E9X Help diagnosing terrible front end vibration

ShocknAwe

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Jan 24, 2018
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I've had bent wheels do this. Then again, sounds like you've done due diligence there. Lug bolts overtorque does weird shit too, I've had shops overtorque them quite a few times.
 

Jeffman

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Jan 7, 2017
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You probably can’t switch front for back wheels, so maybe switching L/R front wheels to see if there’s a noticeable difference.l? If so it’s you’re wheels.
 

langsbr

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Apr 5, 2017
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I hadn't thought of left to right , I can try that. I'm not lowered so I may also try the front to rear - I think the 265s can fit up front.
 

fmorelli

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Ok I just read back through this whole thread, realizing this is a near six month conversation that I had mostly forgotten lol.

So let me net this out ... probably good to recap, noting problem still exists across these facts:
  • Seem to start happening when you install cheap-ass tires with cheap-ass balance. But installing Michelins with a Hunter balance did not solve.
  • You have ~140k on the clock
    • You replaced shocks, M3 control arms (specifically lower arm and tension strut), and I'd assume you replaced your top front strut mount.
    • For completeness sake, I assume you have not replaced all the wearable items in the rear suspension?
  • Wheels have not been checked for rim shell bend or center bend, nor have you had a chance to swap a different set of wheels in.
  • You are wondering about driveline - axles, center bearing, in part because you see the driver seat shaking
So a general rule of thumb - if the car shakes in the wheel, it's front-end suspension/front wheel/front tire, if the car vibrates your butt (and not the wheel) then rear-end suspension/rear wheel/rear tire or drive line. Next, we can isolate the drive line with a simple test. Run the car up to 80-90mph and put it in neutral and coast at that speed. If the problem persist above 70mph while coasting, it's not the driveline but rather suspension/wheels/tires realm.

Hope this helps - feel free to correct any of the above.

Filippo
 
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langsbr

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Apr 5, 2017
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Ok I just read back through this whole thread, realizing this is a near six month conversation that I had mostly forgotten lol.

So let me net this out ... probably good to recap, noting problem still exists across these facts:
  • Seem to start happening when you install cheap-ass tires with cheap-ass balance. But installing Michelins with a Hunter balance did not solve.
  • You have ~140k on the clock
    • You replaced shocks, M3 control arms (specifically lower arm and tension strut), and I'd assume you replaced your top front strut mount.
    • For completeness sake, I assume you have not replaced all the wearable items in the rear suspension?
  • Wheels have not been checked for rim shell bend or center bend, nor have you had a chance to swap a different set of wheels in.
  • You are wondering about driveline - axles, center bearing, in part because you see the driver seat shaking
So a general rule of thumb - if the car shakes in the wheel, it's front-end suspension/front wheel/front tire, if the car vibrates your butt (and not the wheel) then rear-end suspension/rear wheel/rear tire or drive line. Next, we can isolate the drive line with a simple test. Run the car up to 80-90mph and put it in neutral and coast at that speed. If the problem persist above 70mph while coasting, it's not the driveline but rather suspension/wheels/tires realm.

Hope this helps - feel free to correct any of the above.

Filippo

You hit everything on the head as far as status.

I'll do that test tonight/tomorrow, but I'm THINKING I have done that and that a neutral coast above 70 the vibration is still present. I will confirm and report back. Thanks for the help - this is quite frustrating as this came out of nowhere (and to be clear - the fist time I experienced it was after installing the crap tires, and thus that was my initial suspicion.

As far as checking the rims for shell or center bend - is that something a typical balancer can do, or do I need a rim repair shop to do it? I'm also working on trying a different set of wheels to test with.
 

fmorelli

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Someone who knows what they are doing with a tire balancer can figure it out. IMHO generally speaking few aluminum rims are truly straight, so it is not a completely black and white thing. But if there is a suspect rim, a good mechanic with a tire balancer can figure that out.

Filippo
 

langsbr

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After some more testing with full attention paid, the situation is as follows:

Vibration is 'present' but slight at 70, and increases/gets worse at higher speeds.
Vibration gets 'bad' with hard acceleration over 80
Vibration is present on accel and decel, in gear, or in neutral coast.

If I had to judge, I would say in gear, off throttle decel is the 'worst' but it's still present in neutral coasting.
 

fmorelli

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The nice part of being on a forum like this is that the second post to this thread didn't say, "part out." :grimacing:

Definitely odd, and for me, that the problem really presents at such a high speed. Normally this kind of stuff seems to show up at 50-70mph. For me the fact that you have the vibration in neutral leads me to a reciprocating issue - wheel/tire/bearing. And if I recall, shows up more in your butt than in the steering wheel, which makes me head to the back of the car. If it was me, next thing I'd do is get the wheels spun on a balancer and check for inner or outer rim bend, and if center bent. If you wish to experiment yourself, get the rear of the car in the air and put it in neutral so you can spin the wheel. Spin each rear wheel, watching first the outside of the rim, then the inside. You can take a rigid piece of plastic (like a bic pen) and place it on a box so you can firmly hold the end of the bic pen against the edge of the aluminum wheel. As you spin you may see the wheel move further away from the pen, or push the pen back. I prefer a balancer on a visual, mostly because it is harder to see the bend at slow slow speeds (i.e. spun by hand). Anyway that's where your observations would take me.

One other thing - you replaced the front suspension wearables, and the rear shocks, but nothing else in the rear? So at 140k you could have a bad bushing back there. Pretty much any car with 140k on it has eaten its suspension for breakfast, lunch, and dinner. Hope this helps. Look on the bright side - your car is keeping you driving within legal speed limits :cool:

Filippo
 

n54dct

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Sep 7, 2018
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I had a rear brake caliper piston stuck. It would cause the whole car to tremble to the point that even the needles of the gauges jumped up and down. It would appear intermittently in high speed only and it was not connected to braking itself. Problem was revealed only when the pad was shredded to metal. Even if you have big brakes, it doesn't mean one of the calipers cannot be faulty.
 

langsbr

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Apr 5, 2017
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I finally resolved this and am so happy yet aggravated with all the things I did to troubleshoot. The vibration began immediately after replacing the front tires with some cheaper Achilles. It persisted after replacing them with Michelin Pilot Super Sports. I then did the following:

M3 control arms
Guibo

I removed the driveshaft to replace the center support bearing, but upon inspection it was in perfect condition, and there was no play in the u-joint so I reinstalled it.

It just so happened that a friend of mine just bought an E90 with 18 inch wheels. He asked to borrow my DCAN cable while waiting on his, so I asked to borrow his wheels :) . We first put my wheels on his car and went for a drive. Boom - there was the vibration, just as bad as on my car.

We then proceeded to drive my car with his wheels. About 10 feet out of the driveway we could hear a clunk from the front wheels. Slowly got back in the driveway to inspect and didn't see anything immediately wrong. We removed the wheel and then noticed that the wheel weights on his wheels were on the inside edge of the barrel, and were hitting the AP caliper, lol. So no using his front wheels. We put my front wheels back on, and went for a drive with his rears. Smooth as glass - even over 100.

The tires on the rear are 265/35/18 Federal 595RS-RR. They hooked like crazy from day one, and only have about 3500 miles on them, and fairly decent tread left. I checked with my buddy that owns a shop and his distributor still had a few Michelin Pilot Super Sports in the 265/35/18 size (both the front and rear size are used are discontinued in that tire now ) and they were only $150 each. Had them installed - regular balancing - his road force wasn't hooked up.

Test drive and BOOM - all is right with the world. I am very disappointed in the Federal tires. I know they aren't considered high end tires, but boy they definitely hook better than the Michelins. I just wish they lasted a bit longer than an oil change! Thanks all for the suggestions and ideas. I'm glad and frustrated that it was something so simple, and I should know better than to dismiss the easy stuff, but I figured they were still relatively new tires.
 
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Jeffman

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Excellent sleuthing. Congrats!
And I wonder if this is @matreyia ’s problem source as well
 

matreyia

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Apr 19, 2017
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Excellent sleuthing. Congrats!
And I wonder if this is @matreyia ’s problem source as well

Nah...this is totally different than my issue. There are zero vibrations, just noise. Also noise arose before new brakes, pad, caliper, rotors, wheel bearings, flex disc, were replaced and did not go away after they were installed. Tires are new.

Wait next week after rear axles replace, mfactory lsd rebuild kit and front bearings replaced.
 

langsbr

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I hope everything you are doing to troubleshoot are items that are in need of replacement anyways - that's a ton of dough to drop playing parts swap.
 

Torgus

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I hope everything you are doing to troubleshoot are items that are in need of replacement anyways - that's a ton of dough to drop playing parts swap.

Nothing is more annoying that throwing parts at a problem. Something BMW dealerships are awesome at. Assholes.
 

ShocknAwe

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Jan 24, 2018
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GLAD YOU GOT IT FIGURED OUT MAN! Chassis vibrations are the most annoying thing on this platform IMO.

I keep saying... Wheels and Tires, wheels and tires. Get the best quality tire you can, and make sure it's Mich/Pirelli/Continental/Bridgestone/Yoko

FWIW: the Mich PS4S hooks a lot better than the MPSS. Almost like putting 200tw extreme perf summer on there, but with tread that can handle water.
 
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langsbr

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Apr 5, 2017
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I think I'll probably go with a proper drag radial on the next set. I'm hoping traction would improve somewhat with an LSD.

Ideally I'll switch to a set of 17s, but with the bbk it will have to be reverse staggered size which might look dumb. Plus, the only wheel I have been able to find in 17 and 18 is the Apec Arc8s.
 

ShocknAwe

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I was wanting to do 18" front and 17" rear, but couldn't find a reputable wide street tire in 17", and I don't want to run DR all the time. My only caution on going smaller than 18" out back.
 

Torgus

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I think I'll probably go with a proper drag radial on the next set. I'm hoping traction would improve somewhat with an LSD.

Ideally I'll switch to a set of 17s, but with the bbk it will have to be reverse staggered size which might look dumb. Plus, the only wheel I have been able to find in 17 and 18 is the Apec Arc8s.

Are you aware of any 17s that will fit a 335i BBK? IIRC even some 18s will not. Spacers may help in some situations.