New Rear Tires & Alignment now unstable
 

Saturday 05/18/2019 I went to get my safety inspection done at a local shop I regularly visit for inspections & emissions. my 2016 Subaru BRZ failed for rear tire tread being low I called around and settled to get tires done same day at Pep Boys. I wanted all 4 but the inventory was wrong and settled for just two even tho they had a promotion buy 3 tires 4th one free :iono:. Took give or take 4 hours to complete the installation of only 2 tires in the rear Kumho KU22 (Kumho Ecsta 4X II) tires installed. One of the managers comes up and informs me that he believes prior person to have worked on my car broke or didn't properly install my lug nut and he wouldn't be able to quote me for the fix. I figured i'll fix it myself later. He said they might be able to get it on there but just wanted to inform me. I asked for them to just leave it off but he informed me he couldn't per policy. I pick up my ride and ask the technician what bolt was the problem he shares that it was another team member who experienced the problem and it felt fine to him.

I drive off and the car feel fine I get on the parkway and go to over take someone at about 55 to 58 mph and when switching lanes my cars traction control kicks on and brakes feel as if they are locking up. The car almost feels like a boat. I try and reproduce the problem at low speeds like 30mph and nothing. I only experience the problem at 50mph+ when turning.

[ame]http://youtu.be/n95U7N3RfTk[/ame]
https://youtu.be/n95U7N3RfTk

• I have taken off the wheels and checked them visually and reinstalled them making sure they are tight.
• I inflated the tires from 30psi to 40psi and tested and still experience the same problem.
• The problem only happens when going around a curve or changing lanes.

I intend to go back to the shop if I cant resolve the problem on my own but due to work schedule it will have to be this upcoming Saturday.

If someone has had this issue before or experience please share what to look at.

Thanks :cheers:

That sucks,

Did they actually do the alignment? Sounds like the toe is off.
As for the tires those Kumhos those are some greasy tires new. If they non directional try putting them on the other side. If that doesn't work a nice burn out would take that layer of oil off the threads.

Our lsd are really sensitive with low psi tires that must have been the reason why it freaked out.

Besides that nothing much you can do. Eventually they will even out.
There's is always hope that putting new tires up front can fix it, but eh maybe.

Alignment
https://i.imgur.com/Ewf7WGG.jpg

Tire Specs
https://i.imgur.com/pQgoZwJ.png

Photo from rear left facing driver seat
https://i.imgur.com/ABod7qB.jpg

Edited to include additional images

That rear right camber is something i would bitch about.
I would tell them to match the left rear.

4 fucking hours and they couldn't get this shit right?
Nothing pisses me off more than alignment mechanics that can't fucking make thing equal especially when they have a computerized alignment rig.

Thanks i'll try rotating the tires and see if problem persists if it does ill give :burnrubber: a shot.

What tread level is your front tires at?
If you press-hold the traction control to disable it, does all the warnings/problems go away?

My suspicion is that the front tires tread depth is low enough that the vehicle is reading the difference in the circumference of the tires(a tire with full tread is going to move further in one rotation than a tire with 1/4 tread depth), and is thinking that the car is sliding.

New tires can be slippery. Drop the rear psi?

What tires were you running before these? They might just have less traction and you are used to more.

My Mazda 3 came with these tires and I wasn't particularly impressed, seems a run of the mill all season. Not great in rain, got me through 2 inches of snow barely but not able to go up hill. They were better than the Ecsta PA31 I got stuck with on my Honda Accord though.

These days I stick with separate summer and winter sets.

You could try swapping front and rear tires as well.

Rear camber is not adjustable stock so I wouldn't bother complaining about it.

Start with simple first. New tires come with mold release on the tread, so first several miles are slippery. Next, a different tire front to back will often do as you noticed. the side wall allow for different movement and the tread will have different traction during turns. go back to the shop and tell them you want four tires with one free. It is their fault they were out of stock.

Front Tire Michelin Primacy HP 215/45R17
https://i.imgur.com/ib2OIQ0.jpg
"I know it's bad i'll take care of it later."

Rear Tire Kumho Ecsta 4X II 215/45R17
https://i.imgur.com/m5W03aP.jpg


Hey @ls1ac so I'm a contractor at the moment and I'm looking for full time employment on the side. I was interested in the 4 tires at that time but I am fine with two even if they did make a mistake. I want to get some wheels once I secure a full time job and replace all 4 at that time and keep stock for winter and do what @ZionsWrath said he does with his car winter/summer set.

Your old tires are basically warn out.
Repeat, go back and get the other two for safe driving. Mixed tires are much less predictable.

The question I usually ask young drivers is, Do you want to stop and turn or get going fast?


Put the good tires on the front and put the old on the back.
I know it will have uneven wear, but you did not rotate before.

That's not a good idea bro. Even the manual says to put new tires on the rear. Just a little FYI.

I think they do that to err on the side of understeer in wet conditions.

Thank you Twins, I also find that understeer is not as easy to control in spirited driving .I prefer to let the tail hand out.


But I repeat get new matched tires and avoid the possible problems of a mismatched set.