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-   -   Getting wheel vibration at different speeds (http://forums.pelicanparts.com/porsche-911-technical-forum/1003359-getting-wheel-vibration-different-speeds.html)

sadcaper 07-26-2018 08:42 AM

Getting wheel vibration at different speeds
 
So my steering wheel vibrates at different speeds, starting around 55mph. Then it goes away up until 75ish. Then it goes away a bit after that too. Maybe wheel imbalance?

Anything else I should check?

Dmitry at Pelican Parts 07-26-2018 09:13 AM

I would check the driveshaft as well. Other members will chime in with their expertise.

cabmandone 07-26-2018 09:20 AM

Depending on the type of weights used to balance the tires, you could have lost a weight. I'd take it in and have the tires balanced.

Ctopher 07-26-2018 11:32 AM

Quote:

Originally Posted by sadcaper (Post 10121172)
So my steering wheel vibrates at different speeds, starting around 55mph. Then it goes away up until 75ish. Then it goes away a bit after that too. Maybe wheel imbalance?

Anything else I should check?

You say steering wheel....is it just the steering wheel shaking or the can you feel your butt vibrate? Asking to determine front or back and as others had mentioned....balance the wheels being something to consider.

But if its the steering wheel only then up front you have tire balance but it could also be tie rods. Jack the front of the car up and with the steering wheel locked move the wheel left to right and inward and outward to determine if you have any play/movement and if you hear any clicking from the ball joint.

If its rear, the drive shafts are another items to consider beyond balancing.

The big question is has the car sat in a single place for a long time? You could have developed flat spots on the tires. Check pressure and drive a bit but if you are driving at highway speeds and your tires are old with flat spots or more than 4yrs from manufacturer date on the tire its time for new tires. Old tires are dangerous, you could have flat spots, dry rot or a separation of the tread which could come off at highway speeds.


Ctopher

Cory M 07-26-2018 11:54 AM

Always start with the tires, that's usually the problem. Could be a simple unbalanced/damaged tire or a bent wheel. I've also had similar vibrations cause by loose CV joints (on the hub side) and loose/missing motor mount bolts.

1979-930 07-26-2018 12:15 PM

Does it drive like a dump truck?


Sorry; I couldn't resist. :D

wayner 07-26-2018 12:21 PM

Any corrosion?
Check the front forward torsion bar sheet metal mounts too if everything else checks out ok

rnln 07-26-2018 12:52 PM

I would do in order from cheapest:
wheel/tire balance
check wheel bearing
check for wheel round/true
replace tires.
........

irl 07-26-2018 01:12 PM

Quote:

Originally Posted by Dmitry at Pelican Parts (Post 10121211)
I would check the driveshaft as well. Other members will chime in with their expertise.

Driveshaft???

kevinbodman930 07-26-2018 01:32 PM

Check the lug Nuts

Sent from my SM-N950U using Tapatalk

sadcaper 07-26-2018 02:25 PM

Quote:

Originally Posted by kevinbodman930 (Post 10121488)
Check the lug Nuts

Sent from my SM-N950U using Tapatalk

What should the nuts be torqued to?

I’ll check those and then the tire/wheel balance next. The vibration is definitely only in the wheel. Tires are brand new.

Thanks all for suggestions!

pmax 07-26-2018 04:38 PM

Do this check first.

Road Force Balancing | MotorWeek
Quote:

But everybody says alright, we’ll balance the tires. That’s part of the equation but balancing isn’t always the answer. So you have to go a step further. What we have here is a Hunter Road Force balancer. This takes it to a new level.

This roller back here comes out against the tread of the spinning tire. It applies 1,200 pounds of pressure to simulate the weight of the vehicle on the tire as it rolls down the road. Now a computer in the machine, and sensors, sense variations in the tread. Stiffness, or the tire isn’t completely round, or anything that would prevent the tire from rolling smoothly when its weighted by the car.

Then it translates that into a road force reading. We have a warning that it is excessive. Next thing we do is take some measurements.

What we did is we took measurements of the rim. Of course the machine had already measured the tire. Now we can do what is called match mounting. We’re going to take the high spot of the tire and match it against the low spot of the wheel. It’s really more complicated than that, but to make it understandable… that’s what we’re doing. And it’s telling us here that we have 15 pounds of road force in the tire and if we swapped the tire around, moved it around on the rim, such as it’s showing us over here, that we can reduce this to 8 pounds total.

That brings us in spec and that means now we’re going to have a smooth riding tire.

darrin 07-26-2018 06:00 PM

Torque is 96 foot pounds / 130 nm

manbridge 74 07-26-2018 06:16 PM

Quote:

Originally Posted by irl (Post 10121465)
Driveshaft???

I bet he meant driveshafts which is what Porsche calls axles....

T77911S 07-27-2018 03:42 AM

year?
start with: old tires, flat spots, (mine had lots of them :)) balance then bent rim.

a bad bushing in the steering column makes it worse.
then I would look at tie rod ends.
if you get it aligned (after new tires) the tech can tell if the tie rods are bad.
also if you put tires on make sure they check for bent rims.
Porsche rims are pretty stout.

86911cab 07-27-2018 06:58 PM

Start with rebalancing the wheels.

Lyle O 07-27-2018 08:27 PM

Like everyone else has suggested, start with wheel/tire balance. I had a set once earlier that never could get perfectly balanced; alway had a slight issue at 40-50. Turned out to be the tires. Be sure when you are testing the ride you are on a known stretch that is flat, and you use the same stretch each time.

G450X 07-28-2018 06:20 AM

Updates
 
Please provide updates by stage of repair/replacement. I see way too many requests for assistance then silence on the solution, which could help many others. Let us know the fix!

I have a similar problem, I suspect either old tires/poor wheel balance or worn CV joints/lack of fresh grease.

I have a bit of an odd speed dependent roar from the back which could be axles/CV joints in a bind/worn (need fresh grease)? I can kinda “feel” the momentum of the car surge a bit that is commensurate with road speed.

I had an alignment performed a few years ago and the tech said the front end was tight.

Trackrash 07-28-2018 01:13 PM

Agree with most above.

But if it was my car, the first thing I would do is jack up the front end and spin the wheels. Check if the tread runs true. If it is the tire, you will be wasting your time getting them balanced. AHIK.

Good time to check the tightness of the wheel bearings too.

How long has this been going on? On my wife's car there was an imbalance that eventually ruined the front wheel bearings.....

_____________________________________
Trackrash's Garage :: My Garage

jlex 07-29-2018 05:07 AM

If your tires are out of round, no amount of balancing will help. At certain speeds, they will synchronize with each other and set up a vibration. A tire shop can check for out of round tires.
They used to have tire truing machines that would cut down the high spots on a tire, but they don't use those machines any more.... just throw the tire away and put on a new one. Tires are being made better these days, so there is less demand for tire truing.


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