I took my schwinn typhoon single speed into the bike shop to have the rear wheel fixed. The bike was super sluggish due to the original s7 single speed wheel (and likely all 280 lbs of me)so they were going to add a larger cog to it. Upon arriving to pick it up they told me they were unable to fix it because the replacement cog wouldn't line up or fit with the rest of the hub. I'm now wondering if there is any other cog that would fit it and bigger than the og one That it has now which I believe is an 18 tooth. Anyone?