Learn why the ETRTO standard is the only way to ensure a perfect fit and why bike and wheelchair tyres are different.
Bike Sizing VS. Wheelchair Sizing
If you were to go into a conventional bike shop and ask for a 24″ tyre you would likely wonder why it doesn’t fit and is much smaller than your 24″ wheelchair tyre.
Because a 24″ wheelchair tyre is 540mm in diameter whereas a bike’s 24″ tyre is 507mm!
To keep things simple, the bike world typically uses inches as an easier measurement. Its easy to remember your wheel size in inches but also easy to miss the finer fitment details when trying to get tyres to fit wheelchair rims.
The ETRTO size designation indicates the width and the inner diameter of the tyre, a much better system to get an accurate measurement that guarantees perfect fitment.
ETRTO
ETRTO – (European Tire and Rim Technical Organization) is the most accurate tyre sizing standard.
Shown as Width-Diameter (e.g. 25-622) where the first number is the tyre’s width in millimetres and the second is the rim’s inner diameter in millimetres, it ensures perfect tyre-rim fitment for compatibility across different wheel types.
Why ETRTO Matters
It replaces less precise systems (like inches or French sizes) to standardise manufacturing and choices, making it crucial for correct tyre selection be it for an adaptive bike or wheelchair.
Compatibility: Guarantees the tyre fits the rim correctly.
Clarity: Eliminates confusion where diameters like “26-inch” could refer to different actual sizes (559mm, 571mm, 590mm).
Precision: Provides exact measurements for width and diameter.
Inches to ETRTO
A Simplified Breakdown
24″ Wheelchair wheel = 540mm Tyre
25″ Wheelchair wheel (26″ in the cycling world) = 559mm Tyre
26″ Wheelchair wheel = 590mm Tyre
If your unsure what size you have or need – get in contact and we’ll happy talk through how to measure up both your wheelchair and adaptive bike tyres!
Our most popular wheelchair and bike tyres
Schwalbe Marathon Plus Wheelchair Tyre
Schwalbe Marathon Plus Tires are the best option for wheelchair users who want pneumatic tires that resist punctures.
Omobic Trailblazer Wheelchair Tyre
A robust, everyday wheelchair tyre engineered for active users who want dependable performance and reduced risk of punctures. Built with a puncture protection layer beneath the tread that helps resist flats and extend tyre life.
Tannus Airless Wheelchair Tyre
Never let a puncture stop you again with Tannus Airless Tyres.
Maxxis Minion DHR II (27.5x2.4")
The trail version of the Maxxis Minion DHR II features the same tread pattern as its downhill counterpart, but utilises lighter weight casings. With side knobs borrowed from the legendary Minion DHF, but widened to provide more support. Redesigned, wider shoulder knobs for better cornering, Paddle-like centre knobs for improved braking, ramped and siped tread to roll fast and track straight under braking.
Tyres
Exoquad V2 Tyre (20×4.0″)
Schwalbe Al Mighty (26×4.8″)
Maxxis Minion DHF (24×2.4″)
Maxxis Minion DHF (20×2.4″)
