Warning: Stop using WD-40 as a chain lube, I learned the hard way on a customer's bike
I used to spray WD-40 on every chain that came through my stand in Denver because it was fast and cheap. After 3 chains snapped on test rides in 2023, I switched to a proper dry lube like Finish Line and started measuring stretch with a Park Tool CC-3.2 every 500 miles. Now I get 3 times the chain life and no more comebacks. Anyone else got a cheap shortcut that turned out to cost way more in the long run?
Did you ever check if the WD-40 was actually getting into the pins or just sitting on the plates? That stuff is mostly solvent, so it strips whatever lube was left and then flashes off, leaving the chain dry as a bone inside where it matters. A $10 bottle of dry lube and a $15 chain checker will save you way more than three snapped chains and angry customers.