I have a van with steel wheels and as I require to get a spare had toyed with the idea of buying 2 alloys and keeping the originals as spares. Ok, I would have ended up with 2 spares. But reality set in and I wondered why I should do this apart from the aesthetic point of view. Alloys are lighter but are not going to make any significant difference to a caravan gross weight. A few tins of beans can soon cancel that out. They can also stick to the drums and can be a b...r to get off. So I have decided to get the steel wheel as a spare and spend the rest on beer.
A recurring problem with caravans is loss of a wheel and so we are told to check wheel bolts with a torque wrench at regular intervals.
Yet caravans come with wheel trims that make it less than simple.If you don't tie them on with nylon ties they fall off.If you do tie them on its hard to get at the bolts.
Alloy wheels make it easier to do this and the 5 spoke type are very easy to clean
Alloy wheels do stick to car brake drums but a caravan brake drum is flat with no raised centre section so I have never found sticking to be a problem.
Have to be honest and say no complaints about my wheel trims. They are not tied, and have never fallen off in 2 years and over 20000 miles. But it was not a UK caravan.
When I bought the van, alloys were an option, but I decided against the extra cost being amean old sod.