How to Measure a Rigid Mountain Bike Frame

rigid mountain bike with seat tube frame measurement

Rigid mountain bikes are the oldest type available, which is why they are also known as “traditional mountain bikes.”

They are ideal for beginners and those who want off-road capabilities with minimal costs and maintenance involved.

Knowing how to measure a rigid mountain bike frame will ensure you get the right fit, feel comfortable while riding, maximize your performance, and avoid injuries.

Follow our measuring instructions below and use our online calculator to find out the recommended rider height and leg length ranges.

How to Measure a Rigid Mountain Bike?

Measuring a rigid mountain bike frame focuses primarily on the seat tube length, as it’s the most important metric for determining the bike’s overall fit for the rider.

However, each manufacturer might have slight variations in their sizing charts, so finding the right size mountain bike and narrowing down the fit is not always that easy.

To simplify this process, and to make sure you’re getting the best possible fit, we recommend using our online frame size calculator.

Follow the seat tube measuring instructions below and then choose your seat tube length from the drop-down menu.

Our calculator will then show you a printable rider size chart with the recommended height range and leg length range for the corresponding frame size.

Frame Diagram

Measuring Instructions

Identify the top of the seat tube, where the seat clamp holds the seat post.
Identify the center of the bottom bracket (it's the axle that holds the crank arms together).
Measure the distance between the two points (C-T) - this is the length of the seat tube.
Record your measurement in both centimeters (cm) and inches (to the nearest half-inch).
Select your bike size from the drop-down on the right to see a rider height chart.

Traditional Mountain Bike

Rider Charts

Once you know your bike's frame size, select it from the drop-down to see how tall riders should be to use this bike.

Notes

Center to Top (C-T) - This is the length of the seat tube, measured from the center of bottom bracket to top of the seat tube.

Metric (cm) - Road bikes are measured in centimeters.

Frequently Asked Questions

1. What is a fully rigid mountain bike?

A fully rigid mountain bike is a bike that has no suspension at all. These mountain bikes have a rigid fork and rigid frame (hence the name) and are typically popular among beginners. Rigid mountain bikes are also the most affordable type and require the least amount of maintenance.

2. How do I know what mountain bike size bike frame to get?

To determine what mountain bike size frame to get, you should first measure your inseam length and height. Once you know these measurements, consult a mountain bike size chart or an online calculator to find out what size is recommended for your body metrics.

3. What size is a 29-inch mountain bike?

The "29-inch" in a 29-inch mountain bike refers to the diameter of the wheel and has nothing to do with frame measurements such as seat tube or top tube length. The wheel diameter can't and should not be used to determine the recommended frame size for adults, only for kids' bikes.