I did a search for Tire Pressure and can't believe that I got Zero hits.... So I just got a new set of Bridgestone Battle AX BT45F for my 77 R100RS. I've read anywhere from 32 to 43 (manufacturers stamp) .

Steve -
The 43, if it's stamped on the tire, is probably a maximum pressure the tire can withstand and NOT a recommended running pressure.

My experience is limited, but I know the present-day pressures tend to be generally 2-4psi higher than originally suggested in your owners manual. Try pressures in those ranges (cold) and see which you like. Pressures will affect the harshness of the ride and the cross-section radius. So it's going to be a personal choice between comfort and responsiveness.

You'll find it.

Hey Wobbly ( great handle)

So I did the 10% test. Pumped the front to 35lb, rear to 38 cold.

Took her out for a hot lap,finishing off on a 20mile 60mph+ run on the slab and then back home.

Re-check the hot tire air pressure, Front- 38, rear 41. Not not quite the 10% , but it was not a "hot" day out, so I'm feeling close. I'll ride it like this for a bit, if I'm going 2 up add a lb or 2 if I'm running heavy and check it again.

Thanks for stopping by
Steve 😉

ps... anyone know how to change my status.... it says new member by I just let my membership lapse & came back in. No big, but just so people know

That makes me curious...
I thought the 77's had bias ply tube tires.
I believe the battle axes are radial tubeless. (So I would assume you used tubes.)
Is that generally an acceptable option ?
What years did the tubeless rims appear ?