First off. Don't be tempted to cover over the old pad. Any imperfections will show. Always work with the seat pan facing up. Start with firmly molding your material on the top, pushing straight down to the side, not pulling off to an angle. Starting out by pulling your material to an angle causes wrinkles that will be impossible to get out later. Once you have the top started off correctly, trim to size and make slits about every inch or so. Leave ample material, so you don't come up short, but only enough to lap about an inch over the bottom of the pan. You can't pull it tight if you leave too much material. When pulling your tabs, do it with the seat pan facing up, don't turn it upside down to do it. That way you can see what is happening on the top of your saddle. No one cares what the bottom looks like. Always firmly pull your tabs straight down. Go off to one side or the other, even slightly, and it will cause a wrinkle. Make sure it's perfect before you fold under. The tabs have to be pulled
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really tight. From start to finish will take less than a half hour. That includes putting the padding on.
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The black seats are from an old worn out leather couch. The white one is new material.