Specifications include, but are not limited to: Chassis: School buses shall utilize diesel fuel unless otherwise noted. School buses with less than 36 passenger capacity, the minimum power plant shall be 160 hp engine or equal. School buses with capacity of 36 passenger or greater, the engine will produce at least 190 hp measured at an RPM not to exceed 2,600 and generate at least 420 foot pounds of torque. Unit 1, 43,44,45,46,47,48,49,50,51,52,54, and 58. (Propane) shall have tanks with a minimum usable capacity of 67 gallons. Units with Option F will have a minimum of 90 gallons useable propane. One spare rim shall be provided. Tires – 11R22.5 on 36-72 passenger (not on flat floor buses), 245x70R225 or 255x70R225 on flat floor buses and 11R22.5 (load range H) on 84 passenger buses. Tire Treads – Steering tread on front tires and mud and snow tread on rear tires. Wheels shall be balanced. All buses shall have front-end alignments.