My Steering Wheel shakes at speeds over 120 mph

[Bill Jennings]

Before needlessly changing parts check for play first in all steering joints and bearings plus check the front wheel bearings as well as get a a proper balance on your wheels. How old and what condition are your tyres, any bulges or irregular wear? Can you find a tyre shop that uses a Road Force balancer? Most tyre shops don't need to balance for high speeds so they just do a basic balance that is usually good enough for posted speed limits.

Cheers

Bill

[mspirito]

I recently had the same issue on a 71 with 15 inch Fuchs . I had them balanced at several different shops and I still had vibration after that. I changed the wheel bearings the rotors brake pads etc. There was no improvement. Finally took the wheels to a shop that used a lug centric wheel balancer and that solved the problem. They need to use the centering device that centers the wheel on the lugs and not on the hub. This information was courtesy of Harvey Wiedeman.

[Nick Triesch]

Why would you go 120 in an old car? Holy cow! If I tried that I would have parts coming out of my tailpipe!

[CCM911]

LOL! I'll bet your car is sturdier than you think.

I think with a tire change and a GOOD balance, our OP will be just fine.

Originally Posted by Nick Triesch

Why would you go 120 in an old car? Holy cow! If I tried that I would have parts coming out of my tailpipe!

[kramer747]

I'm with Nick -seriously -how many are going 120 on a regular basis in an older 911? No one

[ShakinJoe]

Originally Posted by kramer747

I'm with Nick -seriously -how many are going 120 on a regular basis in an older 911? No one

I do as do many others on this board. Many of us are DE instructors and many Club Race. 120 mph is actually quite easy and not unsafe in these cars!

[cgh911sc]

Well, when I was buying my Porsche a 1983, 911 (930) 3.3L I was told the car could be
driven all day long at a 150 mph. So I asked the salesman how he knew that.
I asked if he had ever driven the car he was selling me 150 mph. He said well
no; but it will do it no problem.

It seems many say their car will do 150+ mph etc. but, how do they know their car will do it.

I said okay let’s see... I checked out the tires etc. and took it to the highway.

I got up to the speed limit and kept going for a very short while to about 120 mph
then the shake... Then I let off...

It will not go 150 mph as it is. Not because of the engine but because of the suspension, tie-rods, ball joints whatever…
it shakes.

I can say it will do 120 mph. as it is… but, I guarantee you I wouldn’t go that fast in this car again till I find out why it’s shaking.
To go over 100+ mph ones car needs to be maintained for speed not just for a drive to the store or 0-60 over and over. Some cars just can't go the speeds the manufactures advertise.

I feel if I am to state my car has a top speed of 161 mph then it should be ready to do just that. 120 mph. is a lot less than 161 mph. the advertised top speed.
I had a Mazda RX-7 in the past and at 100mph it felt like it was coming apart. It just wasn’t made for speed as advertised.

I wanted a Porsche because I was told at 100 mph it would be smooth and
could easily do 120 mph. suspension wise.

Thanks all !!!

[javadog]

A 911 or 930 will do those sorts of speeds without a problem. There's obviously something wrong with yours. Once it's fixed, it will be capable of those speeds again. It's a 30 year old car and there's something wrong with it. Not the fault of the car, per se, it just needs a little work. Take it to a decent shop and have them sort it out for you.

JR

[tom1975]

Tell me guys,
What about shock absorbers?
Could this be the problem?

[rcotton]

Second on getting the tires reblanced with road force variation. As a tire engr. I can tell you a blanced tire can be a long way round and cause vibration atspeed and many shops don't check road force when mounting tires

[davemccorkle]

Well I have a 72 very modified with a 2.7RS setup that I have done 160 in many times. I love it! No vibrations either.

[javadog]

Then there's another possibilty... if this car was just purchased it may have been sitting a while. I've had a few where it wasn't possible to get the flat spots out of the tire.

JR

[Nick Triesch]

I would have become real Catholic again before I went 120 MPH in my old 85. The car is in great shape for fun trips and some mountain driving. But 120? Not in my 29 year old car! Not ready to see the light! Besides, I know my Grandma would be there and I really did not like her. Nick

[Type911]

I had a RR wheel that was just slightly out of round once that would create a slight vibration at 100 +. Could be your problem.

Why all the worry about high speeds? if your 911's suspension, brakes etc are well sorted it's not an issue. Did several 130+ runs in my 70E before, open road, no traffic. Car's are made to do this all day long.

[Flieger]

Dude, save that kind of speed for the track. I've done 120 briefly in my car and it felt about the same as at lower speeds, just that the front end feels a bit lighter. I have a shake at about 70mph but it goes away over or under that speed. I just live with it. It is the tires.

By the way my tires will flat spot big time if the car sits for a week. Takes a good 5 miles on the freeway before they get round again.

[haycait911]

is there anything at all at 60mph, even slightly? I've found that when I had a tire problem, balance or roundness or whatever, it would show up between 40 and 60 mph, then much more dramatically at exactly double that. in my experience, if it recurs at double speed like this, it's a tire/wheel issue. not mechanical.

funny, this thread reminds me of a thread I posted a while back, about my '67 getting light and twitchy over 140 mph. got the same kind of comments.

get the problem fixed and drive it as you like. I've had every porsche I've ever owned to redline in fifth, except the 914, it just didn't have the juice to get there, 800 rpm short.

[haycait911]

also, find a shop that can balance the tires on the 'fingers' that go in the bolt holes, instead of the center hole.

[fintstone]

All three of my Porsches will easily do 120. My first one was a little scary/sloppy, but it had bad tires and needed struts. None of my current cars have similar suspension problems.

[cgh911sc]

It sounds like the Porsche 911 (930) will do 120+ speeds.

Saying it and doing it are two different things.

I just don't wish to attempt any high speed driving in any car
that can't really do it just because it looks like it can.

I understand street trash, pot holes, etc. but the car coming apart as a norm
is another story. I wouldn't drive my Jeep over 85 mph on the highway no matter what the speed limit says as it's just not doable safely.

I wish to safely drive 120 mph, understanding road conditions, and not think I am driving totally out of control or being unsafe.

Some long open roads I have been on demand safe speed consideration.

If a well maintained Porsche is capable of smoothly going 150+ mph then should it be safe to drive at 120 mph.

Some US highways post speed limits of 85 mph now and 120 mph is sure to come in the future.

I wonder how fast most Non-mechanic drivers drive their cars on their morning commute before they worry about danger.

Fun topic… Thanks for the replies…

[cgh911sc]

Originally Posted by javadog

A 911 or 930 will do those sorts of speeds without a problem. There's obviously something wrong with yours. Once it's fixed, it will be capable of those speeds again. It's a 30 year old car and there's something wrong with it. Not the fault of the car, per se, it just needs a little work. Take it to a decent shop and have them sort it out for you.

JR

There just aren’t any good Porsche shops where I live in Dallas, TX. the shops here are only interested in money and lots of it. Asking any questions is viewed as if the customer can't afford the service and is not acceptable.

Older cars are treated badly by the local shops. I found the more one knows about their car the more it's obvious and the less the shops/dealers like you.

Older cars are considered undesirable. They always overcharge and try to stick you. I'm sorry it's that way; but it is. I guess this is why I and others are becoming Porsche machines as a result.

I feel any car intended to be driven over 100 mph should be talked about to insure correct work is being performed then the repair cost should be fair and discussed as well. Not in Dallas... That's probably why allot of Porsches will not go over 100 mph without issue and the non Porsche mechanic owners don't even know it.