A 24x4 bike tyre is a true fat bike size. The important compatibility marking is ETRTO 100-507: about 100 mm wide on a 507 mm rim. It is used on some 24 inch fat bikes, compact e-bikes, junior fat bikes and utility builds that need a large-volume tyre.
Why ETRTO 100-507 matters
The 24 inch label is only a family name. A 24x1.75, 24x2, 24x3 and 24x4 tyre may share the 507 mm rim diameter, but they are very different widths. Some other 24 inch sizes use other rim diameters. Before ordering, read the old sidewall and look for 100-507, or measure and confirm the wheel standard from the bicycle manufacturer.
Check clearance before buying
A 24x4.00 tyre is much wider than a standard 24 inch bike tyre. Check both sides of the fork, the chainstays, seatstays, brake bridge, disc brake hose routing, mudguards and rack mounts. Leave extra room for wheel flex, tyre manufacturing tolerance, mud and stones. If the bicycle was supplied with a 24x3 tyre, do not assume a 24x4 will fit unless the frame was designed for it.
Choosing tread for road, e-bike or loose ground
For street use and compact e-bikes, a smoother 24x4 tread usually feels quieter and rolls better on tarmac. For paths, sand, gravel and loose ground, a more open tread can add traction, but it may be slower and noisier on road. Match the tyre to the surface you ride most often, not only to the widest size available.
Compatible 24x4 tubes
A fat bike tyre needs a high-volume tube. Look for a tube marked 24x4.00, 24x3.50/4.00 or ETRTO 100-507. A normal 24 inch tube for 1.75-2.50 inch tyres is not suitable for a 4 inch casing. Most 24x4 fat bike tubes use Schrader valves, but check the rim hole and old tube before ordering.
Puncture protection for 24x4 tyres
Fat tyres have a large contact patch, so they can pick up thorns, glass and sharp stones. A wide liner such as a 75 mm fat bike Z Liner can help protect the tread area when the tyre and tube setup is suitable. It does not replace correct pressure, a clean rim tape and careful fitting.
Shop 24x4 tyres from 1Bike
1Bike lists 24x4 fat bike tyres, fat bike tubes and protection products with product-page size details. Start with the ETRTO marking, then compare tread, tube compatibility, valve type and the clearance available on your bike.
