Up front, I haven't been on a bike in 25 years.

I'm 5'2" and the store I just bought my bike at said that is the dividing line between a 24" wheel and a 26" wheel. It's not a dedicated bicycle shop so the guy wasn't a bicycle specialist. He brought down the 24" first and held it while I got on it. The seat to ground length fit well so I bought it 3 days ago. Once I got it home, I tried it out, and it just felt wrong. I felt like my knees were chest level while pedaling, even though they weren't. Since it only took minutes to regain balance and steering, I tried to take it on a long ride. After a third of a mile I was gasping for air and could barely move my legs.

Since it didn't feel right, I took it back yesterday and got the 26". Got on that thing and it felt so good. My practice run in the parking lot turned into a 2 mile ride and at the end I was breathing a little hard, nothing significant, and my legs ached a little. Today I was sore all over when I woke up but my legs hurt the least. The only thing keeping me off the bike today was being saddle sore, and I bought a memory foam seat cushion this evening for help with that.

However someone I know online says she runs a motorcycle and bicycle safety course and she's really, really worried about the fit. I have the seat all the way down, and I'm on my tippy toes if I put my feet on the ground while on the bike. I'm pretty sure it was that same way when I was a teen and practically lived on my bike. She's concerned that my inability to put my feet down flat is dangerous, since it will affect my ability to balance when I stop. But clearly a smaller frame that enables me to put my feet flat on the ground is all wrong for me, since I couldn't manage any bit of distance on it.

Should I be concerned about how high up I am? My intention is to stick to sidewalks and city streets, not going off-road. And like I said, I'm certain this was the same fit when I was young and I did a lot of off-roading then, a lot of falls, and I survived with only some scars and great stories to go with them.

Sorry you didn't get a bike that felt right. Can you return the 26" and go to a real bike shop for help getting you on the correct bike. They'll do all the fitting with the purchase. Or maybe visit a few bike shops. Let us know what happens. Good luck.

You should not be able to step flat footed on the ground while on the saddle if thats what this online person is stating.

You need to set the saddle height so you have proper extension when pedaling. The bike saddle is not for sitting when the bike is stopped. When you stop you get off the saddle.

No offense to your motorcycle safety course friend but they don't sound like they know much about bicycling.

A picture of your bike and you on it would help.

Yeah, take it back and go to a different bike shop! Doesn't sound like they have a firm grasp of bike fitting. Maybe google a shop that specializes in fitting...?

+1
Only "crank-forward" and (semi) Recumbent bikes will allow good leg extension while pedalling AND flat-footed ground contact from the same position. Only reaching the ground with your toes is perfectly normal for a vast majority of riders.
Don't worry about THAT.
However, if you have the saddle all the way down, I don't think its the best bike for you. Having to bring the saddle all the way down often makes the bike feel very long.
I see two options for you:
1) empirical
Sounds like you got a decently enjoyable first ride. Even if the fit is weird, it can't be all wrong. Keep the bike and keep riding.
2) return the bike, shop for another bike someplace else. Maybe a 24" - if properly fitted - would have been even better.
Maybe the gearing was totally wrong for you. Maybe..something.

I suspect the 26 will be fine. When properly set up, a cyclists feet on tippy toe just reach the ground and if you liked it well enough to extend the first ride to several miles that is a very good sign. On the other hand, a dedicated bike shop will have knowledgeable staff who will put you on the right size bike. But even more important, you can go back with any questions about mechanical issues or fit and they will be happy to help.

Muscle soreness is normal for unused muscle. Muscle soreness is also normal if you have been happily riding, say 10 miles and suddenly up the mileage to 15 or 20 miles. The rule of thumb if you are increasing miles is to increase no more than about 10%. Give it a few days rest, then do another 2 miles. Welcome to cycling.

Bern

Thanks for the warm welcome.

Someone else not on this forum gave me some links for proper fit and the charts said that 26" is the best fit for me. So yeah, feeling much better about the second bike I got.

My intent for getting the bike is commuting, and it looks like tomorrow is going to be the first commute. Wish me luck!

26" isn't even the bike size, it's the wheel size. Good luck.

if your commute is very far, you can do much better with an efficient style of riding. Check back after a few commutes. you need advice, not from the silly boy at Walmart.

All sounds good to me. Have fun! I don't think I can touch the ground at all with my toe while on the saddle, much less 2 toes. No one who is properly fit can. Your friend is right about motorcycles, but totally wrong about bicycles. The difference with bicycles is that one has to pedal.

To get your saddle height right, while pedaling slowly, move one foot so that the heel of that shoe is on the pedal. That leg should be entirely straight at the bottom of the pedal stroke with your hips not having to be tilted to reach it. Adjust the saddle height by trial and error until this is true.

I remember when I first started riding at 8, it was on a 26" wheel bike and the only way I could get off it was to crash onto someone's lawn. By now, you have the fine points of mounting and dismounting down.

My leg isn't quite fully straight, but the knee is just a tad bent. So far since July 1st I've fallen three times, almost fell a fourth but recovered, in the exact same way. I come to a complete stop, put my left foot down, and the tippy toes don't quite hit the surface the correct way and I do a nice slow fall onto my left side with the bike falling on me. They were all during practice mode, no injuries or pain or even an ache, just a grass stain one time, but the fear of falling at a red light in that manner is still there so I'm not moving the seat up yet.

You don't say what size frame you got. I'm 5'4 1/2" and my last Trek was a 16" frame, I remember. This was with 700c wheels. You need to consider wheels size, frame size, and also how the downtube runs (is it straight or angled down, is the bike a step through model). Sizing a bike just based on wheels size is not a great idea. Since you enjoyed riding the 26" wheel bike, maybe that frame size was a good fit, but you might do better with a 24" wheel on that frame size. Were the bikes both the same frame size?
Also, your height is less important than your inseam. Mine is 29.5" for that 16" frame. If the shop you purchased at can't properly fit you to frame size + wheel size, go somewhere else.
And, you are tilting the bike when you stop, right? You don't just stop with the bike perfectly vertical. You lean the bike which allows you to get that foot down flat.

The reason for the falls is that you kept your butt in the saddle.
Try having one foot on the bottom of the pedal stroke when approaching a stop, get your butt of the saddle (assuming the standing up position) while slowing down to a complete stop, and plant your other foot on the ground at the moment you stop.

Your saddle height seems about right if you have knee slightly bent at the bottom of the pedal stroke.