My mate Gazza, recently had an "off" at the race track - but he's ok.
http://www.planetsoarer.com/offset/4129.jpg
The Before shot - note wheel is still on !
Gazza scored these 18 inch beauties for only $880 for all four - bargain! Multi fit inexpensive wheels are a bit heavy, relatively soft, come with 10 holes for studs (fit more cars this way) and have a large 70 mm centre hole (fit more cars see). Five of the wheel stud holes are 114.3mm and fit the Soarer - the other 5 holes are for other cars - this is called "multi-fit". "Multi-fit" is your guarantee that the wheels were not designed specifically for your car.
The Soarer, Toyota and Lexus cars come with a 60.06mm centre spigot to support the wheel - a 70 mm centre hole is big enough to go on any car - it's a "multi-fit" centre hole that slops around on the studs putting tremendous shear stress on the studs.
The wheels were fitted without a centre spigot (or is it spiggot?) ring to the wheel.
Motor vehicle manufacturers use a central location collar on the stub axle hub in order to accurately locate the wheel. The wheel collar diameter varies, depending on the make of vehicle.
Many replacement allow wheel manufacturers use an adapter (spigot ring) to vary the diameter of the locating hole. In this way, a particular wheel can, by changing the spigot ring, be used on a variety of vehicles.
The spigot is the bit in the centre of the hub that you rest the inside centre of the wheel on whilst aligning the studs and screwing back the wheel nuts. On generic after market wheels, the spigot hole inside the wheels is a lot bigger than the spigot on the car. So what you need to do in this case is fit spigot locating rings. These are just rings of aluminum or hard plastic, that fit over the spigot on your car and then have a proper fit with the spigot hole on the wheel. If you don't have the spigot taking all the weight of the car, chances are you'll break one or more studs when you drive the car hard or have to brake hard. Remember the wheel nuts are simply there to hold the wheel on, NOT support the weight of the car. Also, as there is nothing to centre the wheel, you'll notice the wheels go in and out of balance because as you drive around, they'll move around on the hub.
More information on offset and spigot rings see the offset page.
http://www.planetsoarer.com/offset/spigots.gif
Bingo! Three broken studs. The wheel vibrates, wobbles and the other studs work loose once some studs are sheared through. See the rusty ring around the middle? That is roughly where the spigot ring should go supporting the wheel on the hub. The studs cannot support the wheel force - they can only hold the wheel on the hub. Studs are one and half times weaker in shear than tension. Once a stud shears it places more load on the other studs. Usually the wheel wobbles nuts off before all the studs shear.
Once the wheel comes off first thing it does is wreck the guard, ouch!
http://www.planetsoarer.com/offset/4686.jpg
Carnage!! What a mess.
http://www.planetsoarer.com/offset/4688.jpg
With the wheel going off in the distance the car hits the deck and the brake disk grinds into the ground. When the disk hit the ground at high speed on the track it cracked as it's not designed as a wheel. Garry replaced both disks, and all studs.
http://www.planetsoarer.com/offset/5849.jpg
http://www.planetsoarer.com/offset/5851.jpg
And from the dude who posted the link.
Though that article says ...
"So what you need to do in this case is fit spigot locating rings. These are just rings of aluminum or hard plastic, that fit over the spigot on your car and then have a proper fit with the spigot hole on the wheel." ...
I would never use a plastic spigot ring on any of my cars.
The spigot ring is there both to transfer the weight of the car to the wheels via the spigot ring (instead of the studs), and also to ensure that the wheel is kept centred to the hub.
If you use a plastic spigot ring, there is the potential for play to develop (just like plastic and rubber bushes wear), whereas a metallic spigot ring of the correct grade of metal is going to be far more robust.
If I was going to use a set of multi-fit wheels on one of my cars, I'd get an engineer to machine up some high quality spigot rings - that way he can make sure all the clearances are correct, you know exactly what grade of metal has been used to make the spigot rings, and a high quality machined spigot ring which has been machined specifically for the clearances on your car is likely going to be a much better fit than an off the shelf spigot ring.
And of course with a high quality spigot ring, the wheel will be perfectly centred on the hub, which helps reduce vibration, makes sure that the only job the studs are doing is holding the wheels on (instead of the studs bearing the weight of the car) and will make everything last longer.
- Adam
