BRZ not stable at highway speeds
 

I recently bought a '16 BRZ Limited in early March. Today was one of the first days I really got to drive it more than 20 miles on open highway and not to the dealership.

At 500 miles, my alignment was out, they fixed the rear toe and everything now is in spec. Now at 628 miles, cruising around 70-75mph (yes within speed limits) my car will literally shift left or right and it doesn't matter which lance since I know the road crown can give a slight pull.

Around a slight right bend on the highway, the car literally went half way into another lane.

Had the alignment checked elsewhere, still in spec. I even looked under the car and found nothing out of the ordinary.

Now I know the car is light and it was a bit windy, but I never felt unsafe driving a new car. My C5 vette will handle these slight bends like nothing even in tornado storm weather. Granted it has a much lower COG, wider tires, and beefier suspension.

I'm wondering if this is normal for the BRZ, or if lowering it and having wider tires will help. Or is there something actually wrong with the vehicle.

what is "within spec" that the alignment people are telling you? do you know the numbers? sounds like you have a problem with the toe to me. I'm assuming your car is stock, and the "stock" alignment has a wide range that can be considered within spec.

Show the alignment print out. Within spec may still have variances. Example the spec can be -.08 and .08 and you can be sitting at both extreme ranges per side.

Been to 127mph and it felt very solid. I suspect misalignment. I would have it checked by a different shop.

makes two of us. even after I slammed my twin running around -5 to -6 camber all the way around it felt stable at 120mph and i was driving without an alignment at the time. Just put the coils lcas and all that and drove around till the next paycheck. never had my car pull to a side unless its windy out

OP sounds like a one off issue or whoever did your alignment missed something.

14 hours a week spent on the highway and it takes curves like it is on rails. There is something not right.

^Yup, get the exact specs from them.

I did over 600 miles yesterday from the northern NY 'burbs to within 75 miles of the Canuckistanian border in northern NH and back, interstates and back roads in all sorts of weather at all sorts of speeds and not a problem with stock tires that have ~40,000 miles on them. There is something not right with your car.

ps: ooh I had my best mpg tank ever at 34 with an avg speed a little over 70mph :)

misalignment or defective tires.

They screwed something up or something is defective on your car. I routinely cruise at 100mph+ and my BRZ is laser straight and stable. I have wide sticky tires too so I'm putting more load on the steering and suspension.

Hood starts to wiggle, sure, but tracks perfect.

I am curious if it was extreme wind (but sounds like you took that into account).

Were there grooves in the pavement? I know on my motorcycles that can make my bike shake.

And the obvious most likely answer...something is just wrong with suspension bits (all the stuff people above me mentioned).

I am not super-mechanic or anything...could it be something wrong with the steering wheel/column and that set up?

^^ One thing in that article bugs me. It says new tires always go on the rear. I've always done exactly the opposite, if I'm only replacing two they go on the front.

Our cars are sensitive to the wind at highway speeds.....well mine is anyway. However, I honestly don't mind it or feel unsafe. I love the feel and handling of this car. I am sorry if you are not satisfied with your purchase.

I second that. Car has always felt firm on the ground, regardless of speed or wind. :burnrubber:

Then you have been doing it wrong.

Fronts wear much more quickly, steering and braking happen there and you need them to be better in wet so why new on the rear? It doesn't make sense to me.

2016?
Been over 100 smooth as butter. 2013

The goal is understeer. It's safer. More grip in the back, especially in the wet.

I have noticed on grooved concrete road surfaces mine tends to wander back and forth like that. On the other hand stuck like glue on asphalt. I am an alignment tech and I would also be curious to see the numbers as others have said just because it is green doesn't mean its good IMO.

better tires always on the rear:

http://www.ft86club.com/forums/showthread.php?t=98681

http://www.ft86club.com/forums/showthread.php?t=103302



http://www.tirerack.com/tires/tirete....jsp?techid=52

"The ability to sense and control predictable understeer with the new tires on the rear and the helplessness in trying to control the surprising oversteer with the new tires on the front was emphatically proven."

"When replacing only two tires, the new ones go on the front.
The truth: Rear tires provide stability, and without stability, steering or braking on a wet or even damp surface might cause a spin. If you have new tires up front, they will easily disperse water while the half-worn rears will go surfing: The water will literally lift the worn rear tires off the road. If you're in a slight corner or on a crowned road, the car will spin out so fast you won't be able to say, "Oh, fudge!""

http://www.popularmechanics.com/cars...nked-10031440/

"Stop with the “even ifs.” No matter if your vehicle is front-, rear-, or all-wheel-drive, a pickup, a sporty car, or an SUV: If you buy only two new tires, you should put them on the back, according to tire manufacturer Michelin North America."

https://blog.allstate.com/new-tires-rear/

"The worn rear tires have less tread and lower hydroplaning resistance. They can lose their grip on wet roads, causing the rear end of the vehicle to swing around out of control."
http://www.discounttire.com/dtcs/infoTiresRear.do

You may want an alignment that's 'stable' and not zero toe... This car requires attention, you can't half doze behind the wheel like you can in so many cars. Part of its turn carving comes from a sensitive setup. So, while the alignment may indeed be an issue, it may also partly be expectations that aren't quite in line with the car's tendencies.

Push is the safe recommendation, so new tires always go on the rear.

I think another way to say that is: Understeer can be recovered from by just slowing down (the automatic response by most people) while sudden oversteer is harder to recover from.

from unplugged: "Now at 628 miles, cruising around 70-75mph (yes within speed limits) my car will literally shift left or right and it doesn't matter which lance since I know the road crown can give a slight pull."

I have a 2015 FRS bought new. I felt the same sensation when my car was new. It was an odd sensation surely. It was not as though the car was wandering, it was as though the entire car was shifting, just slightly, to the left or right in my lane (and constant at freeway speeds). Over a period of miles (can't recall how many...but I'd guess well over 1000 miles) this went away. I believe it was because the tires were new, possibly those little nipples on the surface of the tire left from the molding process. Eventually those nipples wear away...or simply that the tires broke themselves in. (My car came with the Michelin tires.)

>>So I'd say, put more miles on the car, and the problem will heal itself.<<

My advise: Give the car plenty of time to break itself in, and you getting used to what to expect from the car. Don't monkey with more alignment advise, changing tires or suspension pieces right now. Give it time and many more miles first.


As for this: "Around a slight right bend on the highway, the car literally went half way into another lane." I have no answer, as I was not in the car with you. You might want to dismiss this as a fluke, if it never seems to happen again. Possibly a huge gust of wind as you rounded a curve ?


Edit:I see now you've got a C5 Vette, so you quite possibly are already aware of things I've stated below...which may be similar to BRZ

Since this model car is lower to the ground than most other cars, we feel sensations we would not feel if the car were raised off the ground more. You'll also note: Can't tell exactly where the front of the car is when attempting to park up to a parking stop (cement strip). You also won't get the advance viewing notice of holes (potholes) in a road's surface you'd get in other cars. You'll have to be very careful entering or exiting into or out of a business entrance from a highway. Can't easily see just where the curb ends and entrance begins...you're too low to see these things. These are some of the tradeoffs of a car which can handle corners better than most other cars.

Hmmph, learned something good today. Thanx guys. I'm always surprised at how many mistakes I've made over the decades...

One thing I've noticed is that brand new tires give a Squirrelly feel for a hundred miles or so.

Mine pulls too. Its tire grooves. Get new tires.

A truly good alignment guy can work wonders. The Roger Krause Racing guy ended up taking a crowbar to my xA suspension. It would align perfectly in spec bent, but it still had an issue. The tires were so out of round, the car still pulled to the right. Interestingly, they also insist on not aligning with a person in the driver's seat. They said they get tons of complaints of the car pulling when they do that. They do way more alignments and racing tires than anyone here, so I imagine they know what they're doing.

I always put new tires on the rear. If I get a flat in the rear, I move my front tires to the back and put the spare up front. It takes longer, but if you understand what happens to the rear tires around a corner, you'll want to have good tires there to come around a corner safely. Since your front can be corrected using the steering wheel, always keep your worn tires or spare up front.

I'm very familiar with rear wheel drive cars. And having had a higher HP/tq car too which sits lower than my BRZ, it still behaves very well on highway at those speeds.

I left my print out at the dealer so I'm going back this week. It looks like the toe in the rear is fighting between left and right. When applying throttle, it's more noticeable than without. Although it could also be the tires.

I did drive it again at night without the heavy gusts of wind, and it wasn't as bad as during the day. So that definitely played a part in my experience.

I'll follow up later this week with more updates.

Reading what we've both written this morning I realize I did not describe properly the sensation I felt when my car was new.

>What I felt, in my car when it was new...Try this. Sit in a chair,(actually toilet is best here...LOL) rock your upper torso to the left and to the right, moving it only slightly left and right, but constantly continuing the motion. That's what I felt with the new car/new tires, at freeway speeds. < Yet I've never felt this sensation before in any car I've driven or owned, and I've owned lots of cars.

Though different from what you describe, I did not notice any difference with throttle application or on deceleration. And this was on asphalt, what we have mostly around where I live.

Certainly I've noticed this car, with these tires, loves to stick in the grooves of concrete which has grooves designed to keep tires from hydroplaning. But that's normal for many tires. And these surfaces are not everywhere on concrete fortunately.

With about a thousand miles on my car, I took an 8000 mile cross country and back trip. I was very happy with this car as a freeway cruiser. Additionally, during that trip, I briefly, very briefly drove my car wide open. I was very surprised at how buttoned down it felt at that speed. During that trip I also drove the car in high winds, and it handled them very well, though now with over 26,000 miles on the car, not so well in winds.

I've never been happy with the lack of on center feel of the steering at freeway speeds. I think this car needs more caster in it's steering. The steering also lacks tactile feel of what the wheels are doing. Where the steering really does have that feel is on winding back roads, asphalt and dirt. Fortunately we have tons of those roads around here...and those are conditions in which this car totally rocks.

Something is screwed up in the alignment IMO. Either that or something is loose in your suspension.


Doubt it has anything to do with tires, when the car has less than 1,000 miles on it.


Why was the alignment messed up from the factory? Any explanation / story there?

Surprised no one has said this yet, but have you checked your tire pressures? If they aren't even it can cause handling issues that seem alignment based.

I have felt that "shifting" sensation also but it was after experiencing one of my rear tires exploded going 80mph on the freeway. After getting a replacement tire I felt every shift the car was making at highway speeds because I was traumatized and paid more attention to it. From what others are saying it seems the shifting feel is a character of the car. Suddenly pulling into another lane while cornering, however, doesn't seem normal.

Totally agree. First thing to check especially with bikes.

Although I do get caught out every so often myself

My car had an alignment done as part as the PDI?
I was told that they get "shook up" in shipping and that they align every car that comes in the dealership?
Maybe my dealership just went above and beyond though...

What?
They get "shook up" from a boat and truck ride?
Should we be getting daily alignments from driving?
If the dealer told you that they are bullshiting you for some weird unknown reason.

Maybe the boat hit an iceberg :iono:

Attachment 135262

Hey Captain...........better make sure those cars get an alignment when they unload...........

Are the tires on there bigger than the stock ones? I've had cars with bigger tires installed over stock size and they sometimes tend to wallow in the ruts in the road more than a stock size and make it steer goofy.