See the link under the Links & More Info tab to purchase these (the small silver parts) if you don't already have them

Size ETRTO Weight 27

Make adjustments and repairs with the speed of a Formula 1 pit crew

bigger isn't always better

Chainring sizes- 32-36T

Pirelli SporTUBE - 48mm - 29 Inch - Presta - 2.1-2.3 Inch PDP|PLP|Brake Rotor Type See the link under theThe SporTUBE is the most classic cycling inner butyl tube range, the standard interpretation of the most used air retention system in the worldA complete range with the size and specification for every kind of cyclist and discipline, from road cycling to urban commuting. MODEL SIZE WEIGHT VALVE TYPE VALVE COLOUR MATERIAL COMPATIBILITY SporTUBE 27. 5" x 2. 1 2. 4 200g Presta, 48mm Silver Buty1 Disc and rim brakes