You know the score, the idler pulley rubbers on the GTE disappeared long ago, and the chain clatters against the plastic pulley. slowly digging into it and trying to make teeth out of it. Yes you can get a special toothed idler pulley from T cycle, but actually getting one without having to cut off a limb, is difficult. DADAH!! a solution.
We had someone stay a while back, who sold and repaired Kirby vacuums, thos 50's style ones from over the pond, and he left behind some spares. Amongst them was some drive belts........
, ah, so I cuts one in half, width wise, I does, with a sharp blade, so I now have two thinner ones. I then takes off thee pulley, cleans it, turns the thin belt inside out so the knurled bit is outermost, and stretches it over the pulley, Well it fits good and tight, and is very thick rubber. The difference is amazing. Just googled, and they are about £7 for 3, (that's 6 when sliced in half) , and I's well chuffed , I is.