I just installed new Shimano SPD-SL pedals (R540) w/ floating cleats and my left side is much tighter than the right side even with the tension all the way out. The weird thing is, I am left foot dominate and mostly dismount left side so you would think I'd be able to muscle out of a cleat easier on dominate side...NOT. I'm about to swap the left and right side cleats, but I was wondering if that doesnt work is this something that will even out after a couple hundred clip ins and outs? Should I modify the tight cleat a little?
the lion from within must guard his palace, because everybody's going to try to take a sip from his chalice
KrautFed, I've had interferance with MTB shoes' tread around the cleat and the pedal which required some tread trimming, on another pair shimmed the cleat to get it to a working height and another time a set of new cleats that wouldn't work with the pedals it was boxed with tho' everything was fine with the old cleats reinstalled (new cleats were a tad too thick). On the other hand I do have one pair of pedals that only work with one pair of shoes that I never figured out, your worse case scenario.
On the R540 and road shoes, you shouldn't have any interference as mentioned by bradtx above. I also have those pedals and am right foot dominant, but I find it a lot easier to unclip with my left foot than right, but mostly because I've always done the left first and often leave the right clipped in at stops.
You may want to check to see if your cleats are angled about the same on both shoes and whether or not one foot points inwards or outwards more than the other. Other than that, it may just be a matter of practice. On one side you may be pulling more up or down instead of directly sideways to release. The mechanism releases with sideways motion, so if you're pulling a little more upwards or downwards as well, you are losing some of the sideways force that is needed to unclip.