[1lE_1LE]

This is the first time I've had to buy new rims for a car so please bear with me. Thinking about snow tires, I went to tire rack like most of you have, and found new rims are very likely necessary. So straight to FB market place to try and find a package while the demand is low and hopefully prices are too.


My understanding is that 18x8 et32 is on on the cusp of the smallest wheel we can put on the SS 1LE. I found another member with the same size in his post. https://www.camaro6.com/forums/showthread.php?t=480919

HOWEVER, when on the tire rack website there's a notice about needing to replace just the brake pads as to remove backing plates. the notice is copied below.

"WARNING!! 18" wheels will only clear Brembo brake package if the caliper weights (early models) are removed or the OE brake pads are replaced with aftermarket pads that do not contain weights on the backing plates (later models). Please verify proper clearance at the time of the installation to avoid damage to the wheel and brake caliper. Some brake noise may result from modification." https://www.tirerack.com/wheels/Whee...kageFlow=false

Does anyone have any insight on this? Sounds weird that the pads make the difference on the fitment of the wheel. Being in med school while dailying a race car, I'm trying to stay as budget friendly as I can



My next question is about the wheel bore. On the BBS website, there's no wheel bore listed for this exact wheel. It just shows PFS, which they claim is a “Precision Fitment System” to properly fit the wheel to the center hub of a vehicle. The BBS system uses a fully machined aluminum ring that maintains the correct tolerance between the wheel and the car. There is an aluminum ring and wire retaining clip system for this as well. Is this a german car exclusive thing? I really thought it would be as easy as just ordering a hub centric ring to correct the Hubcentricty.

Should I be looking for a PFS system that corrects to 66.98 (6th gen wheel bore)? Again, any insight would be greatly appreciated.

[Msquared]

I can tell you that a base Camaro 18x8.5 et32 wheel fits on an SS 1LE with stock-sized 245/50/18 tires. Didn't have to remove anything from the calipers or pads on my 2020. This is a more budget-friendly way to go if you can find a decent set for sale around you.

My advice is to forget about hubcentricity. That's not what locates your wheels or holds them on the car: the studs and lug nuts do that job exclusively. Hubcentric wheels are only useful for help you easily install the wheel on the car, but literally millions of vehicles have been put into service without that "feature" and somehow they all manage to survive. But of course, if you get stock base model wheels then they will be hubcentric.

[Uncle Sam]

I bought 18s from Tire Rack. I use stock pads and had no issues. Any big "ears" on the pads could hit the wheels, but I have never seen that. Be careful where your wheel weights are as they may rub at full lock, i.e. backing out of a parking spot. The wheels I received came with a plastic insert that fits in the wheel and is no big deal, just keep track of them when you switch to your summer tires and wheels.

https://www.camaro6.com/forums/showthread.php?t=590964

[Dabjbr]

You can buy hubcentric rings on eBay. Doesn’t matter if they’re plastic or aluminum. I’ve had plenty wheels with plastic rings and they’ve worked fine… that includes big, heavy 100lbs wheel/tire combos on my truck.

I agree with msquared that they don’t actually carry load. However, I still recommend the cheap insurance of rings. Why?

They ensure the wheels are installed and centered. = Easier install.

More importantly…
When they’re not used, you run the very very slight chance of pinching your wheel with the lug nuts and possibly (hairline) cracking the stud holes when tightening on the nuts. Again, this is rare but more of a chance when one rushes the installation or uses a Pneumatic gun to rapid fire the nuts on.

You can read about the possible problem here. I write about the issue with my truck.

https://www.ramforum.com/threads/add.../#post-1676781

[pbsinternet1le]

I'm using apex sm 10 and without hubcentric rings the lugs were noticeably loose after track sessions. After the rings were added almost no loosening..

[Warrior102]

There are lug centric and hub centric vehicles, your car is hub centric, keep it that way. I purchased rims from the Tire Rack for my Tundra that were not hub centric and it was a special kind of hell as I never achieved proper balance, never. I eventually ate it and replaced them. The Tundra hub was something like 60mm and the rim bore was maybe 2-3mm larger and no one makes rings that thin. There are thousands of rims out there that do not require bandaids get some you'll be happier.

[Msquared]

There is no such thing as a "hub-centric or lug-centric" vehicles. All modern cars have hubs with a raised pilot section, and most (maybe all?) come from the factory with hub-centric wheels whose pilot bore fits around that pilot fairly closely. The only reason for this is to aid wheel installation on the assembly line. The pilot and bore is not what precisely locates the wheel. The studs and lug nuts are the only parts that do that. All modern vehicles I know of come with tapered seats in the wheels and tapered lug nuts that fit into those seats precisely. These are what locate the wheel precisely with a tight fit when lug nuts are torqued. This is a much tighter fit than any hub pilot and bore, which is by necessity not tapered and not an interference fit (because if it were, you couldn't slide the wheel on). And the idea that a plastic ring will better locate your wheel on the hub than five tapered seats and nuts torqued to 140lb/ft is laughable.

If you want to use hub-centric wheels on your car, of course that's fine and it won't hurt anything at all. But let's not fill the OP with anxiety and cause him to avoid a bunch of good wheel choices by telling all kinds of horror stories that aren't true. Lack of hub-centricity is not the reason anyone's lug nuts come loose or their wheels won't balance. Lug nuts come loose because they aren't torqued properly or maybe because there is grease on the tapered seat or a stud stretched or had other damage. Wheels sometimes don't balance because they aren't true or the tire is bad. That happens. Again, literally millions of cars and trucks have been put on the road with lug-centric setups, even from the factory, and wheels aren't flying off and they balance just fine. I myself have many, many miles (including track and autocross) on wheels that were not hub-centric. Likewise, many hub-centric setups have still not balanced properly because a wheel or tire wasn't good. Again, I myself have a set of factory base wheels and tires that are hub-centric and don't quite balance out right (I'm sure it's just the tire). Let's not go overboard.

[Warrior102]

Actually the raised hub and fitted bores main function is to absorb and dissipate shear stress on the lugs from road impacts allowing the hub face, lugs and lug nuts to deal with longitudinal stresses. I replied to the OP with my experience with non hub centric wheels, two sets of tires that were road force tested with Michelin AT's and Continental TerrainContact AT. Always had a shimmy, new rims same Continentals much better. As always YMMV

[Msquared]

Originally Posted by Warrior102

Actually the raised hub and fitted bores main function is to absorb and dissipate shear stress on the lugs from road impacts allowing the hub face, lugs and lug nuts to deal with longitudinal stresses.

Negative, Ghost Rider! The pilot and bore should never take shear loads when the car sitting on its tires...ever! Those shear loads are taken/resisted by the friction between the wheel face and hub mounting surface with clamping (normal) force provided by the lug nuts. This is why it's important to keep those surfaces clean and non-greasy. If the studs or pilot/bore end up taking shear loads, then you risk shearing off the studs.

It has to be this way if you think about it. First, the biggest shear forces on the wheels and studs would be from braking (or maybe from launching if it's a prepped car at a drag strip with real slicks). Those forces go around the pilot/hub and so it can't resist them. If what you are saying were true, you'd be putting immense shear loads on the studs every time you hit the brakes. Second, as I said before, the fit of the bore to the hub is not precise or snug enough to react shear loads properly. There would still be lots of movement and massive wear of the bore if that were happening. Third, again, many millions of cars and trucks have been run with lug-centric setups, including many race cars even at the pro level. This just isn't a thing.

I replied to the OP with my experience with non hub centric wheels, two sets of tires that were road force tested with Michelin AT's and Continental TerrainContact AT. Always had a shimmy, new rims same Continentals much better. As always YMMV

You just had a bad set of wheels. If this were evidence that hub-centric wheels were required for proper function, than all the vehicles out there with lug-centric rolling stock would have vibration problems...and they don't.