Can a motorbike out brake a car?

**henry** · 30th April 2008, 14:20

I know I'm probably wasting my breath and shouldn't get into a pissing match over this but...

A vehicles weight, or inertia, doesn't significantly alter is braking performance. The dominating factor is the friction between the road and the tyres. Cars have a bigger contact patch so can apply a greater stopping force to the road.

In a corner it's all about sideways force before the tyres slip. On a bike it is a little over 1G. Cars can handle way more than that.

**Grub** · 30th April 2008, 14:35

I believe that cars do in fact stop better than a bike due to coefficient of friction and all that ... but I like this story better ...

The McLaren M10A CanAm car could do 0-160kmh-0 in 6.3 secs ... way cool.

**Mikkel** · 30th April 2008, 15:31

Originally Posted by nodrog

superbike vs supercar

http://www.youtube.com/watch?v=ZZKRp...eature=related

Nice video

Originally Posted by henry

A vehicles weight, or inertia, doesn't significantly alter is braking performance. The dominating factor is the friction between the road and the tyres. Cars have a bigger contact patch so can apply a greater stopping force to the road.

In a corner it's all about sideways force before the tyres slip. On a bike it is a little over 1G. Cars can handle way more than that.

Well, you ALMOST got that right. The size of the contact patch is, without going into meaningless detail, determined by only two factors: the weight of the vehicle and the tyre pressure. (The area is equal to the weight of the vehicle divided by the tyre pressure.)

There is one factor that makes it harder for a bike to utilise it's braking potential to the same level as a car: stability. Whether it be lateral or longitudinal.
If you brake too hard you'll end up doing a stoppie which is not ideal. (conservation of angular momentum around the front wheel...).

Cars cornering at more than 1G only happens due to down force - AFAIK there hasn't been made a tyre with a coefficient of friction higher than 1.00 yet. (so that should make it a little LESS than 1G for a bike)

Originally Posted by henry

Never read so much bullshit.

Well, take solace in the fact that at least you contributed

**Morcs** · 30th April 2008, 15:35

Cars will always outbrake a bike with skilled drivers.

Anyone see the top gear episode - 1098 versus meircegulago? the duc got wasted under braking.

And actually mark, cars can corner faster than bikes. Shit load more grip and downforce.

**henry** · 30th April 2008, 16:01

Originally Posted by Mikkel

Well, you ALMOST got that right. The size of the contact patch is, without going into meaningless detail, determined by only two factors: the weight of the vehicle and the tyre pressure. (The area is equal to the weight of the vehicle divided by the tyre pressure.)

You missed the third and probably most important factor. The car has four flat wide tyres and the bike has two curved tyres.

**Monty69** · 30th April 2008, 16:28

I recently watched a documentry about supercars and sportsbikes doing 0-100-0 times. The sportsbikes were generally much faster in acceleration but under brakes the cars would gain the time back. So cars can out brake a bike.

**YellowDog** · 30th April 2008, 17:13

Hey Dan. Can you tell me where you hold AWNMR?

May be interetsted in going along.

**PrincessBandit** · 30th April 2008, 17:22

Originally Posted by AllanB

In that Mission Impossible movie on the Speed Triple (yummy) Tom (weirdo) Cruise stopped from god knows how fast on the front wheel while pulling a gun out of his pocket and then spun it around (while still doing before mentioned stoppie) and shot the baddie.

Hollywood is so full of crap - every motorcyclists knows to keep both hands on the bars when doing stoppies at 160.

You're just jealous of yummy Tom's exceptional stunt man skills.

(p.s. yes I was taking the yoo-rine btw)
and while i am sure lots of riders only use the 2 finger braking application, i was told at the bhs course to always use all (Ripper Roo92 got told off for only using 2 fingers!)

**AllanB** · 30th April 2008, 17:35

Well stunt man was not what I was thinking - but it rhymed with stunt

I bet you lot would stop pretty fast for this traffic gal.

**cowboyz** · 30th April 2008, 18:30

Originally Posted by rachprice

http://www.youtube.com/watch?v=7Oz44oGaI4c
I thought bikes would outbrake cars but then I dont know much at all!
btw fifth gear? what a fuckin rip off of top gear.

that 1098 looks nice. Loving the wheelie on the last corner.
If you are going to spend $150000 you might as well buy something you can have some fun on.

**rocketman1** · 30th April 2008, 19:49

I guess at the end of this I have learned one thing and that is that I should attend a Course that teaches me How to brake.
Braking over and over in controlled conditions must improve your distances.
It is something that bike clubs should consider running at track days maybe.

**Subike** · 30th April 2008, 20:00

A lot of information in this thread,
good arguments from all involved
I have had to rethink my own views upon this subject and say that my first post is wrong.
I guess that in the perfect situation that a bike may be better, but this world is not perfect, so that situation may never appear.
I now think that I may look at my following distances in heavy traffic and allow a bit more room for movement, or keep escape routes more in mind.
Thanks all posters for some awsome information, good links, good debate.

**scracha** · 1st May 2008, 08:22

Originally Posted by rachprice

http://www.youtube.com/watch?v=7Oz44oGaI4c
I thought bikes would outbrake cars but then I dont know much at all!
btw fifth gear? what a fuckin rip off of top gear.

BBC cancelled top gear. Channel 5 then took most of the top gear staff and created fifth gear. BBC realised the "new format" was a good one and reintroduced top gear. So basically the new top gear is a fuckin rip off of fifth gear.

**henry** · 1st May 2008, 08:39

Originally Posted by Subike

I have had to rethink my own views upon this subject and say that my first post is wrong.
...
I now think that I may look at my following distances in heavy traffic and allow a bit more room for movement, or keep escape routes more in mind.
Thanks all posters for some awsome information, good links, good debate.

That's what these forums are for. To learn from people with more knowledge and / or experience. The worrying thing is how many idiots still think they know better.

Good on you.

**Mikkel** · 1st May 2008, 09:36

Originally Posted by henry

You missed the third and probably most important factor. The car has four flat wide tyres and the bike has two curved tyres.

No I am very much aware of the difference in profile between cars and motorcycles. I happen to own one of the former and two of the latter.

What you fail to realise is that the profile of the tyre has (almost) no impact upon the size of the contact patch - only the shape. Besides the size of the contact patch is not what determines the amount of traction you have available. The only thing that matters in relation to traction is the force on the wheel (the weight on the wheel if you want) and the coefficient of friction.

If you don't like it I suggest you take it up with Dr. Isaac Newton.

Originally Posted by AllanB

I bet you lot would stop pretty fast for this traffic gal.

Ah the good old anti-speeding campaign from back home