When my wife had a stroke I discovered that a wheelchair with small swivelling front wheels was very hard to push on rough rally fields. I modified a pushable chair to have 4 large tyred wheels to manage the rough terrain. (You have to tilt the chair back to turn a sharp turn). Picture at
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anyone needs this free just ask & I will try to get it to you. If no reply I will take it to the town's disabled stall.