Maxxis Rambler 27.5 x 1.50 Gravel Tyre - SilkShield - TR - Folding Bead - 40-584Maxxis Rambler 27. 5 x 1. 50 Gravel Tyre SilkShield TR Maxxis first real Gravel Bike tire. The Rambler has the volume you need for good comfort and the tread pattern you need for speed and control. The narrow centre studs are beveled and therefore roll very well on hard surfaces, open side studs provide predictable cornering on different types of ground. SilkShield: SilkShield offers protection from bead to bead whereas Silkworm is found under the