I never read this thread until now and WOW, I’m completely blown away by the responses.
In my mind, without a moments hesitation you absolutely should force your son into riding a bike. No question whatsoever.
That said, you first need to decide what kind of kid do you want?
To me, as a parent, I want mentally strong, self-confident kids, who aren’t afraid to try new things and take on challenges. I also didn’t want them to ever miss opportunities for fun with friends because they didn’t have a some basic skill.
I actively pushed mine out of their comfort zones and forced them into the life skills I thought were important. They’re now self-confident, active, physically fit adults (late teens and early 20’s) and try many new experiences (safely).
If you want that, you need to lead them and push them. When you push them out of their comfort zone, they’ll see what they can accomplish and that feeds on itself and that confidence grows over time. To me, that is the absolute essence of being a parent.
If you don’t want active self-confident kids, just follow their lead and let them do only what they want. That’s certainly the path of least resistance which is always the easiest zero conflict path, especially as a parent. IMO it’s also the path a lazy parent takes, and abdicates their responsibility as a parent. But you need to decide for yourself.
However if you do take that path, don’t look back and wonder why your kid’s overweight, eats junk food and and plays their PS4 in the basement all day. You know exactly why.
My son saw no value in swimming and didn’t want to learn at all. I explained that I (as his dad) made the choice that he was going to learn to swim. That was NOT his decision because I believed swimming was an important life skill to have. (I have a friend who, like your wife, avoids all water activities - I absolutely did not want my son to be burdened by that crippling fear his whole life.)
At his first lesson he refused to go in the water, so I literally told him learning was not his choice, that was my choice. His only choice now was whether he went in by himself or I threw him in the water (to his instructor). He looked me in the eye, saw I was serious and jumped in and never looked back. He thanks me to this day for it. He’s a strong confident swimmer.
When it came to riding a bike, neither my son or daughter wanted to. They saw no value, no interest etc etc. I forced them to and explained why they had no choice: I felt that it was an important skill to learn and once they learn they’ll never forget it etc. I also told them I’d never force them to go for a ride if they didn’t want to and I didn’t care if they ever went riding again, but at least they’d have the option to do so if it ever came up. Both begrudgingly agreed. For a while they rarely rode, but later they both fell in with friends who cycled everywhere. They thanked me.
I have yet to meet a parent whose adult kid has come up to them and said “I’m so glad you let me you always get me get my way and do only what I decided I wanted to do. So happy you never pushed into riding a bike or swimming, I’m so much better off now as an adult.”
If you do teach him to ride, my suggestion is no training wheels or running behind. Take the pedals off the bike and have him scoot himself along. His balance will come quickly and once he’s travelling decent distances add the pedals back on. I ran behind my daughter for a couple days until she got it. Someone suggested taking off the pedals and my son learned on his own in less than 2 hours.