On 11/11/2018 6:03 PM, John B. slocomb wrote:
On Sun, 11 Nov 2018 10:29:03 -0800 (PST), Andrew Chaplin
wrote:

Has anyone a pointer to a table of pressures for such a tire? Barring that,
a formula for their calculation. The tires have to carry a load of
about 100 Kg.

I've got a smartphone app from Berto Tire (downloaded from Android
Play Store) that says for a normal road bike with 650B x 47 tires, 22
lb bike weight and 220 lbs rider, the tire pressure should be 45
psi(rear) and 32 psi (front).

The typical rule of thumb is to shoot for the tire to sag 15% of its
diameter when loaded. According to that, you'd want your rim to get 7mm
closer to the ground when you load up the bike. I'd just do some trial
and error with the pressures until I got that result. And I'd keep in
mind tire pressure really doesn't have to be extremely precise.


--
- Frank Krygowski