Old 07-13-18, 10:59 AM
Senior Member
Join Date: May 2011
Location: Upstate NY
Posts: 3,818

Bikes: Bianchi San Mateo and a few others

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 632 Post(s)
Likes: 0
Liked 1 Time in 1 Post
According to this old Araya catalog shot I found, it looks like SS-40 rims had a hooked bead. If so, we should be able to rule out hook-beaded tires on straight-sided rims as the source of the problem. (It would be pretty easy for robertorolfo to confirm whether or not the rims have a hooked bead in person.)

BTW: If we were dealing with straight-sided rims, I'm not sure that it makes any difference whether a tire has a folding bead or not. It obviously makes a difference whether the tire has a straight-sided or hooked bead, and hooked tires may need to be run at low-to-moderate pressure so they don't blow off the rim. But all other things being equal in regard to tire construction, an aramid fiber (e.g. Kevlar) filament inside a folding tire's bead should perform pretty much the same as a steel wire in a non-folding tire. Both materials are capable of withstanding the tire's pressure and will thus hold a tire's circular shape when inflated. And it might seem counter-intuitive since Kevlar is quite flexible, but it's actually much more resistant to stretching than steel.

Getting back to the actual problem... Between the slit in the tube, the 'bang', and the tire being off the rim, it does sound like the tire's bead is somehow becoming unseated. It could just be a poorly matching tire/rim combo. It could be that you got the tube pinched under the tire's bead when mounting/inflating. It wouldn't explain the tire being off the rim, but a problem with rim strips or tape can cause blowouts on a double-sided rim, as the tube can expand into spoke holes and stretch 'til it ruptures. (What kind of rim tape or strips are you using?)

Last edited by SkyDog75; 07-13-18 at 11:04 AM.
SkyDog75 is offline