When I was a kid I could ride my single speed town style bike and my 10 spd road bike with no hands and both were very stable. Now, I'm new to riding again, and I haven't really been on a bike to speak of in decades until the last few weeks. I bought a new hybrid and while its a dream to ride, one thing I've noticed is I can't let go of the handlebars and ride hands free. My wife said she noticed the same thing on her new hybrid. Its like they're so responsive that the slightest lean or bump in the road will send them off course if your hands aren't on the bars. Is this just a peculiar characteristic of the hybrid style frames or what? Yes, I realize its not a safe practice, but occasionally it would be nice to go hands free long enough to reposition sweaty clothing, etc.

I was never any good at riding no-hands on anything, but I suspect the frame geometry, and straight ends on a typical hybrid fork, make handling a bit more hairy. (Can't recall the proper term -- 'caster' -- 'rake' or something -- I plead old age!)

This gave me a flash-back of that one fine day when I took my hands off and the wind caught my deep profile carbon wheels.
Result...

When I was a kid it was nothing... now I wouldn't do it if you paid me. Lol

it's simple. And not strongly depends on bike geometry. Just practice a little bit

The head tube angle and fork rake are probably much steeper than your old bike. Also consider that after several decades of not riding that your responses and balance are not as sharp as when you were a teen. I know my responses are not what they once were but my common sense has improved considerbly. I enjoy my hybrid more than the road bike now.

^^^ This. Beach cruisers typically had a 66-67.5* head tube angle, a 69* seat tube angle, about a 47-48" wheelbase and a massive amount of trail compared with a modern mountain bike with a 71* headtube angle, a 73* seat tube angle, a 42-43" wheelbase with much less trail to allow for quicker steering response. The steering was purposely slow and the stability was purposely high on those older bikes, so riding with no hands was a breeze.

ability to ride without hands has to do with the strength of your core

Practice Practice Practice! I find even switching between bikes time to time I don't feel so comfortable riding hands free !

After doing about 1000km on my road bike I finally found that I can actually RIDE it and steer it for a good few hundred feet at a time with some slight curves as long as the road/path isn't to choppy !

I don't recommend filling your hands up with stuff while doing this either, you should always be alert and ready to grab the bars !

Lack of core strength would be my guess.

Yes, I could do that as a kid on my bike...

But my Cannondale R500 requires constant attention to the bars -- the bike is simply too responsive to put it on auto-pilot. It's not a matter of balance -- I can sit on it while stopped or nearly stopped. But, the bars need guidance on all but the smoothest of roads. Without hands, one small bump, crack, or stone and me an the bike would go down...

It does not even feel safe to rest my hands in the middle of the drop bars -- not enough leverage to maintain control on a rough road.

I can ride my Road Bike, Full Suspension MTB, Hardtail MTB, and Hybrid all without hands without problems on paths, smooth trails, roads, etc. My Focus hybird is super-stable, I could ride for miles if I had to. I was riding with my buddy on his old steel Schwinn Hardtail on a railtrail one day and I rode no-hands for a period of time to grab a snack and some water. He tried and could NOT let his hand off the bars. So, when we took a break, we switched bikes. I rode his Schwinn without hands for half a mile, he could not let go of the bars on my Focus. So I'd say it takes some getting used to riding without hands, and some people have the innate ability, and some do not.

By the way, I can wheelie any of my bikes also.... many people have a problem with that, too.

How many of those old bike had steel rims?

I remember going from steel rims to aluminum on the same bike and I couldn't ride no handed as easily anymore. The old rims gave a lot more gyroscopic stability. It's like riding no handed on my motorcycle (easy) versus my dad's scooter (impossible).

I used to ride my old steel-framed, steel rim MTB with no hands all the time when I was younger, like 12-13 years old. I could even go around corners on the neighborhood streets with no hands, and just a slight lean. But nowadays, no way. I guess I'm probably just out of practice.

I used to ride all kinds of bikes no hands --- but my current (hybrid), no way.

My original 10 speed (Raleigh Record c. 1973) likely had steel wheels (I really don't recall) but I could ride that no handed through several miles of city streets while carrying a pizza. Now, I get shaky in 100 yards.

I managed to do something like 4.5 miles around El Dorado Park no-hands on Radagast the Beige-and-Black one morning. Haven't been able to manage more than maybe half a mile at a stretch on the Black Pearl. Core strength is a huge contributor at the outset, but steering responsiveness is also very much a factor. In my unscientific opinion.

Same thing when I was a kid, no hands no problem. Tried it with my hybrid the first few rides( after a 35 year break) and almost fell. My guess is bike weighs less, center of gravity is higher and older and slower. After a few months of being back in the saddle it is getting easier to ride with no hands.

Couldn't do it as a kid. Can't do it as an adult. I have trouble balancing on 2 feet sometimes.

Phew. I thought there was something wrong with me. I used to ride with no hands as a kid but certainly not today. Perhaps if I found an old beach cruiser style bike I could try it out. Or not. It's not like I am going to ride no handed down the street yelling "LOOK AT ME! HEY MOM, LOOK. LOOK, MOM, NO HANDS"

As a kid, going to school, I would even challenge myself to not touch my handlebar for the entire 5 mile ride through suburban traffic ... very hard but doable once you get good at it

Practice is key ... it shouldn't have much to do with your bike.

Yeah I'm sure it's practice. Core strength? Come on, like I really had better core strength at 12 than I do now at 32.

I ride no handed from time to time on my full suspension Trek Fuel while pulling 2 kids in a bike trailer... One time someone honked and yelled at me to get my hands on the bars... I *almost* gave that person a one finger salute...but then realized it probably doesn't look very smart. I ride no handed all the time, have for a long time. I have noticed when I switch between bikes (roadbikes, mtn bikes, etc) sometimes I do have to adjust.

CAnt do it yet...getting better at it though!

Indeed.
I ride no hands on my aggressively set up TT bike from time to time while training to relieve my back and those TT bikes sure are twitchy and difficult to keep straight.