Two-up touring: what the load really changes on a bike

You're off for a week, two-up, with two panniers and a top box. The bike is the same one as yesterday and it rides the same for the first ten kilometres. Then comes the first hard stop, the first tight roundabout, the first mountain descent: the bike dives faster, picks up more reluctantly, and the rear tyre makes a working-rubber noise you've never heard from it.

The bike hasn't changed, the mass has. Going from 100 kg on board to 190 kg means adding close to half the weight of the machine again, and putting nearly all of it high up and at the back. Factory settings are calculated for a solo rider of average build: two-up and loaded, they are outside the intended range. Bringing everything back into line takes an hour and costs nothing.

Start with the payload — it's written on the bike

Payload is the maximum authorised weight minus the kerb weight. It's on the manufacturer's plate, often on the frame near the headstock, and in the handbook. Nobody reads it, and that's a mistake: it covers rider, pillion, the kit you're wearing, luggage and any accessories you've added.

Do the sum honestly. An 85 kg rider in full kit makes 90. A 65 kg pillion in kit makes 72. Two panniers and a top box packed for a week, that's 25 to 35 kg. Total: 190 to 200 kg. Add a luggage rack, a screen and a set of soft bags and you're over what a lot of machines will accept.

These are segment ballparks, not your bike's figure: yours is on the plate. Going over isn't just an administrative matter — payload also governs the load indices of your tyres and how the suspension copes.

Pack low and near the centre, not high and at the back

At equal mass, two loading patterns don't behave the same. Ten kilos in the bottom of side panniers, at wheel-spindle height, are barely felt. The same ten kilos in a top box, 50 to 60 cm behind the rear spindle and 40 cm higher, make the bike lazy turning in and, above all, sensitive to weave — that slow wallow of the back end that shows up around 120 or 130 km/h and simply didn't exist unladen.

• Heavy items low and ahead of the rear spindle: tools, lock, liquids, shoes. Bottom of the panniers, never the top box.
• Bulky and light up high: spare helmets, waterproofs, sleeping bag. That's what a top box is for.
• Balance left and right to within 2 kg. One side carrying 5 kg more shows up in slow corners and wears you down by the end of a long day.
• Nothing heavy in front of the bars. A loaded tank bag degrades the steering faster than anything else.

Most top boxes on the market are rated between 3 and 10 kg, a figure marked on the mounting plate or in the instructions, and that limit belongs to the mount, not the lid. The trade-offs between luggage types are covered in our guide to choosing hard luggage.

Rear preload: the one adjustment that really is compulsory

Preload doesn't change spring rate, it changes where the bike sits in its suspension travel. Without adjustment, a loaded machine ends up squatting: it has used half its travel before it has even moved, it bottoms out on sharp ridges, and its geometry has changed — so its stability has too.

The method needs two people and three measurements. Free length: bike on a paddock stand, rear wheel off the ground, measure from the rear spindle to a fixed point on the bodywork. Static sag: bike on its wheels, nobody aboard, same measurement — the difference gives the compression caused by the machine's own weight alone. Laden sag: rider, pillion and luggage all aboard, feet on the pegs, someone holding the bike upright.

For road use, the usual target for laden sag is on the order of 30 to 35 per cent of rear wheel travel, with the exact figure in the handbook. Adjust, then measure again: a click of preload can't be judged by feel. If you're on the stop and still sitting too low, that's no longer an adjustment problem — it's an under-rated spring or a shock at the end of its life. The full method, front included, is in the article on setting suspension preload.

Rebound next, and only next

Once preload is right, the bike sits at the correct height but the shock has more energy to dissipate. The classic two-up symptom: after a speed bump, the back end comes up and bounces a second time. That's a lack of rebound damping, the brake on the spring's return.

Wind on two or three clicks of rear rebound from your solo setting, ride, and judge it on a sharp ridge at a steady speed. The right setting lets the wheel return quickly but without a secondary bounce. Too much rebound and the suspension packs down over broken surfaces: the bike goes hard and loses grip. Only touch compression if you're still bottoming out with correct preload.

Tyre pressures: the two-up figure already exists

Almost every manufacturer gives two sets of pressures, solo and two-up or laden, on the swingarm sticker, under the seat or in the handbook. The difference is mainly at the rear, often on the order of 0.2 to 0.4 bar above the solo figure, sometimes with a small addition at the front.

• Always cold, after two hours standing or less than three kilometres at gentle speed. A hot tyre reads 0.2 to 0.3 bar higher, and correcting hot amounts to running it under-inflated.
• Check every two days on tour. A tired valve makes itself known above all under load.
• Under-inflated and loaded, a tyre gets hot. That's what destroys a carcass on a summer motorway run, far more than mileage does. The mechanism is set out in the guide to motorcycle tyre pressure and wear.

Braking: what gets longer, and why

In pure theory, mass doesn't change stopping distance at equal grip. In practice it lengthens it, for three concrete reasons: the brakes have more energy to turn into heat, so they run hotter and lose bite at the bottom of a descent; the fork dives further and reaches its stop sooner; and the rider brakes less hard because he can feel the pillion arriving in his back.

Allow 20 to 30 per cent more margin on your safety distances, and change technique on descents: firm, short applications followed by release, rather than continuous pressure that cooks the pads. Check the level and colour of your brake fluid before you leave: three-year-old fluid, full of moisture, announces itself at exactly the third hard stop of a loaded mountain descent.

The headlight pointing at the sky

This is the most commonly forgotten item, and the most visible to everyone else. A motorcycle headlight is aimed for a solo attitude. Two-up and loaded, the back squats, the front lifts, the whole attitude tips. One degree is enough: at a typical headlight height, a beam aimed to meet the road at fifty metres ends up above the horizon. You dazzle everyone coming the other way and you see less far, because the useful part of the beam has gone off into the trees. Worth knowing: headlamp aim is one of the items the annual MOT checks, once a bike is three years old — but always unladen, so a pass says nothing about your loaded touring setup.

The no-equipment method: park facing a wall at 5 metres, solo, and mark the top edge of the beam with masking tape. Load the bike completely, pillion included, and look at where that edge has gone. Correct it with the headlight's vertical adjuster, screw or wheel depending on the machine, until you get back to your mark. Some bikes have a quick corrector designed for exactly this. Put it back to the solo setting when you get home.

The order to work through before you leave

Do it a week ahead, not the night before: if a spring or a shock turns out to be the problem, you still have time to react.

1. Estimate the full load honestly and compare it with the payload on the plate.
2. Distribute it: heavy low and centred, balanced side to side, top box kept light.
3. Set rear preload using the three measurements, then rebound.
4. Take the pressures up to the two-up figures, cold.
5. Correct headlight aim with the bike loaded.
6. Check brake fluid, chain tension and lubrication, and the tightness of the luggage mounts.
7. Ride 20 km loaded before you set off, including one hard stop and one tight roundabout.

For the figures specific to your machine — target sag, two-up pressures, torque settings for the pannier mounts — L'Atelier's technical assistant produces them from the make, model and year, without you having to dig the handbook out of a drawer.