Getting started with choosing the right sized bike for you!
Making sure you choose the correct frame size is very important when buying a new bike. The correct fitting bike will be more comfortable, more efficient and more fun to ride.
We know that choosing the right sized bike can be tricky, even for experienced cyclists. The correct frame size depends on the type of bike, your height, your riding style and your preference.
Our bike sizing guides give our customers advice on choosing the right sized bike, and try to help you understand the process a little more.
However it is only a guide and we always recommend visiting our store or contacting one our highly experianced professional staff instore on 01704 835720 or email us at email@example.com, if you are in any doubt about the size bike you need.
How are bikes measured?
Bike sizes are determined by the frame size, based on the length of the seat tube. Most manufacturers measure from the centre of the crank axle (bottom bracket) to the top of the seat tube, where the seat post is inserted. See picture Below.
Some manufacturers measure their models from the centre of the top tube where it meets the seat tube, to the crank axle. This can be a little confusing and mix up the sizings, so if ever in doubt please do contact one of out experts.
Bike companies often quote sizes in different ways, some give the size in centimetres(all road bikes, and lapierre bikes), some in inches(most popular, used by brands such as specilaized, trek and marin) and some as a frame size (such as Small, Medium, Large, etc). This again can cause confution so do not hesitate to contact us for help.
Although the size of frames are based on the measurement of the seat tube, it’s not just the seat tube that changes depending on the size. The entire frame changes in proportion to the frame size, also some components such as bar width and stem length.
What measurements will you need?
In order to size a bike correctly you should consider your height and inside leg measurement along with your riding style and the style of the bike itself.
Measuring your height is best done by standing upright against a wall with your legs together (shoes off) and shoulders back. Place a pencil on top of your head, holding it parallel to the floor and mark the wall. You can now measure your height easily against the wall.
Your inside leg measurement is taken from the floor (again, no shoes) to your crotch. It is probably easier to get someone to do this for you.
If your height is on the border of two bikes sizes your reach is often the deciding factor in which size to go for. To find out if you have a short or long reach measure your Ape Index (your arm span minus your height) – if you have a positive ape index then go for the larger size, if you have a negative ape index go for the smaller size.
Stand over height.
Stand over height is the clearance between the top of the top tube (also known as a cross bar) and the bottom of your crotch. It’s important that you have adequate clearance in this area to avoid contact when you’re stopped and astride the bike. For road and hybrid bikes 1 to 2 inches of clearance is required, mountain bikes require 2 to 4 inches.
It is important to be able to stand safely over the bike when stopped. Therefore, a clearance of at least two inches should exist on all the bikes you ride. It can be thought of as a safety net to prevent injuring yourself if you need to jump forward off the saddle suddenly.
What type of bike and what style of riding?
Different types of bikes are sized in different ways. A 58cm road bike will be quite a different size to a 58cm time trial bike, so it’s important you look at the sizing chart or contact the store for more information about the bike you are purchasing.
Road, triathlon and time-trial bikes are the most important to size correctly, so we do advise contacting the store before ordering to double check your sizing.
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 manoeuvrable bike may prefer a size smaller than they would normally take. Likewise a cross country racer that is looking for a quicker mountain bike may prefer a size larger than they would normally take. Basically there is no right or wrong when it comes to size – choosing the right bike does come down to personal preference and what you feel is comfortable and right for the riding that you do.
What can you adjust on the bike?
You can adjust a number of components on the bike to fine tune the bikes "ride" to your preferences.
- Saddle height
In order to create sufficient distance between the saddle and pedals it is possible that your saddle will be raised too high for you to sit on and touch the floor with both feet. Even on tiptoe. This is perfectly safe for adults, and conferdent riders,providing you have sufficient clearance above the top tube.
To get the best out of each pedal stroke, your saddle should be high enough that your leg almost fully extends at the bottom of each pedal stroke. To check this put one crank arm in line with the seat tube (at approximately the 5 o'clock position for the right hand pedal and 7 o'clock for the left). Place the heel of your shoe on the pedal. Your leg should now be straight. This now means that when riding, using the balls of your feet, your legs will extend sufficiently to allow their muscles to work efficiently.
Though this is the best for efficiency and comfort it will not suit all styles. Jump, BMX and DH bikes are just a few exceptions. A lower seat position allows a greater ease of movement over the frame. This is especially important for tricks and steep technical terrain.
- Saddle angle
The saddle nose can be tilted upwards or pointed downwards. This will vary your weight distribution on the saddle. Most commonly, the saddle is set parallel with the floor. The saddle can also be moved forwards and backwards, moving you nearer to or further from the handlebars. Personal choice is all important, so have a play around to see what you prefer. We set our bikes up to an angle and position that suits most riders.
- Handlebar height
Some bikes have easily adjustable handlebar heights thanks to the classic quill type stem. The more modern "a-head" type of stem is a bit more difficult to adjust but usually possible. The higher the handlebar in relation to the saddle, the more comfortable the ride position will become as you are less stretched out and bent over. The lower the handlebar, the more aerodynamic the rider becomes, possibly at the cost of backache.
- Shifter/brake angle
Brake levers and gear shifters can be angled to suit your preference. In order to get the most power from your hands it is felt that your fingers should form a straight line with your arms when applying the brakes. This should also be the most comfortable position. The brake lever reach (distance from the handlebar) can also be adjusted in some cases. This is especially useful for those with smaller hands.
Again if you are unsure about any sizing please contact our experianced staff on 01704 835720 or preferably come instore for your best fit!
|Rider Height||Inside Leg||Frame Size Suggested|
|ft & ins||cm||ins||cm||ins||cm|
|5+||152||27 - 29||68.5 - 73.5||18||48|
|5.1+||155||27 - 29||68.5 - 73.5||18||48|
|5.2+||157.5||27 - 29||68.5 - 73.5||18||48|
|5.3+||160||28 - 30||71 - 76||19||50|
|5.4+||162.5||28 - 30||71 - 76||19||50|
|5.5+||165||29 - 31||73.5 - 79||20||52|
|5.6+||167.5||28 - 30||71 - 76||20||52|
|5.7+||170||28 - 30||73.5 - 76||21||54|
|5.8+||172.5||30 - 32||76 - 81||21||54|
|5.9+||175||31 - 33||79 - 84||22||56|
|5.10+||177.5||30 - 32||76 - 81||22||56|
|5.11+||180||32 - 34||81 - 87||23||58|
|6.0+||183||32 - 34||81.5 - 86.5||23||58|
|6.2+||188||33 - 35||84 - 89||24||60|
|Rider age||Inside leg||Wheel size|
|2.5 - 4||13 - 15||33 - 38||12|
|3.5 - 5||15 - 17||38 - 43||14|
|4.5 - 6.5||17 - 19||43 - 48.5||16|
|5.5 - 7||18 - 20||45.5 - 51||18|
|7 - 9||19 - 23||48.5 - 58.4||20|
|9 - 11.5||24 - 27||61 - 68.5||24|