I'm not sure if you studied the data, however from what I can tell very little changed before and after the alignment. They did what appears to be a simple ‘toe & go’ (only adjusting toe - not camber, not caster). The minor changes in the camber and caster are likely measurement tolerance and the effect of the small toe changes. Caster will not affect tire wear - toe and camber are the contributors there.

I wish I had data from my car - but by the time I got it (8K miles) the tires were wearing nicely. By the 13K with my first tire change - no issues so I've not even had mine on a rack to check (26K and still nicely wearing). I don't mess with a car's alignment if the wear is good.

From my observations, albeit not as much initial toe-in as I’d like – you were effectively zero toe prior to the alignment. Zero toe should not cause excessive inside wear, however if you weren't in the car when the alignment was done and they did not use weights to simulate a driver (almost no shop does) - it's possible when you sit in the car the changes in geometry could result in some toe out (not good for inner tire wear). On my fun cars I usually run 1/16” to 1/8” toe-in [0.1 to 0.2 degrees, tire size dependent); but that's with me sitting in the car since that's my normal driving mode (alone). IMHO Jag’s camber specs are rather aggressive; your negative camber of 1.3 degrees per side is likely why you have the inside edge wear if there's no change in toe with your weight. My guess is that you’re not pulling high g forces on a regular basis on mountain or twisty roads.

I believe negative 1.3 degrees per side is excessive for any street car. For perspective - I used to run -3/4 degrees ( -1 degree on the race car) on our Fox body Mustangs because I auto-crossed and drove on race tracks. Those cars have crappy geometry so you need to dial in negative camber to compensate for the lean going into turns (as the car rolls, the wheels compress but didn’t change geometry much so 1-2 degrees of body roll would put the tire flat). With a good suspension geometry (front) you never need excessive negative camber because the suspension keeps the geometry close to the static condition as it changes movement. In other words, there's not much camber change while the spring compresses (i.e. the body rolls) so you don't need to bias your 'static' alignment to compensate for limited change during roll. I’ve not studied this geometry in detail, but I’m highly confident it’s quite a good geometry.

If your rear tires are not exhibiting significant inside edge wear, then you can likely leave the rear alone but I also think that is overly aggressive negative camber as well.

In short, I don’t think you’ll see any change in wear from this alignment. If you want to prevent this from happening again, I’d recommend you drop the front alignment to perhaps -1/2 to -3/4 per side up front. If you do that, it may not be a bad idea to reduce the rear negative camber as well – perhaps in the -3/4 to -1 degree range. As much importance, I highly recommend you sit in the car while they make the adjustments. In fact, make sure you're sitting in it when they take the as-found readings - that would be good data to know (i.e. what changes and how much when you sit in it from your as-left above).

I’ve found very, very few capable alignment shops/techs that actually understood what they were doing. I’ve only used 2 guys that got it (one retired, the other my bud [shop owner - racing buddy for 35 years] trained to understand all elements of suspension geometry). It takes a mathematically inclined technician to get it – they are hard to find.

If you wish to chat further, PM me and I'll share my contact information with you.

 

I forgot to mention, Bridgestone tire was our sponsor (discounts and points when road racing) - we ran RE71Rs. In a racing environment, due to the crappy geometry - hard braking wore the inner edges the most - cord would eventually start peeking through. Bridgestone shared with us that when the cord started showing, we had another 30 minutes race time before we needed to worry .

 

Ahh yes good point! I had not heard "Set the toe and let it go" for some time!
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Inmanlanier –

Thanks very much for all your detailed analysis and insight. Great information and advice. Only problem is I will need to find a competent shop somewhere near northern Virginia to accomplish the tweaking. (anyone ?) I agree with your conclusion that I probably won’t see much change in the wear, and I certainly don’t want to rip up these brand new PS4S.

I was skeptical when the JLR dealer showed me the data –I agree not much changed and the front before specs weren’t that far off. They allowed me into the shop while they were doing the alignment, which was nice. So they tried to explain “Total Toe” and “Thrust Angle” to me. But it was hard to hear with the noise and a bit of a language barrier.

I was not in the car during any of this, and I’m not a lightweight. The rear tire wear was just fine. The car is a pleasure driver and when I get on twisties I would say (without any real reference point) that my aggressiveness is probably only a 6 out of 10 of what a braver soul might do on public road. I always leave DSC on. I’d like to get to the track someday just to feel out how the car breaks away (RWD) and practice recoveries without spinning off the side of a road and into a tree.

The car drives amazingly and I have no complaints about the handling. But just about anything would seem like a dream compared to driving my truck every day. Thanks again for your perspective – I think everyone here can learn from it.

 

I always tell folks - asking is free. To that end, why don't you see what they'd do to let you bring it back, sit in it and have them recheck. If your toe is not appreciably out, have them dial the front camber back to my recommendations (-3/4 per side). Even if the front toe is out, I'd have them dial that back anyway.
If they say no - perhaps you can find someone else in the area that has a clue. If you know any road racers - reach out and ask them who they have align their cars.

 

Inmanlanier - yep, you're right - it never hurts to ask the dealer and see their response. I can take your (sanitized) input and see what they say.

But question for the forum - as a backup - does anyone have any alignment shop recommendations within an hour's drive of Northern Virginia? Thanks in advance.

 

My tires were just changed yesterday on my 2016 R, I got 23,980 Km out of them and put on Michelin PS4's and what a difference. The rear was down to 3/32 but I was lucky enough to get a nail that forced my hand for new rubber.