Can't stop on a dime

Part 2.

In the previous column to this, I emphasized that stopping isn’t just braking, it’s a process that starts long before the pads hit the brake rotors. Narrowly, it’s the sum of:

• Perception time and the distance we travel as we come to realize we have a problem,
• Reaction time/distance, plus
• Actual braking distance

Even optimistically estimated, the first two segments amount to nearly twice the distance as the last, and in a lot of hazard circumstances, could be much, much farther.

Translating that to numbers that relate to common crash speeds:

• 80km/h = 22 metres/second
• Optimistic perception plus reaction time = 2 seconds
• So, 44 metres before the pads touch the rotors, meaning that we’re still doing 80 km/h at this point. Having already travelled roughly half the length of the average city block or football field
• Expert braking at this point can haul our bike down to zero in about 28 metres
• Definitely not a dime
• If it helps, that’s a total stop distance of 236 feet in old money. Or, two hot days’ walk for the chihuahua

Now, about the myths I mentioned last time.

First was the problem of perception time, which isn’t the mythical 3/4 second. It could be anywhere from one to five seconds. If we happened to be looking at the wrong thing at the wrong time, and it took three seconds to spot the problem, we’ve covered an additional 44 metres, or about two more semi truck/trailer lengths.

Uh-oh. This is going to hurt, Harry.

Second is the mythical “expert,” the person who practices maximum braking from high speeds on a very regular basis (daily). Valentino’s calmly generating that best-case braking distance in a controlled setting, with ideal road surface, brakes, and tires. At about one g of braking force, the bike’s capacity.

Is this you, June? Ralph?

In the heat of the moment, at speed in highway traffic, on the roads we actually ride, and based on the amount of actual experience/practice we have with maximum, full pressure braking, things are going to go a bit differently.

Setting aside the mythical expertise and ideals, in the real world even experienced riders only generate about 0.7 g, or 70% of the bike’s braking capacity, so that braking distance moves down the road another…

Inexperienced, but newly trained, riders apparently only show about 0.5 g of braking force on average, which should be starting to ring some seriously loud alarm bells. In testing, that translated to just a hair under double the braking distance of our esteemed expert.

Going back to Perception Response Time for a moment, research tells us that new riders and drivers are also slower to identify hazards that require evasive manoeuvres. So a trained new rider is actually going to need somewhere in the region of two small sized countries to identify, respond to, and stop for a sudden hazard.

New riders without training don’t bear thinking about.

Myth number three: maximum braking.

This is the problem of acquiring expertise. It takes a lot of time and correct practice. It is not the case that practice makes perfect. It does make (relatively) permanent.

Only perfect practice makes perfect. The 10,000 hours of practice that it takes to achieve “mastery” of a skill is 10,000 hours of practising the right thing. Otherwise, you get mastery of rubbish.

Maximum braking results from mastery of braking skills. Riders who lack the specific training, and adequate practice, to accomplish mastery, are not likely to suddenly achieve maximum braking when terror suddenly demands it.

Consider how this translates to typical riding experience. How many riders out there do you suppose routinely practice full-on sudden braking at all? Of them, how many practice that braking from the maximum speeds at which we ride?

I’ve worked with experienced riders who took advanced rider courses, for whom the higher (not high) speed braking exercises were mind-blowing. Mainly because we just don’t do this stuff, so we’re actually not “experienced” in critical skills at all.

Myth number four: maximum braking effort.

The shortest stop possible requires not just the application of maximum braking skill, but also maximum braking effort. Here again, so many of us are compromised by real-world conditions, including the surfaces, brakes, and tires involved. Also, though, those conditions include us.

It turns out that, even or especially when we have to, we tend not to apply full pressure to the brake levers. Instead, riders and drivers apply a big chunk of that pressure, but not the whole meal. Until it’s too late.

We’re “sufficers”, not “optimizers.” We’ve learned how to get by for the most part, so that’s our default position. We don’t generally go right nuts on the thing and do everything possible, just enough to do. But that gets in the way big time when we’re in crisis because the default isn’t going to cut it this time, Jasper.

So, when there’s trouble up ahead, the mythical being who can easily stop to avoid it isn’t actually at the controls. We are.

Give some thought to what advanced training and regular practice might mean.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.