I joined a Sunday mountain bike group for a ride in Ho Chi Minh City, there were 10 of us from 6 different countries.  We had a short 30min ride on the highway and then we arrived at the park.  It was a 8km single track loop with sharp up and down hills.  Some of the track was quite over grown with weeds so it was difficult to see the ruts and rocks.  We had lots of laughs getting stuck and being bumped around.  My bike was a hard tail and I also discovered the suspension at the front was locked out so it was a very bumpy ride.

At one point I had to get off and push my bike up a small hill.  As I did this my back wheel fell off!! The nut from my skewer had fallen off, so I was stuck in the bush about 20km from where we started.  One of the riders got his driver (yes, very common here) to get the part from the bike shop and drive out to meet us.  Our leader then gave me his bike to ride and he got the nut from the front and put it on the back and then rode very gingerly to the café.  I got my bike fixed and we rode home, however one of the guys got a flat so he had to get a ride home.

We rode about 40 km and I think the highway riding is more dangerous than the actual park riding except when your wheel falls off!