Clever idea as it saves you having to remove the wheel ... handy for nutted wheels, hub gears, etc? Not cheap at over £15 though.

http://practicalcycles.com/products/254 ... -tube.aspx

I honestly can't believe it works (and just because they're selling it doesn't mean it does ).

Shirley it'll create a dead-spot on the tyre where the ends butt. Plus, over time and use, what with the tyre flexing and squirming plus some "friction" between the tube and inside of tyre, won't the ends get worked together or apart?

Boggled, but then I'm no

A friend used to use split inner tubes, last saw them around 10 years ago. The ends tapered and overlapped which seems a better design to me.

Don't know supplier.

With hub gears I often fix a flat without removing the wheel anyway. Although if caked in mud and balanced on a tussock with heavy hail falling things might be different

Specialzed used to make a version, tapered ends like Dave says.

Got one in the garage here, called "dirt worm".

26", never seen a 29 though.

http://youtu.be/oa36wTCvBZo

This is nothing new, been around for BMXs for years. Though the ones i've seen have tapered ends that overlap.

Yep - old hat. Very popular in small wheel sizes for Bromptons and the like where removing the rear wheel can be a lot of hassle.

You could make your own couldn't you?
Cut tube, seal each end with superglue, insert into wheel and inflate.

A CTC better bodge for a slashed or blown out tube was to cut it at the slash and tie a knot in each end, bung back in the tyre, inflate and ride home....