Do I need hub centric rings??

[nhs15]

1970 911t. Put on ATS 6155 classic wheels 15x6 all around. 205/55 Yoko s-drive tires. Look perfect and are perfectly balanced on the machine but car still has a shake around 50 mph which is annoying. Even put the weights on the outside on the wheel. My guy says I need hub centric rings. Any recommendations?

[porsche930dude]

Id switch the front to back and try again just to be sure its not a wheel. an when you put them on be more careful. tighten them all finger tight first and rotate to get them as centered as possible

[Flojo]

even new tires can be faulty.
I haven't heard of ATS 6155 classic ever needing centric rings on a 911(?!).
check the tire, check the shocks, check the alignment.
then double check.

[Cory M]

does the ATS wheel center engage the hub now?

[175K911]

Recommend going back to your tire guy and ask him to RoadForce balance them. He would need a Hunter 9700 RoadForce machine to do this. the 9700 puts a load against the tire/wheel assembly while it spins on the balancer to simulate vehicle weight on the tire. It will tell an "experienced" operator if there's a problem with a tire, a wheel, or if spinning the tire on the wheel say 90 degrees will make it better. But I emphasize experienced, it's not the same as just putting on a regular balancer and watching numbers pop up.

Having been in the tire business a few decades ago, I have seen first hand how a balancer can "zero out" a tire that's shaped like an egg. The machine says it's balanced but it's till an egg.

[Flojo]

Originally Posted by 175k911

.. How a balancer can "zero out" a tire that's shaped like an egg. The machine says it's balanced but it's till an egg.

+1

[nhs15]

Thanks. I'll ask if he uses the Roadforce machine.

This is how they sit on the hub.

[dad911]

Were you using these wheels before w/o problems?

A problem at 50 mph seems excessive, I've lost stick-on weights and not felt it at 50.

[Trackrash]

The first thing you need to do is to jack up the front of the car and spin your wheels by hand.
That is the ONLY way to determine if they are running true.

FWIW, all the 911s prior to '74 have don't hub centric rings. The Fuchs are aligned using the spherical nuts the same as any wheel on the older 911s.

I have had problems with the "spin" ballancing of my Fuchs when I have bought new tires over the years.

I have a bubble balancer in my garage and have used it successfully to re-balance wheels on new tires that vibrated.

It is my theory that those machines used in tire shops don't center Fuchs wheels correctly. Your wheels may have the same issue.

[Uwon]

Trackrash ^^^^^ +++1
Another possibility may be that since the inside of the outside centres do not appear to be machined, it may indeed be off center when clamped down with the rubber donut.
My tire guy has this neat gizmo that only clamps onto the stud holes to avoid marring of the paint. Obviously, it would work for you as it locates the true center of the five studs.



Hope you solve such an irritating issue.
Johan

[brighton911]

The really nice balancer our local guy has (don't know the brand) locates off the wheel studs, not the center. If one is locating off the center, I can see that to be a problem.

[175K911]

With a hubcentric wheel, it is perfectly acceptable, in fact highly recommended, to spin the wheel on a balancer with a centering cone ONLY if the cone is installed from the back side of the wheel, to replicate how the wheel centers itself on the hub. I have all my Fikse race wheels balanced this way, and I'm balanced at triple digit speeds on the track.

Unfortunately many shops short cut the process and install the cone from outside the wheel so it's "centered" where the wheel cap goes. This is not precisely machined like the rear section of the wheel and doesn't usually properly center the wheel. It may work fine for the typical minivan wheels and tires, but not for our wheels.

Looking at the OP's pictures above, you can clearly see how this outer piece isn't tightly machined, with rough edges. If the tire shop coned these wheels from outside, it'll never balance.