Vibration above 80mph
 

Hi,
Current setup:
2013 BRZ MT, stock suspension, 68,000 miles, 17x9 Gramlight 57dr, hubcentric rings, 245/40r17 Michelin PSS tires, catless UEL header, tune.

Its my daily, I do track it.

There is a vibration in the chassis above around 80 mph. I feel it mainly through the seat. I had the wheels rebalanced since that was the low hanging fruit. It is not the front wheel bearings, i know what that feels like. The vibration does not come through the steering wheel or get worse when turning the wheel above 80.

The vibration is the same whether I'm in 6th gear or downshift to 5th or 4th going the same speed. So my initial inclination is that is not the driveshaft.

At some point I will put the stock wheels back on to completely eliminate the wheels/tires as the root cause.

I think that should be enough information but I'm sure you'll ask if you need something else.

If that doesn't fix it the only other thing it could be is the rear wheel bearings?

Any other ideas?

I am having the same issue. Though Mine manifested after my LS Swap. It's a somewhat speed based and gets worst as speed rises. Had my new driveshaft balanced multiple times. Wheels balanced and even replaced tires. Next up is trying road force balance to make 100% sure they aren't slightly bent. I replaced a cv joint on rear axle that helped quite a bit. I am starting to wonder if my other axle is broken/worn as well.

Alignment yet?

Hmm, I have not done a recent alignment. Good point, I will try that as well.

im having this same issue

I had the same problem when I put wheel spacers on. I tried reinstalling them a couple times but couldn’t get the shake to go away until I took them off.

Thanks for the input but I have no wheels spacers.

Rotor's could be warped, and tires could be cupped. I would check these too

I would start by checking alignment. I've found that this type of behavior can be caused by large deviations in alignment from left to right in either the front or the rear. It'd have to be off quite a bit, but it's completely possible. My factory alignment was off a surprising amount right off the dealer lot, after your 68k miles and hard driving it's worth having it checked.

The driveshaft speed is fixed in relation to wheel speed. It's probably not the driveshaft but I figured I'd throw it out there just in case.


Does the vibration frequency seem to correspond to wheel speed, or is it about 4 times as fast? That'll narrow it down for sure.

How do warped rotors play a roll unless you're braking?

Dumb question but when you're experiencing this is it always on the same stretch of road?

The reason I ask is because from what you've said it's around 80mph, and to do that in most cases you'd be on a freeway/highway of some sort. Does this happen on all of the ones you travel on?

I know where I live there are some stretches of some freeways where there's kind of off-putting vibration, but it's easy to tell other cars are experiencing it too. It's just a result of the road being total crap with ripples or other imperfections; other roads that are nicely paved feel fine. Also with our suspension we feel imperfections much more easily than other cars.

Makes sense, I didn't think that through properly.

Considering wheel speed is about 18 revolutions per second, I would say that it is closer to that than 72 revolutions per second (driveshaft speed).

That was the very first thing I considered. It does it on all roads. Thanks for the thought tho.

You got it. I'll defer to the other guys regarding alignment & wheels.

Here's what I would never recommend doing. I would never lift the rear end on jack stands and idle the engine with it in gear.

Then I would definitely recommend against watching and feeling for wobble and uneven wear in the wheels/tires.

Don't do that.

I would always start with this. Or even rotate front to back, see if the vibration moves to the steering wheel.
Just because it was balanced, doesn't mean it was balanced, if you follow.

Because with disc brakes there is usually some amount of friction between rotor and pad whether you are braking or not. You might not feel it at lower speeds, or unless you are actually braking, but at 80+ mph it might be felt.

This is probably not the cause of vibration, but if you rule out everything else, it's worth considering.

Without inspecting the vehicle or knowing more details, it's gonna be tough to figure this out, so I'm just throwing out ideas that haven't been mentioned yet.


EDIT: Your hubcentric rings could also be the cause. Are they plastic or metal? You said you track your car, it's usually not advised to track a car with plastic hubcentric rings. They expand and can melt with the heat so this alone could be the cause of the issue. Hell, even metal rings can have this problem. They can expand/contrast/warp/etc etc. It's worth removing them and making sure you center your wheel correctly with the lug nuts and then seeing if the vibration is gone.

As long as your using the correct lug nuts, you really don't need the rings.

They are aluminum. If I try the stock wheels and it goes away, I’ll add this to the list of things to check.

Definitely have never done that. I’ll make sure to avoid that. That would be terrible if I accidentally do it.

I beg to differ.

I'm not here to argue with you, but there are lots of people all over the internet who back up my claims.


We'll start with our own forum:

http://www.ft86club.com/forums/showthread.php?t=23877

and now we'll move onto others;

https://grassrootsmotorsports.com/fo...y/13593/page1/

https://grassrootsmotorsports.com/fo...m/85470/page1/

http://www.m3forum.net/m3forum/showthread.php?t=336496


a guy in this thread had the rings fuse to his wheels:

https://forums.nasioc.com/forums/sho....php?t=1522131




Now, i'm not trying to say you shouldn't run them. That's totally your choice. But they are really only used to center the wheel on the hub when you tighten your lug nuts. Most aftermarket wheels are lugcentric, so as long as your using the correct lug nuts and you installed the wheel correctly, you shouldn't have any issues.



We are trying to diagnose a vibration issue, so I suggested something that other people have had issues with in the past.


I don't have any on my car, and it drives smooth as butter at 100+ mph.


So you can beg to differ all you want, but nobody else suggested it so I did. It's easy enough to check and see if the rings are causing the problem.


He tracks his car so his metal rings could of very well fused to his wheels, and might be creating a small amount of friction with the wheel/hub that is only noticeable at higher speeds.


OP: Please keep us updated! I'm curious to what is actually causing the vibration.

They're not fused to the wheels. Last time I rotated my tires, they fell out. Obviously, I put them back in.

Weekend synopsis.

Definition;
Original condition: Aftermarket wheels in the orientation that was causing the original vibration.



Action 1: Jacked up car and made sure aftermarket wheels were seated properly. No abnormal wobble was observed when wheels were rotated.

Action 2: Put stock wheels back on. Drove it up to 85mph. Smooth as butter.

Action 3: Put aftermarket wheels on except put back wheels on front and front wheels on back. If the rear wheels were out of balance, the vibration would migrate to the steering wheel. Vibration was much less than original condition, almost entirely gone. There was still a decent amount of vibration above 90mph.

Action 4: Rotated wheels again, back to original condition. Vibration was the same as after Action 3. Vibration did not migrate, wasn't as bad as original condition, and decent vibration above 90mph.

Hypothesis: I don't think its the wheels, given the above conditions. Would the wider wheels and tires amplify an issue with alignment? Since the stock wheels showed no vibration, maybe the alignment isn't that bad but with the wider wheels and tires maybe I'm able to observe it better?

Any other thoughts? Might try different hub rings.

I run MPSS on 17x9 with the same problem. Alignment is spot on but unlike you I haven't had my wheels balanced.

Is there play in your hood? My hood moves a bit and I'm thinking that may be contributing to it but not sure.

No play in my hood

Sounds like the vibration follows the vehicle speed and not the engine speed...?
If so, your engine should be fine. Everything after the engine (clutch, transmission, drive shaft, etc..) could be the reason. Seems like some imbalance somewhere is coincident with the resonance. Since the OEM wheels are smooth as butter, maybe it's your aftermarket wheels/tires/spacers.
Anyway, unless the aftermarket parts are from a top tier OEM supplier with high Quality Control standards, ALWAYS stick with OEM.

Wheels are Gramlights, tires are Michelin PSS, hubcentric rings are Muteki. Muteki is the only brand I don't know. Gramlights aren't an OEM supplier but definitely a top tier manufacturer. This also has started recently and haven't smacked the wheels at all to throw them out of shape.

Who mounted & balanced the wheels? You may have already done this, but have you tried a different shop for re-balancing? I know for one that the Belle Tires near us doesn't do very high speeds

What alignment specs are you running? The alignment shouldn't cause a vibration unless the specs were way off, but you ruled that out with testing your stock wheels. Wheel/tire size shouldn't matter, I run an 18x9.5 with a 265/35/18 and have zero issues.

I would have the shop who balanced your wheels, rebalance them. Also, ask when was the last time the balance machine was calibrated. If they don't know or it wasn't recent, then get them balanced somewhere else.

I'm assuming you hand tightened the lugs in a star pattern and then torqued them to spec as well. It hasn't been mentioned yet, which lug nuts are you using? Gram Lights (and most other aftermarket wheels) need a 60 degree tapered lug nut (most aftermarket lug nut kits are).

Even good manufactures have quality issues. Appears to be a wheel, tire issue. Out of round or balance or bent. You could start by only replacing 2 tires with the new ones then narrow it down to different tires on the front. I would not run different tires on the back.

This is why every time I rotate my tires, I get the new fronts balanced as well.

Being RWD, sometimes the rear tires can spin relative to the rear wheels and throw the whole thing out of balance.

I had the wheels rebalanced at American Tire depot. I don't think its a balancing issue bc when I rotated the aftermarket wheels the vibration did not transition to the steering wheel. Doesn't vibration through the steering wheel either mean bad front wheel bearings or wheels out of balance?

I haven't done an alignment since I've owned the car (2 years).

The wheels were balanced at American Tire Depot. I originally got them installed at Costco but then rebalanced at American Tire Depot. I have Project MU lug nuts. They are tapered 60 degrees.

If you haven't done an alignment in two years, and you've been tracking it, the tires could be wearing uneven, causing the vibrations.


I would get one done, and if that doesn't solve the issue, replace the tires.


I still think you should try without the hubcentric rings, but not aligning a car for two years is probably the culprit.





Typically yes, but for your mileage, it seems low for a wheel bearing issue.