There’s a little more to a bike fit than the right frame size. Here are some tips for making sure you buy the right size bike, and get it correctly setup.
Side note: We’ve also covered professional bike fitting if that’s of interest.
Before buying a bike
Bike frame size
There are two main ways bicycles are sized, in inches for mountain or hybrid bikes and centimetres for road bikes (and some of the sportier hybrids). The number denotes the length of the seat tube from the centre of the bottom bracket (where the cranks are inserted) to the top of the tube. It is ultimately a fairly meaningless number on its own and simply used to give a rough guide as to bike size.
No two bikes will be exactly the same, even if they have the same length seat tube. Depending on the intended style of riding the manufacturer has made the bike for, the various parts of the frame will all be different lengths and angles. Therefore, knowing what size you need in a bike is a good start, but not guaranteed to get you the right bike. This is where trying a bike out is your best option.
Most bike shops will let you test ride a bike before you commit to it. Be critical of the bike while you are trying it. Ask yourself questions like:
- Do you feel like you are reaching too far or are you too scrunched up?
- Do you have to raise the saddle almost the whole way up to get it big enough, or is the saddle slammed into the top tube?
- Do you want to be upright or riding in low position and does the bike allow for that?
- Does the bike feel as stable or as responsive as you would like?
Once you have had one or two bikes, you will start to get an idea of what kind of riding position you do and do not like. When looking at bikes now, I look at the geometry charts and compare them to the dimensions I know about with my current bike. Generally the most important measurements to pay attention to are numbers 11 and 13 on the diagram below. 11 is the standover height – how long your legs need to be minimum to fit, although ideally you want at least a few cm’s extra clearance. 13 is the reach, which is a basic measure of, well, reach to the bar, which will only mean something if you compare it to your current bike.
As someone who is generally a big geek, I really like geometry charts and trying to figure out what bike frame might be best. I think it is a useful exercise in understanding more about positioning and bike behaviour if you are trying to get more into cycling as a sport, regardless of how amateur your interest may be (incredibly so in my case).
After buying a bike
Knowing how to set your saddle height is an important skill for being a regular cyclist and bike purchaser. If you make any changes to your saddle, shoes or bars, then you will need to readjust your saddle. It may also get changed when you take your bike for servicing.
To get the correct saddle height is fairly easy. With the shoes that you will be riding in most sit on the saddle with a friend holding the bike for you – or stick one knee out against a wall, whatever feels comfortable. Place your heel on the pedal and put it all the way down to the bottom or 6 o’clock position. Like this your knee should be straight.
The saddle can move forwards a backwards on the rails, and therefore you can tweak your reach to the bars. This will not fix a bike that is too big for you, but can make your position on the pedals more comfortable and mean that your sit bones hit the correct part of the saddle overtime you sit down.
You can also change the angle of your saddle. Ideally you want it to be pretty flat, but it is ultimately a personal decision as to whether you point the nose down or up, and it will vary by saddle and riding position on the bike. Similarly saddle shape can make a big difference to how a bike feels, even if it is not exactly related to fit – check out our post about finding the right saddle.
You can be on the right size frame but find the reach just a little too long or short. If this is the case you can change the length of the stem attaching the bars to the steering column. Again, this is something you don’t want to change drastically, and is best to get advice from your local bike shop, but it can make a good bike fit great.
Along the same lines, you can change the angle of your stem. All of them are reversible so can point up or down. When I got the Genesis Flyer, it was inverted and my reach was a tiny bit too long. I found flipping the stem around so it pointed up 7° rather than down made all the difference.
The width and shape of your handlebars can make a big difference to comfort, especially if they are drop bars. Width, reach and drop can all vary and make a huge difference to your comfort on a bike.
The width is supposed to be roughly the same as the width of your shoulders so your arms are in a straight line and not compressing or over extending your chest. Reach to the levers can vary and make a bike a bit too big, much like the stem. The depth of the drop can be too great, meaning you never use that part of the bar, or too shallow meaning it’s pointless. If you struggle with any of these things, you can ask a bike shop to recommend a new set of bars and have them instal and set them up for you, or you can do it yourself.
I think the most important piece of advice is find a good bike shop that understands your need and has a range of bikes for you to try out. This is what I did when I got my first proper bike and it worked very well.
What are your tips for getting the right bike size and setting it up to fit you?
Join 10,221 fellow cyclists who are subscribed to the London Cyclist newsletter
Sign up for our free newsletter to get...
- Advice on the best cycling gear
- A Friday roundup of all the latest London cycling news
- Exclusive content not available on the blog
Subscribe today, and get exclusive access forever! (It's free)
*No spam, ever!
As seen on The Guardian, BBC and The Independent.