# How do you calculate bike geometry?

## How do you calculate bike geometry?

You can measure it by finding the height of the rear axle and the height of the bottom bracket, then subtracting one from the other. It’s another key measurement quoted by bike brands on their geo charts.

How do I determine my stack and reach?

Stack is the vertical distance from the centre of the bottom bracket to the mid point at the head tube. Reach is the horizontal distance from the centre of the bottom bracket to the middle of the head tube.

### Is bike geometry measured in mm?

Ranges could be anywhere from 15mm-35mm (or greater) depending on the type of bike and manufacturer. Little to do with geometry, the seat post diameter is also commonly measured and is typically comes in a 27.2mm and ‘oversized’ 30.9mm or 31.6mm.

How do you measure head tube angles?

Head tube angle – often shortened to ‘head angle’ – is measured from the horizontal to a line running down the centre of the fork steerer tube.

#### How do you measure front center?

What is Front-Center? The distance from the center of the bottom bracket to the center of the front wheel axle. This measurement is taken from the side view of the bike, ignoring the z-axis such that the width of the axle or bottom bracket does not come into play.

What is BB drop?

BB Drop is the vertical distance between the centre of the bottom bracket, and the axles of the front and rear wheels. This is a fixed, static measurement. Once a bike is built up and has no rider on it, this doesn’t change. BB Height is the vertical distance from the ground to the centre of the bottom bracket.

## How do you calculate top tube length?

What is Top Tube Length?

1. Actual (Center-Center): Measured along the length of the top tube from the center of the seat tube to the center of the head tube.
2. Effective (HT Top): The length of an “imaginary” level tube extending from the center of the seat tube axis to the top of the head tube.

What is BB drop on a bike?

Definition BB Drop is the vertical distance between the centre of the bottom bracket, and the axles of the front and rear wheels. This is a fixed, static measurement. Once a bike is built up and has no rider on it, this doesn’t change.

### How much should the bottom bracket drop on a cyclocross bike?

Contrast this with a typical drop of 55-65cm for popular production cross bikes. Cyclocross bikes earned a higher bottom bracket back in the days when racers competed with clips and toe straps.

How do I use the bike geometry calculator?

Use the bike geometry calculator to determine the impact of a number of geometry modifications including installation of anglesets, changing wheel sizes, fork travel or offset, and installing an extended crown race or lower headset cup.

#### What is BB drop and BB height?

BB Height is the vertical distance from the ground to the centre of the bottom bracket. This can vary on a bike for numerous reasons. Tyres and fork lengths are the biggest culprits for adjusting the BB Height of a bike. Other Factors to Consider… Typically, bigger wheels will have a bigger BB Drop.