This means I know which stem to bring with me, depending on how close the new bike numbers are to my known stack and reach. When I attend a new bike launch event I look for 580/385 (for road), or the closest thing to it. I have two beefs with T-shirt-style sizing: has any company that uses T-shirt sizing ever had to sell a bike face-to-face? Being told you’re extra small or small, or any size for that matter, is a bit of a sensitive topic for a lot of people.Īlso, what does your small have to do with another brand’s small? This is even more meaningless, confusing and arbitrary than top tube length.įind the vertical measurement from floor to whatever (cockpit or frame) location you want to quantify Thomas McDaniel / Immediate Media Getting used to new numbers Stack and reach also gets rid of the struggle between centimeter and T-shirt-style frame sizing, which by the way is ridiculous. The legendary top tube can do no such thing. It can even give a good idea of how many spacers are needed and a solid guesstimate for stem length if known stack and reach values are accessible (and they always are, if you have a tape measure and a wall). The most relevant application is to give shop staff, bike fit folks, or riders the ability to compare two totally different bikes’ sizing parameters, with no flawed perspective resulting from tube shapes. The difference between the first and second measurements in their respective ‘X and Y’ coordinates is your stack and reach. Two measurements.įrame stack and reach, handlebar stack and reach, or even elbow pad stack and reach come from two additional measurements. The first step is to determine your bottom bracket location in the vertical and horizontal. But is it really complicated? I’d argue that it’s no less confusing than T-shirt sizing for a bike, but more on that shortly.ĭo you really need special tools for determining stack and reach? No, you need a tape measure and a wall (preferably a square wall). It is true, stack and reach forces an entirely new batch of numbers on us. Technically, you can measure to any feature, but for the sake of being relevant, those three are by far the most common locations. These values can be calculated to the center-top of the steerer tube, the center of a handlebar, or the rear edge of an elbow pad. Stack and reach is essentially any point on the bike, relative to the bottom bracket, measured against true horizontal (x) and vertical (y). The measurements are relevant to the horizontal and the vertical, neither of which are typically present in bike design. It is, for all intents and purposes, ‘outside’ the system. Stack and reach is a system of absolute measurement. This schematic makes the process pretty straightforward - four measurements can give you frame, handelbar or elbow pad stack and reach numbers Thomas McDaniel / Immediate Media Furthermore, it’s unaffected by anything an industrial designer can influence. There is nothing proprietary about frame stack and reach, except the actual measurement, of course. Not to mention the variation of measuring that theoretical top tube.ĭon’t believe me? Pick five random brands and look at their geo drawings and it quickly becomes apparent how ‘proprietary’ measurements have become. What about offset seat tubes? How does a ‘corrected’ top tube measurement take that in to account? Simple, it doesn’t. “Fake news - there’s ‘horizontal’ top tube,” the crowd retorts. Ironically, if you asked a modern frame builder to create a new bike for you, they’d likely first ask for your stack and reach. The reality is this: with modern carbon designs, the top tube has been a misleading measurement since the first signs of sloping tubes.
#MOUNTAIN BIKE GEOMETRY CALCULATOR PROFESSIONAL#
database of bike measurements that may or may not have fit professional riders (and thus was only applicable to professional cyclists). It quickly becomes apparent how ‘proprietary’ measurements have becomeĪll this was largely an artifact of Italian designs and several archaic seat height methodologies, some based on the C.O.N.I.