Most of the time, like this:
https://lh5.googleusercontent.com/-U...2/_MG_2454.jpg
Narrow wheel, outermost inner rib removed, bottom of the tyre's glue bead glued to the flat part of wheel. The outer ribs on the wheel are there, but they're not glued to anything.
Sometimes, if there's a lot of grip and I can't quite handle it, like this:
https://lh5.googleusercontent.com/-U...2/_MG_2454.jpg
[IMG]file:///C:/DOCUME%7E1/U46041/LOCALS%7E1/Temp/moz-screenshot-1.png[/IMG]https://lh3.googleusercontent.com/--O1ifG5leqk/S5bLoURjSDI/AAAAAAAALTE/5gZCDlLL-Gg/s512/_MG_3410.jpg
Narrow wheel, outer ribs removed, so the tyre is soft laterally, thus forgiving.