Riding Skills 101

Improve your motorcycling skills
with Survival Skills Rider Training

Start your journey into better biking here!

Survival Skills|FREE better biking tips for all motorcycle riders

Learning biking Survival Skills isn't expensive...
...because these tips are FREE for all bikers

Avoiding diesel and other slippery spills

Some years back, there was a long discussion on the problems of diesel on one of my favourite forums. My first introduction to the slippery nature of fuels spilled on the road came soon after I'd taken my 125 up to London. I stopped at a pedestrian crossing, three bikes came flying past me, turned right and promptly formation-crashed. As I pulled away, the 125 span the back wheel. Even that early on in my riding career I knew that wasn't quite right and took the corner rather more slowly than the other bikes. A truck was parked halfway up the hill with a split tank and some fireman throwing bags of sand around it. The slick reached right down the hill to where the bikes had crashed. That was a while ago, and on purely observational evidence, it seems to me that fuel spills are much less common than when I was a courier. Moreover, evidence from police accident investigations suggests that despite the popular belief that oil and diesel cause bike crashes, the real crash numbers are low. That might be why most of the correspondants who had mates "who have crashed on diesel", surprisingly few actually put up their hands and said "I've crashed myself".

Nevertheless, it's as well to be on the alert. As with all hazards, the first thing to consider is where we might find it, secondly how to spot it, and thirdly and to have some idea of what to do if we do spot ANY oil, diesel or petrol spill - they are ALL slippery.

Where might we find diesel and petrol (it's slippery too) spilled on the road? The obvious answer is where vans, trucks and buses start with full tanks. And that means ports, industrial estates and bus depots, particularly in the morning. Leaving aside the random spills from a split tank, or from the van that had taken off its sump on high kerb round a traffic-calming 'pinch point' (it didn't get far but left quite a slick for half a mile), keep an eye open where vehicles change direction - corners, junctions and particularly roundabouts are likely problem areas.

Combine a roundabout with exits marked INDUSTRIAL ESTATE and we should be on alert. Back when I was a trainer in Lydd, my homeward route took me round the Ashford ring road, which has a dozen industrial estates round it. Just as I was slowing for a right turn at one of the roundabouts, a guy on an R1 flew past signalling right as well. Knee out, he vanished around the back of the island but never reappeared. Going round rather more cautiously, I avoided the big streak of diesel and stopped to lend a hand. Rider unhurt but bike rather sad, having flipped over after sliding into the kerb. I left him arranging a van ride home. If we're apply the 'stop in the distance we can see to be clear' rule, don't forget it applies to road surface too.

Another good rule-of-thumb is that diesel spotted on one corner will probably reappear on the next. Another courier followed me carefully round one left-hander leading out of one London square as we both avoided the diesel. He overtook me, and promptly crashed on the left-hander leading into the next square just few hundred metres further on. As I stopped to help him untangle the bike from the railings, he said: "I didn't expect diesel on that bend too".

Err, right. So where did you expect it?

Most spills either come from overflows on over-filled tanks (much rarer now) or when drivers forget to put the filler cap on. Don't laugh - I forgot to put the bike filler cap on once, because the tank bag covered it. A lapful of fuel reminded me, but the driver won't know. The fuel is likely to be be spilled outwards so look for it on the outside of the lane - near the centre line on a left-hander or the kerb on a right-hander. But don't forget a oncoming vehicle could slosh it our side of the centre line on a right-hander too.

Watching the surface is one reason for not trailing a vehicle ahead too close. If we see temporary slippery road signs or even police SLOW triangles, take care - it could be a spillage or even accident ahead, and there may well be a slippery cocktail of detergent, diesel, engine oil and antifreeze on the road.

See if you can spot the spill. In the rain, oil produces the familiar rainbow effect. It looks scary because the rain washes the oil right over the road, but in fact the rainbow effect is produced by a layer just one molecule thick. A single drop of oil can produce a big circular rainbow patch. It's slippery but not lethal - the tyres will cut down to the surface. But if we see the rainbow right across the road, then it's a bigger spill. Try to see which way the rainbow's being washed - the source is probably in the other direction and that's the area to keep clear of.

Unfortunately, in the dry, there's no warning rainbow. The best advice I can give you is that fresh oil and diesel is very wet-looking and very shiny. It's looks like 'very wet water' for want of a better description. A big diesel spill in the dry can often be smelled. So use your nose. A dulled black streak is almost certainly an old spill, and unlikely to be particularly slippery. But it's worth knowing that if it rains, old spills can be 'reactivated', particularly by a short shower after a long dry spell.

Don't forget petrol can also be spilled. It's just as slippery as diesel but harder to see - it looks like water. Whenever possible, keep clear of any unusual wet-looking patches.

Interestingly, in that forum discussion, there was little useful advice, beyond declarations that "it'll will have you off if you hit it" statements.

Ideally, we do want to stay off it if possible. It's just a matter of having the speed and lean angle in hand to change line and direction. But sometimes we simply have cross a spill. It's straightforward enough if we can avoid leaning and braking (the usual instinct) as we cross it, and instead keep the bike as upright as possible. For that reason if I find a spill mid-corner, I tend to steer INSIDE it, even if that means sacrificing my view round the bend. Why? I may have to cross it. If I'm on the inside, I can pick the machine up and cross it upright, before leaning over again back on clean tarmac. But if I'm on the outside and need to cross it, I actually need to increase my lean angle. Not a good plan. And don't forget that the tyres will take a moment to clean off - don't bang the bike straight over on its side, but ease it over.

Look ahead, think ahead, plan ahead, and oil and diesel should be no more than a minor - if potentially dangerous - irritant.

Kevin Williams
Survival Skills Rider Training

...because it's a jungle out there


If you have enjoyed these Survival Skills articles, you can help me stay awake and keep writing. Just click the button below to buy me a coffee!

Buy Me a Coffee at ko-fi.com

* follow Survival Skills on Facebook and find new tips every week.
* discover Survival Skills books 



Subscribe to our Newsletter

Book a training course

What is Survival Skills all about?

How are Survival Skills Courses put together and taught?
The Making of a Good Instructor - musings on my Driver Education course

Would a National Standard for advanced training be appropriate?
Writing a riding tip - what detail is necessary?
What to do if you've had an accident
Accident Statistics - dispelling some myths

Improver or advanced, pragmatism or perfection?
Piling on the miles
Compartmentalisation & Practice -  the key to learning new skills
Countersteering - Question and Answer

Braking Rules and Tips
Over-confidence and Riding at the Limit
Practice makes Perfect
The Danger of Misunderstanding
Learning from your Mistakes
A Moment of Inattention
Staying Warm
Staying Awake
Don't just ride for yourself, ride for others
Filtering - what's legal and how to do it
Cornering Problems 1 - Lean or Brake?
Springing into Summer - polishing off the winter rust
Group Riding - Rules and Tips
Awareness of Risk and Risk Management
Cornering Problems 4 - Stability and the "Point and Squirt" technique
Cornering Problems 3 - Staying out of trouble! Pro-active Braking or Acceleration Sense?
Cornering Problems 2 - Staying out of trouble
What is Risk?
Avoiding Diesel
The Vanishing Point - is it enough?
Posture - the key to smoother riding
When the Two Second Rule is not enough
Riding in the Dark
Roundabouts - straight lines, stability and safety
Slow Speed Control
Aquaplaning - what it is and how to deal with it
Rear Observation - when to & when not to!
Staying upright on icy roads
KISS - 'Keep it simple, Stupid' or Low Effort Biking
Overtaking Safety - avoiding vehicles turning right
Proactive versus Reactive Riding
Living with  Lifesavers
Which Foot? The Hendon Shuffle - Question and Answer
Carrying a passenger - Question and Answer
Riding in the rain
Riding in strong winds
Sorry Mate, I didn't see you - an analysis of SMIDSY accidents
Ever gone into a corner too hot and had it tighten up on you?
The Point & Squirt approach to corners
A time to live...
Target Fixation - Question and Answer
The Lurker, the Drifter and the Trimmer
The five most important things I learned as a courier
Overtaking - Questions and Answers
Precision riding - or keeping it simple?
Wide lines, tight lines, right lines - the law of Diminishing Returns
Surface Attraction
Euphoria - when your riding is just too good to be true
Straight line -vs- trail braking
Sit back, close your eyes, relax... and hope for the best
Before you overtake, do you...?
Do you need to blip the throttle on a downshift?
Holiday Riding Tips 1 - Dealing with hairpins (a new occasional series)
Holiday Riding Tips 2 - The (drive on the) Right Stuff
Why SMIDSYs happen
Avoiding dehydration - riding in hot weather
Riding errors - and avoiding them
Season of mists and mellow fruitfulness - riding in fog
Where does Point and Squirt come from?
Overtaking - lifesavers and following distances
Offsiding - what is it, and why you should think before you do it!
Anger Management - dealing with "red mist" and "road rage"
That indefinable gloss
Overtaking on left-handers - experts only or best avoided?
Apex or Exit - what's important when cornering?

Developing 'Spidy Sense'

Armchair Riding - how to improve summer skills in winter

Working towards a BTEC in post-test instruction part 1

Working towards a BTEC in post-test instruction part 2

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
This archive of articles is provided free to read and download, but is not for commercial use. Contact me for re-use rights.

IMPORTANT: The information on the Survival Skills website is for your general information and personal use and should be taken as a guide only. Survival Skills Rider Training provides no warranty or guarantee as to the accuracy, timeliness, performance, completeness, clarity, fitness or suitability of the information and materials found or offered on this website for any particular purpose and we expressly exclude liability for any such inaccuracies or errors to the fullest extent permitted by law. It shall be your own responsibility to ensure that any products, services or information available through this website meet your specific requirements and you acknowledge use of any information and materials is entirely at your own risk, and that neither Kevin Williams nor Survival Skills can accept responsibility for your interpretation or use of this information or materials. The content of these pages is subject to change without notice. 

 Copyright © 1999 - 2019 Kevin Williams and Survival Skills Rider Training