[tdi250]

I had the same problem, they seem a little too large in diameter to fit tight to the wheel, plus they are not wide enough to go over the full rim.

You can cut the inside part of the rim off if you want but I left mine on, just glue them on and they will stay on, then if you ever want the wheel for use with normal minispikes etc you can use it again.

I don't know why they are a little large on diameter but if you glue them on it doesn't seem to matter, apart from looking a little wobbly when you spin the wheep by hand.