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Significant steering vibration between 60-70mph - tie rods?
Hey guys, looking for a sanity check on what I"m seeing and my plan of action. 997.2 C2 6MT, bit less than 80k miles. Have only had the car a few weeks.
Between 60 and 70mph (haven't dared take it faster) the steering wheel vibrates quite a bit, and the "planted" feeling of the car/steering disappears. Steering suddenly feels loose, car feels darty, tramlines on road grooves. At lower speeds the steering feels generally okay - small amount of play at the center, more than I'd like in fact, and it's almost certainly not "normal".
I made sure the tire pressures were back to spec (they were way out, and mismatched), but that made no difference. Reseated wheels and torqued to spec, didn't help. Tightened the upper and lower U joints on the steering column, no difference. With front wheels in the air I shook the wheels to check for obvious tie rod play - couldn't really tell. No obvious popping or anything. Likewise in turns I don't hear popping/knocking sounds that would obviously point to the tie rods. One aspect of the behavior that makes me lean towards the tie rods (besides their age) is that I can damp the vibrations in the steering based on how firmly I hold the wheel. To explain - if I am going 65mph and release my hands, the wheel looks like a paint shaker. If I grab the steering wheel with two hands, at 9 and 3 oclock, the vibrations significantly diminish. One hand on the wheel it's somewhere in between.
If it was the control arms, sway bushing, shock mount, wheel balance etc, I'd expect that how I'm holding the wheel makes little difference. So I have a set of replacement inner and outer tie rods, and I was planning to install those tomorrow, then take it to get aligned - and while there have the front wheels road force balanced. I happen to know the previous owner never had the tie rods changed, so at worst, I've replaced something that needed replacing anyway. But since none of the other potential culprits - control arms (both), front shock top hats, sway bushes/endlinks, wheel bearings etc are also original, my worst case is that it's not the tie rods, and I'll have to start shotgunning the other parts at it.
How old are these tires and what's the condition of them? Know how to read DOT-mandated date? I'd say have tire balance checked but you also may have some wear in front suspension pieces.
Certainly could be the wheels - I know they had been "reconditioned" in March of this year, so perhaps they're out of round, or just weren't balanced properly. No spacers. Could be as simple as a weight having popped off. Don't think that could be the whole story, as the steering feel even at a walking pace just isn't right when near on center - or when parked for that matter. Wheel balance issues wouldn't come into play at those speeds, I think. Also wouldn't think that a firmer grip on the steering wheel at highway speeds would have any impact on the behavior, if it was wheel based. The wheels will spin no matter how you hold the wheel.
Tires are Hankooks, about 9/32. Not new, but not ancient either. I know wheels/tires are the most common culprit for vibrations here, so I'll definitely get the road force balancing with the alignment. Possibility that it's control arms is what really concerns me. Much bigger expense, and by the time I had all the bits to do it, it'll be too cold to do in a carport. Fingers crossed that stuff can wait until Summer as was the original plan.
I had a more extreme example of this when I bought my old e30. It had 197k on it, with a blown steering rack, and worn out...everything. Tons of play in the steering, hair raising drive to get it back home. After rebuilding the rack and adding new inner and outer rods, the steering was sublime. One other change I made at the same time was to ditch the rubber guibo in the middle of its steering column. Some small BMW vendor developed a metal biscuit that was meant to bolt in place of the guibo, but I just drilled out the big rivets holding each side of the guibo and bolted the two halves of the column together. I could see the 997's eventually having need for something like that once they're old enough. Could see the guibo when I tightened the U joints last week, but it wouldn't be easy to get out. I think the rack would have to be dropped, and the whole column removed from the car.
I wouldn't actively seek a shop with 'road force balancing ' equipment as it is just a gimmick to take more money from you. .
Any tire shop worth a crap can balance a tire. Just get them checked out. And yes, an out of balance tire will show its ugliness at certain speeds and not at others.
Are you running factory sized tires?
I will say that Hankooks are generally a poor driving tire in my experience.
Had a very similar issue with vibration after changing my lower control arms. I thought it was a tie rod issue, but a wheel balance solved the problem.
Steering wheel vibration is typically just a balance issue on front tires. Start with a simple wheel balance (and alignment for good measure) from a reputable shop. One of the front wheels likely threw a weight.
balance wheels with road force balancer, at shop that knows how to use one. Thats what its for, to diagnosis balance problems. I would bet tire, wheel balance problem
Are your wheels OEM or aftermarket? If aftermarket are you using the proper lug bolts for the wheel seat type. Porsche wheels require a radius or ball seat and some aftermarket wheels need a taper or conic seat. Using mismatched bolt and wheel seat types will exhibit this behavior at higher speeds as the wheel moves around. It will also destroy the seats on the wheels.
Also, the center bore of the wheel needs to be exactly 71.6mm. Anything larger and the wheel will move around at high speed.
Darty steering can also be an alignment issue if the front toe is set to close to 0. Under a little load the wheels can shift a little on a slightly worn suspension or because of the rubber bushings between toe in and toe out which can provide for a very unsettled feeling.
Hankook evo2 tires are fine. We've run multiple sets of them on my wife's car.
Yup, it was the tie rods. Finished the work today and took it on a short test run up to 75mph, and vibration was gone. Will need an alignment of course, though I kept it very close. With the old inner/outer rod out I measured distance between fixed points on the inner and outer with digital calipers. Then separated the old inner and outer, and counted the number of turns it took, using a straight line I'd drawn on the assembly as a reference. I screwed the new outer onto the new inner the same number of turns, and then checked the distance on the same fixed points with the calipers. Steering wheel stayed perfectly straight during the drive.
Some notes on the job - took about 3 hours spread across a couple days, but a little over an hour of that was working out how to get the whole front end in the air for the first time,
and determining what tool/method would be best for removing the inner tie rod. The answer ended up being ye olde pipe wrench. Not the tool to use if you want to reinstall the same inner tie rod, but since it was going in the trash it was acceptable.
I had a 36mm combo wrench (hilariously large next to a standard 10mm), but with the rack fully extended it didn't quite make it into the wheel well for the wrench to square up to it, so that ended up being an unnecessary purchase. Also bought a 1-7/16 crows foot wrench, that's the closest SAE size to 36mm, and all that I could get delivered on short notice. The crow's foot still required an extension to attach it to a wrench, and moving the fulcrum around meant it wouldn't do the job to break the inner tie road loose, so that's why the pipe wrench was called on. But the crow did come in handy - after the pipe wrench broke the inner rod loose, it was enough to complete the work of backing it out, and later it was necessary to torque the inner down (55ft/lbs). Use loctite, there aren't any lock washers used with this rack.
Lastly, throw your pickle fork in the trash. These things are awesome and not very expensive..
Tie rods used were Delphi from Pelican, total cost was around $105 for those, plus another $40 in tools, of which $25 were used. I didn't replace the boots, those were in very good shape.
Very pleased to have the car composed at speed. I've still not put a whole tank of gas through it during my brief ownership, but between the B&M shifter, 993RS motor mounts, new rear tires, and now the repaired steering, it's already much improved. Looking forward to seeing what it will be like with other refreshed suspension components when I do those next summer. Thanks for the assistance everybody!
I wouldn't actively seek a shop with 'road force balancing ' equipment as it is just a gimmick to take more money from you. .
Any tire shop worth a crap can balance a tire. Just get them checked out. And yes, an out of balance tire will show its ugliness at certain speeds and not at others.
Are you running factory sized tires?
I will say that Hankooks are generally a poor driving tire in my experience.
road force is just a gimmick? Even though there are physics involved that make your statement completely wrong? Perhaps you don’t know how road force works. I promise you road force variation works.
Yup, it was the tie rods. Finished the work today and took it on a short test run up to 75mph, and vibration was gone. Will need an alignment of course, though I kept it very close. With the old inner/outer rod out I measured distance between fixed points on the inner and outer with digital calipers. Then separated the old inner and outer, and counted the number of turns it took, using a straight line I'd drawn on the assembly as a reference. I screwed the new outer onto the new inner the same number of turns, and then checked the distance on the same fixed points with the calipers. Steering wheel stayed perfectly straight during the drive.
Some notes on the job - took about 3 hours spread across a couple days, but a little over an hour of that was working out how to get the whole front end in the air for the first time,
and determining what tool/method would be best for removing the inner tie rod. The answer ended up being ye olde pipe wrench. Not the tool to use if you want to reinstall the same inner tie rod, but since it was going in the trash it was acceptable.
I had a 36mm combo wrench (hilariously large next to a standard 10mm), but with the rack fully extended it didn't quite make it into the wheel well for the wrench to square up to it, so that ended up being an unnecessary purchase. Also bought a 1-7/16 crows foot wrench, that's the closest SAE size to 36mm, and all that I could get delivered on short notice. The crow's foot still required an extension to attach it to a wrench, and moving the fulcrum around meant it wouldn't do the job to break the inner tie road loose, so that's why the pipe wrench was called on. But the crow did come in handy - after the pipe wrench broke the inner rod loose, it was enough to complete the work of backing it out, and later it was necessary to torque the inner down (55ft/lbs). Use loctite, there aren't any lock washers used with this rack.
Lastly, throw your pickle fork in the trash. These things are awesome and not very expensive..
Tie rods used were Delphi from Pelican, total cost was around $105 for those, plus another $40 in tools, of which $25 were used. I didn't replace the boots, those were in very good shape.
Very pleased to have the car composed at speed. I've still not put a whole tank of gas through it during my brief ownership, but between the B&M shifter, 993RS motor mounts, new rear tires, and now the repaired steering, it's already much improved. Looking forward to seeing what it will be like with other refreshed suspension components when I do those next summer. Thanks for the assistance everybody!
This is good information, thanks. . I'll be doing mine in a few weeks.
Get a road force balance as other suggested. Further, it will most likely be cheaper to have done at a Chevy or Plymouth/Dodge dealer..... why? They now need this sophisticated equipment to support the Corvettes and other high-horse cars they are selling. Further, they need a BIG balancer that can take these big wide wheels we have. Also, these sophisticated road force machines will tell the tech if your wheels are out of round.... bent.
I was out of town visiting family.... small western PA place..... the only place that had a machine big enough to take my wheels was Chrysler/Plymoth/Dodge dealer but they were booked. I found a Chevy dealer over in Ohio that could take me. He noted two of my stupid 19" rims were bent. I tell ya, I really hate these larger rims... just fashion stupid. I have been driving for 40 years and never bent rims until I had these dopey, greasy kid stuff 19" silicone falsies. And get off my lawn!
Road force balance is not a gimmick.... and the machines are really sophisticated and will tell you about the health of the tire and wheel. A good tech will actually, break down the wheel/tire, and shift the position of the tire on the wheels to give you a great balance.... ask them about this.
Oh... tie rods, control rods, sway links.... they usually clunk when going bad.... drive slowly over an undulating surface that twists the car.... you will hear them.
12-27-2018, 09:14 PM
Significant steering vibration between 60-70mph - tie rods?
