Scooters argue about 10-, 12-, 14- and 16-inch wheels; underbones do not. Every single one on Honda and Yamaha’s Vietnamese pages runs 17-inch wheels (retrieved 23 September 2026) - the longest-standing wheel standard in the country. Here is why.
What the manufacturers fit
The commuter class runs 70/90-17 front with 80/90-17 rear: Wave Alpha, Blade, Wave RSX, Future 125, Super Cub, Sirius. The CT125 runs 80/90-17 both ends for rougher ground. The sport class widens rather than grows: Winner R and Exciter 155 VVA run 90/80-17 front with 120/70-17 rear; the CBR150R steps to 100/80-17 front and 130/70-17 rear - still 17 inches.
Why 17 inches wins here
Rim diameter buys sidewall stability and rolling efficiency: a big wheel bridges potholes and holds a line over broken tarmac better than a small one - our potholes guide covers exactly the strikes this design absorbs. It also supports the underbone’s long-travel, load-carrying brief: these bikes carry families and deliveries, not just riders. The trade - a narrow tyre contact patch and slower steering response than scooter rubber - is acceptable at underbone speeds; our scooter wheel-size comparison covers the other side.
The tube question
The standard fitments traditionally run inner tubes (Yamaha publishes tubed tyres for the Sirius); the sport class runs tubeless - our tube-versus-tubeless guide covers why that changes puncture behaviour at speed.
Rental context
The price-published classes here (Wave and Sirius, 150,000 VND/day) run the classic 70/90-17 and 80/90-17 fitments - cheap, available everywhere in Vietnam. Contact us to confirm current availability of any model.