Having just seen @putteesinmyhands post SPIDER RIMS the wheels have no centres, so spares are lighter ( half the steel is missing). The rim sits on a hub, with the rim held in place by tapered collars and nuts.
I was a scaley, therefore have no idea about trucks.I’ll make it complicated then...!
Does the vehicle come with split rims or spider rims or possibly a combination of both?
It may even have split rims on a eight/ten stud hub!
Don’t stress I answered it for you, the rims have no middles! EnjoyI was a scaley, therefore have no idea about trucks.