at neg 3 camber and zero toe or close to it in either direction, typically not a problem. Toe that's far off center AT ANY CAMBER setting will chew up tires fast. Very fast.

I run past neg 3 on a racecar that's comparable enough to an M3. I run + or - 1/8" overall toe (and anything in between) depending on the track and no issues with wear. Go much farther past that, and your nuking the outer or inner tread. Or DOT radials. Or slick.

I'll take some pics of my race tires that are well used and at 1/16" to 1/8" toe out later and post. Perfect wear. Awesome setting for initial turn in, helps the car rotate, etc. but highly not recommended for the street.

[timmo]

Mine is a street setup on this car. It's a moderately aggressive alignment for the street, but I've had excellent wear and do drive it hard.

Camber front: -2.0
Camber rear: -1.8125
Caster front: 7.1
Total Toe front: -0.1172 degrees <-- 0.5mm per side toe in
Total Toe rear: -0.2344 degrees <-- 1.0mm per side toe in

I measure toe at the outermost edge of the wheel face, convert into degrees. You start to reach the point of diminishing returns trying to measure 0.5mm - you need to use thin, brightly colored fishing line (and a darker scientific ruler) if the string alignment setup you get uses thicker string. Otherwise, the strings on some kits are too thick and measuring to anything below 1.0mm accurately get challenging.

Starting to go a bit off topic on this thread, sorry guys. But I went through my DIY alignment and was wondering if you've ever had any issues with setting toe? I had some issues with inconsistencies with toe. I set it to being about 0.5 mm toe in each side, but a quick test drive revealed steering that pulled to the left. Came back, and one side was almost 4 mm out. Re-set it, and all seemed okay in urban areas, but on highway it still pulled to the left. I was thinking it could be some preload in the bushings (like the steering guibo for example) that may have caused it.

I had my car on scale pads that were leveled side to side, they were on a slight slope front to rear. Had coloured fishing line tied around two jack stands, and I basically ensured that the front and rear centrecaps were the same distance from the line. Then set toe by measuring distance from front and rear of the rim to the line.

[Casa de Mesa]

Starting to go a bit off topic on this thread, sorry guys. But I went through my DIY alignment and was wondering if you've ever had any issues with setting toe? I had some issues with inconsistencies with toe. I set it to being about 0.5 mm toe in each side, but a quick test drive revealed steering that pulled to the left. Came back, and one side was almost 4 mm out. Re-set it, and all seemed okay in urban areas, but on highway it still pulled to the left. I was thinking it could be some preload in the bushings (like the steering guibo for example) that may have caused it.

I had my car on scale pads that were leveled side to side, they were on a slight slope front to rear. Had coloured fishing line tied around two jack stands, and I basically ensured that the front and rear centrecaps were the same distance from the line. Then set toe by measuring distance from front and rear of the rim to the line.

It might make sense to break this out into a separate thread. Here I go anyway. Sorry OP.

Yes, I have had issues in particular with toe. Caster is a PITA to measure accurately too. Some lessons I've learned through lots of sunk hours:

1. You have to make sure the box you are creating around the car is squared up to the vehicle perfectly accurate. This is by far the most important step because if you get this wrong, all other measurements are completely useless.
   • Regardless of vehicle, I take off the wheel center caps and measure against a machined surface (e.g., wheel hub, not a dust cap). You want to remove any potential variances from the equation and I don't trust the plastic caps or hammered-in dust caps, just too many potential variances.
   • If you can't get to a machined surface (it's tricky on these many cars and the M3 / 3 Series), mark the string directly off the wheel centerline with a sharpie. Then take two measurements per wheel, measuring from the wheel face that the center cap goes into. Measure just ABOVE and BELOW of that center cap (on the wheel, PERPENDICULAR to the ground) to the mark on the string and average the two measurements. Use this method on the other side of the car (L/R). When the averaged values are equal per wheel you're good. This isn't ideal, but it has worked for me when I can't get to a machined surface I feel good about.
2. Once you think you have the box square, measure it again.
3. How did you measure the ground you're working from to ensure it's level from left-to-right? It should really be level everywhere (left, right, front, back), but it's more important it's level left-to-right. I use a laser level and carpenters square to ensure the ground is level, then use 1/8" plywood or vinyl floor tiles to shim up the ground if needed. Look at the captions of the pictures in this article here.
4. When you measure at the string, if your ruler is not at 90 degrees off the wheel (when measuring toe) or the hub (when setting up the box in step 1) every time you measure, you may get incorrect readings.You can use a carpenter's triangle to square it every time you measure (pain in the ass, but works) or get a ruler that has the same indicators per side - only mm or only inches on the same side of the ruler. Then when you measure, it should look something like the image I mocked up and attached below. Put the ruler against the wheel face / hub / machined surface, then move the ruler fore & aft until the string is perfectly aligned against the ruler like the image below. In the example image below, the accurate measurement is 15mm on both faces of the ruler.
5. Did you roll the car after setting toe? I have found that until the adjustments you made start to "take a set", rolling the car to settle the suspension and remeasuring will help. It's a tedious process... but this is also why I ultimately ponied up the coin for Smart Strings because once you set the box in step 1, you can roll the car and not have to re-setup the box all over again. HUGE time saver.
6. I assume you're also setting rear toe? Your front toe can be dead nuts on, but if you have a rear toe / thrust angle issue, your front axle will be compensating while driving down the road. The higher the speed, the more compensation you'll need.
7. You could be right, you might be pre-loading bushings. If you set ride height at all, you want to loosen the fasteners wherever you have a rubber bushing. Then set ride height, snug the fasteners while the car is on the ground and the bushings are loaded, then jack the car up and torque them when you can actually reach them. I will say that I'm not sure if bushing pre-load will affect measured toe *too* much, but it's good to rule this factor out.
8. Did you disconnect one end-link of your front and rear sway bars? More pre-load potential.
9. Did you set your pressures equal on the same axles? That is, both fronts are at 30psi, both rears are at 28 psi. (whatever you set your pressures to)
10. I'd look at Obioban's thread HERE on setting up the suspension. It has some other great nuggets of info I won't repeat here, but it's worth the read.
11. Lastly... go look at the SmartStrings manual HERE. More really great tips, like setting the steering wheel straight. I don't use any special tools, but take a long piece of conduit, roll the windows down. Rest the conduit on the door edges. Then use bungee cords or soft rubber clamps to lock the steering wheel to the conduit. I have Turner's steering rack alignment tool, but think mine could be machined incorrectly because I always end up with the steering wheel on about a 20 degree angle after using it. The conduit-out-the-window method has always work perfectly for me, regardless of vehicle.

[timmo]

Yes, I have had issues in particular with toe. Caster is a PITA to measure accurately too. Some lessons I've learned through lots of sunk hours:[LIST=1]

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.
3. Pic is below, but the scale pads sit inside a homemade leveling plate which use 4 bolts (1 on each corner) to adjust height and level of each individual plate. Front to rear was a bit off, but we made sure left to right was as accurate as can be by using a big-ass level. I’m fairly confident that this was as level as it could’ve been.
4. Yeah, we used a metal ruler with the same graduations on either edge, and ensured that the string was parallel to the graduation lines.
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.
6. Yes, I checked rear toe and it was off. After my track day my car had a slight pull to the left and the car felt like it was wandering a bit, and the rear toe was 0.06 deg out on right, and 0.2 deg in on left. Sort of makes sense, since I distinctly remember hitting a curb slightly sideways with the left rear tire, and landing back onto the track surface slightly sideways. I loosened the 3 trailing arm bolts and nudged it back out so rear toe should be correct.
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?
9. Pressures are equal
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

Anyways, I’ll be re-doing my alignment next weekend with:
- Steering lock
- Need to roll the car back and forth rather than just bouncing up/down
- Measure off the rim face adjacent to centre cap and not the centre cap itself




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:

Street
Camber: -1.2 deg
Toe: 0.1 deg toe in

Track
Camber: -2.7 deg
Toe: 0.15 deg toe out

So my plan was to basically slide the camber plates back and forth, without doing an alignment, and that toe would more or less consistently hit 0.1 deg in or -0.15 deg out with street/track settings. But it seems that given the inconsistencies with toe when the camber plates are moved, it's not something that can be done without re-alignment every time? Which sort of makes me want to settle on a compromised setting that I won't really touch, maybe something like -2.3 deg camber and near-zero toe.

[Casa de Mesa]

Hey timmo, will reply when I can (it's Monday... work is spinning up), likely via PM. Feel like we're butchering the original topic.

[pawa_k2001]

Anything to do with alignments is fine, information can be used by anyone. Casa, if you can, please post the maths you have on doing alignment, most of my setup will show up today, some tomorrow. Shopping for a 360 laser now.

I did some quick bumpsteer checks on my ride height of 13.7" front. At 1 5/8ths compression, I am getting alot of toe-in at the top, as in 6.5mm toe-in at 1 5/8ths compression(outer lip of 19in wheel). Will be lifting my car to 14" front since that will save around 1.3mm toe-in at 1 5/8ths compression. Just a guess but I think my softer front spring is allowing more compression which causes a lot more toe-in at sharp cambered corners. In slow corners I get some push(understeer) which doesn't help with life of the inside shoulder.

[Casa de Mesa]

Anything to do with alignments is fine, information can be used by anyone. Casa, if you can, please post the maths you have on doing alignment, most of my setup will show up today, some tomorrow. Shopping for a 360 laser now.

Cool, will get it up here tonight.

[Casa de Mesa]

Turns out that you can't upload an .xlsx file. I'll figure something out (Google Drive, Dropbox, etc.).