I have had a series of conversations with a family member about getting a new bike. The points of this conversation included selling a bike already in the stable; selecting a new frame including material and style; wheelset type including rim brake or disk brake; handlebar style; and numerous other issues. This discussion includes whether an existing bike can be modified to fit the perceived needs of the new bike or whether the concept requires a new bike. If it is a new bike, is there a model on the market that meets the needs or can be easily modified to work or does it involve starting with a frame and building up everything component by component.
For most of this conversation, the underlying idea of my family member is that it is possible to put together one bike that will fill all of his needs. He calls the bike a "Monster Cross" bike, which is probably a mountain bike frame, but could be a steel cross frame, it will run on 29" mountain bike wheels that will fit a mountain bike style tire, but probably a slick tire, and probably have disc brake. It will also have drop bars. It will not have a suspension fork. This bike will then have the ability to cover any trail that a XC mountain bike could cover, but with the added advantage of more hand positions and less weight than a mountain bike with a suspension fork. This bike could also be used for any dirt road, dirt trail, paved trail or road use.
Part of this idea is correct. By building up a strong frame and wheels it can stand up to most anything except big "hucks" or "drops". By having slicks it will also roll reasonably well on any paved surface, but will excel on any dirt or gravel surface where a traditional road bike with narrow tires will dare not dwell.
I appreciate the one-item-fits-all-needs concept. I like the utility and sensibility of having one tool for all the purposes. That is why I drive a station wagon. I like the utility of the extra space, but without the size or hassle of a bigger SUV or 4-door truck. My station wagon doesn't do everything, but it does most things well. It doesn't, however, do any one thing "great". And ultimately, that is why I see bikes differently and therefore I have a hard time with the one-bike-works-everywhere idea.
Maybe that is because I go on lots of group rides. I know that I couldn't keep up with road guys on a bike with mountain bike tires. I know that I couldn't keep up with mountain bike guys (or even follow them over some of the baby-heads and technical stuff) on a narrow-tired, drop bar bike. And I certainly couldn't keep up on a race course with a significant disadvantage in the weight of my bike and rolling resistance (not to say that younger, stronger riders don't do exactly that, but I'm just sayin' . . . ). So, for me, it makes sense to have a bike for each of these things that I like to do.
I don't, by the way, have a bike for every type of riding; I don't have a "downhill" mountain bike because I don't like that style of riding; I don't have a track bike because we don't have a velodrome around here (although that is an excellent idea); I don't have a time trail bike because I can't justify the money for one (although maybe some day). I do, however, have a road bike that I can race; a 29" mountain bike that I can XC race/ride; an old, left-over mountain bike that I fitted with a rear rack and panniers that is great for family trail riding and picnics, not to mention commuting to work; and I have a bad-weather/rainy day/cross-capable/commuter-capable road bike made up from a cast-off frame and left-over parts. Sure, that is more than the average guy, but I don't want my surgeon using a Black-and-Decker for my operation or to use my ball-peen hammer when I need a sledge-hammer. The tool should fit the need. I like versatile tools and I eschew single use items if anything else will work (an aside - for instance, why does anyone buy a hot dog cooker when a pan will work?).
So, is a Monster Cross bike a good idea? Sure, if you have a need for one, but I think I'll keep my quiver full of options for now. Besides, I really like bikes.