# How are rear bike hubs measured?

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Axle size (rear): Rear hubs are sized according to the diameter and length of the rear axle (measured in millimetres).

## How do I know what size my bike hub is?

Measure the rim width (W) and divide by two. This is the rim half-width. Measure the distance from the near sidewall to the center of the average spoke hole (L). Subtract this number from the rim half-width.

## How are Hub sizes measured?

The hub length is the measurement through the middle of the wheel (or hub) measuring from end point to end point (or bearing to bearing). You’ll want to make sure to measure through the center of the wheel and not just the outside as there will be space in your rim that will go unaccounted for.

## Are all bike hubs the same size?

Typically speaking, modern mountain bike rear hubs will feature a width of either 135mm, 142mm or 148mm. 142mm is the standard on many mountain bikes across a range of riding disciplines, however, 148mm (aka Boost spacing) is increasing in popularity.

## What are the different types of bike hubs?

There are four types of hubs available: the track hub, the flip flop hub, the freewheel hub or the cassette hub. The recommended way to go for a fixed gear setup is to construct a new rear wheel. You can use a track hub in such an activity. The distinct feature of any track hub is their stepped threads.

## What is wheel hub size?

The outer diameter is the hub bore of the wheel and the inner diameter is the diameter of the vehicle hub. For example, a hub-centric ring size of 73-67.1 would mean that the wheel center bore is 73 mm wide and the vehicle hub is 67.1 mm wide.

## How is ERD calculated?

Measure the length of a nipple (dimension B in the figure) and add it twice (once for each nipple). The result is Effective Rim Diameter (ERD). Thus, ERD = A + 2B.

## How do you measure a Wheelbuilding hub?

Start by measuring the width (W) of the rim with a gauge caliper and divide it by two. This is your rim’s half-width. Measure the distance from the near sidewall to the center of the spoke hole (U). Now, subtract this number from the rim half-width.

## Are 27.5 Wheels stronger than 29?

27.5 in. wheels have faster acceleration while 29ers are more efficient on longer rides. Smaller wheels accelerate faster than larger wheels. … Larger wheels place the weight of the spokes, rims, tubes and tires farther from the center of the wheel, resulting in higher rotational mass and slower acceleration.

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## How do I know if my bike wheels are compatible?

Look at the sidewall of your tire to find the tire size that will correspond with your new wheel size. On road bike tires, you’ll see a number pairing such as 700×23. The first number (700) is a size which roughly corresponds to the outer diameter of the tire in millimeters.

## What does a hub do on a bike?

The hub is the central part of your bike’s wheels (front and rear), which connects to the wheel’s rim via the spokes and through which the axle is fitted, enabling the wheel to freely spin on two sets of bearings.

## What does ISO hub mean?

Centerlock is a proprietary standard designed by Shimano that uses a splined interface and a lockring. ISO is an open standard that uses six bolts to attach the rotor to the hub. There are Centerlock and ISO rotor options for almost every brake currently available.

## What is the difference between freewheel and freehub?

Both wheels have hubs, but only the rear wheel has a freewheel. On most modern bikes with multiple gears, the freewheel is built into the rear hub and the whole assembly is called a freehub. … The freewheel was built into the rear gear cluster and that whole assembly screwed onto the hub.

## What does freewheel mean on a bike?

(Entry 1 of 2) : a clutch fitted in the rear hub of a bicycle that permits the rear wheel to run on free from the rear sprocket when the pedals are stopped.