I found this tip on another forum nearly 10 years ago, at £3, delivered, it remains amongst the best value purchases I ever made. A genuine ice hockey puck, used a thousand times as a jacking pad, between my trolley jack and all manner of chassis, engines, motorbikes etc. Virtually indestructible and won't mark your motor! https://www.amazon.co.uk/varies-Ice-Hockey-Puck/dp/B0073UQTMI