Tire sizes look like a code because they are one. Read three numbers correctly and ordering a tire or a tube stops being a guess.
Reading a metric size like 70/100-19
Many electric motorcycle tires, including the ones sold for Surron and Talaria class bikes, use a metric style size such as 70/100-19.
- 70 is the section width in millimeters, measured across the tire.
- 100 is the aspect ratio. The sidewall height is 100 percent of the width, so about 70 mm in this case.
- 19 is the rim diameter in inches. This is the number that has to match your wheel.
Rim diameter is not negotiable. A 19 inch tire only mounts on a 19 inch rim. Width and aspect ratio can vary within what the rim allows, but check rim width and your fork and swingarm clearance before you go wider than stock.
Matching the inner tube
A tube is sized by the rim diameter and a range of tire widths. A 70/100-19 tube is a 19 inch tube, and it needs a 19 inch rim. If the tire and the tube disagree on rim diameter, the tube will not seat. Our Pivotrax 70/100-19 inner tube is listed for stock 19 inch rims.
Reading fat tire sizes like 20x4.25
Fat tire e-bike tires use inch sizes. 20x4.25 is a 20 inch diameter tire with a 4.25 inch section width. The first number is the wheel size it fits and the second is how wide the tire is. Fat bike rims accept a range of widths, so check your rim and frame clearance before changing width. The listing for the Kenda Kraze 20x4.25 states it fits bikes that come with 20x4 to 20x5 tires as stock. It is sold as a single tire, so add two to your cart if you are doing front and back.
Check these five things before you order
- Read the size printed on the sidewall of the tire you have now.
- Confirm the rim diameter in inches matches the new tire.
- If you are changing width, check fork, swingarm and fender clearance.
- Order the matching tube size.
- Not sure? Send us the sidewall text and your bike make and model before you order.
Tires and tubes we carry
- Pivotrax Cyber street tire, five sizes from 12 to 19 inch
- Pivotrax 70/100-19 inner tube
- Kenda Kraze 20x4.25 fat tire
Browse everything in Tires & Tubes or the wider E-Bike & E-Moto Parts collection.
Barely Normal is an independent retailer and is not affiliated with Sur-Ron, Talaria or any other brand named here. Brand and model names are used only to describe compatibility.