Oysi Medium Chassis65 is designed to ride flat using a base setup of 65mm outer wheels and 58mm inner wheels.
The maximum outer wheel diameter is 68mm and maximum inner wheel diameter is 60.00mm.
A wheel recess in the soul plate is required similar to the first chassis.
The max outer wheel that fits without a wheel recess in the soul plate is 62.00mm.
For your quick reference regarding wheel sizes:
Base design flat riding wheel size combos are: 68/60, 65/58, 64/57, 62/55
Alternate 'flatter' riding wheel size combos are: 68/59, 65/57, 62/54
Rockered wheels size combos are: 65/59, 64/58, 62/56
The MC65 is available in two wheelbase lengths: 257mm and 269mm. The chassis physical size is the same for both and the different wheelbases are created by change of the outer axle locations.