Okay so i have been building up a single speed mtb over the last year. Its a old bike new components 26 inch tires. I'm running 2.2 graffiti UK's. I'm planning on running a sinz 175mm crank. This bike is supposed to be my city bike not to much incline but i need to be able to get up to a decent speed quickly. Any recommendations id appreciate it. The front chain-rings gotta be between 34 40.