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Re: Staying safe on a bike

Posted: Wed May 11, 2016 2:49 pm
by akirk
Interesting the comment about horses - my first business was R&D for safety products in the equestrian world...
If you see the stats in that world you would have no issue in being on a bike - I think it was a Hughston Sports Medicine Foundation report which demonstrated that you were 20x as likely to end up in hospital from a horse than a motorbike, though the type of accident / injuries were likely to be more severe for the biker
Alasdair

Re: Staying safe on a bike

Posted: Wed May 11, 2016 6:37 pm
by StressedDave
Horse wrote:
StressedDave wrote:Just about every traffic officer of my acquaintance and long standing in their role also had large numbers of pins, plates and other ironmongery in their forearms . . .


. . . Raises an interesting question:
Was it poor training, inappropriate tasking (ie they were ordered to) or bad personal choice which led to their downfall? If it was several people rather than just one or two, it sound like a system failure somewhere.

A combination of having to ride in all weathers (inappropriate tasking) under intense pressure and simply the amount of time doing it - an 8 hour shift on a bike (at least 60% actually riding the bike around) for 5 days a week and 48 weeks a year for 20+ years adds up to a lot of mileage. Even with a small probability of accident, sooner or later your number comes up.

You might add in slightly dodgy equipment - those bikes are freighted to the gunwales which makes them a little less stable and prone to high speed weave amongst other things.

Re: Staying safe on a bike

Posted: Wed May 11, 2016 6:52 pm
by GTR1400MAN
StressedDave wrote:You might add in slightly dodgy equipment - those bikes are freighted to the gunwales which makes them a little less stable and prone to high speed weave amongst other things.

Yep, the reputation of the Honda ST1300 was destroyed. People still refer to the Pan weave, yet with sail (screen) down and sensibly loaded, with correct tyre pressures, they are fantasticly stable.

Re: Staying safe on a bike

Posted: Wed May 11, 2016 8:45 pm
by Astraist
Practically all elements of attitude and method in advanced driving is transferable to riding. Some of the differences that come to mind:

Ergonomics.
Controls: Steering, braking and gears, as well as the ability to use body weight to balance each of those inputs.
Primary safety, or rather lack of (even ABS doesn't do quite what it does in a car) and the risk of falling off.
Secondary safety.
Positioning: Greater flexibility in lateral position, enables filtering.

I subscribe to the school of thought that some of the driving population can ride bikes and some simply cannot. It boils down to how hard can the rider concentrate (while still being relaxed) and how intenstive is their sense of self preservation.

I also hold that, in those entirely unforseen events, a car and bike might both not to be able to avoid the impact, but the car driver would be able to prevent any tragic outcomes.

Re: Staying safe on a bike

Posted: Thu May 12, 2016 7:03 am
by Horse
GTR1400MAN wrote:
StressedDave wrote:You might add in slightly dodgy equipment - those bikes are freighted to the gunwales which makes them a little less stable and prone to high speed weave amongst other things.

Yep, the reputation of the Honda ST1300 was destroyed. People still refer to the Pan weave, yet with sail (screen) down and sensibly loaded, with correct tyre pressures, they are fantasticly stable.


Inthe 1980s it was the same with BMWs!

Re: Staying safe on a bike

Posted: Thu May 12, 2016 7:42 am
by StressedDave
I was going to mention that. I was called out a (fortunately) few times to the aftermath.

Re: Staying safe on a bike

Posted: Thu May 12, 2016 8:46 am
by Horse
I had a long chat with someone who was involved with the ensuing claims. [I had no axe to grind, I'd have told each side the same, if asked] It seemed that the issue wasn't just the weight on the rear of the bike (bearing in mind that police bikes are single-seat, so the radio and panniers are mounted much further forward than civvie bikes) but the way it's mounted ie rigidly.

Worth noting that IIRC Triumph deliberately mounted panniers to be flexible.

That said, the old BMW R bikes of that era had bolted-together frames and weren't known for rigidity. I always assumed that was why police riders were trained the way they were, to stand a chance of getting out the other side of bends ;)

Re: Staying safe on a bike

Posted: Thu May 12, 2016 9:02 am
by StressedDave
Weave is a horrible thing to try and analyse. Adding extra spring-mass-damper systems to it doesn't help that process. Was it Prof. Robin Sharp you were chatting to?

Re: Staying safe on a bike

Posted: Thu May 12, 2016 9:15 am
by Horse
Can't actually remember! Guy phoned me out of the blue. IIRC I would have recognised his name, wasn't he the leader of the team at Manchester [?] Uni which developed 'stable' front suspension for bikes in the late 70s/very early 80s? Albeit they just reinvented the leading link fork.

Re: Staying safe on a bike

Posted: Thu May 12, 2016 10:17 am
by StressedDave
Robin was the chap at Cranfield (and then Imperial later on) who did a lot of analysis to work out exactly what was going on. ISTR (I haven't read the papers since I stopped the old job) that it was a function of chassis stiffness, weight distribution and centre of gravity height. Anything that could act as a tuned mass damper (such as the flexible mounts for the pannier & kit) to reduce the peak response was desirable.

He's still at it - http://www3.imperial.ac.uk/pls/portalli ... /50172.PDF is a paper from one of his PhD students. Haven't read it yet - my desire to deal with control issues is a little limited, but if you like Bode plots, have at it.