1) Why is it that a normal passenger car 2.0 litre inline-4 engine has a redline at e.g. 7500 RPM, a GSX-R bike 1.0 litre inline-4 has a redline at 13 000 RPM, and a 3.5 ccm RC-car engine has a redline at 40 000 RPM? 2) Is it a rule of thumb that, the smaller the engine, the higher the redline of the engine will normally be? If so, why is it like that? Is it because a bigger engine has heavier moving parts and thus cannot be moved back and forth as quickly as lighter parts (too much mechanical stress/wear - they break? What happens?)? But bigger and heavier moving parts - doesn't bigger also make them stronger? Maybe not equally stronger to keep the redline at the same level as the weight goes up? 3) How does F1 engines go to 18 000 RPM (and race bike engines go to what? Over 20 000?)? I've heard before, "short stroke, light and good parts, only has to last one race". I think the first two are ok arguments, but the last one is a little strange, how can it work perfectly fine for the entire race, then break? How does it break? Does the connecting rod between the piston and crankshaft break or something?