Kbarter

Was setting up some Panaracer 38c tires on Hunt Carbon 30 rims and the rim exploded at about 80psi when I was trying to get the bead to set. Reached out to Hunt, noting that the max PSI on the rim was 100, and got this reply.

Hi Kent

Thanks for getting back to me with the information.

There is one point that you make that I must correct you on, in that the tyre size has no impact on the rim's maximum pressure rating, this is incorrect, the tyres size and volume is the biggest factor of all with regards to the pressure that a bicycle rim can handle, hence why you always work to the rim's maximum pressure and not the tyres.
Exponentially as the tyre size and most importantly the tyres volume increases, the pressure that the tyres bead will place on the rim increases significantly, this is why rim manufactures scale the maximum pressure ratings dependant on the tyre size being fitted.

As from the information listed on our site, the max pressure for the Hunt 30 Carbon Gravel Disc rim with a 38c tyre is 40 psi, when fitting the tyre you went to double (and potentially higher) than that of the rims max pressure rating, in addition you also went to 20 psi above the tyres max pressure rating of 60 psi. For future tyre fits on our and other manufactures wheelsets, please work to the max rim / tyre pressure and work to the lower of the two units when fitting your tubeless tyres.

As a company we will always do what we can to assist riders, in this instance we would offer the rider a crash replacement discounted rim to replace the damaged unit, however I can offer you a replacement rim as a 'free of charge - goodwill gesture' that you can get the wheel rebuilt with at your local bike store. At present we we will have replacement rims back into stock for December week 2.

Curious if the volume not psi argument is legit.
Thanks,
Kent