Understanding TM-B's Geometry

Every bike has a set of measurements called "geometry" that determine how it fits your body and how it feels to ride. This page breaks down what each measurement means, in plain language, so you can understand your bike's spec sheet without needing to be an engineer.

Frame Geometry 

New to bikes? Start with the 3 measurements below: they matter most for comfort and fit. 

1. Stack: how tall the front of the bike feels

Stack is the vertical height from the bottom bracket (where the pedals attach) up to the top of the head tube (where the handlebars sit). A higher stack means a more upright riding position - easier on your back and neck. A lower stack means you'll lean forward more, which is common on performance bikes.

2. Reach: how far you stretch to the handlebars

Reach is the horizontal distance from the bottom bracket to the top of the head tube. It tells you how far forward you'll need to stretch to hold the handlebars.

3. Standover height: will you comfortably clear the bike when stopped

This is the height of the top of the frame at its lowest point (where you'd straddle it with your feet flat on the ground). It's different from saddle height, this is about clearing the frame safely when you stop, not about pedaling comfort.

Pick the right Top Frame size

• Since the seat tube and frame are one swappable module, your first fit decision is choosing the right Top Frame size for your height.

Learn more about the different Top Frame options here.

Then, learn how to adjust the TM-B to fit your own unique frame.