Talk Morgan Forums Community For Sale & Wanted Looking For inner tubes for +4

Hi,
This is the first time on TALKMORGAN,
I am looking for inner tubes for my +4 1991 M16 2seater, which size do I need and where is the best to buy?
The tires are Dunlop racing 500.15
Does anybody know the torque for the wheelspinners?

Best regards,
Bart+4