Camchain and tensioner seen up close in a cutaway bike engine

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Slippery When Wet

Blog Date - 09 November 2015

Yep indeedy folks! It's that time of year again when taking a corner with confidence becomes merely a vague memory. Here comes the rain, the cold and sooner or later the ice and snow. No longer will I find myself stuck behind a car on my favourite stretch of twisty lane, from now on the cars will be stuck behind me as I gingerly wobble my way around another diesel covered roundabout or polished tarmac bend.

When it comes to sticking to the road cars have one major advantage. The number of tyres.

Let me set up a scenario A. There is a corner with a small patch of diesel upon it of approximately one square foot. A car is taking the bend at a sensible speed and one tyre is on the slippery patch, the other 3 tyres are on "good" tarmac. As such the driver will not even notice the loss of grip as the 3 other tyres hold the car on line. On the motorcycle being ridden at a sensible speed if either of the tyres pass over the diesel the rider will at best feel a heart stopping twitch, at worse they'll bin it. 

In scenario B the corner now has a streak of diesel 10 feet long and 1 foot wide following the curve. This scenario is actually quite common due to a full tank overflowing as a truck takes a corner. Again the car is driving at a sensible speed and finds both offside or nearside tyres on the diesel. While this will stress the grip of the 2 other tyres on the "good" tarmac it is still quite likely the car will remain on line and very few drivers will even notice. On a motorcycle even at sensible speeds if you find both wheels on the diesel, you are going down.

As long as a car has one tyre from each axle in traction it will remain on track. The same applies to a motorcycle, except there is only one tyre for each axle. So we can deduce that motorcycles are at a much greater risk from slippery patches upon the roads. During the winter when the roads are often wet these slippery patches are desperately common. On a dry day a drop of oil or diesel remains a small drop that is too tiny to be of concern. As the rain falls this drop spreads out and along with the reduced grip of the wet tarmac it becomes a major issue. 

just a drop of oil on the tarmac next to my finger for scale
Just a single drop of old engine oil or diesel...
engine oil spread across wet tarmac
Can spread out like this!

Secondly for the rider is the level of risk. In a car if a driver loses traction at sensible speeds on a slippery surface this usually leads to bent bumpers, insurance claims and the hassle of sorting all this out. For the motorcyclist all these things apply plus injury, often serious injury. Car drivers FEEL safe in the rain.

For the driver rain is something happening out there, outside the warm safe confines of the cabin. Not only does the rider have to deal with the loss of traction and fear of injury he or she will also be struggling with a wet visor leading to poor visibility. No matter how well wrapped up the rider is the cold will be getting in somewhere as well as some degree of wet ingress. Bikers are already facing a physical battle even before the risk of injury.

nasty unknown substance that is slippery on a road
It's not just oil and diesel that causes slippery roads.

So riding a motorcycle in the rain is in fact very hard. Many riders view this as a hardship too many and choose to leave the bike tucked away in the garage and become part of the 4 wheeled brigade in endless queues. Me, well I'm too tight to use the car and I sort of, kind of, weirdly relish the challenge. I do have one pet hate though. While I am delicately feeling my way around soggy junctions and rainbow covered corners the car drivers think it's a good idea to get up real close and personal behind me. This, at the time when we motorcyclists are at our most vulnerable. 

So here's to another 6 months of coldness, wet roads and tailgating tin boxes. 

PS. Don't ever call Bon Jovi "Rock Music". 

Reader's Comments

S Latchford said :-
I'll try and get out on my old 600 as much as poss this winter Ren, not bothered about salt and rust covering it that much but for me it's the ice that is the main problem, it sneaks up on you as the days get colder. One day you find a hard frost where the day before felt just as cold but was ok.
I've had a few moments on ice, it's an awful feeling, I've also had the horizon turn upside down as I've gone down on the very hard and frozen Tarmac, I just hope my local council (Bury) keep on top of gritting my route to work.
But like you say there is actually satisfaction too as you ride along all wrapped up and waterproof in the cold freezing air.
01/01/2000 00:00:00 UTC
Ian Soady said :-
I had 40-odd years of that "satisfaction" but am now in the fortunate position of not needing to enjoy / suffer it!

What always scared me was people tailgating me in very slippery conditions when I knew that if I dropped it there was no chance of them avoiding me.

I remember one very slippery commute on the Commando when I slid off on black ice when I tried to stop for a ped crossing. It was so slippery I couldn't even stand up and had to drag the bike to the gutter with some willing help so I could get it upright again.

Although I thought I'd seen it all, last summer I was caught out by algae in a ford down near Worcester. I took it cautiously at around 10 mph in second, didn't touch the brakes or throttle but was on my ear on the slimy stuff before I knew it. Again a helpful passer-by gave welcome assistance - and he ended up on his backside which was a bit cruel.

I think the problem is fertiliser washing off the fields and feeding the algae.
01/01/2000 00:00:00 UTC
Ren - The Ed said :-
I have never found nor do I expect to find a way of riding a motorcycle safely on ice - unless you have the means to fit studded or spiked tyres. I'm not sure they'd even be legal here in the mild UK.

You both point out that ice is often a hidden danger. Winter's darkness creates and then hides the ice from view. My only advice is if there is a risk of ice then either leave the bike at home or if you must ride then keep to the busiest roads possible. Like Ian and S Latchford I am fortunate enough to own a car but I prefer not to use it.

I've not fallen off in a ford Ian but I sure know how slippery it is. If you ever have the need to explore more slippery fords around the UK check out wetroads.co.uk
www.wetroads.co.uk...
01/01/2000 00:00:00 UTC

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