I'm 5'7" and I bought a 58cm frame road bike. When I stand on the ground, the top of the bike is right at my inseam(?) (crotch) not in a painful way but I definitely feel it. I have the seat as low as it can go. I visually compared it to my existing mountain bike and the seat is the same height.

What are the differences between road bike and mountain bike seat heights? Can I ride this bike with no problems or have I made a mistake buying a bike too big?

The road bike drop bars are definitely further away than my mountain bike flat handle bar, if that matters?

Nobody likes to be told they made a mistake, but I think you made a mistake in buying a 58cm bike. That's not to say you CAN'T ride it. But I think you would enjoy it more if it were about 4 cm smaller on the frame size scale. Without seeing your proportions, my head says 54cm would be the first one I'd suggest trying.

Thanks for the honesty! I think driving 40 mins to check it out made me irrationally buy it. I'll ride it for an hour and see how I feel then.

Do you have any tips for what to look out for? (like what parts of my body should or shouldn't ache) My back was a bit tired after testing it out for 15 mins but I chalked it up to the seat being raised and not having ridden a bike since March.

Taller equates to longer as well.

Bicycles are proportional - the longer top tube is a likely cause of you back fatigue.

You can find a shorter stem that will help, but the steering will be different.

One word of caution - a panic stop and the top bar wins!
rusty

at 5'7", you're a size 52.
sell the 58 and save yourself time now, because you will be force to sell it anyway after trying to make it fit only to find out it won't

Really no more has to be said, the above advice says it all. List the bike again for sale while the selling is still hot.

I know you want to make it work but even a clown can ride a six foot uni-cycle. Doesn't mean we should. Apologies to the clowns on this board.

Your range in a road bike is 52-54 cm give and take.

I usually ride a 58 and I'm 6'2"

The quick answer is that it is too big. I'm 5' 9" with a 32.5" inseam and a 58 is too big. 54/55 with a 55 TT is perfect for me. My Masi (58) has a 58 TT and that's too long.

I'm 5'6' and ride a 53 cm bike. I think I handle it quite well but I would not want it to be even 1 mm bigger. A 52 or 51 cm frame would probably be a better fit for me.

I have a friend that has a 54 cm bike he is trying to sell me, same 700 cm wheels as mine. It is a different make frame than mine. Although it is 1 cm bigger the top tube is very close to the same height from the ground as my 53 cm frame. So I think there are differences based on frame design. My next bike is going to be smaller than my present bike.

I have been shopping for a road bike, and tried a Trek 58cm. I could barely reach the pedals with the seat at the lowest possible setting and the reach was too long. What surprised me was that the Trek site indicated that I needed a size 58 after inputting my height, inseam, and whatever else their system uses. Ended up with a 56cm. I'm 6'.

Some shops offer a 30 day return policy. Might see if there is something like that if you bought it from a store. Otherwise, it's time to sell.

I am a bit taller than 6'-2" and the shortest frame that 58cm, I normally check the top tube length to make sure that I am not too stretched out riding the bike. I also like a bike with a longer head tube so I can sit a bit more upright.

Take it back to the shop and exchange it for something that fits you better. I'm somewhere between 5'6" and 5'7", have a 29.5" inseam. The size of frame that I'm using is 48cm. I can stand over the toptube and lift the bicycle about an inch before it stops at my crotch. A frame that is small on you can be adjusted by using a longer stem.