Hi Den,

>The bike is 6T Thunderbird. The book is the workshop Instruction Manual covering models from 1945 - 1955.

>The book says 18 and 19. I had been advise with modern rubber to increase by 2-3 pounds.

Way, wa-aa-ay too low - modern tyres might <u>look</u> (a bit?) like the ones Meriden fitted seventy-odd years ago but, like other things (e.g. oil), their design, materials and construction aren't anything like they were when your "book" was written - sidewalls are much more flexible for one thing, that requires higher pressures. Whether you fit Conti radials or new Dunlop K70/Avon SM, the tyre makers still advise 28/29 psi front, 32/33 psi rear on these old heaps (I know this because I've spoken to their techies).

Also, whoever "advise with modern rubber to increase by 2-3 pounds" was talking out of an orifice other than the one in the lower half of his face; even back in the early 1970's, Triumph, Dunlop and Avon advised higher pressures than those (then 24 psi front, 25 psi rear).

>>I had put 29 psi in the front tyre and 1 pound less in the rear.
>>No wonder it was like riding a brick.
>today’s ride was far better than Saturday’s.

As I say, 29 psi in the front tyre is about right, "1 pound less in the rear" never was/is.

"better" on 18 psi front, 19 rear, something else is wrong - suspension not working correctly? If yes, road shock absorption that should be done by the suspension is being done by the under-inflated tyres.

Risking stating the obvious, under-inflated tyres are a points- and fine-gathering offence. Maybe unlikely you'll be pulled for a "free MoT" but, involved in an accident, your insurer won't be sympathetic.

Hth.

Regards,