Purchasing a mountain bike (MTB) online can become difficult. The virtual experience provided by online shopping exchanges the feeling of hopping on a bike to get an intuitive feel of the merchandise.
This can cause incompatibility problems that can lead to problems when riding a bike. Let's explore these incompatibilities and how our frame size chart can help you find your perfect bike match.
The effects of an incompatible bike on a rider can be summed up into three things:
If your bike is incompatible with your height and build, your posture will be affected. A bike frame that's too small for you will make your posture curve inward. That is, your back will not be straight, and your arms and elbows will be a little too close to your torso. The same goes with your legs and knees.
On the other hand, if your bike is too large, there's a tendency that you'll stand over your pedals more when you're cycling, and when sitting, you'll lean forward towards the handlebars of your bike.
Both instances cause strain on your body, and, as a result, you may feel fatigued due to your body compensating for the incompatibilities.
If your bike is too large, your extremities tend to be farther from your torso than they should be. As a result, your arms and legs will not maximize their range of motion because the bike's size offsets it. Similarly, if the height of your bike is greater than your supposed standover height, you'll tend to lean the bike over to one side when you do a full stop, and you'll have to jump on the bike before you can pedal.
A bike can be overly responsive if the frame's too small. You'll tend to wobble because your arms are trying to push the handlebars forward to maintain balance. Also, your legs won't work as hard as expected, which will make it hard for you to get the momentum your bike needs to stabilize.
The end result of an incompatible bike fit is discomfort. You'll feel like riding a bike takes work when it's supposed to feel like you're just sitting while you rest your arms on the bars as your feet and legs move naturally. Instead, everything will feel like it's too cramped or too far from your body. Ultimately, riding a bike will become unenjoyable for you.
The bike frame has a lot of areas that can be measured. However, to simplify things, sellers only base the mountain bike's frame size on one measurement– the length of the seat tube. The seat tube's length isn't measured fully. Instead, it starts from the bottom bracket's axle up to the bike frame's top tube.
On the other hand, if you're looking for a kid's mountain bike, makers usually measure it based on the wheel size. For example, a 29er mountain bike frame size chart measures the bike based on 29-inch wheel size as the highest value, but this chart can go as low as 12-inch wheel size.
Different metrics are also used. But to accommodate all bikers from different mountain bike disciplines, we've created the recommended measurements for both inches and centimeters and associated sizes for each measurement.
The measurement of the rider is always taken into consideration when judging a bike's frame size. However, measuring yourself based on standards will help you accurately decide what bike size to get even without hopping on a bike. Here's the standard of measurement you can do on your own.
Bike sellers often show the rider's height alongside their recommended bike size. It would be good to know your exact height. To get an accurate measure, stand with your back behind a flat wall with your bare feet close together, allowing a minimum of six inches clearance between your two feet. Your back and head should be parallel to the wall. Place a marker (preferably delible) on top of your head and draw a small point or line on the wall. Then measure the distance from the marked section of the wall down to the floor.
The inseam measurement is useful to get an accurate measurement of your allowable stack height. When measuring your inseam, you'll have to stand with your back against the wall and your feet on the ground and at least six inches apart. Hold a marker just comfortably under your crotch area and let the marker leave a dot or a line on the wall. Afterward, get a tape measure and get the distance from the marked area down to the floor, and you should have an accurate measurement of your inseam.
The following measurements below are what most bike sellers are offering. It also has the recommended rider's height and inseam measurements for each bike size. The purpose is to give you an idea of what bike size you should get based on your height and inseam measurements.
You are encouraged to check the maker's frame size mountain bike chart as it may have further details on a particular product you wish to get.
Height |
Inseam |
Seat Tube Length |
Frame Size |
|---|---|---|---|
| 4'10” - 5' | 26 inches | 13 inches |
Extra Small |
| 5' - 5'3” | 27 inches | 14 inches | Extra Small |
| 5'3” - 5'7” | 28 inches | 15 - 16 inches | Small |
| 5'7” - 5'9” | 30 inches | 17 - 18 inches | Medium |
| 5'9” - 5'11” | 31 inches | 18 inches | Medium |
| 5'11” - 6'2” | 32 inches | 19 inches | Large |
| 6'2” - 6'5” | 34 inches | 20 - 22 inches | Extra Large |
| More than 6'5” | 36 inches | 23 - 24 inches | Double Extra Large |
Height |
Inseam (Centimeters) |
Bike Size |
Frame Size |
|---|---|---|---|
| 147cm - 152cm | 66cm | 33cm | Extra Small |
| 152cm - 160cm | 69cm | 35cm | Extra Small |
| 160cm - 170cm | 71cm | 40cm | Small |
| 170cm - 175cm | 76cm | 43 - 45cm | Medium |
| 175cm - 180cm | 79cm | 45cm | Medium |
| 180cm - 188cm | 81cm | 48cm | Large |
| 188cm - 196cm | 86cm | 50 - 56cm | Extra Large |
| More than 196cm | 91cm | 58cm - 61cm | Double Extra Large |
Height |
Inseam (Inches) |
Bike Size Length |
Frame Size |
|---|---|---|---|
| 4'10” - 5' | 26 inches | 13 inches | Extra Small |
| 5' - 5'3” | 27 inches | 14 inches | Extra Small |
| 5'4” - 5'5” | 28 inches | 15 - 16 inches | Small |
| 5'5” - 5'8” | 30 inches | 17 - 18 inches | Medium |
| More than 5'8” | 31 inches | 19 inches | Large |
Height |
Inseam (Centimeters) | Bike Size |
Frame Size |
|---|---|---|---|
| 147cm - 152cm | 66cm | Extra Small | Extra Small |
| 152cm - 160cm | 69cm | Extra Small | Extra Small |
| 162cm - 165cm | 71cm | Small | Small |
| 165cm - 172cm | 76cm | Medium | Medium |
| More than 172cm | 79cm | Large | Large |
If you're browsing through some bikes online or inside a physical store, you can check the bike frame's specifications if the following measurements are available, or you can ask a specialist for the size.
Normally, the following criteria are used for road bikes, but mountain bikers also adopt them. The three criteria you should consider are below:
The standover height is the distance of the mountain bike's top tube to the ground. The ideal height should be low enough for you to stand over the bike frame's top tube while your legs are straight and your feet are firmly planted on the ground. In addition, the top tube should allow ample clearance to your crotch area.
