I thought I knew everything about bikes when I was riding my road bike for years. This was until I was proven wrong at the local shop when I decided to purchase a mountain bike for a change. I got to know that the frame of a mountain bike is sized differently from a road bike.
You might know about other bike frame sizes and still be unaware of mountain bikes. So, if you’re someone who’s never purchased a mountain bike or looking to upgrade your riding style, you’ve come to the right place. Stay with me as this blog will get you covered. Reading this guide will make your next mountain bike purchase easy.
Different Parts of the Frame that Need to be Measured
Several parts of a mountain bike need to be measured to know its frame size. Out of these, the two most important are reach and stack. There are other factors to consider too. These are head tube angle, wheel size, chainstay length, etc. This will be discussed in detail. Keep reading to know about them.
How to Measure Mountain Bike Frame Size?
Traditional mountain bikes were sized on the length of the seat tube and according to how tall a rider was. This was not the best way of sizing a mountain bike, as the rider would end up with a high-top tube and quite a short bike.
Now, this way of sizing suits a road bike as most of the time you are in the saddle. But, for a mountain bike, it is not a practical method. Therefore, modern bikes have sizes ranging from extra small to extra large.
Following are some of the parts of the frame you need to check to measure your mountain bike frame size :
1. Reach
It is the horizontal distance between the bottom bracket and the centre of the head tube. This is important as it determines the length of your cockpit. If you have a reach that is too long, you’ll feel stretched out. If the reach is too short, you’ll feel overly upright and immobile.
2. Stack
It is the vertical distance between the bottom bracket and the centre of the head tube. It is less important than reach.
3. Head Tube Angle
It means the angle of the head tube and the ground. A slack mountain bike has a short head angle of about 65 degrees and is more stable even at high speeds. A steep head angle is about 70 degrees, and it feels as if the front wheel is more planted.
4. Chainstay Length
It is the distance between the rider’s centre of mass and the rear axle. With a shorter chainstay, the rear wheel of a bike is more under the rider. A bike with a longer chainstay has a longer wheelbase. This means more stability on rough terrains even at high speeds.
5. Effective Top-tube Length
This is the distance between the top centre of the head tube back to the centre of the seat post.
6. Wheel Size
You also need to check the wheel size. Usually, wheels are about 27.5″ or 29″ inches. On the other hand, older bikes have comparatively smaller wheels of about 26″ inches.
7. Riding Type
Riding type also makes a bike frame different. For an aggressive rider, a smaller frame is better. This allows the rider to handle the bike well. But, for a casual rider, a larger frame is better as it guarantees more comfort.
Click here to learn more about What Size Bike Frame Do You Need?
Mountain Bike Frame Size Chart
Before giving you a mountain bike frame size chart, you need to know one thing. These frame size charts are different for men and women. But, you do not need to worry. I will provide both. So whether you are a man or a woman, this article will answer all your queries.
Mountain Bike Frame Size Chart for Men
| Rider Height (Feet) | Rider Height (Centimetres) | Recommended Frame Size (Centimetres) | Recommended Frame Size (Letters) |
| 4’10” – 5’2” | 148cm – 158cm | 33 – 37 | XS |
| 5’2″ – 5’6” | 158cm – 168cm | 38 – 42 | S |
| 5’6″ – 5′ 10” | 168cm – 178cm | 43 – 47 | M |
| 5’10” – 6’1” | 178cm – 185cm | 48 – 52 | L |
| 6’1″ – 6’4” | 185cm – 193cm | 53 – 57 | XL |
| 6’4″ – 6’6” | 193cm – 198cm | 58 – 61 | XXL |
Mountain Bike Frame Size Chart for Women
| Rider Height (Feet) | Rider Height (Centimetres) | Recommended Frame Size (Centimetres) | Recommended Frame Size (Letters) |
| 4’10” – 5’2” | 148cm – 158cm | 33 – 37 | XS |
| 5’2″ – 5’6” | 158cm – 168cm | 38 – 42 | S |
| 5’7″ – 5’9” | 168cm – 178cm | 43 – 47 | M |
| 5’10” – 6’1” | 178cm – 185cm | 48 + | L |
How to Measure Mountain Bike Frame Size in Inches?
Doing conversions can be annoying. But a mountain bike frame size chart in inches would make it easy. You can look for your fit from the size chart provided below.
| Rider Height (Feet and Inches) | Recommended Frame Size (Inches) |
| 4’10” – 5’2” | 13″ – 14” |
| 5’2″ – 5’6” | 15″ – 16” |
| 5’6″ – 5′ 10” | 17″ – 18” |
| 5’10” – 6’1” | 19″ – 20” |
| 6’1″ – 6’4” | 21″ – 22” |
| 6’4″ – 6’6” | 23″ – 24” |
Hold on. Do not miss some of the famous questions asked by riders regarding their mountain bikes. Do give them a read.
Frequently Asked Questions
1. How to measure mountain bike wheel size?
There are several ways to check that. You can do it in either of the following two ways:
- Checking your tyre markings
You will find your wheel size written on the tyre. For example, if you’ve got a 28-inch wheel, you’ll see 28x or 700x written on the wheel.
- Measuring your rim
Measure the diameter of the metal wheel rim from one edge to the other. While measuring this, do not include the tyre. For instance, if the diameter is 559mm, you have a 26-inch wheel.
2. How to measure trek mountain bike frame size?
Earlier, trek mountain bikes were measured by the length of the seat tube. Whereas modern bikes are sized based on reach and not the length of the seat tube. In addition, manufacturers use alpha sizing so you can find your right fit without any hustle.
Also, you can measure a trek mountain bike frame by following the size chart guide below.
| Rider Height (Feet and Inches) | Rider Height (Centimetres) | Recommended Frame Size (Alpha Size) |
| 4’9”-5’1” | 147-155 cm | XS |
| 5’2”-5’3.8 | 153-162 cm | S |
| 5’3.4”-5’7.7” | 161-172 cm | M |
| 5’6.9”-5’10.5” | 170-179 cm | ML |
| 5’9.7”-6’2” | 177-188 cm | L |
| 6’1.2”-6’5.2” | 186-196 cm | XL |
| 6’4”-6’7.9” | 195-203 cm | XXL |
Conclusion:
The frame size of a mountain bike is an essential component. If you get yourself a small frame, you will end up in a bad position. I hope this guide will make you confident enough to purchase the best mountain bike for your height and body type.
If it is not enough, you can still visit a shop to get more information. However, keep one thing in mind. Mountain bike measurements vary from one brand to another. So, always check it before buying. Besides, you can only enjoy a ride if the bike fits you well. If it is making you uncomfortable and irritated on the whole ride, know that it is not the right fit.