Can You 'High-Side'?

[Richard A Thackeray]

A collegue who rides motorbikes/track-days/etc..... was asking me

We all probably know what one is on a m/bike

Normally the bike loses traction for various reasons (oil/wet surface, diesel, etc...)
When cornering the suspension is compressed to a certain extent
Then, as the bike 'regains' grip/traction, the suspension extends/rebounds, throwing the rider up into the air
This generally happens very quickly, with no reaction time

Maybe a bit extreme, but the bike here, loses traction on the white line, & then 'bites',
"Ouch!!!"

SO.........
I thought for a moment, & yes, to an extent you can - or an equivilant

Obviously on a road bike, there's not the suspension issue to take into account
But, I do know that I've had moments* when the bike starts to slide (for same reasons as given above)
As long as the brakes aren't applied - or are released - the wheel(s) should start to rotate after the poor surface is cleared
Granted, the bike may had stood up by now, but there is the need to straight-line, to regain control

Has anyone else thought about it this way

There's also a 'LowSide'

*The last time it happened to me was on a roundabout, not far from me (jct 31/M62), there's a Truck stop down there, where drivers fill up, after delivering to the Industrial Estate
I was circumnavigating the r/bout (from Castleford side, towards Normanton) & both wheels started to slide
Mentioned here in the last paragraph
It ended up almost vertical, as they gripped again, I was lucky as there was no traffic in the adjacent 'near-side' lane, otherwise the correctant straight lining would have caused me (& them) at the least a big scare

 

[Hugh Manatee]

I'll never cycle again!

 

[Thorn Sherpa]

Ouch to both awful crash on the motorbike and I feel the cyclists pain! Luckily it's been a while since I've had a high speed fall but can remember when I came off on the way to work in shorts it wasn't pretty! As soon as the front wheel goes you know it's gonna hurt!

 

[Tangoup51]

I've certainly experienced what you're describing.

I was riding along a metal-surfaced bridge and as it came to an end I started to turn off the bridge and onto pavement.
As I was turning and my front wheel had bitten onto the pavement but my back wheel that was still on the metal, let-go during the cornering.

With the bike firmly in hand, I was falling to my side to quite a large degree (though, can't tell you how far I was leaning over)

But luckily the rear wheel ran out of metal-bridge and bit sharply onto the pavement regaining traction. (Still cornering at this point) - This snappily put my bike upright with little-to-no fuss. Wasn't as jarring as I was expecting it to be.

But as for it to "high-side" It just did not feel like there was enough momentum to both put my bike-up right and then throw it over. - As I say, it felt rather numb and dull when it snapped upright, as if there was a cushion I was smushed up against when it launched me upright.
Which was surprising given how both fast (10-12 mph) and far I leaned over.

I reckon that despite the weight of the motorbike being low-hugging to the ground in relation to the humans weight, the motorbike weight is
a factor in that momentum. And possibly the smaller wheel size too.

But I'm no expert and going off experience.

 

[Smokin Joe]

I reckon that despite the weight of the motorbike being low-hugging to the ground in relation to the humans weight, the motorbike weight is a factor in that momentum. And possibly the smaller wheel size too.

But I'm no expert and going off experience.

That's about right. A motorcycle is a lot heavier than it's rider so that when it whips suddenly as it does when a sliding wheel suddenly regains traction it will throw the rider into the air. Even the lightest racing whippet will outweigh his bicycle so he will dictate where both go during a loss of control.

 

[bpsmith]

Doesn’t the power being put through the wheel cause the rapid reaction when the tyre grips during a high side?

We don’t have that on a bicycle. Even Quadzilla would struggle to recreate it.

 

[Tigerbiten]

To get a high side crash on a bike, you probably need to lift the back wheel.
So probably not by yourself on the flat.
But going over a cars bonnet can well be called a high side crash as you fly through the air ....
Maybe overcook a downhill corner at speed, a bit of gravel, hit a curb at a shallow angle and you may well be flipped to the outside if the front wheel buckles.

 

[Bollo]

To get a high side crash on a bike, you probably need to lift the back wheel.
So probably not by yourself on the flat.
But going over a cars bonnet can well be called a high side crash as you fly through the air ....
Maybe overcook a downhill corner at speed, a bit of gravel, hit a curb at a shallow angle and you may well be flipped to the outside if the front wheel buckles.

I reckon that’s about right. Unless there’s something like a curb to catch the errant wheel, once front wheel (on a road bike at least) has gone then it isn’t going to come back with enough traction to flip you over.

 

[Richard A Thackeray]

That's why it's the extension/rebound of the (motorbikes) suspension, after being compressed by cornering forces, once the bike regrips, that de-seats the rider

My phrase was to an extent you can - or an equivilant
Whilst there's not the power, there is a certain amount of momentum, once that tyre has overcome the diesel patch/gravel/etc....
The weight of the riders body will surely want to obey Newtons First Law, as it tries to continue travelling?

 

[Tangoup51]

That's why it's the extension/rebound of the (motorbikes) suspension, after being compressed by cornering forces, once the bike regrips, that de-seats the rider

My phrase was to an extent you can - or an equivilant
Whilst there's not the power, there is a certain amount of momentum, once that tyre has overcome the diesel patch/gravel/etc....
The weight of the riders body will surely want to obey Newtons First Law, as it tries to continue travelling?

Others have said suspension is an element in this maneuver, but I am lead to believe (on assumption, I admit) that there are many kinds of sophisticated suspension systems out there, especially for a sport of this caliber.
If the suspension was indeed the issue, this would of been investigated and invested into to fix the issue. Suspension is no longer a slap-happy compressed spring. Especially not at this price point.

But even if the suspension was from the 1920s you have to consider that the forces in the suspension are relatively small when compared to the initial bite of the tire. The power from the suspension is only a tiny echo from the real-deal at the tire.
That power is what ultimately de-seats the rider.


The problem here rests in the simple fact of what is occurring. Stay with me.


A large amount of forward momentum is being directed at a solid object. - In this case, the solid object is the tires level of traction and the forward momentum is when the bike kicks out and presents the wheel sideways toward to the direction of travel. - or rather, a direction the wheel wont travel. (these wheels don't go round sideways!)

As you'd expect this leads it to simply topple over. Exactly the same action as if you was trying to shove a tall box.

The ways to reduce this action would be too..

Decrease forward momentum < by reducing the speed. This is the same as not pushing as hard on the "tall box"

Decrease object solidity. < By making the object move to disperse the momentum and prevent it toppling.
- The wheels don't go round sideways.. so replacing tires & wheels with balls?

So as you can see it's not an easy problem to fix. But weirdly as road bikers we do actually meet this criteria.

Our forward momentum is generally much less than that of a GP motorcycle (or any motorcycle, really.)
And our tires (and wheels) are much less rigid than that of a motorcycles. Our larger, spoked wheels create much more flex in this maneuver
It also can be said the more stable gyroscopic forces that a larger wheel is creating makes it harder to topple over.


But there are other factors too, such as how high the mass is from the ground (how tall the box is) and how much traction is avaliable (how immovable the box is)

Given that we have less overall mass than a GP motorcycle and less traction, it seems to be very uncommon.

But even if you was going "fast enough" so you had enough mass for this to occur and wielding the stickiest of sticky tires - it's much more likely that our softer tires will just pop off the rim or the wheel goes pretzel.

So yes, my conclusion is that it can be possible for road bikes to high-side in the exact same way a GP motorcycle does..

If we have completely solid wheels, stiffer & stickier tires and going fast enough to compensate for our lack of overall mass compared to the motorcycle...
...
but in reality we won't be able too. Atleast not due to a completely flat surface.

 

[hatler]

I've always been of the view that the vertical component of the rider's velocity is a result of the bike rotating around the sticking point. When the tyre 'sticks' the bike is going sideways and it is leaned over. As it sticks the bike (with rider) rotates and that introduces a good deal of vertical velocity to the rider. Suspension might add to this effect.

 

[Siclo]

The closest thing I think I've seen to a high side on a bicycle was poor old Beloki when Lance ran across the field.

 

[I like Skol]

I think I did this a couple of weeks ago (sort of) on a ride with @dan_bo who was behind me at the time and may have seen proceedings.

While cutting across the back of Rishworth towards the A58 I really nearly lost it on one of the hairpin bends when my back wheel lost grip because I was braking hard into the turn. I wish it could have been caught on a Go-pro or similar so I could see if I looked like a floundering idiot or skilful pro when I managed to keep control of the bike (just) and make the corner while remaining right-side up.

I was on an unfamiliar road and passed my two ride mates just before a downhill corner that turned out to be sharper than predicted. I braked harder than I should have done going into the corner to scrub enough speed to make the turn and as a result of unweighting the back wheel so much it lost traction and stepped out. Don't ask me how I did it but I managed to adjust my balance enough to get some weight on the back wheel which then gripped and kicked back just enough to hop back into line..... just in time for me to continue braking in the corner which led to a repeat of the slip, grip, hop sequence. I'm not sure if this happened two or three times in total as it happened so quickly but the wheel/bike definitely kicked back with enough force to hop when it regained grip. Probably the closest thing to a high-side as you are going to get on a pedal cycle?

 

[Tigerbiten]

You outweigh a bike by about the same ratio which a motorbike outweighs you.
So on a bike you've a good chance of damping/absorbing any upward/sideways flipping motion.
Good luck in damping all the motorbikes upward/sideways flipping motion due to the extra energy imparted.

I would say the major difference between a bikes and a motorbikes high side crash is ....
On a motorbike, you'll get thrown off. On a bike, the bike gets ripped out from under you.

 

[dan_bo]

I think I did this a couple of weeks ago (sort of) on a ride with @dan_bo who was behind me at the time and may have seen proceedings.

I was on an unfamiliar road and passed my two ride mates just before a downhill corner that turned out to be sharper than predicted. I braked harder than I should have done going into the corner to scrub enough speed to make the turn and as a result of unweighting the back wheel so much it lost traction and stepped out. Don't ask me how I did it but I managed to adjust my balance enough to get some weight on the back wheel which then gripped and kicked back just enough to hop back into line..... just in time for me to continue braking in the corner which led to a repeat of the slip, grip, hop sequence. I'm not sure if this happened two or three times in total as it happened so quickly but the wheel/bike definitely kicked back with enough force to hop when it regained grip. Probably the closest thing to a high-side as you are going to get on a pedal cycle?

Indeed you did. Was funny.

I've had a similar thing locking up the back of a fixie from 20 odd mph in traffic. The back tyre distorted and I could feel the whole thing kicking when it recovered. Eye opener.