What size bike do I need? What I found as a beginner (height chart and fit check)
Your height gets you close. The bike's own size chart and three quick checks on the bike get you the rest of the way. I'm learning bike repair from zero on a $258 Walmart bike, and I wanted to know how sizing really works, so I dug into the makers' charts and RideLoadout's data. Here's what I found.
What size bike do I need for my height?
Most adult hybrids, gravel bikes and mountain bikes I looked at come in sizes like these. Treat them as a starting point, because every maker draws the lines a little differently.
| Your height | Usual frame size |
|---|---|
| 4′10″ – 5′2″ (147–157 cm) | XS |
| 5′2″ – 5′6″ (157–168 cm) | S |
| 5′6″ – 5′10″ (168–178 cm) | M |
| 5′10″ – 6′1″ (178–185 cm) | L |
| 6′1″ – 6′4″ (185–193 cm) | XL |
The biggest lesson for me was to check the chart for the exact bike. For example, the maker lists the Ozark Trail G.1 Explorer Flat Bar, the model I'm learning on, in medium for riders about 5′5″ to 5′10″. Every bike page on RideLoadout shows its maker's chart, and Find the right bike matches bikes to your height for you.
What if I'm between two sizes?
From what I read, the smaller size suits you if you want a more upright, easier-to-handle bike, or if your legs are short for your height. The larger size suits long arms and legs, or long rides where you like to stretch out. The advice I saw most often was to ride both if you can. Ten minutes on each tells you more than any chart.
How do I know if a bike fits me?
These are the three checks I found again and again:
- Standover. Stand over the frame with both feet flat. You want about 1 to 2 inches (2–5 cm) of space under you on a hybrid or road bike, and a bit more on a mountain bike.
- Seat height. Sit on the saddle and put your heel on the pedal at the bottom of the stroke. Your leg should be straight. When you pedal normally with the ball of your foot, your knee keeps a slight bend. The Set saddle height guide in the app walks through it step by step.
- Reach. With your hands on the grips, your elbows should be slightly bent and your shoulders relaxed. If you feel stretched out, the bike is too long. If your knees almost hit the bars, it's too short.
Does wheel size change the size I need?
Not much for adults, from what I found. A 29″ mountain bike and a 27.5″ one in the same frame size fit about the same. What changes is how the bike rides: bigger wheels roll over bumps more easily, while smaller ones feel quicker to turn. Kids' bikes are the exception, because there the wheel size is the size. See the kids' bike size guide.
The bike fits, but something hurts. Now what?
RideLoadout's help pages point to small changes first:
- Sore knees usually mean the saddle is too low or too far forward. See Knee pain.
- A sore back or neck often means you're reaching too far. A shorter stem or flipping the stem up helps. See Sore back, neck or shoulders.
- Numb hands come from too much weight on them. See Numb hands or sore wrists.
If you want to check sizes for a specific bike, Find the right bike or open the bike's page from Trek FX 2 Gen 4 and Giant Escape Disc 3 to compare two common choices. I'm writing up every repair as I learn it, in order: see my journey.