On my C1 Cag type alum rims, I have a small tire machine, the rear racing tire went on so easy and filled right up. Don't know what I did to the front tire, tried the rope trick & etc., still no luck so for $10 the tire guy let it sit in the hot 2 days and aired it up. I cleaned the rim beads w/ fine wet dry sandpaper under water, the new tire beads where good and they still loose air in a couple of days, that's your China stuff, but it's Cheap,lol. I have 4 new tubes, but using tire sealer on the C1 for now, not taking them tires back off. I ordered 2 fronts & 2 rears, they sent me 4 of the same, there 90/100-6.5" tubes, so they fit front & rear,lol.