What Size Road Bike Do I Need?

Got your eye on a new road bike? Knowing what size bike you need is crucial, and so we have put together this road bike size guide to help you on your way. We've also got experts in store at Hampton Wick and Oakham who can provide a full and in depth professional bike fitting if required.

How are road bikes measured?

Understanding bike geometry is crucial when selecting the proper size and fit for a road bike, but remember there are variations in geometry across different bike models and manufacturers.

Although road bike frame materials may differ, the structure remains consistent. A bike frame is made up of a top tube, head tube, downtube, bottom bracket shell, seat tube, seat stays, and chain stays. The frame and fork when spoken about or sold collectively, is referred to as a frameset.

Understanding a road bike's geometry is crucial in determining the ideal bike size for a rider, as it encompasses specific measurements and design variations that affect overall comfort and performance.

Road Bike Frame Geometry

Road Bike Frame Size Guide

At the core of any road bike is the frame This is what the components, wheels and all the other elements that make up a bike are attached to. Modern road bike frames are most commonly made of aluminum or carbon fibre.

How is a road bike frame size measured?

A road bike’s frame size is typically measured in centimeters (cm) and is determined by the length of the seat tube. This measurement runs from the centre of the bottom bracket to the top of the seat tube.

However, it’s essential to note that different manufacturers may have varying frame sizes, so it’s crucial to consult with an expert if unsure.

A general rule of thumb is to allow only 1 inch or so of clearance over the crossbar/top tube when standing over the bike. This ensures you have enough room to maneuver comfortably without compromising on the bike’s geometry.

What Size Road Bike Do I Need?

Use our frame size guide below to help you establish what size road bike is going to be best for you. You'll want to find a bike that puts you in the best riding position so that you perform better and enjoy your cycling more. An ill fitting bike can be uncomfortable and cause injury.

Road Bike Size Chart

Height (Inches) Height (cm) Road Bike Size
4'8" - 5'1"
 
143 - 155cm 44cm / XXS
5'1" - 5'4"
 
155 -163cm 48cm / XS
5'4" - 5'7"
 
163 - 170cm 51cm / S
5'7" - 5'10"
 
170 - 178cm 54cm / M
5'10" - 6'0"
 
178 - 183cm 56cm / L
6'0" - 6'3"
 
183 - 191cm 58cm / XL
6'3" - 6'5"
 
191 - 196cm 60cm / XXL
6'5" - 6'9"
 
196 - 205cm 62cm / XXXL

Other Important Considerations When Buying a Road Bike

When and Where Do You Ride the Bike?

If you are predominantly riding in hillier areas, weight may be a significant factor. Should you wish to ride it all year round or solely in the winter, material and durability would be a key consideration.

What Size Road Bike Do I Need? 

Whatever material, colour scheme or brand you choose you need to ensure that the road bike size fits you first. An incorrectly sized bike can affect handling and increase the chances of injury. Proper bike sizing involves taking specific measurements, such as height and leg length, and understanding variations among different manufacturers.

Consulting a road bike size chart can help you determine the correct road bike size. These tools assist in finding the perfect bike fit based on your measurements.

What Are Your Cycling Goals?

If you are buying a road bike to race on, a more aggressive geometry, with a shorter headtube and shorter wheelbase, should be considered, whereas if comfort and long days on the saddle are more important to you a slacker headtube angle and longer wheelbase.

Which Brand is Going to be a Perfect Fit?

Although not as important as size and considering where you want to ride with it, the brand is worth looking into. Some brands specialise in certain types of bike, while some have long and illustrious histories and race pedigree that you can be a part of. At Sigma Sports, we boast a wide range of brands with models to suit every road cyclist. You'll find models from Pinarello, Cannondale, Specialized and Trek to name just a few.

Road Bike Frame Materials

Although the elements that make up a frame are the same, the material in which the tubes are made from can differ greatly depending on price, use and brand priorities. The good news is there is a frame material out there for all needs and budgets. We have taken a deeper dive into some of the most popular materials and looked at the pros and cons of each.

Aluminium Road Bike Framesets

The go to for many mainstream bike brands, aluminium balances weight with strength and is a good option for those with a slightly lower budget. Durability and versatility are two key attributes that aluminium possesses, with them being resistant to rust and easily manipulated to make bikes that ride exceptionally well.

Pros - Relatively lightweight, affordable, responsive

Cons - Not as light as carbon fibre and not as strong as steel. For those looking for a high quality aluminium frame or aluminium frame bike the Specialized Allez and Cannondale CAAD ranges are both good options.

Carbon Fibre Road Framesets

Now the most popular frame material for premium road bikes due to its lightweight credentials, strength and stiffness. Carbon fibre frames are the choice for high performance cycling, as they can be easily transformed into aerodynamic shapes.

Pros - Lightweight, stiff, available from many custom and mainstream brands, offer a more forgiving ride than aluminium

Cons - More fragile than the other materials should it experience an impact and for those on a tight budget you may compromise on quality. Should the frame be damaged though there are options out there to get it repaired.

The choice when it comes to carbon frame road bikes is vast, with everything from ultra-fast and aero Bianchi Oltres to the more comfortable and endurance-focused Trek Domanes to pick from.

Shop our range of carbon fibre road bikes.

Steel Road Bike Frames

The original material bike frames were made from and still with a strong contingent of loyal fans, steel is favoured for its durability. Although the heaviest material of the four, where it loses points on the scales it makes up for it when it comes to ride quality. Alongside titanium, steel is well regarded for those looking for comfort due to its road dampening properties.

Pros - Strong, easy to repair, provides excellent comfort

Cons - Heavy, limited mainstream brands make steel frames, not the stiffest material

Specialized Tarmac SL8
Cervelo Soloist Road Bike

View All Road Bikes

Get the Right Size Road Bike with a Custom Build

Looking to build a dream road bike from scratch? Have our workshop put one together for you or check out Trek Project One. Should you require further assistance, feel free to get in touch with one of our experts.

Road Bike Sizing FAQs

What is stand over height?

Stand over height refers to the distance from the ground to the top of the road 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.

Are women's road bikes sized differently? 

Most road bikes are now available in unisex sizing. However, some road bikes are designed with the female form in mind and feature a design that allows for shorter reach, narrower shoulders and smaller hands.

How do you measure your height for a road bike frame? 

To find the right 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 length 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 taking your inside leg measurement easier!

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