First Rain in Butte
It has not rained in Butte for 23 days. At 5:30 p.m., a light shower begins as Erin leaves work on her 1982 Yamaha Seca 400. She is two miles from home. The route includes a steep downhill approach to a stop sign, a painted crosswalk, a steel manhole cover in the turn lane, and a final gravel alley entrance. Erin's rear tire has 3/32 inch tread; the front is new. She uses the rear brake only in town because she was told it is 'safer.' Traffic is heavy and the pavement is slick with oil residue. She is wearing a rain jacket but no overpants; her jeans are getting wet. Her commute is short, so she thinks she can skip rain gear.
1. Why is this first rain especially slippery, and how should Erin change her braking?
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The first rain after 23 dry days is especially slick because oil, dust, and rubber residue on the pavement mix with water before washing away. Erin should use both brakes, not the rear only, and apply them progressively. Rear-only braking on a downhill wet surface invites a rear-wheel skid and gives less stopping power. She should double following distance, keep the bike upright, and avoid braking hard on the painted crosswalk or the steel manhole cover, which are much slicker than asphalt.
2. What should she do about the steep downhill stop and the gravel alley entrance?
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Before the downhill, Erin should slow down and select a lower gear so engine braking helps. She should brake before the slope, use both brakes smoothly, and avoid holding the rear brake hard at the stop sign. At the gravel alley entrance, she should cross upright and at low speed, not while leaned or braking hard. If the rain intensifies or she feels the rear tire step out, she should pull into a safe lot and wait; 3/32 inch rear tread is marginal in rain. Wet jeans also reduce comfort and grip on the seat, so overpants are worth the stop.