JF22

[QUOTE=fuego;14066531]Did you have spacers on all 4 wheels? What size and were they hubcentric?

7mm front 14mm rear H@R hub centric removed front only

Mumbles

If your wheels are balanced, then its probably your spacers

semicycler

There is a difference between balancing wheels and road force balancing wheels. A tire can be balanced in the shop yet still show signs of imbalance when mounted on the car. Most tire shops do not have the capability to road force balance. Higher end speed shops and your local pcar dealer should have the proper Hunter equipment to do the job. Call a few of your local shops and ask if they can road force balance your wheels.

Spacers without the extension lip to keep your wheel centered are also notorious for causing vibrations. Thinner spacers sub 10mm thick rarely have the lip. Porsche fortunately has a split style lip on the hub to allow for split style spacers. Pull off a rear wheel, remove the center wheel cap, then reinstall the wheel with the spacer while visually checking that all the mating surfaces touch. I had a front vibration issue a few years ago that was due to flat 7mm spacers and the OEM lobster wheels. See this thread on 6speed: http://www.6speedonline.com/forums/9...c-spacers.html

Petza914

What wheels are on the car - are they OEM or aftermarket. Are you using lug bolts with the correct seat type for the type of wheels installed. OEM Porsche wheels use a ball or radius seat. Many aftermarket wheels use a tapered or conical seat. Mixing these two things could result in exactly what you describe where the wheel is moving off-center under load - the same thing that would happen if you were running spacers that were not hub-centric. Many people believe you can go up to a 7mm spacer without it needing to be hubcentric and that's not true. There should be centering flanges on your wheel carrier and these should fit into the center bore of the wheel tightly enough where the wheel is actually stuck on them and you have to wiggle it left and right / top and bottom to get the wheel off. If once the lug bolts are removed, you can simply lift your wheel off, it's not being centered tightly enough. Hub-centric spacers should be the same way and the spacer should have it's own hubcentric centering bore and flange. The bore is used to mate the spacer with the wheel carrier flange and the spacer flange mates to the wheel bore, both of which should be exactly 71.6mm.

If you decide to get new spacers, get them from Adaptec Speedware (a sponsor here) as they have the proper bore and hub-centric flanges on all of their spacers, even the thinner ones.

Also check the lug bolt seat type and wheel bolt seat type. Even if they match, examine the seats in the wheels carefully to make sure someone didn't install and torque them down once using bolts with the wrong seat type and actually damaged the seats in the wheels where now even the right bolts don't hold it securely under load.

That hop you describe is the wheel getting offcenter and then bouncing the car up and down. From what you've already addressed, your problem is in the wheel, spacer, or bolt area.

If you need a set of high-quality bolts for 10-14 mm spacers, I have a spare set of proper World-Motorsports Ti ones that I took off my Cayenne. I bought tapered seat wheels for it and had to buy another set of the bolts from World with the proper seat. They have about 1,000 miles on them and are for sale in The Marketplace.

alan111

I had this issue on my 650i 2 years ago. I bought "hubcentric" 7mm spacers bought with no lip to balance the wheel when mounting. I tried tirelessly to remount them but I still got heavy vibrations, albeit at different speeds. In the end, I just scrapped them and bought 10mm spacers with the mounting lip. Problem solved immediately.

fuego

Ohhhh, I hadn't considered that!

You know, I think I actually came across your exact thread during my searching. I do agree that the hub flange is too thin with 7mm spacers. $250 a set is spendy, but who else makes them like BK? Price is market correct I suppose.

Do you tighten your wheels in the air?

Spacers are 7mm hubcentric Eibach items; I'm waiting on amazon to deliver another wire brush before I get the rears off and give it a closer examination. My rear wheels will come into contact with the strut if I take the spacers off and run them, so maybe I'll get a set of 10mm to replace.

Edgy01

Always do this from the least expensive to the pricier. Start with rebalancing the tires. You may also discover that you have a bent wheel, or two. Todays roads are terrible on these fine cars and ultimately take a significant toll. Then, tires, wheels, alignment. Adding non-factory parts like spacers can add to the complexity of troubleshooting so pull them off for awhile to remove them as a variable.

2011-sy-carreras

I had 7mm spacers in the front with no hubcentric lip and 15mm rear that has a lip. The fronts were fine with my 19" Carrera S II rims and summer setup, but had vibration with my 18" Carrera IV rims as a winter setup at highway speeds.

After spending a lot of time and money rebalancing tires, and checking rims for out-of-roundness, finally switched my 7mm fronts to ECS tuning 8mm spacer kit which come with a hubcentric lip. The switch to a hubcentric lip corrected the issue.

Based on all the avenues I took to correct, feel it was a combination of issues, but the 8mm ECS tuning spacer with a hubcentric lip dampened and made the vibration issue go away. Though from time to time still deal with flat spotting of my Pirelli snow tires. From reading up on these snow tires, they have a tendency to flat spot. It does go away after driving on them for about 10 to 15 minutes.

The flat spotting does not happen all the time, but easily remedies itself on first driving the car. See it like bringing the car up to oil temperature. Overall, the tires handle/feel good as winter performance snows.

fuego

Last night, I had a chance to check my steering rack per German888's advice. Everything looked good and dry. The bolt was the right spec, so I didn't retorque. I did have my roommate hit the brake pedal so I could fully torque the wheels to 94 ft-lbs while they were in the air.

That seemed to shrink the mph window of shaking, and it doesn't shake nearly as often. If I hit a smooth piece of tarmac, it'll be smooth for a 30sec gap before coming back. This was done in conjunction with setting my coilovers to max damper stiffness. I did some A/B testing with min/max stiffness; results were, at min. stiffness the car exhibits very poor highway manners which may exacerbate the shaking but is certainly not the cause. At max. stiffness, the chassis is really great (shaking aside) and isn't nearly as harsh as I thought. They seem to be operating in their ideal range. It most likely means they need a rebuild however.

I'm going to investigate the hub issue a bit further. For those of you with stock Porsche wheels, how tight does the wheel fit to the hub? I don't have locating pins, so when I miss the bolt hole by a bit, I can usually put my hand on the caliper edge, and sort of pick up the wheel to rotate. Too loose?

Is teflon tape an ideal material to reduce clearance?

Also, my new spacers are in and should be going in this weekend.

P.S. I downloaded a live album by Joy Division a while back... it came on while I was working in the garage. This song blew my mind. The guitars are so so heavy and sound nothing like their studio albums.

Petza914

All of my wheels fit tightly to the hub-centric lip to the point where they don't get fully drawn to the rotor hat until I start tightening the bolts. Removal takes rocking the wheel back and forth to get it off the hub, so it sounds like that's the root of your issue in that the wheels aren't fitting tightly enough to the hub-centric lip. They should be 71.6mm exactly. Not sure what to recommend for you to use that would be durable enough to hold up. One idea might be to have your rotor hats high-temp powdercoated. That would keep them looking good and non-rusty and add a little thickness to the lip.

Ducati_John

Don't use teflon. Use steel or aluminum, ie, wheels and hubs that are the right size.

captainbaker

Fuego, My stock wheels are snug on my stock hubs. I think you found your issue. I also agree with Ducati-John on all points.

fuego

It won't be a permanent fix. I just need something to confirm. Then it'll be new wheels!

docdrs

3M makes an excellent spacer shim

fuego

I made a breakthrough! It still has a vibration but is so much less dramatic, I'm going to consider this a win.

I got my ECS spacers in this week so on they went. They were loose fitting on the hub as well as against the wheel, so I tried a method docdrs recommended by using masking tape on the lips to center the wheels further and reduce slack. I cut cute li'l strips of tape. It was like arts-n-craft hour at school. I know some may cringe but it's just on the lips and is not sandwiched anywhere on the hub. I applied that to all of the loose wheels, which were 3/4. Maybe one could be a bit more snug. The ECS kit came with a new set of lug bolts, and I took a long, hard look at the old set. I didn't like the length of the fronts, so the old set was recycled to the front.

Whatever remaining shaking must be from:
- leftover slack the tape couldn't take out
- non-roadforce balanced wheels

I'd like to thank everyone for their views, comments, and tips. I wouldn't have examined so many things with a fine tooth comb without your help.