rear wheels for single speed
 

Why are wheels for single speeds so heavy? I can see 2 reasons. 1. They use at least 32 spokes and the spokes are always straight (ie not butted). Why do we need so many spokes and why not butted? 2. They have solid axles. Has anybody any idea if a quick release with a chain tug to stop the axle pulling over would work? It might save weight and would be easier to get on/off when fixing punctures. Can you change the axle form solid to quick release? Any ideas anyone?

A lot of SS/fixed bikes seem to be marketed toward people who do tricks on their bikes, i.e. bar spins, riding stairs, other such nonsense. The wheels are over-built so they don't taco under the pressure. Your best option it to build a set of wheels using parts you pick out, and you can get weights pretty low.

SS wheels aren't necessarily heavier than their geared counterparts, although aaronf is on to something with his suggestion that SS wheels are built around strength.

A lot of it also has to do with the fact that SS cassette hubs and freewheels are fairly heavy components.

Also, not all SS wheels are built with straight gauge spokes, just the less expensive ones. If I wanted to spend the extra dollar per spoke I'd probably build double butted.

Solid axles are necessary in SS rear wheels because they're better suited to handling the drive/brake rigors of a single speed, especially when chain tension is achieved with a tensioner, but people use QR with chain tugs all the time. I personally don't think it's ideal since the actual QR shaft is substantially smaller in diameter than a 3/8ths axle. My buddies who run tug nuts on QR in an SS application are constantly readjusting.

There are solid to QR swap kits, but I'd weight the pros/cons before spending the money. I'd personally never run a SS rear wheel without a solid thru axle.

Thanks for the suggestion. Anyone any ideas about changing current solid axle hub to be quick release?

some hubs are easier to do than others. I think Surly hubs can be done in about 10 minutes, since they use nice standard threadings. Just pull out the solid axle, and put in a hollow one. Other brands, it's the same idea, but comparability might be an issue. As long as you can find an axle to fit the cones you should be golden. You might need to cut it down to size, I don't think any QR axles come stock in 120mm