What Size Bike Do I Need?

Sigma Sports Bike Size Guide

Ready to invest in a new bike? You are certainly in the right place at Sigma Sports. One question you will need to answer is 'what size bike frame do I need?' But don't worry if you aren't sure this guide is here to help you find the right size bike, as are the experts in store at Hampton Wick and Oakham, who can provide a full and in depth professional bike fitting if required.

How to Measure for a Bike

Whether you are a pro on the World Tour or a weekend cyclist, there are tons of options when it comes to bike sizes. If you have the correct measurements in place, there is bike size to suit you.

The measurements you need to know

• Your height
• The length of your inside leg
• The frame size of your chosen bike

These details unlock everything and make it much easier when you come to browse for bike sizes that are going to suit you best. Whether shopping online or in-store for a bike, knowing the correct size bike is crucial.

Remember: the frame size is just about the only thing you can't adjust on a bike. Whether you are doing a custom bike build or shopping for a bike that is prepped and ready to go, knowing the right road or gravel frame size will set you well on your way to finding your new bike.

Manufacturer Bike Size Guides

Unfortunately bike sizes aren't universal, for instance a medium bike size from a Cinelli may differ to that of a Trek, so you will need to check the measurements of each bike brand. Luckily when you shop on the Sigma Sports site, the accurate sizes are listed on our bike product pages.

What Size Bike Frame Do I Need?

Comfort is king when it comes to cycling, you will enjoy your bike more and get better performance out of it when it fits you correctly and you are in the right riding position.

We've put together a bike size chart as a starting point for cyclists, plus we have dedicated size guides:

• Road Bike Size Guide 
• Gravel Bike Size Guide 
• Mountain Bike Size Guide

Sigma Sports Bike Size Chart

Keep in mind that the below is a general bike size guide, sizes vary between different models and types. When selecting a bike, remember to consult the specific size chart available on the product page and speak to our experts in-store or online if you are unsure.

Bike Size Guide FAQs

What size bike do I need if I am across sizes?

If the bike sizing charts are giving you two different frame sizes, you might be in between sizes, meaning both bike frames could work.

To choose the best frame size, focus on the ‘reach’. Reach measures how long the bike feels when you’re riding it and is affected by your upper body length (also known as your sitting height). If you have a longer than average sitting height, opt for the larger frame and vice versa if shorter. if you are lucky, you may find a perfectly sized bike in our clearance! 

How do you measure your height for a bike frame?

To find the right bike size, you will need to measure your height. To do this, start by marking the wall at the top of your head and measuring from the floor to the mark, then using a tape measure, measure your inside leg by standing against a wall with a book between your legs and measuring from the top of the book to the floor. Having someone assist can make these measurements easier!

How to measure a bike frame

Bike frames are sized based on their seat tube length, usually measured from the centre of the bottom bracket or the crank arm bolt. Depending on the brand, this can be measured to the top or centre of the top tube, with mountain bikes typically measured in inches, while road bikes are measured in centimeters.

What is stand over height?

Stand over height refers to the distance from the ground to the top of the bike's top tube. To ensure safety and comfort, measure your inside leg with shoes on and subtract 2cm to find the ideal stand over height, providing necessary clearance for quick dismounts without injury.

How to measure a bike wheel size

To measure a bike wheel size, place the wheel vertically and use a tape measure to determine the diameter from one edge of the tyre to the other, passing through the centre. Additionally, check the tyre sidewall for the size marked in inches or millimetres, such as 26", 27.5", or 700c.