As an insulator by trade it sounds like you had what we call Armaflex on your roll bars. Goes by a bunch of different names now a days, K-flex, Armalock, Armacell, etc. Which is an easier more flexible padding/insulation for what your doing. The polyethylene type insulation, what you will find in home depot/Lowes, is a more rigid/less flexible insulation. plus the self seal or glue on the polyethylene doesn't work as well on bends. Either one you use they need to be coated with a UV coating, what we call Armaflex paint, for outside use. Easy to apply and looks good with two coats. Can also be tinted to whatever color you may want, comes in white and you would have to tint yourself. Your best bet is locating an insulation supplier near you, also any HVAC supplier will sell it also just a tad more expensive. If you use the Mcmaster-carr link, the first link is for the Armaflex type, the second polyethylene type, but the coating at the bottom is not the type coating you want. One thing to remember is Insulation is measured by OD of the pipe your installing it on. Example 2" copper is 2 1/8", 2" schedule 40 is 2 3/8", etc. So measure the OD of your pipe and if they don't have that actual size go the next size larger.. Use a really sharp knife to cut it!! When you have to go around a bend put your seam on the side of the bend not in the throat or on the back...