135 mph steering wheel vibration

[Krockit1]

Finally got a chance to wring her out on a nicely empty portion of the interstate. This car just seems to get more planted as the speed builds. Smooth as silk through the wheel, arrow straight and rock solid... to 135 mph. Then, and all of a sudden, the steering wheel started kicking back a nasty vibration. Very pronounced, like an unbalanced front tire or a suspension part fail. Front tires are at 75%, rears probably under 45%. OEM fitment Conti Sport Contact 3's on 220's. All bone stock from the original build sheet. But again, to 135 the car was silk. Any ideas?

[Ghetto2315]

Wheel Weights?

[mdosu]

wheel weights likely, also check air pressure.

I've never taken my car north of 110 mph, but I would also consider the quality of the road you were on too...a lot of small minute imperfections are more pronouced as your speed increases. And we don't really live in a country with glass smooth roads.


With some of those magazine tests for max speed (Top Gear, perhaps Road & Track & others), the manufacturers send in a technical expert to ensure the car is prepped properly to go anywhere north of 150 mph. they check air pressure, wheel bolt torque, etc etc..just so the reviewers don't incorrectly attibute a maintenance/setup issue as the actual car's deficiency, which can be damaging if reviewed and written to their subscribers or viewers.

[surlynkid]

i have been to 140 per the speedo (AiM Solo DL said 132) with no vibration problems like that. check wheel balance.

[Krockit1]

Some good places to start, thanks. Car's cooled off now I will ck the tires- TPMS never signaled, though. If it's a balance issue, wouldn't it start to vibe out before 135? I mean it was like a switch was flipped....

[thekurgan]

Originally Posted by Krockit1

Some good places to start, thanks. Car's cooled off now I will ck the tires- TPMS never signaled, though. If it's a balance issue, wouldn't it start to vibe out before 135? I mean it was like a switch was flipped....

Most balance vibrations happen between 55 and 75. I think in the manual, or on the door, if you're travelling over 100 mph, there is supposed to be an increase in the tire pressure due to the downforce applied to them IIRC.

I'm curious to know the cause.

[F1Venom]

Above 80, the steering wheel does become a bit more jittery. But then again the surface could have been bumpy.

[Krockit1]

Both right side tires were 1/2 pound less than driver's side. And yes, speeds over 100 mph have a higher recommended pressure in the manual. I did not have my tires to that poundage as I hadn't planned for this little run, but there it was, a wide open highway just begging for WOT so I let'er eat! I will inflate to those autobahn pressures and try it again. Ah, hell, you can bet the road will be one big knot of Priuses, minivans and semis this time

[Krockit1]

Originally Posted by F1Venom

Above 80, the steering wheel does become a bit more jittery. But then again the surface could have been bumpy.

That's the thing, it was stable, smooth and on rails until it hit 135 or thereabouts. I only glanced down for an instant when the vibration started and it was just under 140 somewhere. The was absolutely NO untoward harshness, vibration or shimmy, etc, before that speed was reached. The steerring wheel was actually calm. In fact the car is so stable and laser like at speed that I am now hesitating doing a wheel mod, spacers, etc. The 220's are growing on me because the stability is so right. Just need to get some new tires, for certain. Compared to my previous (Porsche) experiences, this car instills a lot more confidence at speed, at least in the straights. 911s and even the mid-engine Boxsters, from my experiences anyway, have a tendency to get front end light at high speed and it takes some getting used to.

[Denk]

All of my vibration issues were noticeable to me around 80 mph. All of my vibration issues were fixed with another wheel balance. It could be a little funky tread wear on your tires that are the issue at that speed...just guessing. I'll bet a new set of tires with a road force balance would do the trick. Yes, 220's are awesome!

[pughdxk]

I mean it was like a switch was flipped

[surlynkid]

Stop at 134.

[M5Rlz]

I had vibration at 70-85 and then went away. Turned out to be a bubble in one of the tires.

Balance and check for bubbles.

[i001947]

Originally Posted by Krockit1

Finally got a chance to wring her out on a nicely empty portion of the interstate. This car just seems to get more planted as the speed builds. Smooth as silk through the wheel, arrow straight and rock solid... to 135 mph. Then, and all of a sudden, the steering wheel started kicking back a nasty vibration. Very pronounced, like an unbalanced front tire or a suspension part fail. Front tires are at 75%, rears probably under 45%. OEM fitment Conti Sport Contact 3's on 220's. All bone stock from the original build sheet. But again, to 135 the car was silk. Any ideas?

Was the M button with all of the settings engaged on, while you were in triple digit mode?

[Krockit1]

Originally Posted by i001947

Was the M button with all of the settings engaged on, while you were in triple digit mode?

Yes it was, and DSC was still engaged.

[doubleo]

Check your tires.. I have gone up to 150mph and no vibration.. just a bit of hand sweat

[CanAutM3]

Most likely tire/wheel balancing. Vibrations is a very complex topic. Different excitation can yield to different hamonics and vibrations depending on speed. Further, the faster you spin, the stronger the excitation forces.

It clould also be a bent wheel. The deformation is small enough that you don't feel it at lower speeds, but as the speeds increase...

With my street tires, the car is silky smooth all the way to top speed (my car is delimited). With my track wheels, wich ar impossible to keep balanced (high wear rate and rubber pick-up), the whole dash starts to shake like hell upwards of 120mph due to the vibrations.

[Sleeper519]

Ever plugged one of the tires or had to use the fix-a-flat foam sealer do thingy? It is actually a liquid of not inconsequential volume, that will roll around in the tire and exaggerate the vibrations at high speed.

(ask me how I know)

[Peahi]

Originally Posted by surlynkid

Stop at 134.

Yeah, be careful man...you might have just dodged a yardsale.

I don't wanna be reading a "I just crashed my M3 in Wisconsin" thread soon. Take it to the track.

[saeedg48]

check wheel weights. also leave edc in sport not sport+ for top speed runs.

[Krockit1]

I purchased this car in June and had the dealer remove the tires for rebalancing and to clean the wheels inside out. Dealer inspected and declared all four were good to go save the wear, which not incidently was very even, no cupping or incline wear because of the camber. I didn't care what he said, because before he prepped the car for me, the same was done for brake inspection during the PPI by the shop that did all the post warranty stuff on my Porsches and 330i. Top shelf guy, and he said everything was good to go. No plugs, bubbles, etc. So this is an interesting mystery. I was going to run these tires through spring then get new so I wouldn't have to store through winter on the new shoes, but now I think I'll run some RE11 or PS2 in OEM fitment to see if that solves it. Also will have the installer check all the rims for straightness. Thanks Fellas for the insights. And the fatherly advice! Even though I am probably older'n all of ya !

[signes]

Did you by chance have 1100 lbs of wood flooring in the trunk?