I have a modified Topeak iglow which is designed for road bikes. I zip tied wide plastic panels to fit my 4" fatbike but you can get the idea if this angle works. The clamp is designed for smaller posts and I think it might be too narrow to block 1.9" heavy spray, but you could always add material like I did. Thin Kojaks probably wouldn't be a problem. This is as close as I could get it to the tire. Otherwise just buy an mtb fender and cut it to size. FYI, small tires won't reach an indoor trainer's roller; I was just using it to adjust my saddle.