Tyre Pressure and Rims

Not sure if it has already been covered by but a recent poster had a pretty scary photo of a basically exploded rim, sidewall just torn right off the body, looks like the tyre at first until you realise it’s the rim, crazy. Anyway, it made me wonder, what is the story with tyre pressure ratings for rims?

My understanding is rims have specific limitations on the pressure they can safely stand just as tyres do but rims never have this information on them (where as tyres pretty much always do) so I never really thought about it. Looking at manufacturers sites for some rims I own and while it’s fairly easy to find details for new rims it can be quite hard for anything older.

What’s the general feeling here, I guess if you are running below 110psi most decent rims are unlikely to be a problem, I am probably more concerned about the track when pushing the pressure higher (say around 140psi) and more exotic sizes, such as the 451 rims that came on my Mini-Velo which have max 65psi tyres but feel a bit splashy so I want to push them to 100psi if I can.

Based on the fact that you don’t really hear much about rims self-destructing I would guess that most reasonable track rims can take the pressure of the more more common tyres used on the track (I am talking about clinchers in all cases mentioned here rather than tubs I should say).

For my 451’s, I run 1 1/8" tyres, rims are H PLUS SON CR56 (zero information available on these and manufacturer hasn’t replied to me), so wondering if I am same to push to 100psi on those rims (I now have the tyres to do that).

Nothing like a picture of a mechanical failure to make you totally paranoid :slight_smile:

The rims will be fine above 100 psi until the minimum thickness of the rim gets below 0.9mm, measured below the hook. I start getting twitchy when it measures below 1.0mm, as there is no certainty that I am measuring the very thinnest point of the circumference.

Some rims have wear indicators.