OK, I want to order some 4x4s tonight, but I dont know what size to get. My leg is 9 inches at the bottom and about 13/14 inches at the top. I’m 6’ 3" so they need to be long. A 4 inch difference at the top between the large and the small is a HUGE difference. will this matter?
You’re tall enough to need the large size…get that.
The important measurement is “E” in that table. You want the longest pads you can get that will fit between the middle of your kneecap and just above the top of your shoe. The other measurements are pretty much a universal fit for most people.
You want “E” to be as long as possible to keep the armour from sliding down your leg during a crash. If the armour can slide down too far it will expose your knee as you slide on the ground. If it’s long enough to extend down to just above your shoe your shoe will stop it from sliding down.