Vibration above 80mph

[D-rek07]

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?

[DustinS]

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.

[8RZ]

Alignment yet?

[D-rek07]

Originally Posted by 8RZ

Alignment yet?

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

[Submarinesonce]

im having this same issue

[ShansBRZ]

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.

[D-rek07]

Originally Posted by ShansBRZ

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.

[JeremyR]

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

[Tristor]

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.

[Ultramaroon]

Originally Posted by D-rek07

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.

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.

[N1rve]

Originally Posted by JeremyR

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

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

[spike021]

Originally Posted by D-rek07

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?

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.

[D-rek07]

Originally Posted by Ultramaroon

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.

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).

[D-rek07]

Originally Posted by spike021

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.

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