Tumbler is a light orange, green-striped concrete mixing transport truck. He is the loudest machine on Bob's team.
Tumbler is very noisy, and due to his large size he thinks he is strong, brave, and tough. He's prideful and tends to brag about his size. But all and all he's got a gentle side he shows to his friends, particularly Dizzy.
- Season 15 - Tumbler and the Skate Park and Tumbler's Perfect Promenade
- Season 16 - Tumbler and the Ice Rink, Lofty's Banana Tree and Breezy Bristle
- Tumbler is one of the machines who hadn't been seen using a Talkie-Talkie.
- In the UK dub, Tumbler speaks in a heavy Cockney accent. But in the US dub, he speaks in an eastern Bronx accent.
- Tumbler was the largest machine before his size was beaten by Rubble.