The Strida Sx is a single speed folding bike with 18 inch wheels. The Strida SX includes upgrades from the Strida Lt single speed model. The upgrades include a Quick Release seat mount that makes adjusting the seat height easier. Also included is the Strida alloy rear rack with an added weight carrying capacity of 10 kg. This Strida model is equipped with alloy spoke 18 inch wheels.
A Strida with 18 inch wheels provides a smoother ride than 16 inch wheels. The larger 18 inch wheels also provides a higher gear ratio and is faster but the 18 inch wheels do make it harder to climb hills.
Please note, if you would prefer a Strida bike with 16 inch wheels I can swap the model SX wheels to the Model 5.0 16 inch Strida wheels. Interested, please ask for more details.
For an explanation of the different Strida models visit this page.