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Lean IN? Or lean OUT?

A new video by FortNine has certainly set a whole herd of cats amongst the pigeons.

It’s entitled: “Motorcycle Riders – You’re Leaning the Wrong Way”.

It came out on Sunday – the 12th of September – and by 9am on the following Tuesday (when this post first appeared in the TIPS on TUESDAY series on www.facebook.com/survivalskills) this morning, had notched up well over half a million views!

In the video Ryan uses his usual mix of amusing delivery with solid science to talk about the benefits of changing riding position between:

  1. leaning in (the modern racer style)

  2. staying in a neutral in-line position (what some UK riders refer to as ‘Hailwooding’ after the legendary British race Mike Hailwood)

  3. counterleaning (which here in the UK we tend to call counterweighting)

The video description says: “Ever notice that police motorcyclists lean their bodies *away* from a turn? They’re trained to. But why might this uncommon body position be helpful for our motorbikes?”

And Ryan goes on to explain how moving the mass of our body around affects the dynamics of riding and why counterleaning / counterweighting is helpful.

Not too surprisingly, the ‘response videos’ flew thick and fast, including one on the MotoJitsu channel – highly rated by many – entitled ‘My Response to FortNine’s Video About Leaning The Wrong Way’.

So I watched that too, and I don’t disagree with what Eddie says either, though he could have trimmed his commentary down from fifteen minutes to about sixty seconds!

So why stick my oar in at this point?

The answer to that is essentially in two parts; firstly, in all the science, demos and humour it’s easy to miss the messages. Secondly, there are a couple of important extra points that weren’t covered.

So let’s deal with the messages first. Is it best to lean IN? Lean OUT? Or just stay neutral?

The answer is that it depends. It depends on what you are trying to get the bike to do.

So let’s run through the logic of why we might want to change our position atop the machine.

Let’s get counterweighting out the way first, as it’s actually the easiest to explain. It’s a SLOW(ish) riding technique. Usually, it’s taught as a way to tighten the bike’s line to make it easy to negotiate tight corners. And that’s why it’s taught by many trainers, myself included. That’s the long and the short of it and if all you want to know is IF I teach counterweighting, then now you know.

But if you want to know the WHY of how it benefits riders, then I’m afraid what follows is going to be a long explanation. But I’ll try to make it a logical sequence of ideas for you to follow.

MASS – the bike has mass, and so does the body. Off the bike, each separately has its own centre of mass – it’s defined as the point at which, if you stuck a big enough nail through either your body or the bike, and gave them each a spin, they’d be balanced and could come to rest randomly, in any position – just like a wheel, there would be no heavy spot.

For your body, your centre of mass is somewhere just under your belly button. It’s slightly lower for women, incidentally.

COMBINED CENTRE OF MASS – but as soon as we climb on to the bike and ride away, they’re not separate. So we have to have to talk – and think – about the COMBINED centre of mass.

WHY CHANGING BODY LEAN CHANGES BIKE LEAN – as I’ve just mentioned our bodies have mass and and so does the bike. But as we don’t have a rod through the seat and stuck up our backside, the mass of our bodies on top of the bike and the mass of the bike beneath our bodies are free to move independently. That’s why we can lean in, lean out or simply stay inline with the bike…

…but only up to a point. The two masses are ‘coupled’.

This simply means that our body mass and bike mass are linked because we are sitting on, and connected to the machine. This is pretty obvious really, because we have to maintain a connection with the bike even as we move our body mass around.

We only ‘uncouple’ from the bike when we fall off. And then each mass is free to do its own thing.

ACTION AND REACTION – because the mass of our body and the mass of the bike are coupled, something interesting happens. If we move to shift our body position – and thus move the centre of mass of our body – the bike has to move IN THE OPPOSITE DIRECTION to maintain balance.

Here’s an easy demo. Stand upright, feet together, hands on hips. That’s you, sat on your bike – you’re upright and so is the bike. Now, from the waist LEAN TO THE RIGHT. You’ll find that your hips just moved TO THE LEFT.

Lean the top of your body to the left? Your hips move to the right.

Your body has to ‘hinge’ in opposite directions, to maintain balance. If you try to lean the WHOLE of your body by pivoting at the ankles, you simply fall over. So the top half of your body leans one way, the bottom half of your body leans the other – they operate as separate masses that are coupled together.

Now imagine you’re sitting on the bike. Your legs are now locked onto the bike, but the top half of your body can still move. Lean LEFT? The bike moves to lean RIGHT. Lean RIGHT? The bike leans LEFT.

This HAS to happen – although bike and rider have separate masses, they are coupled together by our legs. And that’s why moving and LEANING our body changes the LEAN ANGLE of the bike beneath us.

THE RADIUS OF A TURN IS A PRODUCT OF SPEED *AND* LEAN ANGLE – if we fix our SPEED, then we have to lean MORE to get round a tighter turn and LESS to get round a more open turn. OR… if we fix our LEAN ANGLE, we have to SLOW DOWN to get round a tighter turn and SPEED UP to get round a more open turn…

…or we can mix-and-match.

A really open corner can be taken at a modest lean angle and quite quickly at the same time, but a really tight hairpin will need both a reduction in speed AND an increase in lean angle.

Now, here’s the rub. Most of us will have realised that bikes simply DON’T like balancing at single digit speeds and that makes accurate steering difficult…

…and that compromises our ability to make really tight corners.

So it follows that if we go a little faster – till the bike is balancing itself again – it’s actually a bit easier to steer accurately. But that extra speed may make it difficult to lean the bike enough to make the turn…

…so we counterlean / counterweight.

WHY LEANING OUT TIGHTENS A TURN – the first extra explanation I’ll add is WHY body shifting works to changes the radius of curve the bike follows. If we counterweight (so the bike leans in as the rider sits upright) we increase the lean angle of the TYRES…

…and a TYRE that leans more, automatically turns on a tighter line.

Try rolling a coin. If it’s upright, it rolls straight. If you lean it over and roll it, it goes in a circle. If you lean it over more, it rolls in a tighter circle.

The tyres do the same, and carry the bike around the turn with them. The greater the lean angle OF THE TYRES the tighter the radius of the turn AT THE SAME SPEED.

We don’t need maths to prove that (though it can be done), we just need a simple demo.

Find a car park, line the bike up next to a straight white line then stand next to the bike. Keep it upright and turn the bars to full lock. Then walk in a half-circle and stop. Now lean the bike into your hip and walk round the rest of the circle.

You’ll find that you don’t end up where you started, but actually INSIDE that location. The bike turned tighter in the second half of the turn when you leaned it over at an angle.

You can play with this, leaning the bike just a little or rather more (easier with a light bike!) and you’ll find that the more the bike leans, the tighter it turns!

So what happens if we LEAN IN on a tight turn? We sit the bike UP which reduces the lean angle of the tyres, and in turn that makes the bike follow a wider line. We’ll struggle to get round the tighter corners – the only other way to get the bike turning on a tighter radius once we’ve FIXED OUR BODY POSITION is to slow down – and as I’ve already said, that wrecks our ability to steer accurately.

So it’s LEANING OUT to tip the bike IN that allows the bike to turn tight whilst keeping the speed a little higher enabling us to turn accurately and STILL NEGOTIATE TIGHT TURNS.

As I said, you don’t need to trust the maths is right, all you have to do is find a car park and try it out. But once you have twigged this, pretty much everything else falls neatly and logically into place.

WHY MIGHT WE NEED TO LEAN IN TO A TURN – the usual explanation for leaning in to a corner whilst carving a smooth turn AT SPEED is that it increases ground clearance.

But we’re not racers. We’re not riding at huge lean angles and we not at the extreme edges of tyre grip on the road – at least I hope we’re not – and that means almost all the debate based around whether or not body position can save a slide or whether we’re risking “grounding out the bike” is almost – but not quite – completely irrelevant…

…if you are riding a machine with limited ground clearance (such as most cruisers) or a heavily laden bike that has compressed the suspension (such as the Tracer 900 I was riding in New Zealand in 2019), then modern tyres DO allow lean angles that are steep enough to allow various bits of the bike to hit the deck.

On the Tracer, it was the centre stand that went down first. But even here, the solution was not to try to hang off to maximise ground clearance…

…it was simply to SLOW DOWN so I didn’t NEED to lean over so far!

There is one positive benefit. From the point of view of the counter-steering force that is necessary to keep a bike turning, leaning in actually helps the bike steer with less effort. It’s worth experimenting – you should be able to find a bike lean angle and a body lean-in angle which actually cancels out the need to maintain a counter-steering input – you could (in theory – I wouldn’t try it) take your hands off the bars, and the bike WOULD keep turning.

I find it makes wet-weather riding more relaxed on fast roads – the bike just seems to track better through the wet corners. But I don’t do the full Marc Marquez ‘hang-off like a gibbon’ technique – I just lean in by bending at the waist – what some people describe as the ‘kissing the mirror’ approach.

CHANGING DIRECTION REQUIRES MASS TO MOVE – when we reverse direction, we also have to reverse the lean angle and it takes effort to move mass. Got a handy weight? I’ve got a couple of arm exercisers – they’re only little ones, just 1 kg. But they serve to make the point.

Take one weight in each hand, hold them down by your legs. You’ll feel gravity trying to pull them out of your hands. Now lift each weight until it’s level with your shoulder. Even with a titchy mass like this, it takes a bit of muscle effort to move it from down by your knees to shoulder height.

This effort is known as WORK.

Now, try putting both weights in one hand and lifting them to shoulder height. It’s harder, isn’t it? You’ve just done TWICE THE WORK by lifting two weights at once.

Go back to one weight but this time lift it till it’s over your head. You’ve just moved the weight through TWICE the vertical height. So this is also TWICE as much work as the first exercise where we lifted the single weight to shoulder height.

With the weight directly over your head, your arm’s a bit like an upright bike. The weight has mass, but it’s supported by the bones of the arm, then the shoulders, spine and legs. The rider sitting on an upright bike is similarly supported by the rigid structure of the bike.

Now, with the weight still in hand, lower your arm till it’s stuck out at right angles to your body. As soon as your arm is off the vertical, gravity is pulling the weight down. Now lift it again till your arm is vertical again. It’s an effort to fight gravity.

Now, back to the bike and rider. Imagine the bike is upright – the bike is balanced, with the combined Centre of Mass of bike and rider supported by the bike via the tyres.

But what happens when we roll the bike over to a lean angle of 45 degrees to the vertical? Gravity pulls the bike over. And what about when we roll the bike upright again? We need to lift the mass of bike AND rider back upwards till the combined Centre of Mass is balanced over the tyres. We need to do WORK to get the bike to roll upright. So every time we come UPRIGHT again, we have to do this work.

Here’s the clever bit. Remember the COMBINED CENTRE OF MASS – that is, the mass of the bike AND the rider added together? Remember they are coupled, but can move independently?

Now, imagine that you are leaning IN and mid-corner. We’ve actually moved our centre of mass DOWN compared with a rider in a neutral position. And you should now see that in order to get the bike and rider’s mass back to the vertical, we actually have to lift our body back up from that lower position – and that means we have to do MORE WORK.

And that means bigger inputs at the bars to get the bike to roll upright at the same rate as a rider sitting neutral in the saddle, or a reduced rate of roll for the same effort.

And more work means more effort from the rider. As anyone who’s done a track day will know, climbing back and forth over the bike is actually quite tiring, if you’re not used to it.

Next imagine that rather than leaning IN to the corner, we lean OUT. Think about how that changes the movement of the centre of mass of the RIDER when we roll the bike into a corner. The RIDER’s Centre of Mass doesn’t move down so much, and it doesn’t move sideways so much. And that means when we come to ROLL the bike back up t the vertical position, we have to do less work to get bike and rider upright again…

…OR we can do the SAME amount of work, and roll the bike upright MORE RAPIDLY!

THE BIG BENEFIT COMES IN S BENDS – the big benefit of counterleaning / counterweighting is felt in S bends where we have to switch rapidly from upright to one lean angle then to the opposite lean angle, and finally back upright again.

With the body mass moving less, the bike can change lean angle more rapidly for the same effort compared with a rider leaning in, and thus changes direction in less distance too.

Or we keep the rate of roll the same and simply work less hard to get the bike to follow the same path. And all that’s needed is to LEAN OUT.

WHAT ABOUT SUSPENSION MOVEMENT – a point that wasn’t mentioned and immediately occurred to me (and some of the other video viewers) was to think about the movement of the suspension. It works – obviously enough – in line with the bike itself.

And so it should be equally obvious that if we want the suspension to soak up a bump easily, we need to hit it upright or as near to upright as possible. If the bike is leaned over a long way, the ‘bump’ begins deflects the entire bike upward, lifting, reducing traction and destabilising the machine.

And this is suggested as another reason for leaning in to a bend, as it pushes the bike upright. So in theory a rider who is leaning in and hits a bump mid-corner will have the suspension more upright and thus able to absorb the bump more effectively than a rider who is rider is leaning out and tipping the bike over harder.

But once again, it’s a matter of degree. Non-compliant suspension only really becomes an issue at serious lean angles. So if we hit a bumpy stretch of road and need to corner, there’s a simple answer – slow down!

And that offers an alternative strategy – get the bike upright over the bump.

This is my advice to riders on my Survival: URBAN course who may find a speed bump mid-corner – slow down, then take a two-part line that allows for the bike to take the bump upright mid-bend.

MIND YOUR HEAD – for the road rider there are also a pair of solid safety issues to be made. If we the body lean in to a corner, our head is a long way towards the inside of the turn – we’re effectively making bike and rider ‘wider’.

Now think about this in context with what we might hit our head on! Leaning into a right-hander (in the UK) puts our head potentially close to oncoming vehicles. Leaning into a left-hander (in the UK moves it close to the inside of the corner and close to trees, walls and so on. Watching TT riders lift their heads out of the way of telegraph poles is quite scary.

But as we’re not riding that fast, counterleaning / counterweighting does the opposite, and keeps our heads out of harms’ way.

[EDIT] And Steven Wilkinson reminded me of the other plus for counterleaning / counterweighting, which I meant to include and forgot. He said in the first comment on the post: “I’ve always had a tendency to counterweight, mostly in an attempt to see a little further around the corners where there’s high hedges (and there’s a lot of high hedges around Devon)”. It may not move our heads much, but it does give a slightly better view. [/EDIT]

[EDIT] KEEPING THE EYES LEVEL WITH THE HORIZON – although there are a few riders who seem to be able to function perfectly well with their heads at funny angles, for most of us our balance system functions best when our eyes are level with the horizon.

Ryan actually flags this mentions very briefly the ‘vestibular system’ but it’s worth a mini-explanation in its own right. The vestibular system helps control balance and eye movements but it doesn’t work using just the little semi-circular canals in the the inner ear. It also uses input from the eyes.

If the vestibular system is upset, the results – amongst others – can be dizziness and disorientation. With all the movement on a motorcycle in motion, the eyes play an important role and Dave Haines reminded me of this point when he said in the second comment: “I’ve always sat in-line, traditional 90’s superbike rider style, with a giraffe neck keeping my head level”. [/EDIT]

WHAT ABOUT SAVING SLIDES – well, to be perfectly honest, I don’t have dirt bike skills and I don’t know much about recovering slides off-road, let alone riding in a way to deliberately slide a bike round corners. All I’m going to say is that if slides on the road are a routine event, there’s either something very wrong with the roads, the tyres… or your choice of speed / lean angle.

MOVING AROUND BEATS SITTING LIKE A SACK OF SPUDS – final point. Many riders I watch through corners aren’t just staying inline because they choose not to lean in or lean out, they stay inline because their hips are locked to their spine and their entire body is rigid.

This is not a great way to ride because every time the bike hits a bump or a gust of wind catches the bike, the rider’s own stiffness tends to feed straight into the bars…

…and that exaggerates any wobbles and weaves.

So the very fact that a rider CAN switch between the lean in and lean out positions – provided they are using the right techniques in the right place – helps keep the rider LOOSE on the bike even if in fact they are staying inline and ‘Hailwooding’ a corner. And a loose rider is far less likely to feed the bumps and wind blasts back into the steering and this means a smoother, more controlled line through the corner.

And some riders seem to make it a point of honour not to move around whatever the circumstance. All I’ll say to that is that they are losing some potentially very useful machine input.

CONCLUSION – LEANING IN, COUNTERLEANING & SITTING INLINE ARE ALL VALID POSITIONS – but each works better in certain places than the others, and some work better for certain bikes. Like so many things to do with motorcycles, multiple techniques work better than just one, and it’s down to us to try them out and find out which type of lean gives the greatest benefits for what we ride, where we ride it, and how we ride it!

Thanks to Edward Tew (third comment) to remind me I’d also forgotten to add a conclusion!

FORTNINE – Motorcycle Riders – You’re Leaning the Wrong Way https://youtu.be/U1mSavQ_DXs

MOTOJITSU – My Response To FortNine’s Video About Leaning The Wrong Wayhttps://youtu.be/FwOTovVqlq0

That’s it. Apologies for the long read. It was an even longer write, trust me on that! But I hope it clears up some of the potential confusion that the FortNine video and the numerous responses have created.

Look out for my ONLINE WEBINARS on the FIRST WEDNESDAY of every month – the next is Science Of Being Seen is up next on Wed 6 October, and the November talk will be about braking into and mid-corner.

——————————– NOW AVAILABLE – LIVE BETTER BIKING TALKS CHECK OUT SURVIVAL SKILLS ONLINE TALK SERIES! https://survivalskills.tidyhq.com/public/schedule/events ———————————

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