What Is My Wheel Size?

This is the most common question we get asked.

Firstly - don't worry too much about the wheel size before ordering. We offer the kit in ANY size for ANY type of bike, and we can help you check your wheel size after you order. Once your order is in our system we'll invite you to our order portal to confirm your specifications - such as wheel size.

Swytch wheel sizes correspond with the ETRTO (ISO) wheel size measurement standard.

Note: Most adult bicycles (except folding bikes) have a standard ETRTO 622 wheel (28"/29"/700C)
In the meantime, if you want to work out for yourself what your ETRTO wheel size is, here's how you can:

Option 1: Ask the bike seller

If bought online: Check the bike details on the retailer's website, there will be a "specifications" section which should list the specific ETRTO wheel size.

If bought in-store: The ETRTO wheel size is often in the specifications manual that came with the bike, otherwise, the seller can tell you.

Option 2: Check tyre markings

Most bikes have the ETRTO wheel size marked on the side of the tyre.

The images below summarise where to find the ETRTO, French version and English version tyre markings.  Swytch Wheel sizes match the last three digits of the ETRTO marking. Using the picture below, the ETRTO marking 47-622 means that the 622 Swytch Wheel would fit this tyre. ETRTO markings always take the form of ##-###.  Once you find the ETRTO marking, you can use the table below to match it to the Swytch Wheel size.My tyre only has English or French markings, what size wheel do I need?

If you can not find any markings on the side of your tyre, then the next option is to measure it yourself.

Option 3: Measure yourself

A final option is to measure the diameter of the rim in mm, which is the approximate equivalent of ETRTO:

1) Place the tape from the centre of the wheel to the tyre's inner edge where it meets with the rim. Take down this measurement in mm. This is the inner radius of the tyre (R). [E.g. 317mm]

2) Multiple R by 2. You now have the diameter of the rim. [E.g. 317*2 = 634mm]
3) Subtract 10mm from the diameter. [E.g. 634-10 = 624mm]
4) Match your measurement with the Swytch Wheel size table above, it should come within ±3mm [E.g. 624mm = 622 Swytch Wheel]
A marking on the side of the tyre is a more accurate and easier way of finding out your wheel size and should be used whenever possible.

Not Sure? Contact Us

If you are unsure you can open a support ticket here: https://swytchbike.zendesk.com/hc/en-gb/requests/new

Haven't Registered Yet?

If you are interested in placing a pre-order and aren't already on the waitlist, make sure to register to here: https://www.swytchbike.com/p/universal-ebike-conversion-kit/

Written by @lenny on July 19, 2019