Bike performance off road has to with the tread pattern and the width of the tire, in addition to the diameter of the wheel. The smaller the wheel the more likely it is to side slide and be more influenced by potholes etc.
My wife had a mountain bike with slick tires and it was terrible off road, changed to knobby tires and it was completely different handling.
PM me if you have any questions.
2004 Ford F550 6l Lariat SuperCrew, Fontaine Bed,
Link Systems Air Ride
2011 Sterling 32RL with Michelin XPS tires