CST Tyre 12 1/2 x 2 1/4 C1737 (MX125)

CST Tyre 12 1/2 x 2 1/4 C1737 (MX125) is a versatile replacement tire designed for small-wheeled bikes and lightweight urban rides. With the MX125 designation, this tyre is built to fit rims that use the 12 1/2 x 2 1/4 sizing, delivering dependable performance when you need it most.

Designed by CST for riders who demand consistent grip and easy maintenance, the C1737 (MX125) blends a practical tread pattern with a durable rubber compound that stands up to daily wear. Its profile and casing are tuned for predictable handling on pavement, asphalt, and paved trails, so you can ride with confidence whether you're commuting to school, cruising the park, or tackling a gentle rail trail.

Key benefits

• Exact fit for 12 1/2 x 2 1/4 rims (model C1737 / MX125), making replacement straightforward without chasing incompatible tires.


• Urban-ready tread pattern that grips wet and dry surfaces, helping you stay stable during stops and cornering.


• Durable rubber formulation crafted to resist everyday wear from road debris and curb encounters.


• Compatibility with standard inner tubes commonly used on small-wheeled bikes, simplifying maintenance and replacement.


• Low-maintenance performance that extends intervals between tire swaps, so your rides stay on track.

Who is it for?

• Parents replacing worn tires on kids’ bikes that use 12 1/2 x 2 1/4 sizing.


• BMX and freestyle riders seeking a reliable, everyday tire for casual riding and light tricks.


• Urban commuters and neighborhood explorers who value consistent traction and straightforward installation.

Tips for installation and care

• Ensure you’re matching the tire size 12 1/2 x 2 1/4 with your wheel’s bead seat and rim width to ensure a proper seal.


• Use standard tire levers and a compatible inner tube if your setup is tubed; check the sidewall for any specific inflation guidance.


• Keep tires inflated to the pressure recommended by your rim or tire manufacturer for optimal performance and longer life.

Choose the CST Tyre 12 1/2 x 2 1/4 C1737 (MX125) for a reliable, ready-to-ride replacement that keeps your small-wheeled bike performing at its best. Whether you’re upgrading worn tires or stocking up for routine maintenance, this tire is built to deliver steady grip, easy mounting, and lasting value on everyday rides.