**Contents**show

Take the length of spoke you just used and double it. Now add the bend-to-bend caliper measurement, and this will be the ERD of the rim. For the example rim in Figure 7, we used 260mm spokes. So 260mm + 260mm + 48.4mm = 568.4mm.

## What is ERD on a bike rim?

Effective Rim Diameter (ERD) is the diameter on which you want the ends of the spokes to lie. Most people prefer it near the end of the spoke nipple.

## How do you measure the size of a bicycle rim?

Using a tape measure, place the bottom of the tape at the lowest point of the tire (on the ground) and measure in a straight line to the centre of the bike wheel to find your wheel radius (as shown in the image above). Multiply your wheel’s radius by two to find the wheel’s diameter.

## What is the diameter of a 26 inch wheel?

The typical 26-inch rim has a diameter of 559 millimetres (22.0 in) and an outside tire diameter of about 26.2 inches (670 mm).

## How do I know what size spokes I need?

The measurements and information you need to determine spoke length are:

- The number of spoke holes in the hub and rim.
- The effective rim diameter, called the “ERD”
- Hub flange diameter at the spoke holes, also known as the Spoke Pitch Diameter.
- Left and right hub flange spacing relative to the hub center.

## How do you measure inner rim width?

Internal rim width (IW) is the distance on the inside of the rim between both walls. The external rim width (EW) is the distance from the outside of one wall to the outside of the other rim wall. Take the internal rim width and add the thickness of the rim walls, and voila — you get the external width.

## How do I measure my bike wheel size UK?

Measuring it…

The way to measure a bikes wheel using the ISO system is to measure from the centre of your hub to the outside of your rim.

## Where is ERD measured?

The ERD is that point in the rim where the end of the spoke sits (given that we have spokes of an ideal length). Think of two different rims intended to fit a 700C road tire.

## What is the diameter of 700C wheels?

The 700c (622 mm / 29 inches) is the most common wheel size for road racing. The 650b (584 mm / 27.5 inches) wheel size is used in specific areas. Each wheel size offers unique advantages for different kinds of riding.

## How do you measure bicycle tire size?

Check your tire’s sidewall—the numbers there indicate your tire size (roughly its outer diameter and its width, but not always in that order). Typical road bike tire: 700 x 32c indicates a tire that has an outer diameter of 700mm and a width of 32mm.

## What size is a 26 inch bike tire?

Most typical 26-inch tires have a width of about 1.75 inches up to 2.2 inches. There are some 26-inch tires available that have a smooth road tread and may be as narrow as 1 inch to 1.5 inches. For downhill mountain bikes, there are tires about 2.5 inches wide, and for snow bikes, even up to 4 inches wide!