This saw plate bending is not an obvious phenomenon.
Andrew Barss is correct in identifying the most important pressures on the saw blade. However, as those forces are equalized, and the blade gets thinner and is run faster and fed faster other, more minor pressures, start to become more important.
Sawyers have been seeing plate bend for years due to cutting pressures. "Self Bending" plate came as a surprise as saw blades got much thinner. The forces on each side are roughly equal but the plate wants to cup due to forces from the outside in. You are correct that it could bend either way.
Think about a 30" mill saw that is 0.070" thick. What they do on these blades is to use pressure rollers to roll compressed bands on one side of the saw blade to prevent cupping. This is called tensioning and compensates for the tension created during running. (Freeborn covers this briefly on p. 25. If you don't have his book I can email a copy free.)
This issue is not fully understood. It is an important part of the Wood Machining Institute Seminars annually. In addition Forintek (Canadian Forest Industries Technology) continues to do work on the matter.
Anyway, the point is that thin kerf saw plate bends more easily due to outside forces but also wants to bend on its own.
1" bore
12" diameter C = pi x diameter Bore has about a 3 inch diameter Rim has about a 36" diameter At 10,000 rpm the bore edge is moving app. 6 mph The cutting edge is moving 70 mph
Tom.
P.s. The Freeborn Carbide Saw manual is free. Lowell wrote it and let me put it on the web. there is no fee and you aren't on any mailing list. Just email for a copy.