SIZE DOES MATTER
Mountain bikes have changed a lot in the last decade or two; suspension technology has improved to the point where it really is hard to buy a poor performing dually, composite construction has advanced massively and become far more attainable, big fat tyres and wide rims now combine to provide massive traction, modern 1x drivetrains keep things simple and quiet while providing plenty of gear range, dropper posts allow you to corner and descend with conviction at the press of a button … and the list goes on.
But of all the advances we’ve seen, it’s the changes in frame geometry that have had the biggest impact on how a modern MTB rides. You’ve probably heard the ‘longer, lower, slacker’ catchphrase used ad-nauseam… but there really is something to it. Wheelbases have become substantially longer, bottom brackets lower and head tubes have become a lot slacker.
One key feature that you’ll encounter on modern bikes is a shorter seat tube relative to the intended rider height. Skip back a few decades, and MTB seat tubes stood as tall as their road-going cousins. Over time the desire to improve the standover clearance led to lower-slung frames with longer seatposts, and more recently dropper posts have further driven the cause. Long travel dropper posts take up quite a bit of space, so seat tubes need to be lower to make space.
"Geometry has made a bigger difference than all the other advances grouped together."
The often unheralded spin-off from this evolution is greater flexibility in bike sizing. Having a compact seat tube means a shorter rider can opt for a bigger frame to obtain a longer reach and wheelbase. Conversely, a
