I've been on quite the mud flap journey on my Y since I lowered it. I've tried all the molded plastic guards from Basenor and others. Last weekend, I finally switched to RallyArmor. The reason is that to my knowledge, they are the only flexible flaps. This completely solved my problem of scraping on speed bumps and breaking them off.
During installation, I noticed they give you specific measurements of where to place the clips. Me, being me said whatever, I'll just clip them where I like. What I noticed is that if you don't place them where they tell you, they will not slide all the way on because they will hit parts of the inner fender. This made me have to remove and try to re-adjust a few clips. To the original poster, could this have been the cause of yours coming off? After trying to remove a clip to reposition it, I feel like RA is being honest that there is really no way for them to fall off accidentally. They were VERY hard to remove. You can see the sharp triangles that dig into the rubber and behind the fender.
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