Hass_Geschafte

Sorry for the thread jack GIG but but thought I'd (hopefully) close out my experience. Last night I removed the front 7mm spacers (the ones that had been carefully installed, twice). On my commute today, on the same stretch of road as yesterday (down to the lane), same ambient temp, same speed - no vibrations.

So either the problem is a complete bastard that only flares up when it has calculated for the maximum torment it can inflict, or the spacers were causing it, at least post suspension overhaul. There were no spacers prior to replacing all those parts last week. The spacers I was running in front were "ECCB" brand from amazon - purchased because their images showed a mounting lip around the hubcentric middle. Clearly that was just for the thicker ones, because when they arrived, no lip. 7mm leaves some mounting ring for the wheels to hug, but apparently not enough.

Lucky enough to find a set of open box rennline 7mm spacers at ECS for $40 that DO have a mounting lip. If when mounted those result in vibrations then I'm done with front spacers. The rear wheels are what really need the help aesthetically anyway. Frustrating experience given how carefully I mounted the ECCB's (two lug hangers and everything), but at $26 it did include extended ball seat lugs that the Rennline's don't, so it will have contributed something.

It's certainly been a lesson in how sensitive the front wheels/suspension is.

G.I.G.

No worries, @Hass_Geschafte . It's helpful to hear your experiences as well and what you're doing to find the source of the vibration.

My buddy swung by this afternoon with his 997.2 C2S Cab and we swapped both front wheels. I drove the same stretch of Interstate at the same speed (~65mph) with his fronts and there was no vibration. I put mine back on and drove it, and the slight vibration returned. It's somewhat relieving to know it's not a steering/suspension component.

I think my next course of action is to go back to Discount to request a road force balance by one of their better techs on their Hunter (in case they used something else when I first had the tires mounted and balanced). The wheel repair shop I went to said they have an old but reliable and accurate balancer. I'm not totally convinced of that, so I'll give Discount one more go at it and if that doesn't work, see what I need to do to start a warranty claim on the tires. I'll also call the wheel shop in the morning to hear what they have to say about it.

qikqbn

Been down this road both with spacers and bent wheels... As mentioned by Hass.... I discovered a while ago that any spacer larger than 5mm will introduce vibrations if it does not have an extended mounting lip built in...Even then it is not guaranteed to work. So I hope that those work out for you Hass. As for me I will not use spacers larger than 5mm on front because of my bad luck. Keep us posted.

G.I.G... I went down the fix a bent rim rabbit hole 2 times... never again. Never solved the vibration. Got a little better each time, but realized that it just changes "at what speed" the vibration raises it's ugly head again. You may think it's gone, but then you hit a higher mph one day that you have not done in awhile and boom, vibration is back again, but now at 95 mph instead of 75 mph. Only solution for me... Replace the front wheels with brand new ones and do not use spacers too large. That is the only way I got rid of my vibrations. Best of luck

Bruce In Philly

The Hunter machines are pretty amazing.... below is a link to their brochure for their top machine. Check it out...... pretty cool eh? I am old enough to remember "bubble balancers" ha!!! a joke compared to today's tech. The Hunter even measures "Tire Conicity".... ha! I thought that only applied to alien heads.

Hunter does not claim to identify tire defects, however, if a tire measures roadforce differently around the tire, it is a defective tire (honestly, I don;t know exactly what they are measuring, but it is the road force roller that does the detecting as I understand it).

Peace
Bruce in Philly

https://www.hunter.com/Portals/0/Media/7123-T.pdf

Bubble Balance:

Bruce In Philly

Regarding spacers.... I don't use them but a few friends told me to only buy Porsche spacers as so many complain of vibrations. Not that there are not good products out there, the stories of vibration are many... according to these guys.

Peace
Bruce in Philly

G.I.G.

Update: I spoke with the wheel shop this morning and they reviewed their service notes. They said everything came out great with my wheels and they stand by their work. So I went back to Discount to have them re-balance the tires. They did all 4 corners and said the front passenger was out by an ounce and the driver's didn't have a single weight on it. So I thought having them balance the wheels may have solved the problem. I did confirm and visually verify that they used a Hunter road force balancer. Then I took it for a quick spin and a couple miles on the same stretch of highway I've been driving as a baseline. It seemed better at first.

I decided to go for another spin after dinner. This time, I drove quite a bit longer on different sections of interstate. The vibration is still there.

Could a slight steering wheel vibration be coming from the rears possibly? Even though Discount said they were fine, could it be the tires causing the issue? My Indy seems to think a bent wheel will always be out of round, yet they were the ones that referred me to the wheel shop.

Also, another anomaly I've found is that the vibration seems to be less pronounced when it's warm out or I've driven on the tires a bit longer. I was thinking it may be due to temporary flat spots when the weather wasn't as good here in CO and I was out of town on vacation, but I've been driving it a bit more lately and I don't think it is flat spots.

I'm beginning to think I'm going insane.

Sporty

So frustrating , i know. Had this on brand new leased cars (MB and Jag) as well. After several attempts balancing, alignment never really perfect just lived with it until lease expired. How old are your tires and when you swapped wheels with your buddy did you do a thorough test drive? I guess next step is to swap/replace tires, then rims if necessary.

Sporty

Also, when they road force balanced them did they adjust the tire and rim relative to their high/low points/weights to counter offset each other? I think they have to dismount the tires to do this; as i understand that is the gold standard method of balancing using the Hunter road force machines.

G.I.G.

My tires are about 2 months old. They're a brand new set of Michelin PS4S's. While I can't rule out anything completely, I don't suspect it is the tires.

They did not. However, the tires were dismounted and remounted at the wheel shop. They might have ended up on the same or similar spot on the wheel.

At this point I suspect the wheels despite them being straightened, but I'm trying to rule out everything else before I buy another set of used OE wheels that could potentially have problems as well.

Bruce In Philly

Regardless of what the rim shop said, the Hunter will tell the tech if the wheel is out of round.

Honestly, I would take the wheel to another tire shop and have them re-balance it. Just pay the price. Someone is not doing things correctly.

Peace
Bruce in Philly

Iceter

If there is a silver lining, it's that you have definitively narrowed this vibration down to the wheels. 99% of the time, a vibration is a wheel and/or tire.

Yes, an out of balance rear wheel can sometimes be felt through the steering wheel.

I think it's time for you to do like Bruce suggested and find another shop. Find a place that specializes in wide wheels with low profile tires like a race shop.

I would have all four wheels done. I would even go so far as to remove the existing weights so the shop is starting from scratch.

Then, if you still feel the vibration and the vibration changes as the tire reaches operating temperature, I'd try to get the tires replaced under warranty.

G.I.G.

It's been to 3 different shops, one of which (Discount) twice. One was my Indy that does all sorts of track cars (Porsche, Vette's, etc.) and while they were able to get them balanced (according to their machine), it was still giving me vibration in the steering wheel. They also confirmed that they use a Hunter that is calibrated before each use, and is fully maintained, tuned, and certified by Hunter once a year. I could give another shop a go at it, but at this point, I still suspect the wheels. The fact that I had the same issue, just worse, with the old tires, leads me to believe that the wheels are to blame.

I'm going to do some more wheel swapping this weekend to try to narrow it down a bit more. When I went back to Discount yesterday, I had them pull all the old weights and start from scratch. Same result. They used a Hunter road force balancer.

I called Wheel Enhancement in CA today, and they do have Lobsters that I could buy that are guaranteed to be straight and true when/if I determine it is a wheel problem. I'm pretty close to exploring a tire warranty claim, but need to rule out the wheels first, or at least determine which wheel/tire combo is giving me fits.

Hopefully I'll know more by this weekend. The saga continues....

Qwksnke

I agree with this. Friend of mine went through this last year on his Dodge truck. After taking it numerous times to a Firestone shop that used a road force balancer with no luck, he took it to another shop with a normal spin balancer. Problem solved

G.I.G.

Update:

Thanks to another Rennlister, I had the opportunity to drive his C2 and do a wheel/tire swap. He also drove my car and confirmed I'm not imagining things. His C2 felt rock solid on the same stretches of road I've driven my C2S and experienced the vibrations.

We started with the fronts. Vibration was still present. Then we swapped the rears but kept his fronts on to keep a known good set on all 4 corners. The vibration persisted even with all of his wheels/tires on my car. He also drove the car and confirmed this. I think maybe when I did the wheel swap with another friend's fronts from his C2S Cab, my test drive may have been a bit too hasty. I should have drove it longer.

As we were swapping the rears back, his Dad suggested we inspect the axles. Both of my axles had quite a bit of slop in/out, and the passenger side also had some rotational play in it if you tried to twist it back and forth. His axles were rock solid. Has anyone had a bad axle or CV joint cause a vibration at highway speeds?

I'm wondering if this might be what I should be looking at.....

993 - High Speed Vibration

Brainz

@G.I.G. I've been following your thread with interest as I've had my own vibration issues I've been chasing (thread here: 997TT Vibration). Your link to 993 - High Speed Vibration appears very similar to mine. Note that both he and I felt the vibration through the body of the car, NOT the steering, and both our issues appears to be a rear axle / wheel bearing. He and I both were able to see a vibration in the rear of the car whilst run on jackstands. In my case, not only could I see the vibration at the wheel hub, but the axle shaft appeared to "jumprope" rather than "spin" about a central axis. Although the 993 owner didn't mention it in his post, my vibration is cyclic, which I've read is somewhat unique to axle / driveshaft issues. I've yet to spend the $1k+ for a new axle, but I hope to get it sorted this summer.

Regarding your issues, I doubt it's a rear axle problem as you're feeling it in the steering, but a quick check would be for you to run the car with the rear wheels on jackstands (be safe and use wheel chocks). You've got a C2S, so you don't have to lift the front, which makes it a little easier. Note that as reported in the 993 post, I too experienced a lot of noise from the transmission while doing this test -- I assume it's gear lash rattle that would normally be quieted by load. What I compared was how much each rear wheel vibrated while running. My right rear wheel was definitely more pronounced, so I swapped the wheels side-to-side and got the same result. It was then that I noticed the difference in how the axles spun which seems to further support the diagnosis of bad right axle (and maybe bearing).

Assuming the vibration is not from the rear, and given that the vibration exists with a known set of good wheels, here's a few other suggestions for your front hubs:
1) Check wheel bearings for any looseness or play. Hold at 12 and 6 o'clock and push/pull. Rotate wheel 1/8 turn and repeat until you've checked all the way around. Also try with grip at 10 and 4 and at 2 and 8. You can try at 9/3, but usually you'll move the steering.
2) Use a dial indicator to measure the runout of your brake discs and the face of your hubs. You may need a mechanic to help with this.
3) Remove the rotors and give the hubs a thorough wire brushing. Consider given the face a light stoning to make sure there's no burrs that are creating runout. Measure runout with a dial indicator and flatness with a straight edge.
4) Consider replacing the front hubs/bearing, starting with the one associated with the bent wheel -- maybe the hit that damaged the rim also damaged the bearing/hub.
5) Replace your bent wheel regardless.

Good luck -- I know how frustrating/annoying vibrations can be to sort out.