How to choose the correct bicycle size for your height?

Choosing a bike frame can be both complex and simple. Don't be intimidated by a bunch of data; just remember a few key points.

The most intuitive and important tip: Straddle and try it out

This is the most classic and reliable method, especially when you're buying a bike at a physical store.

Stand the bicycle upright on the ground, and you stand directly over the top tube (the horizontal bar at the front) of the frame.
Stand firmly with your feet shoulder-width apart.
At this point, there should be a gap between your crotch and the top tube of the frame.
- Road/City Bikes: A gap of 2-5 centimeters (about one to two fingers) is generally appropriate. This way, if you need to dismount quickly, you won't hit a sensitive area.
- Mountain Bikes: Due to bumpy terrain, a larger safety clearance is needed, ideally 5-10 centimeters (about a fist's width).

If your crotch is tightly pressed against the top tube, or you even have to stand on your tiptoes to straddle it, then the frame is definitely too big. If the gap is too large, it might indicate the frame is too small, and you'll feel cramped and unable to extend properly while riding.

Buying online? Measure your "inseam"

If you can't try the bike in person, you'll need to measure yourself. The most important factor here isn't your height, but your inseam length. People of the same height can have very different leg lengths.

How to measure?

Stand barefoot with your back against a wall.
Find a thick hardcover book (like a dictionary), place it between your legs, and push it firmly upwards, simulating the feeling of sitting on a bike saddle.
Keep the book level, then ask a family member or friend to help you measure the vertical distance from the top edge of the book to the floor. This is your inseam length.

Once you have this measurement, you can use a simple formula:

Road Bike Frame Size ≈ Inseam Length × 0.67
Mountain Bike Frame Size (inches) ≈ (Inseam Length × 0.67 - 10) / 2.54

Note: This is just an estimate! Different brands have different sizing standards; some use S/M/L, some use centimeters, and some use inches. The best approach is to take your inseam measurement and check the sizing chart provided on the official website – that will be the most accurate.

Beyond frame size, there's a feeling called "reach"

Frame size (primarily height) determines if you can ride safely, while frame length determines how comfortable you'll be. This length is often called "Reach," which you can simply understand as the distance your hands extend to the handlebars.

If the bike is too long, you'll be stretched out too much, leading to back and neck strain. If it's too short, you'll feel cramped, and your pedaling power won't be efficient. This is difficult to calculate with a formula and relies mainly on feel. That's why I strongly recommend you test ride the bike.

To summarize my advice:

Prioritize visiting a bike shop: Let experienced staff assist you, and always straddle the bike to try it out. If possible, take it for a short ride to get a feel for it. Your body's sensations won't lie.
Do your homework for online purchases: Accurately measure your inseam length, then carefully consult the sizing recommendation chart on the official website. You can also look at buyer reviews to find out what sizes people with similar body types chose.
Don't get fixated on data: Sizing charts are a reference, not an absolute truth. Everyone has different body proportions and flexibility. Minor discrepancies can be fine-tuned later by adjusting saddle height, fore-aft position, or swapping to a different length stem, but only if the frame is generally suitable. A completely wrong size cannot be salvaged.

Remember, the right bike is like the right pair of shoes – you only know it's right after you've tried it yourself. I wish you find your "dream ride" soon!