Quote:
Originally Posted by Xrslug
For the engineering-minded here (not me) — one of the things about road tubeless on hookless rims that I’m wary of is the much smaller difference between optimum pressure and maximum permissible pressure for tubeless-specific tires as compared to clinchers. On a gravel bike (and definitely MTB), lower pressures are the norm, so this seems like less of an issue but preferable road PSI seems extremely close to maximum tubeless tire PSI.
So if I’m understanding what I’ve read (questionable), with clinchers intended for hooked rims, the ISO standard says the pressure limit (I’m assuming before tire blow off becomes a risk) is 1.5 times the maximum stated tire PSI, whereas for hookless-specific tires, *the pressure limit is 1.1 times* the maximum stated tire PSI. So if the max stated PSI for a hookless tire is 76 PSI, the ISO pressure limit before risk of tire blow off could easily be exceeded just using a slightly inaccurate floor pump.
|
I just listened to latest Geek Warning podcast, and this is exactly the takeaway from their hour-long discussion of hookless road setups--that the margin of safety for hookless rims at road-racing air pressure is just too slim for it to make sense at the moment, and why it makes even less sense to go under the ISO standards (which is apparently what Lotto Destny has done by running 28mm tires on 25mm internal width rims). I don't have any hookless rims at the moment, and am not looking to buy any, but it is interesting to see an example of the genuinely greater risk that some new technology development can produce.