Light action speedplay with Zero Cleats
 

It is time to replace my cleats. Is it OK/safe to do this?

Pretty sure they are not compatible

Why? The adjustable float feature will only work when paired with Zero pedals anyway.

Yes, they will work fine, comparing the cleats side by side, the shape is the exact same. I used zero cleats on light action pedals for lots of miles.

Pedal bodies are the same so it will work just fine. Take it from someone who has lots of miles mixing the two. They are a little different in how the pedal body attaches to the spindle, but that has zero (pardon the pun) effect on pedal/cleat compatibility.

Cool. Thanks for confirming it.

Actually, pedal bodies are not exactly the same. Look at the indents that are at the corners of the pedal.

The cleats are indeed interchangeable but I've noticed that clicking in isn't as smooth when you mix-n-match. Atleast that's what it has felt like to me.

FWIW, Speedplay say not to do this.

Of course they do. I've never seen a more litigious company in my life. I'm not a product engineer or anything, so try it at your own risk. However, I've been mixing the two for a couple years now for thousands of miles with no issues. I'm a bigger guy too at 6' 210 pounds. Just rode Zero cleats on Light Action pedals on my way home, including a 3/4 mile section of rough single track on my road bike. I'm going to keep mixing them, but you have to make that call yourself.

Like I said, FWIW.

Light Action and Zeros are not compatible, while the pedal body are the same the crescent spring and pedal indentation is different. You can make a Zero into a Light Action by changing a part on the pedal body but they should not be used concurrently, even if they will fit. Someone tried to get the bike warranted because they crashed using the two pedals, love the look he gave when we told them no.

I agree. You may do whatever you wish on your own bike, with your own pedals and to your own body. However, as a long time LBS sales associate, I will under no circumstances suggest that Zero and LA are exchangeable.