Bing Bang Theories? (Or Why My Tires are Randomly Exploding?)
07-16-18, 02:15 PM
#26
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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.)
I wanted to try a new pair of tires to check the difference in feel, so I'll take the opportunity to check the rims thoroughly.
Originally Posted by Kontact
You can tell immediately after a blowout if the bead crept or the sidewall blew out. You just have to look.
My money is on the tire being mounted incorrectly. It was either too deep in the rim in some spots creating slack in other spots, or the tube was partially under the bead. Assemble your tires with the tube partially inflated so it can't pinch under the bead, and pay attention to how concentric the tire is to the rim as you inflate it. Some tires will do this if the pressure falls too low in storage - you pump them back up, but they've shifted and blow out.
My money is on the tire being mounted incorrectly. It was either too deep in the rim in some spots creating slack in other spots, or the tube was partially under the bead. Assemble your tires with the tube partially inflated so it can't pinch under the bead, and pay attention to how concentric the tire is to the rim as you inflate it. Some tires will do this if the pressure falls too low in storage - you pump them back up, but they've shifted and blow out.
Anyway, we are now one week of riding with the same tires at around 75psi, and no issues.
07-17-18, 03:44 PM
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Whether or not your rim strips are the source of this particular problem, I'd suggest making sure you're using strips or tape that'll resist stretching. The ol' standard cloth tape like Velox works well, and many manufacturers have plastic tape/strips meant for high-pressure tires on double wall rims.
07-18-18, 10:53 AM
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Originally Posted by SkyDog75
If your rims are double-walled (like the SS-40 in the pic), rubber rim strips could be problematic. Rubber can stretch, potentially allowing the tube to expand into spoke holes where it can keep on stretching 'til it bursts.
Update: I finally got around to installing a new set of tires, so I snapped a few pics of the rim during the process. It does seem to have something of a hook, but it doesn't feel particularly pronounced.
Also, these new tires were, errr, new, but they were much more difficult to get on the rim than the previous set (even when the previous set was new), so I really doubt I'll have the same issue again. These are only on temporarily, as a little test for myself, but I'll post an update if anything goes bang.
07-18-18, 12:39 PM
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Bad rim tape can cause punctures, but not explosions. And those do look like hook-bead rims, so if you get a good tube and tire installation, you shouldn't have any problems.
07-18-18, 03:24 PM
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Anyway, with blowouts like the kind I experienced (while not riding), I think you would feel something wrong at least a half-second or second beforehand if you were actually on the bike.
