The reach of a bike is the horizontal distance measured from a vertical line up through the centre of the bottom bracket to a vertical line through the centre of the headtube, and translates to the position of your hands on the handlebar and how ‘stretched’ you are on the bike.

Reach is often used in conjunction with stack height, which is the vertical distance from the centre of the bottom bracket to the top of the headtube. Roughly speaking, stack and reach relate to the length of the toptube and the height of the headtube. A longer reach and lower stack height generally points towards a more aggressive, ‘stretched out’ geometry, while a shorter reach and higher stack height will be found on a ‘sportive’ bike. As an example, Trek’s super-light race frame, the Emonda, has a reach of 38.7cm and a stack of 57.7cm in a size 56cm, while the equivalent size Domane ‘endurance’ bike has a reach of 37.7cm and a stack of 59.1cm.

Bike manufactures may advertise a bike at a given size, and you can be forgiven, to some extent, to expect a bike of similar dimensions and geometry, regardless of the manufacturer. But this is not a level playing field here; just the slightest tweak in geometry or toptube length can have a dramatic effect to how a bike fits and reach is one of the most important factors in achieving a comfortable fit.

Providing you choose a frame with adequate standover height, there will more than likely be a considerable range of adjustment for your saddle height, particularly with a compact frame, but there’s less room for error with reach. Marginal gains can be sought by adjusting the saddle fore and aft, or by replacing the stem with one of a slightly longer or shorter length; 10mm either way would be gauged the maximum acceptable stem change before the handling characteristics of the bike might be altered. What’s important, however, is to get the reach right from the outset.

You should be able to get to the brake levers comfortably while resting your hands on the hoods of the gear shifters and when sitting with your backside naturally on the saddle. Can you do the same when on the drops? The angle of your back will be around 45 degrees to the toptube and your arms somewhere around 90 degrees to your body when on the hoods. You should also be able to allow for a ‘soft’ bend in your arms, around 15 degrees is fine. If your arms are at full stretch at this point then you are likely over-reaching and need to question whether you’re on the right size bike or not.

Touch your toes

Another element of the equation worth considering, and intrinsically linked to reach, is how flexible you are. If you can touch your toes then it’s a good indicator that you might also feel comfortable on a racier bike that’s setup lower at the front end. This can be achieved by changing the style of bike (race rather than sportive) or by swapping around the headset spacers from under the stem until you find a comfortable middle ground.

A newcomer to road cycling will probably find the position of a fully slammed race bike quite alien and very uncomfortable. A bike with a taller headtube and/or a number of spacers that raise the handlebar will afford a much more realistic and comfortable position for the majority of entry level riders, with a level of adjustment afforded. Remember, knowledgeable staff in a good bike shop will know all this and be doing the adjustments for you. Make sure you leave the shop with a bike that’s right for you, both in suitability and size. You want a machine that will be comfortable and rideable, and still allow you to be as aerodynamic (i.e. on the drops) as possible when required.

Most bike manufacturers leave the fork steerer tube uncut to accommodate a number of headset spacers, and give the rider a considerable range of adjustment in terms of handlebar height. You may want the shop mechanic to cut the fork steerer to the desired height – it looks better, after all – but make sure it is not cut until your 100 per cent happy with the setup, and that means time in the saddle. Get used to riding the bike first, find the most comfortable position and only then come back to trim off the excess. Again, the bike shop staff should know this and won’t cut the steerer tube until they are comfortable that you are, well, comfortable.

Speaking of time in the saddle, it’s all very well sitting on a bike in the shop, or being able to pedal it in a turbo trainer, but often it’s not until you have taken the bike for a spin to see how any adjustments affect handling, that you can really get to grips with a bike. An accommodating bike shop will allow you to test ride a bike, even if it’s for a spin around the car park.

It can take time to get things right and find the correct size bike, so either make an appointment with the shop, or go midweek when it might be quieter. Don’t expect to rock-up on a busy Saturday morning and expect the world to move around you. Give yourself time to get the job done correctly.

Remember, once you’ve figured out the type of road riding that appeals to you most, get yourself a bike that’s suitable for the job. Get a bike that you like the look of but, more importantly, feels right when you take it for a spin. Get the best bike that you can afford and make sure you’re comfortable and safe. But more than anything, make sure it fits.