That shimmy at 60MPH....

I had a slight shimmy at around 60-80mph, pretty much gone at 90.. not always there. Less when turning a large radius curve at speed.. so I figured I have about 30k miles on the Continental DWS-06 Plus, so time to take it to get the wheels balanced. They did my Cayenne 's new tires about a week ago with good results. The Porsche dealership owed me a bit of money that I had to take out in service or goods, so I decided to use that money and get them to do a Hunter wheel balance, and they automatically do an alignment check (as you drive into the service portal). Seemed like a great idea. I waited while they did it - about 2 hours - which means they were also doing other things. Got the car back after a Hunter Road-Force balancing, and start heading home. When I reached around 60 - the same shimmy was in the wheel, but worse. This was a step in the wrong direction. I do question the theory of the road-force balance, since to do it completely requires (1) having an out of balance or bent rim - it won't work otherwise (2) having a tire that has a hard spot in it, or a bad balance problem. The road-force balancer presses a roller up against the tire as the tire is rotating to find any out-of-roundness in the tire or hard spots. The operator is then supposed to deflate the tire, break the bead and rotate the tire on the rim so the bend/balance forces cancel each other. They then are supposed to inflate the tire and test and everything will be hunky-dory (haven't used that in about 30 years..) ​ ​ So that's the theory, thing is - if you have wheels that haven't been bent, and wheels that are inherently well balanced (like German wheels are prone to be), then there is nowhere to rotate to to cancel the forces and the whole "RoadForce" theory falls on it's face. ​ So I contacted my service adviser and explained what I felt (apparently the 2 hour interval did not include a road-test of the balance..) He setup an appointment for today. The Porsche Happiness Lady (an attractive very well dressed young lady who greets customers as they walk in..) call me to see if I was happy - I wasn't, but I told her I already spoke to someone. I think she was going to call Roger Penske and tell him I wasn't happy - she was very sincere. So, before I went today, I spent some time figuring out what it would cost to replace every suspension wear point on the car. Pelican returned a parts list with a price of over $5,000. That's front and rear. Plus labor. So that's not happening. So today they were paying attention. They got it in, the tires/wheels were removed and taken to the Hunter machine, and came out "perfect". There was "no issue" of tire/wheel balance. I suggested that the tech go for a drive in the car and feel for himself. He took it out, came back about 15 minutes later, and said, "Yeah, it's got a vibration.." This resulted in the service manager (who, it turns out, I knew in a former life..) and the service adviser and the tech and I having a pow-wow. It was decided to put it on the alignment rack and make certain alignment wasn't causing the issue. It wasn't - alignment was pretty good. They came back and said "That's not it.." So they went out and looked at it again, checking for worn suspension bits - and found none. Everything was good as far as the suspension goes. So what is up? Their final theory was that the tires being 6 years old (DOT date) are suspect, and they're suggesting I replace them. They offered me a nice Michelin all-season package for about $1,900 out the door... they match TireRack's price on tires, the rest is mounting/balancing/disposal/excessive-profit.. The tires are about $900 of that estimate. The question is - what to do? I recall reading here about 2-3 weeks ago about someone who had the same issue, and found some mount for the steering rack that could be tightened up to eliminate this sort of thing. IIRC he said it's accessible via the drivers side wheel well after removing the inner liner. Does anyone recall that discussion? I'm going to search for it using Google (far superior to our internal search), but any help would be appreciated. The posting wasn't terrifically clear about what the bolt was, and I've combed AllDataDIY on mounting the steering rack and didn't see anything, so help would be appreciated!

Speed sensitive shakes are usually the exclusive province of tire balance issues or in some cases a slightly bent wheel can mimic the same effect. The fact that the shake goes away at different speeds would not give me confidence that new rubber on all four corners would eliminate said shake. However, if the tires are well worn and at the replacement age, you aren’t wasting money by eliminating them as a suspect. Since you are considering buying these tires from the Porsche dealer, is it possible to negotiate with them in the following manner: Mr dealer if I follow your diagnosis path and purchase four new tires and the problem persists what can you offer me going forward? Perhaps a reduced rate on further diagnostics chasing the remedy? Have the pageant winner get Roger Penske on the blower immediately! You tell him I want a GT3 from his stable until you fellas figure this out…😂 It would be a bit of a pain but if said dealer has four used wheels with tires mounted that will fit? Mr dealer if you mount those four and the issue abates on a test drive, I will give you the funds for the replacement tires .

Take the left front wheel off and peer in along the top of the rack. Just past the rack boots facing towards the driver. You will see the coupling and the bolt facing you is the clamp bolt. Mine was just over finger tight. One would think this is a known thing as a Porsche Tech.

Hu???? Do they use 24K gold Ballancing weights?

@deilenberger - My hot take is that one of your rims is bent, Don. Time for a wheel specialist. My flow-chart for wheel vibration is always to first have the wheels balanced (which you already did). When that fails, I take them to my wheel specialist who rebalances each wheel for ~$30 and straightens each bent rim for about $95. Helps rule things out. Given that I live in pothole city, he's already straightened a few rims for me these past few years. If you want to entirely rule both the wheels and rims out (not a bad idea), I'd have the new rubber ordered from Tire Rack and drop shipped, and bring along a set of aftermarket TPMS sensors for about $50. The fact that the vibration was WORSE after the road force balancing makes me think that the issue is likely at the wheel/tire level -- as that's the changed variable. I strongly agree with @Boristhespyder that new tires will likely not solve this. I've learned that road force balancing is for stubborn tires. If by chance you are coming up to Boston soon, I say we set up an appointment with my local guy and have him do the once-over. He's the wheel whisperer and you'll have peace of mind before deeper and more expensive digging (suspension). Just a thought.

I guess I wasn't clear: @foodbiker - None of the rims are bent or out of round. They checked that very carefully when they were looking at them the second time (on their nickel). They are all OE Porsche rims that came on the car. @Boristhespyder - They balance out perfectly using the road-force balancer. I'd love to find someone who uses the old spin on the car Hunter balancer since it balances the brake rotors, hub and wheel tire, but I think too many guys got injured using that bad-boy that no one even has one anymore. The problem I see with the road-force balancer I outlined above, the "magic fix" it's supposed to provide can't actually work if the rims is straight and not bent. Everyplace around here has gone to those with a few exceptions, and the exceptions usually are old time tire shops who assign the lowest guy on the tree to doing the mounting/balancing stuff. @Ric_in_RVA - do you mean the universal joint clamp bolt to the input of the steering rack? That's easy. Did you notice looseness or clicking in the steering when stationary if you rocked the steering wheel? @N_Jay - no, nicely coated weights. They did clean off all the old adhesive from other weights that had been on the rim. When the labor rate is $255/hour - even for something as menial as tire mounting and wheel balancing - it's easy to run up a $1,000 labor charge. Ric - I'm going to ask my local mechanic if we can take a look at that clamp. I wonder if there was ever a TSB about that... otherwise it's new tire time. I'm open to suggestions on what all-season is good. I've always liked the Conti DWS series - been running them on cars since about when they came out, this is the first time I might have an issue with one. I can imagine that a slipped belt in a tire could cause this sort of issue and not throw the tire enough out of balance to be noticeable. I've been hearing stories about Michelin's with bad sidewall cracking, and that's actually why I replaced them on my Cayenne (with DWS-06+). The Michelins still had plenty of tread, but the tread blocks on the edges were cracking and starting to throw off little chunks of rubber. These were about maybe 5 years old.. BTW - keep the thoughts coming please. I'm trying to remain open to all ideas, but some can be more or less eliminated - they've been checked for. I think next time I get new tires, I'll ask that after they demount the tire from the rim - to put the rim on the balancer and see if it's out of balance, or there is internal distortion that doesn't show on the outside...

Don - What bothers me here is that if the dealer did a road-force balance and things got worse , that makes me think it is squarely at the tire (or rim) level. To me, that's the smoking gun and the changing variable in the equation. Plus, a specific vibration at a specific speed always reads tire or rim (or both) to me. That would clarify next steps up for me. Also, have the tires been rotated at all? Assuming you're running a square set, that can tell you a lot. The shaking will show up more clearly if the bad tire/rim is in the front. YMMV. If you're already mounting/dismounting new tires, I'd have a rim specialist do the work and have them double-check your rims as they would already be mounting your rims anyhow. Can't hurt? With regards to A/S tires, I'm a Michelin Pilot Sport A/S fan on our MINI Countryman (rebadged BMW X1) and previously on our MINI Clubman. We just blew through a full set in 18 months, but that's with tons of commuting and crap Boston roads. They see snow and all that, yet are still sporty. Just picked up another used set locally for about half price (just 100 miles of wear) and they're going on soon. Tire shop couldn't return them to the manufacturer. If I had tons of cash, I'd try the Michelin Cross Climate 2 TBH. ** One thing that's kind of cool for anyone reading this -- is that my rim guy said that OEM rims that are bent are easier to bend back to true. When the metal is heated, it snaps back into place. Less so with aftermarket rims. Just something to file away. Finally, rim specialists are great as they will take care to NOT mar your wheels (using Hunter, etc.).

Do they have another car that can have the wheels temporarily swapped to your car to eliminate anything else on the car?

That was my suggestion too

OK - a bit more. It's temperature-sensitive. Tire temperature. My mechanic friend suggested I raise the pressure 5 Psi and see how it felt. 35 psi Front, 38 psi Rear. I did that and took off down a local highway with reasonable pavement - same thing, came in at the same speed, was about the same intensity. The tires hadn't warmed up.. The suspension felt quite harsh at those pressures so today I lowered them to 31 psi F, 34 psi R. Felt much better at low speeds. As expected - got on the same highway - and the same shimmy was there, perhaps a bit more intensity than yesterday with the higher pressures, but at the same speed coming and going (starts at 60MPH, pretty much gone at 80MPH). I drove a bit further, letting the tires warm up. As one would expect - the tire pressure went up to about 34 psi Front, 38 psi rear, and the shimmy started decreasing in intensity and range - now the shake/shimmy started around 65 and was gone at 75. As I drove more, the shimmy kept getting into a narrower range, until finally it was barely perceptible. My conclusion - it's temperature sensitive and likely a hard spot in the tire that softens up when the temperature of the tire carcass warms up. The RoadForce balancer was of no use in this case since the rims ARE true and unbent (the RoadForce balancer measures around the lip of the rim to check for out of round..) Even if it found a hard spot there was no corresponding bend in the rim that could be used to offset it. What to do? The suggestion of trying someone else's rims on the front is good, I know another 987 owner in the area who might be cooperative if we had two lifts side by side we could use, but we don't. Only the dealership has that. FWIW - the rack (which must not ever fail since they're dirt cheap used..) Red are the mounting points (to the crossmember I believe) and green is where the steering shaft connects through a univeral joint that clamps onto the end of the steering shaft and then onto the input shaft, all splined so you don't have accidental disconnects.. The steering shaft - these are even cheaper on eBay - less than $50.. the BLUE circles are where the clamping bolts are for the universal joints to the splined shafts. Thoughts? Musings? Etc? Right now I'm still giving thought to tires since I like buying tires and my wife hates when I buy tires (how a marriage survives 54 years is beyond me..) Does anyone have firsthand experience with the newer Michelin All-Seasons? TireRack is playing up Bridgestones - two of theirs are the top rated AS in our sizes, but all of them - Michelin, Continental and Bridgestone all get excellent ratings, varying by 1 point from each other.

@deilenberger - See my above post RE: newer Michelin Pilot Sport A/S. Highly recommend as a tire. The Michelin Cross Climate 2 has a longer tread life but I think is supposed to be less sporty. Makes sense. Right now, our MINI has something similar that's up with the current (soon to be retired) tires and changing the PSI changes the "whomp-whomp-whomp" vibration factor. BTW - Any chance the car sat parked for a long time? Wondering if you've got a flat spot there.

A reply to several messages by @foodbiker : A bit snipped.. I can imagine a reason the RoadForce balance made them worse. If the RoadForce balance doesn't find a bent rim or out-of-round rim, it has nothing to use to compensate for a tire with a heavy spot or hard spot, so it has to ignore that part of the balance procedure. It then balances the tire at low speed, especially compared to the older high-speed balancers.. If the rotation speed = 30MPH I'd be surprised. I didn't have the dealer do the original tire mounting, I had a local Porsche shop do it, and I don't know how they balanced them. Perhaps they balanced them AT high-speed and that results in a better balance than the RoadForce device.. RoadForce balancers are all the rage, but I don't think they are necessarily a great solution to some problems. I had the same sort of issue with some tires on a BMW - the rims were true and unbent, the RoadForce balancer didn't know what to do. The tires have only been rotated side to side since it is a Boxster and Boxsters don't use square setups (you own two of them..) I have no idea where one can find a rim specialist in my area. I did have my Cayenne rims refinished (for the 2nd time - they love curbs) recently by a place that strips and powercoats them. I'll have to ask if they also do rim straightening.. Ummm... Seth you know me and the car. If parked for a long time means 2-3 days when it's pouring, then maybe.. but it gets driven as a daily driver (the Cayenne did about 1,500 miles in the past year, mostly to the dealer and back..) One of the two Michelins is supposed to be superior to the other, and I believe the rear tires are not available in the correct size in one of the Michelin AS (which is why TireRack only returns the one Michelin if you search by tire size.)

Whole lotta analysis to reach the conclusion "Time for new tires ."

@deilenberger - My bad and my apologies! I thought we were talking about your Cayenne this entire whole time, which I figured sees the least mileage in your fleet. Hence, my previous Michelin Pilot Sport A/S recommendations -- particularly as the Cayenne and the MINI Countryman are share the SUV class as opposed to our roadsters. Hope that makes sense -- and that bit of info surely changes things! LOL. Honestly, no idea what Michelin A/S are available for our Boxsters as I'm a summer/winter tire guy. Per my previous two Michelin recommendations, again - those were intended for your Cayenne. Assuming they do make a PS A/S for the 987, it's probably a great compromise as it's a sticky tire like the venerated PS4S and I physically can vouch for that first-hand. Meanwhile, even if available, one probably isn't going to want to put the Michelin Cross Climate 2 on a 987 as those are really for SUVs and you'd lose all the sportiness (why we drive our 98X vehicles). If this was for a ski country car like a Subaru Cross-Trek where the driver doesn't care about sporty handling, I'd say "sure." Yes, our Boxsters are most definitely staggered. If someone else is reading this discussion, keep in mind that if one's tires are directional (often seen in winter tires... like my previous Michelin Alpins), there's no rotation at all. (Plus, I now run "square" (aka, not-staggered) in the winter with spacers, but that's a whole other story...) One key question I didn't ask -- is when did this all start (or when did you first notice it), Don? If this started right after being stored from the winter, that might point to flat spots. As they say, "timing is everything!" Remember any nasty potholes this spring? I totally agree with your Road Force balancing assessments! Great tech, but surely not a cure-all. A RI shop who did my winter tires explained to me that they escalate to Road Force only as a second resort. After calling around a few years back, I was surprised that realize that rim specialists were more common than I thought. I think there are a lot of guys with super high-end rims (especially custom cars) that don't want them dinged up -- going to a rim guy is like going to a cobbler for expensive shoes. Given there's a lot of show car activity down by you in Asbury Park (photographer colleague posts all the time), I bet there's at least one good rim guy near you. Regardless, dollars to donuts, the guy who painted your Cayenne rims may be able to help you directly, or at least point you to the right guy. Again, surely he sees a lot of soft aftermarket rims that need straightening before he preps and paints them. My rim guy does zero cosmetics - he leaves that to painting and cosmetic experts - so YMMV. Absolutely worst case scenario, should you decide to come up in the Boxster, I'm happy to put you in touch with my local guy as it's worth a chat and you could likely drop ship new tires to him. Regardless, ideally you'd sleep better knowing you've squarely ruled out both rims and tires -- and they'd need to be mounted anyhow. Again, sorry for the confusion, Don! Fun discussion regardless as always.

You need a new dealership. $225 Hr for tire work is theft. When they "looked" realy carefully for a bent rum, did they use a dual guage? Twice? (Runnout and roundness)

$225 - That's with the PCA discount.. Normally $240 something.. They had a special for May and June of $60/hour off for local chapter PCA members. One hour discount pays for my PCA membership. I think a dial gauge would be extremely difficult to use on a painted rim, since there are paint thickness variations, etc. From memory, the one time (about a decade ago) that I watched the machine being used, the RoadForce machine had an arm that measured the rim at the tire/bead/rim junction. The problem the operator had was the BMW rims measured perfect, so there was no way to offset any difference in force changes in the tire. Here is what ChatGPT says about the Hunter RoadForce system: There was also a video link: I suspect it may work better with new tires rather than 6 year old tires...

Found a much more detailed explaination of how the RoadForce balance is supposed to be done.. question is - since I can't watch them doing it - are they actually doing the entire process? And it shows how they use a laser (on the newer machines) to check the rim..

I'm following this thread. I am having the same issue with my 987 CS with 5 spoke S wheels and Continental DWS tires about 6 years old as well. I haven't hit any potholes or curbs. Last I recall before I put it in storage for several months it used to be smooth and silky. Fortunately I have a spare set of wheels in the garage. I'm curious to see how this plays out.

I think it will play out with new tires , and probably new Conti DWS-06 Plus... I looked up my receipts. I've owned the car for 6 years (sort of a toy-car record for me..) and the tires were one of the first things I put on it. NJ roads are where potholes are grown for transplanting to NYC. We have a lot of them, about unavoidable. It wouldn't surprise me if it's a combination of the rubber getting hard with age and perhaps a pothole-induced belt damage issue. On motorcycles, it's considered sure-death to ride with a tire over 5 years old, because they DO harden up and with the minuscule contact patch a motorcycle has - that's a real danger. Today the thing felt better when the tires got warm (I could tell watching the TPMS readout, pressures went from 31F, 34R to around 35F and 38R) on the highway. And the shimmy in the wheel was less noticeable and less annoying. To me - this sort of change - a warmer tire because the temps were warmer today - indicates when the rubber softened up from getting warmed up, things were better. If I get fresh rubber on it - I think the issue will be resolved. Right now I'm trying to decide what shop to have mount and balance them. The difference in prices is fairly amazing.. Porsche about $700 + TPMS sensors . Down to a small tire shop without a RoadForce balancer (but they have a balancer) at about $25/tire, I supply the TPMS sensors and it's all good. Difficult decision I have to make before I order the tires .

I’m hoping your issue is solved with the new tires , as I’m leaning toward that as your vexing problem. My first Porsche , an ‘03 996 Base was giving me problems with strange sounds and feedback through the steering wheel. I brought it to an indie shop near me, Bodymotion, and after the shop manager took it for a short drive he informed me that it was definitely the tires , as they were a bit long in the tooth. New tires , problem eliminated. Fast forward to my current iteration, my ‘08 BS, and I notice that if it is parked in my garage for upward of a week or so, when I get it out on the roadway at speeds over 35-40 mph, I feel a slight wobble/shimmy transmitted to the steering wheel. First thing that pops into my head is wheel balancing, but as I just had them all done during a recent four corner TPMS replacement I ignore that inclination and sure enough, after about 10 to 15 minutes of driving the shimmy miraculously disappears. It seems to me that it could be a combination of flat spotting from sitting, and the cold rubber since once warmed up it is smooth as silk. Good luck with the tire swap, keep us posted.

A little late to the discussion, but another car in our family is an Audi A3 that formerly had Conti DWS 06+, and then replaced by Michelin as4s. First the experience with the contis that may be relevant and isn’t something I’ve seen mentioned in the thread, yet. I, too, had a speed sensitive shake that developed in that car over time. I really enjoyed those tires and was impressed by the ride feel and handling, but ultimately they got some really bad cupping on the tread. It was most prevalent at highway speeds, which is unsurprising as I primarily used it for highway commuting, and it synced up to that resonant frequency. It was very apparent that the tire was no longer a cylinder when running my hand over the tread (but that was after it got pretty bad). Now to the comparison of the contis and Michelin . VERY similar. On this tire size, the Michelin was maybe slightly softer riding? But really, if I didn’t know I changed the tires , I wouldn’t be able to tell a difference. I’d have to look at my records, but no evidence of cupping with these tires , yet, but I’ve been a bit more diligent on rotating these tires due to the premature wear on the contis (although they still lasted like… 30k miles?). Anyway, something else to look into. Check into tire cupping. But yeah, $1900 for new tires is way too much. A fresh set of contis should be closer to $1k out the door.

You need to find someone who knows how to use a dial gage to check your wheels for "out of round" on both edges and "side to side" You have seemed to chase everything else.

Thanks. Yes - actually I used the prices TireRack's website posted for 4 installers in my area. One of them is the place that installed my tires last time, another is a place I've used for M3 rims/tires in the past.. so yes - I'm familiar with them. Not needed. The RoadForce machine (watch the bottom video) uses a laser to do that. It's probably more sensitive than a dial gauge (which would have to jump in and out of curb scuffs on the rims..) They aren't bent or out of round (checked twice for that..) and that wouldn't account for temperature dependent changes in the shimmy.

Tires and TPMS sensors ordered. The sensors are about $70/wheel... so that adds up. Total for 4 - around $1,200 before mounting/balancing/disposal/state-fee just because, at $70/wheel. Getting them done Friday the 13th...

Just replaced my TPMS sensors from TPMS .com using these.

Looks exactly like the photos of the ones I ordered from TireRack at 3x the price. Go figure. Too late. Thanks anyway!

Just a data point: I've typically had a bit of steering wheel shake at ~60 MPH in the morning when the tires are cold. It smoothed out after 5-10 miles when the tires warmed up. Figured it was just flat spotting. Last weekend I replaced both front lower control arms on each side (~90K miles). The bushings seemed a little tired when I pried on them in-situ, though after getting them out they really didn't look too bad at all, l so I was thinking I'd wasted some time and money. Past couple of mornings the wheel shake seems to have gotten significantly better, however, so maybe they were more worn than I thought? It could all be in my head, of course, but it did seem to improve things. But don't blame me if you do the work and it doesn't.

I do that kind of thing all the time.. later to realize it's still the same, just the conditions changed (warmer morning, etc..) but I certainly never blame anyone but myself and @foodbiker

I just wanted to come back and close out this thread, since I know other people have probably been as frustrated as I am. Magic. New tires, identical brand/size/model to the old ones. The shimmy is completely gone. They must have hardened up, and perhaps had a damaged belt in one from the NJ potholes.. but if your tires are 6 years old or older, I suspect you can be quite happy with the results of replacing the rubber. It wasn't cheap, probably about $1,500 all in (new TPMs, new Conti DWS-06+, mount, road-force balance), but it feels worth every penny. It drives like a new car now. I took it up to 80, and nothing. I could feel the road surface, but no sign of shimmy. I ran at 65MPH for some distance, the speed it was worst at - no shimmy. The other difference, which is why I commented on them getting hard with age - ride quality is WAY better—the same tire pressure.. but a curious thing. The old tires would heat up, which was noticeable by the increase in tire pressure as I was driving. These surprised me - the pressure stayed right where the shop had set it (31F, 34R) with no sign of pressure increase due to heating. Sort of makes sense - if the rubber is hard, it will require more force to flex and support the car and absorb the bump. That increase in force translates to heating of the rubber and a pressure increase. The only difference between the old and new tires was the age of the tires. It seems 6 years is about it for modern rubber. I wonder how long the new feel will last..

Glad the new tires fixed the shimmy. I'm probably not far from being there myself. Afa ride quality, you can't discount the placebo effect that happens whenever we pamper our precious babies. I feel it whenever I wash & detail mine . And I remember the same thing from my last full set tire replacement. Reminds me that I need to check how long ago that was. I'm no longer putting the miles on it that I did when it was my daily driver to work. I'm sure there is a noticeable improvement with new rubber. Tire noise, grip, handling all are subtle but real improvements. That feedback helps overcome any thoughts that the considerable $$$ were not wasted.

I was following this closely as had the same problem and was running Continental DWS about 5-6 years old as well, thinking maybe that make and model of tire was a common thread. Perhaps it is, but regardless, about 5-6 years is about time to get a new set anyway. It is a shame to throw away a good set of tires with plenty of tread left. Full disclosure, My CS had been in storage for about a year as I was working abroad. I was trying all the simpler and more affordable fixes first. I guess this is my life lesson that my Porsche needs more attention and driven hard more often. I think that is what all my ex-girlfriends were trying to tell me too?