I thought of determining the tire width allowable as my first step. These days 25mm wide is considered skinny and it's common to see 32mm wide tires being run of purely road bikes. many of the road bikes of the 1890s to only a half dozen years ago were designed around 23mm wide tires. As such fitting a tire much wider than a 25 might be unwise due to the too tight clearances. Had this frame had the OEM calipers (designed around those 23 tires) fitting current rims (which are generally wider than those of yester year) might not work well WRT the brake adjustments. Wheels being so key a part of the riding experience makes me think about this aspect pretty quickly. It also was this "on the trails" comment from the OP and his likely running 35-40 wide tires on their hybrid that reinforced my concerns about this frame's practicality. Andy