The Westlander and Scotsman Locomotive project (in Capricorn code) had three important guidelines right from the start: Reliability, Comfort and Versatility. The two pillars on which the concept of Versatility was developed were:
1 - Possibility to mount any size of rubber available for off-roadada
2 - Geometry adaptable to different assets and physical characteristics.
So let's examine the types of wheels and covers that can be used on a Locomotive, starting from the narrowest and most sliding and moving on to the most generous and with more traction.
700 x 32, slick or speckled tread, indicative pressure 60/90 psi (check the pressure indicated on the side by the manufacturer), road use. The fastest solution, with good absorption of irregularities on asphalted surfaces, also allows you to tackle well-maintained and regular dirt roads such as the Tuscan White Roads. They leave a lot of free wheel passage and are the lightest and certainly the fastest solution. Example: Pirelli Cinturato tubeless.
700 x 33/35/38, the formats derived from cyclocross tires, can have more or less smooth treads, from slick to knobby even mud, pressure 40/70 psi indicative (check the pressure indicated on the side by the manufacturer) light or winter gravel use to avoid mud accumulation. Multi-purpose tires, for travel or light off-road routes, remain decidedly smooth, on asphalt they absorb irregularities better than 700 x 32, off-road have a good ratio between high smoothness and traction depending on the type of tread. Excellent for city commuting, even in winter, and for fast Gravel. Example: Ritchey JB Alpine 35, Speedmax 38.
700 x 40/45/50, the Gravel tires par excellence, more or less pushed treads for greater traction and absorption,
pressure 30/50 psi indicative (check the pressure indicated on the side by the manufacturer), for Gravel use. With these tires you can tackle more ruined terrains, from scree to country lanes to military mountain roads and some easy paths. Example: Maxxis Rambler.
650b x 2.8/3.0 o 27,5 x 2.8/3.0 Plus mtb tires, more or less aggressive knobs, excellent absorption of roughness on very bumpy roads, pressure 15/30 psi (check the pressure indicated on the side by the manufacturer). These tires are preferred for very technical routes and to maintain a compact set-up and high stability even with heavy loads. Another advantage is the manageability compared to larger diameters. Example: Maxxis Icon.
29 x 2.0/2.4 the classic mtb tires, the most versatile, available in every nuance of tessellation from semi-slick to Enduro knobby, pressure 20/40 psi (check the pressure indicated on the side by the manufacturer). The tires to tackle all routes, excellent rolling and smoothness, but also great grip and driveability, choosing the type of tread that best suits the terrain to be tackled. Example: Schwalbe Nobbi Nic, Racing Ralph.
29 x 2.6/2.8/3.0 29 Plus, our favorite format, which amplifies the characteristics of the 29, pressure 12/30 psi (check the pressure indicated on the side by the manufacturer). If you want to tackle the more technical routes, passing easily over all obstacles, even using a rigid fork, it will surprise you to see what you can do with this type of wheels. They are wheels that maintain speed well and we consider them the definitive set-up for Bikepacking on very technical and difficult terrain. Example: Surly Knard.