Wet Descent, Two Up, With a Van Waiting
It is a Saturday afternoon in November. You are riding a 400 cc naked bike with ABS, two-up, through a narrow village street with a gradient of about 12%. Combined rider, pillion and luggage weight is 160 kg against a stated maximum payload of 180 kg. The street is surfaced in polished limestone setts, wet after a shower, with a thin film of water and a little diesel near a bus stop. The road bends left at the bottom onto a main road, where a van is waiting to emerge from the right. Rear tyre is six months old with 1.8 mm of tread at the centre. Brakes and ABS are working correctly. Painted "SLOW" markings and a cast-iron manhole cover sit on your line about 40 m ahead. The pillion has ridden pillion twice before, both times in dry weather on main roads.
1. Explain how you manage speed on this descent, and why the front brake alone is a poor plan here.
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Speed is managed before the brake is needed.
- Select a low gear early - second on a 400 cc at 12% downhill - so that engine braking is doing a large share of the work and the brakes are not asked to dissipate the whole descent. Brakes that are already hot at the bottom will not be at their best for the van.
- Both brakes, progressively. The front brake still provides most of the stopping force on a downhill gradient, because weight transfer is reduced but not eliminated by the slope and the passenger. But it must be applied in a squeeze, building pressure, not a grab.
- Why not front-only: on wet polished limestone with diesel film, the available grip is well below dry tarmac. A front-only application puts all the demand on the tyre that has the least reserve and the most to lose; if it lets go on the setts, the bike is down before you can react. The rear brake also helps stabilise the machine at low speed and gives you a second, independent means of shedding speed.
- Avoid braking on the painted markings and the manhole cover. They offer less grip than the setts around them. Plan the braking to finish before you reach them, or pass them upright and off the brake.
- ABS is an assistant, not a licence. It will stop a locked wheel, but it cannot create grip that the diesel has removed, and it will not save a rider who is leaned over on a polished surface.
Sequence: brake in a straight line at the top, release, let engine braking hold the speed through the bend, and arrive at the junction at walking pace.
2. Describe your line and body position through the left-hand bend with this passenger, and what you tell her before you set off.
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Line: a late, wide entry is the wrong instinct on a wet descent in a narrow street - it puts you nearer the centre line and on more of the diesel and water. Take a tighter entry, staying well left of centre but off the gutter and off the setts' polished edge, and hold a single, smooth arc to a slightly wide exit, which gives you room if the van does pull out.
Body position:
- Keep the machine more upright than you would in the dry - less lean angle for the same bend means more of the tyre's grip is available for braking and for the surface irregularities of the setts.
- Weight the outside peg, keep the upper body relaxed, arms bent, no death grip on the bars. Tension in the arms transfers to the steering and makes the bike feel unstable on a poor surface.
- Do not brake mid-bend. All speed reduction happens before the turn-in; through the bend you are neutral or very gently on a trailing rear brake.
Briefing the pillion, before the engine starts:
- Sit still, feet on the pegs, hands on the grab rail or around your waist, not on your shoulders.
- Look over my inside shoulder through the bend - her head and shoulders follow her eyes, and a passenger who leans the wrong way is the single biggest handling problem in a slow wet corner.
- Do not move or shift weight at low speed or at the junction.
- If she needs to stop, tap my side twice; do not stand up or put a foot down unasked.
Why it matters: at 12% downhill on wet setts, the passenger's weight is a handling factor as much as a payload number. The 160 kg against a 180 kg limit leaves only 20 kg of margin - this bike is working near its design case.
3. What extra risk do the diesel and the waiting van create together, and what is your plan on approach?
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The two risks interact, which is what makes them a test question rather than two separate ones.
- Diesel near a bus stop typically sits in a band along the stop line and the gutter, exactly where you would go if you hugged the left edge, and it is often invisible under standing water. It does not announce itself; the first sign is usually the front wheel stepping out.
- Wet cast-iron manhole cover and painted markings are the other low-grip islands on a street that is already marginal.
- The van on the right, waiting to emerge has a driver who is looking for a gap in main-road traffic, not for a motorcycle descending a wet side street. In left-hand traffic, a vehicle emerging from your right will often pull forward to see past parked cars, closing the gap you were planning to use.
Plan:
- Finish the braking early, before the diesel band and the cover, so you arrive at the junction at a speed from which you can stop within a couple of metres.
- Assume the van will pull out. Decide now where you would go: the gap behind it if it hesitates, or a stop before the give-way line if it commits.
- Stay out of the diesel band - ride nearer the centre of your side than the gutter, while staying clear of oncoming traffic.
- Cover both brakes on the final approach, upright, bars straight.
- Do not enter the main road until you have seen the van's wheels stop moving and you have clear sight both ways.
The judgement being tested: the van is the obvious hazard, the diesel is the hidden one, and a rider who fixes on the van will ride straight through the diesel without noticing.