They should fit fine. And no as said it doesn't say on the spokes what sizing they are.

You have V5 Simmons

They wont fit unless he used adaptors, and as I said above, just wait till the right ones come up, because simmons sell all the time on ebay and will surely come up soon enough.

For the centre to bear the load it would have to be tapered in which case the rims would need to be knocked-off to remove. I've never come across this.

My thinking is the load is taken by the studs and the friction against the hub.

The hub takes the vertical load on a wheel, and is not tapered, and the studs hold the wheel on horizontally, and provide no support other than to hold the wheel on the car.

Since the nuts have a taper and are screwed tight into the rim they cannot help but take vertical load.

Since the rim is pressed tightly against the hub the friction generated cannot help but take vertical load.

The centre spigot has to be smaller than the centre hole in the rim otherwise one could not get the rim on without using force and generating damage. Being smaller it cannot take vertical load. Sure, it may touch on one side, but that's not good enough as the wheel rotates. Sure, if the nuts were loosened slightly one might imagine the rim bearing against the centre spigot, but imagine what the movement would do to the studs, nuts, rims, wheel balance, etc etc.

This excerpt is taken from one of many wheel fitment sites that say the same thing

Spigot size is a bit trickier....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 aluminium 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

The fact is the centre bore hole has to matchup with the the protruding hub onthe vehicle. Simple..... why are you debating this?

I debated this because at the very least it has crucial errors with safety and practical implications. I'm not the only person saying this.

If for example you tell someone the vertical load is taken only by the centre, they may decide if they lose a nut or have a bent stud they aren't important unless they corner hard. Or they might buy spigot adapters they don't need and who says they are made well enough anyway?

I have given reasons why i disagree and they address the points made in your quotation. In my experience aftermarket companies can be a long way short on understanding.

To advance the centre-spigot load-bearing stance someone would need to refute my points. The only chance i can see for even a partial refutation would be to argue that the small radius at the centre of the rim and at the spigot locate and bear load in a similar manner to a taper. Even if this is true vertical load is still taken in part by the studs and friction against the hub.

My thinking is a spigot is sometimes used in order to aid fitment of the wheels and keep things going longer if the nuts come loose.

With simmons wheels can you get the centres replaced? Cause my new XR8 has some but would love some polished FR18's on it

Yes you can. If you end up getting yours replaced, let me know how much you want for your old centers.

The ones that are on it arent on the simmons site though. I hadnt seen them before. They are like a multi spoke type. Ill post a pic later