Folding Bikes - over-inflated tyre

Bit of a silly exercise, really, but......
Here in Oz the summer temps get over 40 deg C and being bored one day, we decided to see if the old 70's 24" tube in the old 70's 24" tyre from my old 70's 24" bike would explode if we inflated it way beyond the max 50 psi and then leaving it in the blazing sun against a hot tin shed. Well, it was rock hard and very hot, but.......nothing happened!!
Makes me wonder about the quality of modern 700c racing tyres that I've heard explode in the car park at race meets on hot days.

General rule of thumb is 1 psi change for every 10-deg F temp change, so even a 20-degree rise in the sun isn't going to make a whole lot of difference. I've heard that bicycles tires have very generous over-pressure margins (e.g., a 75-psi max tire won't blow until 125 psi or so), but don't have any hard data.

- Mark

The standard for Japanese tyres was labeling at half the blowoff pressure (on a nominal rim). Rims and tyres have a manufacturing tolerance, so YMMV.