These SKS fenders work well on the 20-inch (406) wheels. They fit tires up to 1.75 inches wide. + + NOTE: These are unmoddifed and will require the bending and cutting of the stays to fit with your particular Bike Friday. If you would prefer a simpler solution that doesn't require mofication check out the SKS Velo 55 fender set also on our webstore. + + If you would like them pre-modifed, let us know in the order notes and we can do so for an additional charge. Please indicate what model Bike Friday you have and wether you have disc brakes or not. Thanks.