I am using 90mm flywheels, but I’m not sure what size pulley to get. Any recommendations? It’s a 5HTD.
Not enough info to give a recommendation in general 16T on the motor pulley to 36T on the wheel is fairly common but depends on kv voltage max speed desired max hill climbing etc. All trade offs
not talking about teeth but length of the pulley
Length of the belt depends on the size of the pulleys you pick to some degree and mount your using. If the belt is too short given large wheels the wheel can run into the pulley. Still need more details than you have 90mm wheels
length is not a measurement used for pulleys. diameter, tooth count, pitch and width
go with 15mm width.