Fooled by tire diameter
I had the bright idea of changing my worn 700c 25mm Conti Grand Prix 4000 tires to new 32mm Conti Grand Prix 5000 tires on my road bike. I checked width clearances at the chain stays and the fork, etc., and it looked like with a little adjustment of chain stay clearance, it would work.
But the idea failed because the new tires were significantly bigger in diameter, even though both were Conti and both were 700c tires. Big disappointment...not to mention surprise that diameters on 700c tires from same manufacturer were different. Oh well.