Why the numbers matter more than the line

It is easy to plan a route that looks lovely on a screen. A squiggle through green fields, a gentle ribbon along a river, a nice little loop back to the start. Then you ride it and discover that the green fields sit on a 12 per cent ramp, the river path is a churned-up mud track, and the "quiet lane" is a rat run at five o'clock. The line on the map told you nothing useful about any of it.

The good news is that the data is out there. Elevation profiles, surface types and traffic counts are all available in the mapping tools most of us already carry in a jersey pocket. Learning to read them takes an evening, and it will save you far more time than that over a season of riding. Think of it as reading the small print before you sign up for the ride.

Reading an elevation profile like a local

Every decent route planner shows you a profile, but the shape matters more than the total. A saw-tooth profile with a hundred metres of climbing spread over twenty small rises feels completely different from one long drag of the same height. Short pitches let you carry momentum; a sustained climb asks you to settle in and work.

• Total ascent per 10 km is the quickest gauge. Under 50 m is flat. Around 100 m is rolling. Anything above 150 m per 10 km is a proper hilly day.
• Gradient spikes are worth checking closely. A kilometre at 10 per cent is a serious effort; a kilometre at 15 per cent may mean walking, especially loaded with touring kit.
• Where the climbing sits decides how tired you will be. Hills in the first third are free. Hills in the last ten kilometres, at the end of a long day, are not.
• Descent steepness matters too. A 20 per cent drop on a wet day with rim brakes is a different proposition from a gentle glide.

If you use a route-planning tool with a routing profile for road, gravel or touring, switch between them and watch the numbers change. That difference is roughly the difference you will feel in your legs.

Surface types: what is actually under your tyres

A route line can mean tarmac, surface-dressed chip seal, compacted gravel, forest track, towpath, or a bridleway that is only rideable in a dry August. Many planners carry surface data from open mapping projects, and it is usually good enough to make a sensible call, though it is only as current as the last person who surveyed it.

Practical rules of thumb:

• Surface dressing is still tarmac, but loose chippings on a freshly dressed road are worth avoiding on skinny tyres.
• Towpaths and canal routes are usually firm and flat, but can be muddy after rain and often have gates or barriers every few hundred metres.
• Bridleways and byways are legal to ride, wonderfully quiet, and occasionally impassable on a loaded touring bike.
• Bike type guides — anything from 28 mm upwards will handle most well-made gravel, but if a route is flagged as rough or unsurfaced, 35 mm or more is far kinder.

Where a planner lets you set a surface preference, use it, then check the profile again. Choosing gravel often adds distance and climbing as the route hunts for a track.

Traffic data and the quiet-road rating

The single biggest factor in how much you enjoy a British road ride is how much motor traffic shares it with you. Most modern planners score roads using traffic volume and speed limit, and many let you set a preference for quieter routes. Take those ratings seriously, but interpret them with local knowledge.

A B-road can be blissful on a Sunday morning and grim at eight on a Monday. Farm traffic appears at harvest. Commuter routes fill and empty like tides. If you are planning a weekday ride, run the route past a mental map of rush hour; if it is a weekend, remember that the lanes around popular beauty spots get busy by mid-morning but the roads themselves often stay quiet.

When a route uses an A-road, check the length of the section. Two hundred metres across a bridge is fine. Fifteen kilometres on a fast trunk road is not a ride anyone will thank you for.

Matching the route to your fitness and your window

This is where most plans fall apart: not ambition, but arithmetic. Your route planner's estimated time is based on assumptions about your speed that may have nothing to do with you, your bike, your luggage or the wind.

Instead, calibrate from your own rides. If a 40 km ride with 300 m of climbing takes you two hours, you know your baseline. From there, add roughly one minute per ten metres of extra climbing per ten kilometres, and factor in the terrain. Then add a buffer of 20 per cent for stops, photographs, the wrong turn at the roundabout and the café that turns out to be shut.

If your available window is four hours, plan a three-hour ride. Touring with luggage, add another 15 to 20 per cent. Into a headwind, more again. It is far better to finish with an hour to spare and time for tea than to spend the last hour grinding into a headwind you did not plan for.

Taking it on the road: offline maps, batteries and a paper backup

Whatever you plan with, make sure it works without signal. Rural parts of the UK still have dead spots, and a phone searching for a network drains its battery fast. Download the map area in advance, and check the download covers the whole route plus a margin for detours.

• Battery: a phone running a mapping app with the screen on will empty in four or five hours. Carry a power bank or a dynamo, and switch the screen off on straight sections.
• Cue sheet: a short list of turn-by-turn notes on a piece of paper taped to the bar bag will get you home when the phone dies.
• Printed map: a folded paper map of the area weighs almost nothing and never runs out of charge.
• Share the route: send the file or the link to whoever you are riding with, and to someone at home if you are heading somewhere remote.

Plan well, but hold it lightly. The best routes are the ones where the data has done its job quietly in the background and you hardly think about it at all.