I have been riding my road bike for about 10k km on those pedals (shimano ultegra spd-sl) and it just so happened that the left one is now worn much more than the right one (check out photos). You should look at the spring/cramp/lock (whatever the right word is:) ) part of the pedal, that black thing which doesn’t let the cleats pop out. Now my left pedal almost can’t hold the cleat in when pedaling , had to tighen it close to the max limit. It still holds but I don’t think it will last long. The right one, on the other hand, still does it perfectly and is almost not worn at all, after even that distance (there is no play/looseness, never tightened it yet).
Any advice would be nice! Such wear on the left pedal – did I gauged it right that the end is nigh for it? How much more can it last possibly? Is it real to by one separate pedal (not necessarily ultegra)? Thanks!