mkwdrs

I need suggestions for an entry level mtn-style bike to ride while riding with my 9 year old son. I would guess that most riding will be on pavement or flat ground, but I want the ability to go on a trail if needed.

Let me state that my son is big for his age and he is in no way an aggressive rider.

I am a big guy and prefer a somewhat upright riding position.

All suggestions appreciated. Will accept used or past year models.

RonH

Stop by your local bike shop (LBS) at look over the selection of hybrid bikes. They come in all sizes and varieties and will support you (a big guy) easily and will allow you to ride in an upright position. Test ride all that the salesperson suggests and those that catch your eye.
Good luck.

sunflowerflyer

+1 for the 700c hybrid suggestion. Your local bike store will have some great bikes in the $300-500 range. If your budget is tight check the used market on Craigslist.

homebrewerdan

I recently made the leap into biking again myself for the same reason -- skating alongside my kid was getting harder to do.

I personally opted for the Novara Big Buzz (https://www.rei.com/product/775488). It had the upright position that I was also looking for, and the 700c tires give you some speed. I'm guessing you don't necessarily need the knobby tires for paved trails/sidewalks/roads.

It also depends on what else you might use it for. In throwing down the $$$ on a new bike, I also decided that I wanted a bike that I could use for commuting to work on (5 mi each way). If that type of thing is in your agenda, check out the Commuting forum where they have many posts that list a whole slew of bikes on any budget.

I also became a fan of disc brakes and was looking for it on my purchase.

Try out some different stuff and see what you like/don't like. My wife chose a Trek 7200, which was not where I ended up (the front suspension wasn't something I was looking for). Lots of options in there.