Descending a wet dike road into a blind bend
You are descending a narrow dike road outside town on a 400 cc single. It is single-track, with grass verges, a series of blind bends, and a 60 km/h limit that nobody obeys. You are in third gear at 55 km/h on a wet October morning after a night of rain. The next bend is a right-hander with a high hedge on the inside, so you can see only about 40 m beyond the entrance. The surface under the trees is covered in wet leaves, and there is a smear of mud where a tractor has left the field. Your visor is fogging along the bottom edge. Your tyres are sport-touring, at the pressures you set a fortnight ago. Halfway round the bend a van comes the other way, straddling the middle of the road because of the narrowness, 30 m away and closing at about 50 km/h.
1. Before you even see the van, what is wrong with 55 km/h in third gear at this bend? Show the reasoning.
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The sight line is the limit. You can see 40 m. At 55 km/h you cover 15.3 m per second, so 40 m is about 2.6 seconds of vision. Your speed must let you stop inside the distance you can see, or you are committed to whatever is around the corner.
The stop. Reaction of one second = 15 m. Braking on wet leaves and mud at maybe 4 m/s²: v²/(2a) = 15.3²/8 ≈ 29 m. Total ≈ 44 m - more than the 40 m you can see, before allowing for the downslope, which lengthens it further. You literally cannot stop in your sight line.
Gear. Third at 55 km/h gives you no engine braking and a sluggish response on the wet. Second, around 35–40 km/h, gives you engine braking, a shorter stopping distance (~20 m in total) and room to react.
Verdict. Enter at a speed from which you can stop within the visible road, teeth off the front brake before the leaves, covering the brake lever with the bike upright and the throttle just off closed.
2. The van appears at 30 m, closing at 50 km/h while you are leaned into the wet right-hander. What do you actually do with the controls?
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Time available. Combined closing speed is about 105 km/h = 29 m per second, so 30 m is roughly one second. There is no time for a plan you have not already rehearsed.
Priority one: do not grab the front brake in the lean. On wet leaves, a snatched front brake at lean stands the bike up violently or washes the front. Instead reduce lean first - a small countersteer input to bring the bike more upright - which frees grip for braking.
Then brake. Once the bike is upright, apply both brakes progressively, front dominant. Keep the bike straight.
Space. Move as far left as the surface allows. The verge is grass and may be soft or drop away, so use it only as a last resort, and cross onto it at a shallow angle, not a swerve.
Eyes. Look at the gap, not the van. Target fixation on an oncoming vehicle is what pulls riders into it.
3. How do the wet leaves and the tractor mud change what you do with the brakes and steering on the way in, compared with a dry bend?
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Leaves and mud are a low-friction layer, not a surface. Grip comes from the tyre meeting asphalt; wet leaves shear away under load, so both braking and cornering forces have to be reduced, and reduced together - whatever you spend on one you cannot spend on the other.
Sequence. Do all meaningful braking upright and in a straight line before the leaf litter. Then be off the front brake and neutral on the throttle as you cross it, keeping the bike as upright as the bend allows. Any steering input across leaves should be one smooth, single movement - corrections are what cause the front to slide.
Rear brake. If you must slow while leaned on a slippery surface, a light rear brake is far less likely to fold the front, though it does little braking.
Line. Take a line that avoids the worst of the mud where the tractor left the field, even if it means a tighter entry, and note that hedge shadows hide damp patches that have not dried all day.