Can a motorbike out brake a car?

[Jantar]

Here we go again. Some very interesting scientific test results for motorcycles at: http://www.msf-usa.org/imsc/proceedi...ngDistance.pdf

Have a look at the table on page 6.

Now for cars, have a look at http://www.movit.de/rahmen/stoptbl.htm

Notice that most bikes do stop quicker than most cars, but that there are many cars that can stop shorter than the best bikes.

[Biggles08]

Just riding behind a van on a tight back road coming down a hill, the van driver braked very heavily for a road off to the right, he couldnt turn right because of a car coming the other way that he had to give way to.
I only just managed to stop, ie the road was so narrow I could get by, I would have ended up in the ditch.
It got me thinking, my bike is new, older bikes probably dont have such good brakes, how would they got on in the same situation.
The question is can a motorbike out brake a new car with ABS etc
Ques. Do I have stay more than 10 car lengths behind a van/car at say 100kmh , can I safely stop in time?
It gave quite a fright actually, as I wasnt expecting such a quick stop,I was lucky to have my hand already with 2 fingers on the brake.
You live and learn another lesson aye

Not a chance! If you had the best of both vehicles the car would out brake a bike every time.....pure physics. For the same reason (well not exactly the same but similar one) a car can corner much quicker that a bike could ever dream to...unless of course your skidmark riding a magic ZXR250 / 400.

[Pixie]

Is it true a bike can keep you drier than any car?

[The Pastor]

its a tricky one with race tracks as the bikes will be having a much higher entry speed (due to the acceleration) to the braking zone, so (if all other factors are the same) would have to brake earlier.

but cars can easily hold more corner speed than bikes, easily.

[Mikkel]

It all comes down to physics.... friction/ transfer of energies etc.... etc....
Remember there is a huge contact area of rubber on the road in a car.. Alas your bike doesn't have this....

The contact area has nothing to do with the amount of available friction. The secret is contained in statement "4 contact points versus 2 contact points for the bike". With 4 contact points there is both longitudinal and lateral stability - with two there is no lateral stability.

i think a bike might outbrake a car at lower speeds,where the mass has less effect,dont forget kinetic energy is related to the SQUARE of the speed.I think the ducati vs car would have been closer if the track was dry.It wasnt just damp it was soaking in some parts

Well, if the speeds are the same - surely the parabolic relationship is irrelevant. As for weight - you available friction increases linearly with mass - as does the intertia, the kinetic energy and the momentum. When braking the mass cancels out - at least in the first approximation - when you start to consider induced torque due to mass distribution relative to the contact points (which is what gives you stoppies and wheelies btw) then it starts to matter.

Friction,,,the thing that stops you,,,is dependant on two things.
Wheight, and surface texture of both the road and the tyre.
Cars have more of both.
Surface area plays no part,,,transport industry tests show that 1 tonne sitting on a very small surface has exactly the same break lose point as the same wheight spread over a larger area.
A simple test is to take a smooth board,place a steel block of a known wheight on one end and tip it until the block moves.
Then take another block of the same wheight but larger surface area and do the same thing.
You will find both blocks move at the same level of tilt.
So the amount of wheels you have doesn't increase your breaking potentual.
It's all about how good your tyres are and how much wheight you can put onto them.
The fact that so many bike riders drive straight up the arse of cars is also a pretty good indercator of cars out breaking bikes,,,,as well as showing lots of bikers are nowhere near as good as they think they are.

Indeed, it's worthwhile pointing out that while weight equals more friction it also equals higher inertia - and in the same proportion.
The only ways to provide higher friction without increasing inertia are: 1) Optimised tyre compounds and 2) Downforce!
Downforce is not really viable for bikes since their aerodynamics suck - the Skyline on the other hand most definitely has got a great deal of downforce (I think it comes with a splitter and spoiler as standard equipment).

nice theory...but your one is gravity induced...

We are slowing movement with friction...like different sized brakes [more pad area etc]...

It doesn't matter - friction is friction and ultimately braking friction on bikes is limited by how much force your front wheel can manage to put into the road. And that force depends upon gravity.
If you can break hard enough to do a stoppie then it isn't your brake system that is limiting your braking potential anymore.

Youre onto it..More tyres more surface contact area, MORE friction ,faster stopping.

It is obvious you have no idea what you are talking about.



Bikes loosing out to cars ultimately comes down to two points:

1. Aerodynamics - they have them, we don't.
2. Lateral stability - means a car can change direction faster than the bike since they don't have to shift weight and tilt the bike over before commiting to the next corner.

[Flip]

Cars do not do stoppies because they have a much lower centre of gravity. Most performance cars also use aerodynamic trickery to generate down force which adds greatly to braking at higher speeds.

[Thunder 8]

It is obvious you have no idea what you are talking about.

Not obvious at all ,you have no idea what i know.

[imdying]

Not obvious at all ,you have no idea what i know.You talk more bullshit than Batman. I'll take more contact area etc over youre bullshit any time.

Wouldn't more contact area give you less grip as there is less force per square inch pushing the tyre into the road?

[Mikkel]

Not obvious at all ,you have no idea what i know.You talk more bullshit than Batman. I'll take more contact area etc over youre bullshit any time.

As I said, it is obvious you haven't got the first clue what you are talking about. There's really no need to provide additional evidence.

Wouldn't more contact area give you less grip as there is less force per square inch pushing the tyre into the road?

Indeed, that's the whole thing - while the area might grow larger the pressure (force per area) just drops. Depending upon what you are trying to achieve the end result is pretty much the same - the force is constant irregardless of contact area. There are some situations where a larger area is better than a small area - and the opposite is also true.

Let's take snow as an example - if you are driving (or riding if you are brave) on deep snow you want to have a large area so you can stay on top. If it is a thin layer on top of a firm surface, you want to have a small area so you can cut through to the good stuff underneath. Same goes for mud... which is why landrovers (good off-roaders) have tall skinny tyres.

[Thunder 8]

As I said, it is obvious you haven't got the first clue what you are talking about. There's really no need to provide additional evidence.



Indeed, that's the whole thing - while the area might grow larger the pressure (force per area) just drops. Depending upon what you are trying to achieve the end result is pretty much the same - the force is constant irregardless of contact area. There are some situations where a larger area is better than a small area - and the opposite is also true.

Let's take snow as an example - if you are driving (or riding if you are brave) on deep snow you want to have a large area so you can stay on top. If it is a thin layer on top of a firm surface, you want to have a small area so you can cut through to the good stuff underneath. Same goes for mud... which is why landrovers (good off-roaders) have tall skinny tyres.

yep ok then.

[Thunder 8]

Wouldn't more contact area give you less grip as there is less force per square inch pushing the tyre into the road?

I guess its really a matter of does it matter really.

[YellowDog]

Like for like - The bike always wins.

Super car with 4 x 19" 255 low profile tyres against the beefiest bike - The car will always win.

Have you seen this video: http://www.youtube.com/watch?v=ZZKRphfVHqI

It really does demonstrate how where the each is stronger.

[imdying]

Heh heh youre funny.

He's an engineer, he pretty much only deals with facts, not what he 'thinks' might be the case. Your opinion is of little consequence to him.

I guess its really a matter of does it matter really.

If it doesn't matter to you, then you might as well not participate in the thread.

[Thunder 8]

He's an engineer, he pretty much only deals with facts, not what he 'thinks' might be the case. Your opinion is of little consequence to him.

If it doesn't matter to you, then you might as well not participate in the thread.

Does him being an engineer mean hes the only engineer on here.You know nothing about me or what i do.Seems to be a lot of bosses on KB. I will do what i want thanks.

[imdying]

Does him being an engineer mean hes the only engineer on here.You know nothing about me or what i do.Seems to be a lot of bosses on KB. I will do what i want thanks.

Sure, fine, whatever... let us know when you bring something to the table other than wah wah wah... it's not a particularly compelling argument.