Tag: surface

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84. ‘All dressed up’ – coping with loose chippings

This is based on an article I wrote for the old ‘Survival Skills’ forum on a now-defunct bike forum back in 2007. Having looked over the text (which has had a mild rewrite for clarity) nothing I wrote two decades ago has changed; at least, not the advice about dealing with the freshly-load surface itself. However, what has changed, and changed significantly, is that we now have solid research evidence showing that chip seal isn’t merely an unpredictable low-speed stability problem — once fully cemented in place and when riding speeds are back to normal, it’s exceptionally destructive to rider clothing once things go wrong. It’s one of the harshest abrasion environments we’ll meet on public roads. That makes clothing choice for open-road riding to the fore. The danger is that riders who accept lighter kit because it’s “fine for ordinary road speeds” may be making assumptions that surface-dressed chip seal roads directly undermine. This shifts surface dressing and chip seal from being “a handling problem” to being “a personal protection problem” too, and that’s something all riders ought to be aware of.

‘All dressed up’ – coping with loose chippings

One worry that new riders have (and I guess a few more experienced ones too) is how to treat roads which have been ‘surface dressed’; this is the low cost repair where a new layer of chippings is simply spread on top of a layer of sticky resin sprayed on the old surface. The road is then re-opened with a temporary low speed limit and relies on the passage of vehicles to ‘roll’ the loose chips into the resin binder to form a permanent bond and create a durable surface. Eventually, a sweeper comes out and hoovers up the remaining loose chips. This surface is quite common on quieter UK roads. In France and the US, I’ve found surfaces treated this way to stretch for miles at a time, and is widely used in Australia and New Zealand where it’s known as ‘chip seal’. The locals cope, so we can too.

Most concerns focus on the loose chippings themselves, and on how each lane of traffic quickly becomes a pair of relatively clear wheel tracks with a ridge of loose stone between them, as well as another ridge along the centre line, and one more at the edge of the carriageway.

Generally speaking, riding in a wheel track makes sense since it’s usually the cleanest line and offers the most predictable grip. I’d normally pick the offside wheel track since it keeps us well clear of unexpected hazards on the nearside, and I wouldn’t attempt swapping lines on twisty road. On narrow roads where oncoming traffic could get close, I’d likely chose the nearside track though.

Either way, it avoids riding directly on the deeper ridges of loose stones, and it’s rarely as dramatic as people fear. Provided we avoid hard braking, excessive lean angles or handfuls of throttle, then we can treat the gravel in the wheel tracks much like any other low-grip surface..

If we genuinely have to ride though the deeper, loose material — maybe the road has only just been reopened to traffic — it’s still perfectly possible to ride through it. Counter-intuitively, trying to crawl along at walking pace can make the bike feel less rather than more stable. A modest, steady speed creates momentum and that helps stability. The bike may squirm slightly beneath us, but that movement is normal and self-correcting. The trick is to use the ‘brace position’ — the posture where we keep our upper body, shoulders, elbows and wrists loose to allow the bars to move around but lock onto the bike with the knees on the tank. This is the key — to stay relaxed and let the bike move under us. But keep good gaps and get braking done early and in a straight line. There’s often more grip available on loose chippings than riders expect, but sudden inputs overwhelm it quickly. Keep cornering lean angles modest, maintain a neutral or gently positive throttle, and wait until the bike is upright before accelerating.

If we need to cross a ridge of loose stones, do it deliberately. My tip here is to turn the bike as much as possible so as to cross the ridge as close to a right-angle and as upright as possible. It should go without saying, we should avoid braking or accelerating while in the deeper deposit.

Other hazards worth watching for include:

    • Piles of chippings mid-corner or at junctions, where traffic sweeps them sideways, and at downhill stops where stones fall from car wheel arches. Brake early and positively, then ease to a stop with minimal front brake pressure at walking pace.

    • Hidden potholes, sunken repairs, and speed humps, which can disappear completely under fresh stone. Visual clues are reduced, so read the wider road environment carefully.

    • Freshly laid high-friction surfaces (such as Shellgrip), which often shed loose aggregate initially. Treat them with caution until they’ve bedded in or been swept.

Finally, I’ve found that speed limits are often set unrealistically low and as a result they are widely ignored. If we ride too far below the prevailing speed, we’re simply inviting close overtakes and being sprayed with flying chippings. I’d recommend riding at something closer to the general flow, whilst leaving a generous gap to the vehicle ahead. That way we can avoid being pebble-dashed as we ride, and we’ll also have plenty of space to brake smoothly if we need to.

Surface dressing isn’t pleasant, but it isn’t a lottery either. With good observation, smooth inputs, and sensible decision-making, it’s just another surface — not a reason to tense up or tiptoe.

 

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57. Surface Attraction

Modern tyres and suspension systems give riders more confidence, but the fundamental principle hasn’t changed: traction is limited not by the rubber, but by the surface; no tyre grips on ice.

Surface Attraction

A while back I read a research paper that examined just where road users actually look. Guess what? Motorcyclists looked at the road surface more than drivers. That surprised the researchers but was predictable because it’s the friction between tyres and road surface keeping bikes shiny side up. The level of grip we have impacts on our ability to accelerate, brake, steer and lean so it’s not surprising that we pay the surface a lot of attention. Nevertheless, it’s important to understand why some surfaces are barely ridable in the dry whilst others give near race track levels of grip in the wet.

Perfect surfaces are the exception rather than the rule, but still riders are caught out and panic when they see a dubious surface mid-turn. Why? Because we need time to react – spotting a problem already under the front wheel is too late.

Scan ahead then anticipate if the surface gets better or worse – a change of colour or visible line across the road often warns of a change, and though they look the same, two surfaces may have very different grip. Anything shiny is probably slippery. It makes sense to follow the Survival Skills advanced rider training approach by planning for the worst before we discover the hard way.

Slippery access covers are found around bends and junctions – don’t brake on them, aim to steer round rather than over. A shiny line could be a tar seam – like glass in the wet. Bumps and slippery surfaces together spell caution – beware cats-eyes when overtaking and paint markings that don’t follow an ideal line.

Discoloured patches could be wet patches, gravel, potholes or polished surfaces. Mud and gravel will wash downhill after rain and accumulate at the bottom of hills. Loose chippings will be pushed to the centre and sides of the cars’ tyre tracks – do we want to brake on those?

Irregular streaks are often fuel spills. Petrol is as slippery as diesel but evaporates quickly. If you smell diesel slow down and search! Guess where you’ll find it – near filling stations, bus depots and industrial estates, on roundabouts and long fast bends.

Watch out for shellgrip – it’s a high friction surface laid near pedestrian crossings and traffic lights, and sometimes on bends too, but rarely far enough round to get the bike upright again. Take advantage of the extra grip mid-corner and we’ll hit the less grippy surface still banked over – a recipe for a slide.

Don’t forget rain! After a prolonged dry spell, all surfaces will be extra-slippery.

Things we can change are tyres, suspension settings and – attitude! Super-soft track compounds just don’t work on the road. They don’t warm up and don’t like rain. Hard track suspension settings don’t allow the bike to follow road irregularities. Stick to road set-ups and road compounds, but even then we need to take some care. Modern tyres have excellent grip but can fool us into pushing too hard – our tyres can only deliver the amount of grip that the surface offers. A super-grippy tyre will have more more traction over wet metal access covers or on diesel. And once the bike starts sliding, it may well panic us into grabbing the brakes and having a crash that shouldn’t have happened!

So beware overconfidence. Don’t ride too fast for the conditions, keep back and don’t follow the vehicle in front. Just because the Land Rover made it round doesn’t mean we will too!

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45. Eleven Essential Tips for riding in the rain

The advice is still very relevant, especially the emphasis on spotting slippery surfaces, progressive braking, careful cornering, and anticipating changes in grip. Modern bikes, tyres, and safety aids have slightly shifted the context, but the fundamentals of wet-weather remain the same, with the emphasis on spotting slippery surfaces (manhole covers, white lines, tar seams, leaves) and anticipating how those surface changes will affect traction, remaining critical.

Eleven Essential Tips for riding in the rain

Rain means wet roads, and wet surfaces means less grip than in the dry, and so we’ll have to reduce our throttle openings, lean angles and increase our braking distances accordingly. The question is “how much?”. Unless we have some idea of how much grip there is, we don’t really know how hard we can accelerate or brake, or how much lean we can use. And we can end up being excessively cautious and then we’ll be harrassed by other drivers. There is nothing wrong with taking care in the wet, but too much caution and we start causing ourselves even more problems. So let’s have a think about the issues.

HOW LONG HAS IT BEEN RAINING – this should be our first question. Prolonged rain flushes surface contaminants away and given a decent surface, wet roads usually have plenty of grip. . But if it’s only just started raining, particularly after a prolonged dry spell, expect the surface to be super-slippery. Oil dripped onto the road mixes with the worn rubber on the surface, creating a slick.

KNOW WHERE TO FIND GRIP – a wet surface that is in good repair and clean, modern tyres should have good grip – it’s a bit hard to put a figure on it, but at least 70% of dry grip should be available. And high grip ‘Shellgrip’ style surfaces give near race track levels of grip even in the rain.

AND KNOW WHAT’S SLIPPERY – but what about the road that’s not in good condition or is contaminated? Some surfaces which are fine in the dry are appallingly slippery in the wet. Now the problem is that no matter how good our tyres, they won’t grip if the road surface cannot deliver its half of the deal. And the quality of the surface has been steadily deteriorating for the last three decades and right now finding a perfect surface is now the exception rather than the rule. So be on the alert for surfaces which are slippery when wet:

metal manhole covers
cats-eyes
white lines and road markings
bitumen tar seams where tarmac is sealed
polished and worn road surfaces
oily surfaces
leaves

Here’s a clue. Most things that are shiny when wet – even leaves – are slippery! So treat any shiny patch on the road as potentially slippery and something to be avoided if possible.

KNOW WHERE IT’S SLIPPERY – and then avoid or take care in those places. A big fear for bikers is spilled diesel. Although figures published by FEMA (the European rider rights organisation) claimed that 10% of all motorcycle accidents were caused by diesel, UK figures suggest it’s less than 3%. Whatever the truth, there’s no need for us to become one of the statistics by being cautious where spills of fuel and oil are most common:

roundabouts
near industrial estates
by garages
on bends and at junctions
between the wheel tracks at traffic lights or stop signs

Treat dark shiny streaks or rainbow patterns with care, and use your nose – you will often smell diesel before you spot it. And remember petrol is JUST as slippery as diesel.

SPOT SURFACE CHANGES – as I mentioned, we may ride from a grippy surface onto a less-grippy one, so we need to spot that as early as possible. Look up the road and try to spot a change of colour. It’s almost always a change of surface. We won’t know whether it gets better or worse, but at least we’re on the alert. A visible line often warns of a change. Oblong shapes are usually road repairs. Irregular areas of a different colour could be a damp patch, a pothole or loose gravel. Streaks are often a fuel spill.

BE ALERT FOR SURFACE WATER – there aren’t too many around but on minor roads, we could come across a ford. Take it cautiously and upright and don’t brake or accelerate hard – they are often slippery with algae under the water.

After a thunderstorm, watch out for surface water beyond the norm! After prolonged or heavy rain, expect flooded surfaces. Avoid riding through puddles as a matter of course – they may conceal a pothole or debris. There’s a minor risk of aquaplaning on standing surface water but watch out deeper water which can cause a loss of control if hit at speed. Any depression is likely to be filled with deep water. Underpasses often flood to surprising depths. Look to see where the kerb disappears to get an indication of how deep it might be.

Watch out for mud, gravel or debris carried into the road. I’ve had to dodge a sizeable log before now. Streams may burst their banks and flow into the road, and we not only have to be careful about the depth of water – look at fence posts or the hedge – but there could well be a strong current. It might be wiser to find an alternative route than attempt to ford it.

KNOW WHEN TO SLOW – in wet weather, many riders will slow down unnecessarily, even when it’s safe to maintain a decent rate of progress. It’s stopping distance we mostly need to worry about, and whilst it increases with speed, if we stretch our planning and open up our following distances, then it should be OK to maintain speed to go with the flow to avoid being tailgated by impatient drivers.

AND WHEN IT’S MORE IMPORTANT TO KEEP A GAP – one of the biggest wet-weather faults I see is following the vehicle ahead too close, too fast. Braking distances increase in the wet, but it’s not just stopping distances we need to worry about. We need to understand how changes of surface affect our ability to stop and maintain control. We really don’t want to find we’re braking over a wet metal access cover that just popped out from under the car ahead.

AIM TO BE SMOOTH – what breaks traction in the wet is often a sudden application of brakes or throttle. Whilst modern bikes have ABS and traction control is becoming common too, kicking either in is not a good idea as it’s disconcerting. And without these aids, there’s a risk of a loss-of-control. Aim to be smooth, but also to be minimalist – the fewer control inputs that achieve a particular result, the better.

Aim for progressive braking. Once the suspension has compressed we can build the pressure – most riders are surprised how much grip is available if we don’t grab a big handful of brake.

Don’t make the common mistake of trying to stay off the brakes then finding you need them at the last moment. Brake early and positively rather than late and harshly – it not only improves stability but gives us options. If we brake earlier than necessary, it means we can release the brakes again if we are unable to avoid crossing a wet metal cover or a painted arrow. That takes away the fear of locking a wheel as we ride over it, and we can reapply the brakes on the other side. It’s not very difficult IF we look ahead and think about what we are doing.

Know how to corner in the wet – there’s no real difference in technique, but it’s more important we get it right. Don’t try to turn in on a closed throttle or on the brakes – if we do, we’re loading the front tyre with deceleration forces just as you want all the grip for steering and it’s easy to lose the front if we hit a slippery patch. Instead, get the braking done upright, get off the brakes in a straight line to let the suspension settle THEN turn in smoothly.

Just as in the dry, the best way to enter a corner on a wet road is back on the throttle, keeping steady power on through the turn, which means using the Point and Squirt late apex approach I teach on Survival Skills Performance Courses through the corner. The biggest steering errors are to turn in too early which guarantees we’ll run wide on the exit, then probably touch the brakes mid-corner to try to lose speed – in the wet this is even more a recipe for disaster than in the dry. In fact, mid-corner, we can probably lean over further than we might expect, which is the way to deal with a tightening bend, but try to avoid sudden or jerky motions. We don’t need to corner at walking pace but just a modest reduction in speed means we can make our direction changes a little more gentle, and use a little less lean angle mid-turn. open out your lines a little and make them smoother. Err on the side of ‘slow and smooth in, and faster out’ – it’s not that important to ride fast in the wet.

Don’t try to open out the exit to the turn by taking a wide, sweeping line. We may need to change line to keep off tar seams, access covers or white paint mid-corner. If we’re on a line that gives us no way of changing position should we need to, then we’re potentially in trouble. If we’re on a sweeping line and aiming for the extreme edge of the lane, and we do experience a slide, we’ve no room to recover. In the wet, I avoid extreme cornering lines – so I can compromise my perfect line to avoid slippery areas. I usually ride in the middle third of the lane, so I have some room for error.

If we must brake in a corner – perhaps because the road ahead is blocked – then use BOTH brakes lightly. Remember – if you’ve not already crashed, there is SOME grip at the front. As the speed comes down, our lean angle usually comes up, and so we can brake progressively harder. The important thing is not to grab at the front brake. With no ABS we’ll probably crash (I’ve bought that tee-shirt), with ABS we’ll have a moment to recover. Although it may be easier to catch a rear wheel lock-up, the rear brake alone won’t offer much braking.

Don’t try to accelerate mid-corner when the bike is still leaned over. A surprising number of crashes in autumn, when the roads are first wet and cold, happen when riders accelerate whilst still leaned over, often when turning right at a junction or a roundabout. The combination of lean and throttle breaks grip and the rear. The answer is to get the bike turned completely THEN open the throttle. Even with traction control, it’ll still make for a smoother turn.

UNDERSTAND HOW TO USE THE GEARS – don’t make the mistake of believing the old advice to ride in a high gear on a slippery surface either. Whilst that might have been effective on a low and slow-revving 50s and 60s Triumph, modern sports bikes will spin up the rear wheel the moment it breaks traction. Wheelspin in a straight line is controllable, just a gentle wag from the rear of the bike. If we’ve not got traction control and we wheelspin in the wet whilst leaned over, we may not get the throttle shut again in time to prevent a crash. Let the engine rev, but accelerate gently – don’t open the throttle so far as in the dry.

And one final piece of advice – KNOW YOUR TYRES – if you intend to ride all year round, fit sport-touring tyres for the colder months of the year. The soft compound sporty tyres really only work in warm weather, and will never get hot enough to grip effectively in cold rain. Sport-touring tyres may not have the ultimate level of grip but they’ll work better on wet roads at any time of the year, and they generally slide more predictably than the grippier tyres that just let go suddenly.

Having just listed all the problems of riding in the wet, you may be surprised to know, I actually enjoy riding in the rain. It can be a lot of fun!

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29. Avoiding diesel and other slippery spills

Unusually this is an area where things genuinely have improved for motorcyclists. Improvements in commercial vehicle design, tighter fleet maintenance standards, and just possibly a faster clean-up of reported spills mean that streaks of diesel on roundabouts and bends are now far less common than they were in my courier days, even in the early part of my instructing career. Police collision data has long suggested that fuel spills are blamed for more crashes than they actually cause, and reduced exposure has only reinforced that trend. However, this does not mean slippery contaminants have disappeared altogether. We still need the same level of anticipation, observation, and margin — if anything, newer riders are likely to be less aware of the issue than those of us with a long backstory of dodging diesel. And it’s always worth remembering that ANY liquid will have less traction that the dry or uncontaminated tarmac.

Avoiding diesel and other slippery spills

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 in a long discussion on the problems of diesel on one of my favourite forums most of the correspondents had mates “who have crashed on diesel”, yet surprisingly few actually put up their hands and said “I’ve crashed on it 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.