scooters are not motorcycles

Frequently the conversation on on-line forums attempts to compare scooters and motorcycles. Personally I'm dumbfounded; because to me anyone who's ever even seen a motorcycle in the flesh must be clear that these things have only one thing in common:

1. two wheels

Everything else in almost every aspect of physics and operational dynamics is entirely and utterly different.

That such comparisons persist can only be

• the person has lived such a sheltered home life as to have done nothing more than just look at pictures
• an indicator of being so ignorant as for it to be shameful (but usually they agressively defend their positions)
• a sign of such complete and utter self delusion as to border on being mentally restricted to a developmental age of about 15 years old

The most common comparison is in braking (lets leave cornering or speed out of this), which the scooter can never compete with a motorcycle and its beyond me as to why I even have to make the obvious clear, but it seems people delude themselves continually still. I've written this post because I'm sick of repeating myself on forums and so I'll simply post this link from now on.

Firstly lets look at my Mercane wide wheel beside a basic "chook chaser" dirt bike (so nothing even fast).

Stopping

The most common myth is that motorcyles have greater than 70% of their braking power on the front wheel (which is true) and so scooters should too (which is not true). Lets get to the first point of delusion "powerful front brakes are needed" so looking at these two I've got the front contact patch of both front wheels aligned. 

Now imagine that someone is standing on the scooter, if you aren't standing almost over the back wheel of the scooter you'll have your weight so far forward and so close to the front wheel its almost begging to pivot around that front wheel and face plant you into the ground. This is why people who have experience and understand reality often say that a strong front brake is a liability on a scooter.

Notice how the most massive part of the dirt bike is right over the back wheel of the scooter? Almost the entire mass of the motorcycle is back to the point of being behind where most people stand (crowded up at the front post). 

Here I've added the relative masses and locations of the Center of Gravity  (CofG) of both the motorcycle and the scooter, the black center of mass of the rider and bike are much bigger than the blue one of the scooter. There is a balance point between gravity (yellow line) and braking forces (red line) Next note how much further back (and heavier) that is on the motorcycle than it is on the scooter?

Notice how far that has to move befoe it goes past the tipping point (which is about when the black or blue line becomes vertical) ...  the scooter CoG is just asking to flip it at the slightest provocation. 

Thus if you use the back brake it can't flip ... obviously right?

EDIT: Now, here's an interesting thing, notice the angle of that black line? Its pretty close to 45 degrees, which would indicate that a motorcycle can stop with a force at about equal to gravity, or about 1G. I just decided to look on youtube for any tests on motorcycle braking vs car braking, guess what I found? I found that a car can brake at 1G and that while an experienced rider (who trains) can stop at 1G too, that most riders were half that ... well worth watching this:

So looking at the even steeper angle of the scooter (its almost falling over before you hit the brakes I'd put it at far less than 0.3G

Next the deluded will just repeat that the rear wheel will skid as the braking forces unload it ... and so this is why I always say "stand back and lower your weight as part of braking", this transfers the weight over that wheel and keeps it on the ground and helps you to stop faster ... so make it a habit.

Relative Weights

Then there is the fact that the scooter itself weighs essentially nothing compared to you. Typical adult human weight will be over 80kg yet the scooter is like 24kg ... in contrast the motorcyle will be over 100kg and then look at the angles of center of gravity where the rider sits (and note how far back it is from the place you've probably been standing. So on the motorbike you're likely to be half or less of the mass, on the scooter you'll dominate the weight.

So your legs are an important (critical) part of the suspension and why scooter suspension is more about just a bit of comfort and not what suspension is really all about, which is

 >> keeping the wheels on the ground<<

Keeping them in contact with the ground so that braking can happen, and cornering can happen.

On the scooter "you are part of the suspension"

Even on an old little 100cc road bike like this, the scooter is clearly just a toy beside it

and again, those same principles mentioned above are there:

1. how far the center of gravity of the rider is positioned(the arse point on the bike is again right over the rear wheel)
2. the center of mass of the much more massive motorcycle (this one weighs more like 120kg)
3. you have strong handle bars to push against and support your weight

So please, if you're riding a scooter, keep the speeds to intelligent levels (less than 30kmh (which is under 18mph for anyone still in that measurement past)) and know that stopping this thing will take time. 

If after reading this you persist in the view that a scooter can stop better and more safely with a powerful front brake then you're at a level of self delusion that is beyond help.

Lastly

If my tone seems harsh, well I can assure you that the consequences of failing to believe this and to train appropriately will be much harsher.

What would I know? Well I've had motorbikes since I was about 12 and grew up riding motorbikes on the farm from about 10, below is just some of my road bikes since 1985

I've ridden motorcycles in more countries over more years and more kilometers than probably most people (although I know some who have ridden more and more diverse than me) ... but I doubt that anyone with much experience (or as we say in Australia "much of a brain") would even be arguing that scooters can stop as fast (from the same speed) as safely as a motorcyle or that scooters should have super powerful front brakes.

So, the King is dead, long live the King ... King Wang

Best Wishes