Wheel Woes

dmnknightomega6 · #1 04-17-2007, 10:28 PM

Hi guys,

I have my RX-8 Rims and was planning to mount them. I lost the lugs that came with it.

There are issues here that i want to sleep better on.

I bought Hubcentric rings that are for a STi, Is it the right size?
Do I need wheel spacers? what size?
Does the stock Lugs Fit on the RX-8? if not what size lug am I looking for?

Finally order of mounting:
Wheel --- Spacer ----- Hub ring ---- Hub

is this right?

Thanks again guys!

Darren · #2 04-18-2007, 12:45 PM

Hiya,

The SVX runs a 55mm offset and the RX8 (18") runs a 50mm.

You should be ok without spacers although if you do need them get them with the correct wheel centre already machined in. The best type are the ones you bolt on to your hub then fit the wheel as normal, they are a little more expensive but less stress on the studs.

I was looking for a pic I had of an SVX in Japan with the RX8's on, looked fantastic, you can also get some Prodrive center caps to replace the Mazda ones.

Quote:

Finally order of mounting:
Wheel --- Spacer ----- Hub ring ---- Hub

Think you want to try the Hub, Spacer, (Hub ring if needed) then the wheel, I find it fits easier that way with the wheel going on last

Darren

dmnknightomega6 · #3 04-18-2007, 09:45 PM

thanks darren,

What size should the spacers be? And a link on where to purchase will be great.

Any Idea on the Lug nut size? is it the same as the Subaru STI.

Thanks

gsodonis · #4 04-20-2007, 05:04 AM

www.tires.com a.k.a. www.discounttiredirect.com(discount tire direct) sells anodized aluminum hib centric rings in all different sizes for $15 shipped. Tell them the ID of the wheel and the OD of the hub and they'll sell/send you some nice, hard (pink color) anodized rings. If you don't have access to a digital or analog set of calipers, just tell them the donor car from which the wheels come (RX8) and that you're mounting them on an SVX and they'll look up the specs for both. I have run them on all my non stock wheels on all different types of vehicles for the last decade.

bwb3 · #5 04-20-2007, 09:41 AM

A stupid question. What happens if you don't install hub centric rings with the wheels? A couple years back I put wheels on a car (since sold) and the tire place said the rings that came with the wheels didn't fit so they just tossed them.
Gene

gsodonis · #6 04-21-2007, 11:30 AM

As the name suggests, hub centric wheels use a lip machined on the end of a hub to center the wheel on the hub.
Bolt centric wheels rely on the lug nuts to center the wheel on the hub (each tapered lug nut centers each corresponding mating wheel bolt hole to the hub assembly).

From an engineering perspective, the wheel studs (or bolts depending on manufacturer) do double duty in bolt centric applications. The studs must withstand the shear forces produced by the rotation of the wheel and they must also withstand the shear forces produced by vertical forces generated by the suspension as it absorbs road irregularities.

In hub centric applications, the shear forces from wheel rotation are the same, but the forces generated by the suspension are transfered to the hub through the wheel/hub lip interface and not throuigh the wheel studs/bolts.

Most of this is invisible to the driver under normal circumstances, but in off road and racing applications, hub centric is more durable and preferred.

What happens if you install road wheels without hub centering rings?
From a safety perspective, most likely nothing as the wheel/braking systems of most cars are engineered with pretty big factors of safety (they're essentially over engineered).

In my experience, I once had a set of +1 size aftermarket wheels that I installed on my wife's minivan. The steering wheel shook horribly and the tire dealer tried three times to re-balance the wheels without success. When I asked about hub centering rings, I was told that the wheel manufacturer claimed that my Honda Odyssey didn't need them as it was bolt centric. I chose not to believe them and bought a set anyway. As soon as I installed the centering rings, all of the steering wheel vibration disappeared.

Moral of the story, if you try and fit aftermarket or non-OEM wheels onto your vehicle and you get a steering wheel vibrations that wheel balancing won't eliminate, try a set of hub centering rings and it might just do the trick.