The 7 Most Important Road Bike Sizing Tips

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So you have decided to treat yourself to a new road bicycle. First of all congratulations, your heart and legs are going to thank you. Maybe not after the first few rides but definitely within the first few months. Whether this is your first road bike or your 101st you still have to make sure it is a good fit for you and your particular style of riding.

Let us assume you are going to go to a reputable bicycle store where the sales people know what they are talking about and they can make sure the bicycle you ride out on fits you and your riding style.

There are a couple of things you have to decide before you get fitted. You have to ask yourself what sort of riding are you going to be doing? Will you be riding to the store and coffee shop, or maybe doing some touring? A lot of people use their road bike to commute to work every day and some will be using it to race at the weekend. Each of these different riding styles means you will have a slightly different fit on your bike.

The second and easier question to answer is are you a man or a woman?

Let us take the latter question first. These days there are almost as many road bikes made for women as there are for men. These ladies bikes tend to have shorter top tubes. Women usually have longer legs and shorter arms than men who are of the same height. This makes a bike with a shorter top tube more comfortable for most women, but not all.

The standard frame is built and designed with  male body in mind. But if you are a lady please feel free to test ride a man’s road bike. In the end whichever bike fits you best is the one you will be riding out of the store.

As for the style of riding you do, the answer to this question is going to affect your position on the bicycle. If you are just going to use your bike to ride to the coffee shop you can get away with an upright position. If you are going to commute to work you will want a more aerodynamic position and if you are going to do some speed work you will need to get low and into a racing position.

All these positions are or can be comfortable but you don’t want to be in the wrong one for your riding style.

When you have decided what size of bicycle frame you want, whether you are a man or a woman and which type of riding you will be doing, it is time to test some bikes.

A respectable bike store will have someone who can give you a good expert fit. If you think you have a physical impairment that will affect your bike comfort/riding or if you just want a more professional critique of your needs there are bicycle fitting studios with video cameras. These places will take film of you while riding a trainer bike and analyse your pedalling.

For the majority of us though a regular fit by a bike shop guy and then some personal tweaking should be fine. And one word of warning, once you start tweaking with the saddle, handlebar and cleat positions, you may not be able to stop!!

Group of road bikers

Correct Frame Size

Let’s start with the most important part, the frame. If you get this wrong you won’t be able to adjust the frame to suit you and you probably won’t be able to adjust the other parts enough to make the bike fit. So pay attention to the fame and the sizes. You have to get the right frame size.

If the frame has a level top tube it is going to be measured in centimetres or inches. This was the way all road bikes were measured but now the manufacturers have come up with compact frames that have a downward sloping top tube. Now the frames can also be be small, medium or large.

Either way when you straddle the bike there should be a gap of 1 to 2 inches from the top tube to your crotch. An easy way to measure this is to stand over the bike, lift it up until the top tube comes up firmly into contact with your crotch, and then check to see if the bike’s wheels are 1 to 2 inches off the ground.

You should also be able to put a couple of toes on the ground when you are in the saddle.

But why is frame size so important? I hear you asking. Surely I can just ride any old bike so long as it doesn’t come with training wheels?

Your body and its various parts will be answering that question for you not long after your first 20 mile ride on a bike that is fitted wrongly.

If you do get the wrong frame size you could end up with back pain and or knee pain. Neither of which are very pleasant and both are easily avoided.

People come in all shapes and sizes and it would be nice if bicycles did as well. When you go into your local bike shop you may think bicycles do come in enough sizes for everyone because you will see all the bikes hanging down from the ceiling and arranged in neat rows all over the showroom floor. But if you take a closer look, a lot of the bikes will be one of 4 sizes if they have the new compact frame style (small, medium, large or extra large) or a size in centimetres of between 50cm and 60 cm. if they have the level top tube.

Two people may be both 5’9” tall but if one has short legs and a long torso and the other person is longer limbed with a short torso the same bike frame is not going to fit both of them. So you cannot just go by the height of a person.

A bicycle shop cannot possibly store enough bikes to fit everyone that comes in through the door so that is why you should ride and test out a few different ones. You will probably also notice that different brands in the same frame size feel different. This is because frame builders sometimes measure their bikes slightly differently.

Before you give up on the whole idea because it seems too overwhelming it is possible to get close to your fit and then tweak it with varying lengths and sizes of things like seat posts, stems and how far forward or backward you move the saddle. Notice I didn’t say “tilt” the saddle. We will talk about that later.

Cycling fast

Length of Seat Post

There are 3 main points of contact between your body and the bicycle. The seat post, handlebars and pedals.

Let’s take a look at the seat post first. This will determine how high you are sitting on the bike. This in turn affects your pedal stroke. Unless you want bad knees, you have to have the height adjusted correctly.

Jump onto your bike, sit on the saddle and put your hands on the handlebars. Put your feet on the pedals and rotate your right foot to the bottom of the pedal stroke. At this point there should be a slight bend in the knee of that leg. This also means that at the same time your left thigh should be just sloping down to the floor.

Try pedalling the bicycle. If you are rocking your hips your seat is too high. If you are noticing pain in the back part of your knee, you should experiment with lowering the seatpost.

At this point you should be aware that raising the seat post makes the seat and therefore your position on the bike move backwards so making your reach even longer to the handlebars. This is why we alter the seat post and saddle position before we do the handlebars.

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Adjusting bike seat

Situating the Saddle

While we are at the seat tube we will discuss the saddle. The saddle can move forwards and backwards. This can help if your top tube is not quite the right length but you can only adjust the saddle a few centimetres. So it will not make amends for choosing the wrong frame size. It is adjusted so that when you have got your correct frame you can get a perfect fit.

Sit on the saddle with your feet in a parallel position on the pedals. ie. level with each other. At this point the front of your forward knee (the one at 3 o’clock) should be in a vertical line with the middle of the pedal and the ball of your foot. This may seem like a small point but the saddle has to be in the proper position.

If the saddle is too far back you may experience pain on the outside of your knee. This could be due to Iliotibial band syndrome and can be alleviated. Try moving the seat a little more forward or lower the seat, or a combination of both these adjustments.

If the saddle is too far forward it may cause pain in the front of the knee and this can be dealt with by moving the seat backwards a bit or by raising the seat, or even a combination of both.

One more point on the subject of saddle positions. You have probably seen some people riding their bikes with the saddle in an extreme upward pointing position and also other people with their saddles sloping down towards the top tube.

I cannot look at these people without wincing in pain and cannot think of a good reason why their saddles are in either of those two positions. Your saddle should be flat and parallel to the ground. If after riding for a few months you want to lower or raise the front by a few millimetres to get a bit more comfortable that is great, but try the flat position first. Your unmentionables will thank you.

Woman on road bike

Handlebar Height

Next come the handlebars. The handle bars can be raised or lowered. The most comfortable position is probably going to be one where the saddle is at the same height as the handlebars. However this is a very personal choice.

I prefer my handle bars to be a touch lower than my seat. This comes from a background in competition where you are trying to get a powerful pedal stroke and be more aerodynamic. You may like this position or may want to go the opposite way and have the handlebars higher than your seat. This is a more upright position and you may find this to be more comfortable.

If your handlebars are too low you may. If you find yourself getting a sore neck or back pain this may be due to the fact that your handlebars are too low so you might want to raise them a bit.

One other piece of information that you might want to bear in mind with your choice of handlebars are their width. Ideally the handlebars should be as wide as your shoulders.

Road bike tour

Choosing the Right Stem

If you have to extend and lock your elbows to reach the handlebars then the stem is too long. You can correct this by choosing a set of handlebars that have a shorter stem. Road bikes have the stem and handlebars as one unified part. So the stem cannot be separated.

The shorter stem will have the effect of moving the handlebars closer to the steering column and therefore making your reach more comfortable.

Road or trail vibrations will pulse through your locked arms and into your neck and upper back causing aching and tiredness. You should be able to use your arms as shock absorbers for the bumps on the road and you cannot do this if your elbows are locked.

A generic rule of thumb that covers different bike styles (including road bikes) and handlebar configurations is that a proper reach (distance to the handlebar from the seat), allows you to comfortably use all the positions the handlebars provide and to comfortably bend your elbows while riding.

Road bike shoe on cleats

Cleat Placement

I am going to assume you will be wearing proper bicycle shoes on your new road bike. You want to get the complete experience and once you ride with cleats you will never look back.

The position of the cleats is very personal. Hopefully you will have your feet facing straight forward and that will be comfortable for you. You can get the sales person in the bike shop to fit them for you and you can be on your way.

However if one of your feet points slightly in or out you can move the cleat in your shoe to compensate for that. You will still get a perfectly stable fit on the pedal and it is going to to help your knees and hips stay in alignment.

Road bikers

Bearing all this information in mind I think it becomes fairly obvious that there will be no single road bike sizing chart that is going to be perfect for everybody. Also there are sizing charts that you have to have a degree in mathematics to understand and then there are sizing charts that are not worth the paper they are printed on, or these days, the pixels they take up.

However there are two that are very useful in their own way.

Inseam Height Bike Size
<27″ (5′ (152 cm)49 cm
5’1″ (155 cm)
5’2″ (157 cm)
27″-29″ (69-74 cm) 5’3″ (160 cm)
5’4″ (163 cm) 52 cm
5’5″ (165 cm)
5’6″ (168 cm)
29″-31″ (74-79 cm) 5’7″ (170 cm)
5’8″ (173 cm) 54 cm
5’9″ (175 cm)
5’10” (178 cm) 56 cm
31″-33″ (79-84 cm) 5’11” (180 cm)
6′ (183 cm) 58 cm
6’1″ (185 cm)
33″-35″ (84-89 cm) 6’2″ (188 cm)
6’3″ (191 cm) 61 cm
>35″ (>89 cm) 6’4″ (193 cm)
6’5″ (196 cm)
6’6″ (198 cm)

The chart should be simple and straightforward. You can find your frame size and then tweak the 3 contact points that we discussed to fit you perfectly. Remember again it is the frame size that is most important.

The second chart is useful because it shows the new compact frames that the manufacturers are producing compared to the sizes of the old traditional frames. You can see which size frame would be best for you and compare the two in the shop.

57-59 cm

Rider Height Bike Size Compact Seat Tube Traditional Frame Size
5’2″-5’4″ (157-163 cm) XS 43 cm 49-51 cm
5’4″-5’7″ (163-170 cm) S 46.5 cm 51-54 cm
5’7″-5’10” (170-179 cm) M 50 cm 55-57 cm
5’10”-6’0″ (179-183 cm) M/L 53.5 cm
6’0″-6’3″ (183-191 cm) L 55.5 cm 59-61 cm
6’3″-6’6″ (191-198 cm) XL 58.5 cm 61-63 cm

With these two charts and the help of an honest and knowledgeable bicycle salesperson you should be able to find the perfect bike for your needs.

You should now be fitted perfectly for the new bicycle. Like I said at the beginning it may take a couple of months to get the seat post, saddle and handlebars into the exact positions that are perfect for you and your riding style but if you have the right frame size to begin with, you can alter the three points of contact in your own time. Just don’t let me see you riding down the road with your elbows locked and your legs sticking out perpendicular to your bike.


6 thoughts on “The 7 Most Important Road Bike Sizing Tips”

  1. Whoever came up with these bike size-per-height of rider size charts was a bloody height fascist for starting the chart at 5’0″ for one chart and 5’2″ for the other chart. There are many people smaller than that and it treats us like we don’t exist. I am 4’9″.

    • Do you use 49cm bike size?

      I have the same height problem.

      I was wondering if I should get 49cm bike since its bloody difficult to get a cheap road bike with 47cm frame.

  2. I have a moutain bike m30 raleigh. Messure 5 8 and 30 inseame and 25 arms the bike seams to small. The length of tube is 22. I feal too upright and the pedals are under me. I want them more behind me but not bent over too much reaching for handle bars.


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