How To Measure A Mountain Bike Frame

Identifying the right size of a mountain bike can be confounding, and that’s why you need this guide. If you want to start a biking schedule, the best thing is to get the right bike for your size depending on your riding style. And, you avoid backaches, better comfort, and bike better. 

In our guide, we have included a simple to read and interpret table that will help you choose the right size for a road bike or mountain bike. To make the process as quick and easy as possible, we have scaled down our measurements to two factors:

  • Rider’s height and inside leg length
  • Frame size

So, how do you identify the right mountain bike frame size?

MTBs are measured in inches or with an S/M/L sequence. The frame sizes are calculated by measuring the center of the crank axle to the top of the seat.

We would like to keep you more informed about this in a step-by-step guide used by bikers like you. See you around.

What To Measure

A lot of sources define bike sizes as small, medium, and tall. We want to be specific so that you only get efficient information, every time and in the best way. To start with, you only need 2 measurements:

  • Your inside leg(inseam) 
  • Your height

Lean upright against your wall barefoot and mark the wall level on your head. Use a tape measure to determine your height. 

To measure your inseam, stand with your legs shoulder-width apart with no shoes on. Measure carefully the length from the ground to the crotch seam (groin). Use a pencil to mark the inseam distance. 

The inseam measurement is to help you get the standover height(length from the ground to the top of the top tube of a bike). You should always allow a 1 inch or more clearance of the standover height. 

How Are Bikes Sized?

Bikes are sized by frame sizes. Some manufacturers measure the reach and stack length(center of the crank axle to the top of the seat). Measurements are indicated in either inches or centimeters. Don’t worry, we’ll go into the details of how to apply these measurements. 

Kid bikes are measured by the sizes of their wheels and not their frames like adult bikes. The diameter of the wheels is from 12 to 26 inches.

How To Determine Correct Bike Size

We have already covered how to measure a rider’s height and inside legs. Let’s see how to correctly determine the different bike sizes of varying rider sizes. 

Road bikes

Rider height(ft/inch)Rider height(cm)Inside leg/inseam(inch)Inside leg(cm)Frame size(cm)
4’10” – 5’0″147 -15224″ – 26″61 – 6647 – 48
5’0″ – 5’2″152 – 15825″ – 27″64 – 6949 – 51
5’2″ – 5’4″158 – 16326″ – 29″66 – 7441 – 52
5’4″ – 5’6″163 – 16828″ – 30″71 – 7652 – 53
5’6″ – 5’8″168 – 17329″ – 31″74 – 7953 – 54
5’8″ – 5’10”173 – 17830″ – 32″76 – 8154 – 56
5’10” – 6’0″178 – 18331″ – 33″79 – 8456 – 58
6’0″ – 6’2″183 – 18832″ – 34″81 – 8658 – 60
6’2″ – 6’4″188 – 19333″ – 35″84 – 8960 – 62
6’4″+193+34″+81+62+

Mountain bike

Mountain bikes are measured differently because they have shorter frames than road bikes to enable a cushy ride and maintain an upright riding position.

Rider height(ft/inch)Rider height(cm)Frame size(inches)
4’10” – 5’0″147 – 15213″
5’0″ – 5’2″152 – 15814″
5’2″ – 5’4″158 – 16315″
5’4″ – 5’6″163 – 16816″
5’6″ – 5’8″168 – 17317″
5’8″ – 5’10”173 – 17817″ – 18″
5’10” – 6’10”178 – 18318″ – 19″
6’0″ – 6’2″183 – 18819″ – 20″
6’2″ – 6’4″188 – 19321″ – 22″
6’4″+193+23″+

Kids and Junior’s bikes

When measuring the wheels, give a 2 inches standover allowance. Smaller bicycles come with a low standover height, hence, you don’t have to include the allowance.  

Rider’s ageRider height(ft/inch)Rider heightWheel size(inches)
2 – 43’0″ – 3’4″91 – 10212′
4 – 53’4″ – 3’7″102 – 10914′
5 – 73’6″ – 3’10”107 – 11716′
6 – 83’9″ – 3’11”114 – 11918′
7 – 103’8″ – 4’5″112 – 13520′
9 – 134’4″ – 5’0″132 – 15224′
13+4’10”147+26′

How To Measure A Mountain Bike Frame With Suspension

Manufacturers got an intelligent way to deal with shocks in rough terrains by introducing rear suspensions and front shocks into mountain bikes. Professional bikers take advantage of potholes in mountaineering because they still feel a lot comfortable riding on any bumpy terrain.  

Initially, we discussed how to measure the frame size of a bike. The frame size is the length of the reach from the top of the seat. We prepared a detailed method on how you can measure a mountain bike with suspension.

  • Identify the seat top tube(saddle).
  • Identify the axle that holds the chainset and crank arms.
  • Get the distance between these two points (C-T) (length of the seat tube)
  • Record the measurement above in both in/centimeters (cm) and inches (to the nearest half-inch)
  • Choose your bike size from the table above to get a rider height

Next, check the correct measurements from the tables above, and enjoy a comfortable ride.

You can use our guide bike to determine the right size of your bike, especially when ordering online. If you feel you’re not comfortable with the size, speak to a bike expert to advise you on your riding style.

“Bicycle frame – Wikipedia” https://en.m.wikipedia.org/wiki/Bicycle_frame

“How to measure a bike frame | Our complete guide to sizing a bike – BikeRadar” 

https://www.bikeradar.com/advice/buyers-guides/how-to-measure-a-bike-frame-our-complete-guide-to-sizing-a-bike/

https://www.wheelies.co.uk/buying-guide/adult-bike-size-guide

“How to Measure a Full Suspension Mountain Bike – eBicycles” 

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