Increase cycling comfort and performance with our DIY road bike fit guide

DIY-Bike-FitA good bike fit is crucial to be comfortable, efficient and free from injury. This is a basic guide to the elements of a road bike that you can adjust to best suit you. It provides a good starting point, but no two people are the same. There are no magic formulas and sometimes it pays to see a professional bike fitter who has all the right tools and experience.

Seat height

Measure your inseam: stand facing a wall and put a book between your legs. Standing straight, mark a pencil line where the top of the book meets the wall. The distance from the floor to this mark is your inseam height. Do it a few times and take an average. Your saddle height should be 109% of this figure. Measure this from your pedal axle (with the crank arm at 6 o’clock) to the top of your saddle.

Seat forwards/backwards

You’ll need a helper and a plumb line. Put your bike on a turbo, making sure it’s level. Warm up for a few minutes, in your cycling kit. Have your helper stop the right-hand crank-arm in the three o’clock position, then place the end of the plumb line on the front of your leg, just below the kneecap. The plumb line should bisect or be slightly behind the pedal axle. If it’s ahead, move the saddle back. If you make an adjustment, recheck your saddle height again.

Handlebar width

This comes down to preference, but a general rule of thumb is that you should use a handlebar of a similar width to your shoulders. Some experts believe that a wider bar gives more control and opens up your chest for easier breathing. Whereas some believe a slightly narrower bar opens up your shoulders and back, reducing muscular fatigue and tightness, as well as making you more aerodynamic. The main thing is that you feel comfortable and in control.

Stem length

Stem length is individual and depends on factors such as frame size, torso length, arm length and general flexibility. The shape and position of your handlebars and the position of the brake levers also affects reach. As a rough guide, you should be able to have your hands on the hoods with an approximate 30-degree bend in your elbows when you are in your normal riding position.

Handlebar height

For many, the most comfortable handlebar height is one where the bars are about the same height or slightly higher than the saddle. Others prefer to ride with a flatter torso and so set their handlebars to be below the height of the seat. This depends on several factors such as rider flexibility and bike frame geometry. We advise you go for comfort first, and then make small adjustments from there.

Handlebar rotation

A good starting point is to have your handlebar drops at an angle of between five and 15 degrees. In other words, if you put a marble inside the bar it would just about roll out onto the floor. Work within this range but ultimately go for whatever feels most comfortable. You can also adjust the height of the brake hoods. Start with the tops in a horizontal position and then fine tune their position until your hands rest comfortably on them.

Cleat position

Find the ball of your foot (the first big toe joint on the inside of each foot). Mark that point with a piece of tape on the outside of each shoe. Place the centre of each cleat 5 to 7mm behind that point. The centre of most cleats is marked with a line. Start with your cleats pointing straight up the centre of the shoe. Only change this if necessary, as most cleats have a degree of “float”– lateral play. Do a test ride and then make small adjustments and keep re-testing until you get a comfortable position.

Frame size

Manufacturers’ sizing charts are normally determined by gender, height and inside leg. The geometry of frames differs between models, so you may not need the same size for all types of bike. If your measurements fall between two sizes, you’ll need to determine your reach. Known as your ‘Ape Index’, this is your arm span (finger tip to finger tip) minus your height. If you have a positive ‘Ape Index’ (arm span is greater than height) you should choose the larger of two frame sizes. Otherwise, choose the smaller one.