Q:

How can I store my extra wheels on the wall efficiently, without hanging them by the rim?

I have 5 pair of extra wheels, which I would like to store on the wall efficiently.
I am a little skittish about storing them using the rim since some of them are carbon wheels and I don't want to risk scratches. Any suggestions?

A:

While I agree that there are no real risks to string your wheels by the rim, there are a number of DIY and commercial wall mounted racks for hanging wheels at the axle.
Wheelzrack makes one good option, and even integrates a storage shelf for shoes and helmets. They support up to for sets of wheels, which may be a good option in your case.

Feedback sports used to offer a Wheel Arm system, which had a bolt-to-wall mounting option (note: the Wheel Arm is no longer listed on home page but they sell alternate models).  These are designd for shop displays, but will work in the home as well, assuming your significant other is tolerant. :-) 
Hope that is helpful.

A:

As suggested by this answer, there's really no problem with hanging wheels or even an entire bike up by the rims. It's a good idea to pad the hook to avoid scratches, but this should be easy enough with some cheap foam or even tape.
Failing that, a narrow shelf with some blocks either side of each wheel to stop them rolling away would work and take up little space. I imagine you could even use a short loop of rope to hold a couple of wheels. To avoid touching the rims, you could loop this between the spokes and around the hub.
If the wall is rough, cover it with some cardboard or thin foam/rubber.

