48 mph? Wow. Mine plods down the highway at 55mph and about 2700 RPM's. I can do 65 but it's over 3,000 RPM's then. I thought about changing the gears, but it is VERY expensive. More than I paid for my bus in fact. I'm going to do the conversion on mine and drive it like it is. If I just can't stand it anymore, I'll change to some better gearing. But my bus is already a dog with its current gearing. Not too much of a problem in Oklahoma though. When I looked into new rear end gears for my bus, it was about $1,500 just for the parts. Geez. And I'm a pretty savvy mechanic and it's not a job I would want to do on my own. I plan to convert this bus and maybe in about 5 years, buying a bigger, newer skoolie to convert. One of the flat front transit skoolie's!