Jc Cook Cycles Wilton Road open 6 days a week Monday to Saturday 9am to 5pm
Jc Cook Cycles Scunthorpe open 5 days a week Tuesday to Saturday 9am to 5pm

Bike Size Guide

Choosing the correct size bike all depends on the type of bike, your height, your riding style, and your preference. A correct fitting bike will be more comfortable, faster, more efficient and more fun to ride. This bike size guide gives our customers general advice on choosing the right size. It is a guide only and we always recommend visiting one of our stores, Please note all sizing information is to be used as a guide only. This is because bike sizes can vary for different brands and models. Personal preference may also influence the size of bike you choose.
Road bike sizing and mountain bike sizes are slightly different and the units used in bike sizes vary depending on type and brand. Road bike sizes are usually given in centimetres, while mountain bike frame sizes are quoted in inches.

Mountain Bike Size Guide

Rider Height (FT/IN) Rider Height CM Suggested Frame Size
4'10" – 5'2"
147cm – 158cm
13" - 14" (X-Small)
5'2" – 5'6"
158cm - 168cm
15" - 16" (Small)
5'6" - 5'10"
168cm - 178cm
17" - 19" (Medium)
5'10" - 6'1"
178cm - 185cm
19" - 20" (Large)
6'1" - 6'4"
185cm - 193cm
21" - 22" (X-Large)
6'4" - 6'6"
193cm - 198cm
23" - 24" (XX-Large)

Road Bike Size Guide

Rider Height (FT/IN) Rider Height CM Suggested Frame Size
4'10" - 5'0"
148cm - 152cm
XX-Small (47cm - 48cm)
5'0" - 5'3"
152cm - 160cm
X-Small (49cm - 50cm)
5'3" - 5'6"
160cm - 168cm
Small (51cm - 53cm)
5'6" - 5'9"
168cm - 175cm
Medium (54cm - 55cm)
5'9" - 6'0"
175cm - 183cm
Large (56cm - 58cm)
6'0" - 6'3"
183cm - 191cm
X-Large (58cm - 60cm)
6'3" - 6'6"
191cm - 198cm
XX-Large (61cm - 63cm)

Hybrid Bike Size Guide

Rider Height (FT/IN) Rider Height CM Suggested Frame Size
4'10" – 5'2"
147cm – 158cm
13" - 14" (X-Small)
5'2" – 5'6"
158cm - 168cm
15" - 16" (Small)
5'6" - 5'10"
168cm - 178cm
17" - 19" (Medium)
5'10" - 6'1"
178cm - 185cm
19" - 20" (Large)
6'1" - 6'4"
185cm - 193cm
21" - 22" (X-Large)
6'4" - 6'6"
193cm - 198cm
23" - 24" (XX-Large)

Childrens Size Guide

Rider Age Rider Height Suggested Wheel Size
2 - 4
80cm - 100cm
12" Wheel
4 - 6
98cm - 106cm
14" Wheel
5 - 7
104cm - 115cm
16" Wheel
6 - 8
109cm - 122cm
18" Wheel
7 - 9
118cm - 130cm
20" Wheel
9 - 11
127cm - 145cm
24" Wheel
12+
145cm +
26" Wheel

What to measure?

Measure your height

Stand up straight with your back against the wall, shoulders back touching it and your legs together. Make sure you look straight in front of you and that you are on a flat surface. Then make a mark on the wall where the top of your head is. Don't forget to take your shoes & any hats off for an accurate measurement. Also ensure the pen/pencil you mark with is parallel to the floor.

Measure your inside leg

While you're stood with your back to the wall with your shoes off, place a ruler, book or similar between the top of your legs touchingthe point you'd sit on a saddle. Make sure it's parallel to the ground then kindly ask a friend to measure the distance from the floor to the top of the book/ruler. This will give you your inside leg measurement.

The type of bike

What type of bike you choose will affect the bike size you buy. The type or style of riding that you do will also affect which size you need. For example a mountain biker that wants to ride more aggressively and would like a more maneuverable bike may prefer a size smaller than they would normally take. Likewise a cross country racer that is looking for a flatter and speedier mountain bike may prefer a size larger than they would normally take. There is no definitive right or wrong size, it all comes down to personal preference and what feels comfortable. The different types of bikes are all explained within our buying guides here.

How are bikes measured

Bikes are measured by their seat tube length. This measurement is normally from the centre of the bottom bracket (BB) or the centre of the bolt that attachs the crank arms. This differs by brand, some measure to the top of where the top tube meets the seat tube, or even the centre of the top tube. Mountain bikes are either measured in inches or descriptive sizes (small, medium etc). Road bikes are in centimetres or descriptive sizes where as Hybrid bikes can be any one of the three. Bikes also get longer as they go up in size (relative to the frame size) but different brands can be inherently longer or shorter than others.

Stand over height

Stand over height is how tall the frame is from the ground. Stand over height measurements are to the top of the top-tube. Ideally you want at least 2cm of clearance between you and the frame. In theory your stand over height is your leg measurement minus 2cm. It it worth measuring your inside leg with your shoes on so you can establish your stand over height. Should you need to jump off the saddle quickly, the clearance between you and the frame will prevent any injuries.

How can I set my bike up in a comfortable position?

Once you've found the right size bike, you need to make adjustments to the bike's set up. Not only will this help you ride more comfortably and efficiently, but it can also help prevent aches and pains. Here's what you'll need to consider:

Saddle height:

Start by adjusting the saddle to the correct height. The quickest way to do this is by putting your heel on the pedal when it's at the bottom of the stroke in the 6 o'clock position, and then checking the bend in your knee. It should be almost straight, with only a very slight bend. If it isn't, simply adjust your saddle height up or down to achieve this. This is easiest to do when leaning up against a wall or a door frame for balance to acheive a nutral spine without rocking the hips.

Saddle position:

Next it's time to consider your saddle's position. It's best to start with your saddle in a level/flat position as this is how they are designed to be sat on. However, if you find this puts pressure on your soft tissue when you lean forwards, then you can try tilting the nose down a few degrees.

Saddle position:

We'd also recommend starting with your saddle clamped in the middle of the rails. This puts it in a neutral position which will work for a lot of riders. If your legs are proportionally longer than your upper body, then you could move it backwards, or forwards if your legs are proportionally shorter.

Handlebar height:

If you're new to riding bikes or are looking for a comfortable position that's not too stretched, you can leave all of the spacers under the stem and keep the handlebar at the highest point. If you need an even higher position, most stems can be flipped upside down so they angle upwards or a adapter can be used. If you're looking to ride faster over shorter distances, you can move some of the spacers above the stem to lower the handlebar and achieve a more aerodynamic position.

Are frame sizes different for women-specific bikes?

Yes, generally the women's ranges have different frame sizes to the unisex ones although they're typically measured in the same way. Women do tend to have shorter upper bodies than men, so the women's specific frames are shaped differently the shorter top tubes accommodate for this allowing female cyclists to feel more comfortable and less stretched out. Women have proportionally longer legs than men, this doesn't affect the seat tube length (saddle height) or stand-over clearance, our bike size calculator is suitable for all types of bikes.
Women who are between sizes on a Unisex bike may choose the smaller of the two recommended sizes.

I'm between sizes, should I go up or down?

Quite often you'll fall between sizes on the chart, meaning you would fit one of two options. Often you might think this is quite an awkward situation to be in, although we'd say consider yourself lucky! The think about riding a bike is that you need to be comfortable, and efficient. Some people ride exceptionally well on a small frame as it will handle differently. Most of which you choose will be personal preference but we'll give you a few things to think about.

Road bikes

Smaller could be better. It is possible to make a smaller frame bigger (for example, by raising the saddle or fitting a longer the stem), whereas if the frame itself is too big for you, you can't cut half the frame off.

Mountain bikes

larger could be better. Feeling cramped is not what you need and handling is the most important thing here. You can always fit a shorter stem if necessary, to reduce the reach to the handlebars.

     
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