Wet leaves, cold tyres and a deer warning at 7:40
It is 7:40 on a wet Wednesday in October, +3 °C. You are riding your 125 cm³ A1 motorcycle to school on a two-lane 60 km/h road through mixed forest. Under the big maples at the 2 km mark the asphalt carries a pressed-down carpet of wet leaves; everywhere else the road is merely damp. Last night your front tyre read 1.2 bar on the service station gauge, although the owner's manual gives 2.0 bar for solo riding, and you topped it up with the same old gauge before riding home. You are wearing summer gloves, your visor fogs at low speed, and your low beam is on. A van is 40 m ahead and brakes late for the bend where the leaves begin. A yellow warning sign with a deer silhouette stands just before the trees, and you know deer move most at dawn.
1. As you approach the leaf-covered bend, how do you change your speed and your gap to the van, and what is the reasoning behind each change?
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Three problems are stacked here. Grip: wet leaves give a small fraction of dry grip, and the van's tyres are polishing them further. At 60 km/h a solo bike needs roughly 40 m or more to stop on dry asphalt before reaction distance is added, and far more on wet leaves - so my riding speed for that bend is well under the posted 60. I do my braking on the clean, merely damp asphalt before the leaves start, upright and mostly with the front brake, then release and let engine braking carry me through. Gap: I drop back from 40 m to at least three seconds (about 50 m at 50 km/h) because the van brakes late and I cannot see through or past it. Hazard stacking: the deer sign and the dawn hour mean a second hazard can appear while I am already committed to a low-grip line, so I need spare time, not spare speed. Leaves also hide painted lines and manhole covers.
2. The front tyre read 1.2 bar instead of the manual's 2.0 bar. What does that tell you, and how do you check it correctly before this ride?
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1.2 bar is a large shortfall, not gauge noise: the tyre was losing air or the old gauge is unreliable, and both possibilities matter. An under-inflated front tyre on a 125 makes steering heavy and vague, deforms the carcass so it heats and can fail at sustained speed, and makes the contact patch inconsistent in the wet - exactly the conditions of this ride. Correct procedure: measure cold, with a gauge known to be accurate, cap off, valve upright and the bike upright, compare with the manual figure for solo riding, and check both tyres rather than only the soft one. If the pressure falls again after inflating, look for a puncture, a leaking valve or a damaged rim, and do not ride until it holds. In this scene my first stop is a garage with a working gauge, not the leaf-covered bend.
3. Where in this scene is grip likely to be worst, and how does that shape your line and your braking points?
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Worst grip is in the wheel tracks under the maples, where wet leaves are pressed into a glossy layer; then on painted markings and manhole covers in the same shade; then on the shaded side of the bend where the sun has not dried the surface. Under trees the canopy also holds damp and frost longer, and the road edge can hide a lip of mud. So I enter the bend wide of the worst of the leaf carpet where that is possible without crossing the centre line, do all braking on the clean damp section beforehand, keep the bike as upright as I can through the leaf strip, and make no steering or throttle change while I am on it. After the bend, the first clear asphalt is where I gently test grip with a light brake application.