Marin wrote:I always wonder if soap residue can lead to blowoffs - I'm a bit paranoid after suffering one right *after* a fast descent - only damage was my hearing & the tire sidewall, but could have been far worse. Although I didn't even have to use soap in this case IIRC.
I'm going to respectfully disagree with bm0p700f: while soap residue won't cause a solidly-mounted tire to blow off, it could allow a marginal tire to blow off when it otherwise wouldn't. bm0p700f is totally right that tension in the bead is the main thing keeping a tubeless clincher from blowing off its rim, but friction between the bead and the rim provides a little extra margin in addition to the retention the bead provides. A little extra margin isn't a bad thing at all.
If a marginal tire were going to blow off due to soap residue, I'd expect it to do so on the first wet ride after mounting. Rain water could reach the tire/bead interface and recreate the same slippery conditions that allowed the tire to mount in the first place. It might make sense to let such a tire seal and dry overnight, but then deflate it (mostly) and dip the tire and rim in the bathtub a few times. The capillary effect will pull water between the tire and rim, reconstituting (and diluting) the original soapy film. Rinsing your wheel a few times will help get rid of the soap.
That said, I'm not losing any sleep over soapy tires blowing off. If a tire is tight enough that you need soapy water to mount it, you're unlikely to blow it off. If it's loose enough that you don't need soapy water to mount it, then there's no soapy residue to worry about.
