We were lucky. On the trail back down, we saw a bike with five on it. The drivers extend the seat a bit and reinforce the wheels with heavy steel spokes and rims. You all just pile on. The drivers wear rubber flip-flops for shoes and you go barreling up trails that only a hiker would attempt here.
People are endlessly resourceful.
One bridge was mostly washed out. We climbed across on foot while they edged the bikes over along a tree trunk. It was a 10-metre drop to the mountain stream below. They looked pretty calm about it all. After, while we snacked on cold rice and noodles, one of the drivers said he normally worried a lot more about the Islamic Liberation Front guerrillas along the trail than the washed-out bridges.