Bought a second hand set and end cap plastic bolt is missing . I have fitted them making sure there is no play , but can I use them without that bolt ?

dont fancy wrecking the cranks .

thanks

its like a stem top cap, there to provide preload before you actually tighten up the pinch bolts (which actually do the securing). Shimano cranks have a “fail safe” plate that sits in the crank arm and engages with a hole in the spindle to stop it falling off.

So yes you can use them without the end cap.

thanks ,but I ll order one anyway .