What is a Spigot Ring?
A spigot ring, or hub ring, is a piece of hard nylon plastic or aluminium that increases the bore size of your vehicles wheel hub to marry up with the centre bore of the wheel you are trying to fit.
The most common reason for requiring a spigot ring, is when you come to fit aftermarket alloy wheels.
On the Elgrand E50, the bore size on the hub is 100mm. If you buy any aftermarket alloys that have a centre bore bigger than this, you will need to get some spigot rings to make up the difference.
For example, the Works Euroline wheels have a centre bore of 108mm, this means a spigot ring with an outer diameter of 108mm and an internal diameter of 100mm is required to fill the gap.
Why do I need them?
If you fit an aftermarket set of wheels that do not have a matching centre bore, you are opening yourself up to some safety issues. The gap between the two bore sizes means you will never be able to get a truly accurate central position for the wheel. This means that, at speed, you will notice some potentially severe wheel wobble. The steering wheel will wobble as you drive, as though your wheels are not balances. In actual fact, what is happening is that every rotation of the wheel is "egg" shaped, with one side being slightly further away from the centre than the other.
This wheel wobble is just a sign that let's you know your wheels are not alligned correctly with the hub. What that is doing, is putting extra pressure on some of the wheel bolts, and putting less pressure on others. This will, over time, cause damage to the wheel bolts, and could even lead to the wheel falling off whilst in motion, which is a huge safety risk for you and other road users.
When fitting aftermarket wheels, make sure you check the centre bore size before fitting, as it's not always obvious that you need them. You should use a micrometer for this job, to get accurate measurements of both, but you can use a tape measure or even a ruler to get a general idea.
Where do I get them from?
If you buy your wheels new from an alloy wheel retailer, then chances are they will send them with the wheels. You should check when purchasing that these are included, because some places will NOT send them. If you are buying second hand, or your new wheels do not come with them, then there are a few places you can find on line that do sell them. For the E50, with the centre bore being so big compared to UKDM vehicles, you might need to get them imported from somewhere like the US or even Japan. Or, if you are certain about the size of spigot ring you need, you could ask a plastic/metal fabrication company in the UK to make some up for you, although this might end up being the most costly option.
In the US, they are known as hub rings, so search for that rather than spigot rings if you need to go down the import route for them.
How do I fit them?
Simple. You fit them onto the centre bore of your vehicles hub. Then, when you put the wheel on, assuming you have the correct size spigot ring, the wheel will sit perfectly central on the hub, keeping the wheel aligned and avoiding putting extra pressure on any one of the wheel bolts.