Bike Wheel Size How To Measure

Now you can take your calculator and calculate the right size.

Bike wheel size how to measure. Measurements like 26 1 which is the 27 5 size and 28x two fractions which is the 29 size are fractional inch markings. Forks will usually be 9mm quick release qr 15mm or 20mm bolt through. The actual iso diameter of a traditional 26 wheel is 559 millimeters. Rear wheels generally need either standard 135mm spacing and qr axles or 142x12 bolt through.

If you find the tire size the first dimension is the tire diameter the second dimension is the tire thickness. Your wheel axle height sets your bottom bracket height. 27 5 650b wheels iso 584 mm. If you are doing it alone we recommend that you use a retractable metal tape as opposed to a plastic tap as it s sturdier and will leave you with a free hand.

Read the second number which will be the wheel rim width. Stand your bike in an upright position or lean it on a wall. Bike frames are measured from the middle of their bottom bracket to the end of their seat tube. If we take the 26 wheel as the base height the axle height for a 27 5 wheel will be 0 75 higher.

Some downhill frames may have 150mm rear spacing. If we then look at the 29 wheel its axle will be 1 5 higher. Fortunately most wheels can accommodate a range of axle standards. Measure the diameter of the entire wheel including rim and inflated tire.

This therefore means measuring the height of the child and matching it to the correct wheel diameter to ensure a perfect and safe fit allowing you to rest easy. When your bike is in an upright position you ll easily measure the size of the bike without the bike tipping onto you. Then use a tape measure to measure the distance from the ground underneath the tire to the center of the wheel to get the radius. Unlike adult bike sizing done by frame children s bike size is done based on wheel diameter.

It s important to note that you cannot mix fractional markings with decimals. Measure the diameter of the existing tire as illustrated above d or look on the tire for the size it looks like this. This measurement used only if the size printed on the tire is no longer legible can be used to determine wheel size. Finally measure the flat part of the tire across the treads to find the width measurement.

Record the tire diameter as this also represents the bike frame size. To measure a bicycle wheel start by standing the bike upright by leaning it against a wall or using the kickstand. Next multiple the radius by 2 to get the diameter. City bike leg inseam cm x 0 685 your frame size mountain bike leg inseam cm x 0 66 your frame size road bike leg inseam cm x 0 70 your frame size.

For example if you measure 14 inches from the ground to the center the diameter is 28 inches.