Originally Posted by
AlanK
I know this thread has been dormant for awhile, but I've read through it and find it interesting. I won't pretend to understand all the physics and engineering complexities, but to me there seems to be a simple reason why 700c wheels would be faster than 26" wheels which doesn't seem to have been mentioned (or maybe it has and I just didn't understand):
All other things being equal (which I know is almost never the case, but for argument sake) the larger the diameter of a wheel the farther it will roll per revolution. Since 700c wheels have a greater diameter a bike with 700c wheels would go a little faster (again, all other factors assumed to be equal) than 26" wheels. Does this make sense at all, or am I completely off base?
The key point is all other things being equal. If you want the same speed with a 26" wheel and a 700C wheel, you gear then 26" wheel slightly taller, so that the gear inches is the same, and wheel size stops being a concern. Having said that, 26" has some advantages, the slightly smaller wheel makes for a slightly stronger wheel under load. Wider rims and tires are easily obtained, the most common width for a 700C wheel is 25mm, the most common 26" wheel tire is 44mm (1.75"), given the same load that means not needing as high a tire pressure, and that means a more comfortable ride, without losing out on rolling resistance.