Green’s Dictionary of Slang

treadly n.

() .

1993

Aus. Word Map 🌐 treadly [...] ‘We also called a bike a treddly or deadly-treddly growing up in the '60s on the Mornington Peninsula Victoria’ [...] ‘I’m from S[outh] A[ustralia]. We spelt it "Treadly" not "Treddly" and a "Deadly treadly" was an old fixed wheel bike that had no handbrakes’.