I have acquired an NC30 frame and swinging arm for my latest project and I have been looking at getting a rear wheel for it. Do I really need a 17" wheel or will the 18" suffice? Are there any advatages of the RVF 400 wheel or the VFR750 wheel? The ride height will not be an issue I can make a new linkage or tie bars up to account for that and machining the hub to accept the vfr wheel wouldnt be an issue so do I stick with the 18" or go smaller? Is tyre size an issue for the 18" wheel?

It depends on what tyres you want to run.

You can get BT-090 which are sporty fast street / trackday tyres in a 150/60/18 size which is standard NC30.

These are well suited to the bike.

In the 17" size you can get plenty more 160/60/17 tyres.

I used to use bt90s on my RGv so if they are available for the 18" wheel I will see if I can locate one of them. Now I suppose I should look at which rear caliper I am going to use.