Originally Posted by
elcruxio
What do we consider properly reported incidents? Officially registered accidents? race crashes? If so, then there are very few tire incidents overall. If we however accept anecdotes, there's plenty to be found with a fairly short search of the other cycling forums.
But then there's the substantial mitigating factors. I don't understand what you mean by this and what is considered substantial?
In any case the safety margins are way too tight. With hookless rims it would seem that a difference of 1mm in tire width is the difference between make it or break it. A 10% pressure safety margin is something you can exceed when you go from an air conditioned garage to ride in hot weather on hot asphalt. Especially if your pump gauge is inaccurate. Also, that 5 bar max pressure is too low for heavier riders in any case.
Just compare against the amount of leeway you have with hooked rims in both tire size and tire pressure.
100%. Hookless tubeless for road bikes seems to work OK for lighter riders. But pressure calculators indicate that for heavier riders, many tire/rim/rider weight combinations require a pressure that exceeds the given tire's safety limit on the given rim.
Here's an exchange from
this previous thread. PsImet2001's attitude toward hookless was neutral at first but changed after he found that none of the rim and tire manufacturers whose representatives he interviewed were able to articulate convincing arguments in favor of hookless rims for consumers. The only clear advantages were greatly reduced cost and increased profit margins for the manufacturers.
Originally Posted by
vespasianus
On the MTB side, hookless rims have had wide use for a long time. They work well and I run my 27.5 x 2.4 tires at 15 PSI (200 lbs) and love the ride. Never once even burped a tire at those levels.
Originally Posted by
Psimet2001
You just touched on why they "work" over there= 15 psi. The issue isn't about burping on road it's quite literally about tires being blown off the rim. Its the other end of the spectrum.
The most troubling thing for me is that the parts of the industry that will talk about it openly just use in house rules of 150% of target pressure. That's a 1.5 safety factor. That's the LOWEST safety factor I have ever run into in my engineering life. Especially in a consumer product.
The worst part is that not everyone even agrees on going that "high". Hushed anecdotes say some OE's have been fine with 1.2-1.3.
Think about that: If they are rating a particular tire and rim combo to 70 psi then that means they have experienced blow off at 84 psi.
Keep in mind that even all these years after we went to "wider" 23mm rims (13 years ago) we are still having an impossible time convincing people not to ride pressures in the 115 psi range for road.
Old habits die hard. This is an absolute recipe for more than a handful of deaths. Also...84psi? how accurate is your crappy pump that you've used for 15 years? I've run across new *redacted* pump gauges that are as much as 15-20 psi off at lower pressures.