Can a motorbike out brake a car?

[gatch]

Surface area plays no part

Without even looking further into it I don't believe this for a second. You would have people believe the a motorbike would brake in the same distance if it was running 30mm pushbike tire as opposed to 120mm motorbike tire ?

[NDORFN]

Your Naive....

Your grammar sucks.

[Thunder 8]

Without even looking further into it I don't believe this for a second. You would have people believe the a motorbike would brake in the same distance if it was running 30mm pushbike tire as opposed to 120mm motorbike tire ?

Youre onto it..More tyres more surface contact area, MORE friction ,faster stopping.The bit of steel analogys got fuck all to do with rubber on the road.Perfect conditions etc when braking full on hardly exist,try out breaking a car in an emergency stop at speed...........prepare for hospital.

[cowpoos]

Your grammar sucks.

http://en.wikipedia.org/wiki/Na%C3%AFve <--- there you go idiot.

[Dare]

http://en.wikipedia.org/wiki/Na%C3%AFve <--- there you go idiot.

Think he was referring to your/you're. Hahaha, not spelling.

Pretty sure 4 wheels and all that weight = more friction & better braking. And the side-side turning time with that ducati made a good point. Never really thought of bikes as being less agile than cars but there it is.

Makes me wonder what the braking properties of one of these would be!
Looks almost as fun as a bike...

[steve_t]

Your grammar sucks.

You're stealing Hitcher's job

[mossy1200]

applied traction force against weight to determine distance to stop.
Bike equals less contact patch .. negative
Bike also equals less weight to stop...positive
Bike tyre equals softer compound...positive
Slipery surface will move advantage towards larger contact patch.
Reaction time is the killer.
Rider watching what is happening beyond the car stands a lot better chance.
If you let the car knock off 20kph before you start to brake then you give away all the advantage and the distance has allready decreased before you start braking.
Skill of rider is factor

Conclusion .RIDE LIKE YOU LIKE LIVING.

[lankyman]

Not a hope in hell.... less weight pinning it down and a bike has about 4 inches total tread on the gorund maximum at any time a car has 4x 8-10 inches.

Also less weight means less kinetic energy to be reduced...remembering that most bikes weigh about 1/6 of what your average car does.
I have always been under the impression that on a track a car is quicker through the corners, and the bike will make up the difference through being able to accelerate/decelerate a hell of a lot quicker (due to it's huge power:weight advantage)

Example:
Yamaha R1 weighs 270kg (with rider) and has 180hp
A car weighing 1400kg and will need 933hp to acheive same power:weight ratio

[Dare]

The bike will make up the difference through being able to accelerate/decelerate a hell of a lot quicker (due to it's huge power:weight advantage)

Example:
Yamaha R1 weighs 270kg (with rider) and has 180hp
A car weighing 1400kg and will need 933hp to acheive same power:weight ratio

The difference is a bike needs a short wheelbase to achieve quick turns and as such is liable to flip over forwards/backwards. This is why some cruisers can stop faster than sport bikes and why drag bikes are so long.

Against that skyline the Ducati seemed slightly heavy due to the large engine, I think a light 600/750 could have held it in corners/braking and still edged ahead in a straight line... Just an impression though.

[bane]

I have always been under the impression that on a track a car is quicker through the corners, and the bike will make up the difference through being able to accelerate/decelerate a hell of a lot quicker (due to it's huge power:weight advantage)

Well, we now know that even a humble Mazda 3 can easily outbrake a CBR1000rr with a semi-pro rider (by ~7m at 100kph). Also, even I can achieve that stopping distance time after time in the car - but unlikely I would have the skill to get the best stopping distance out of the bike...

The issue the bike has on the track is that because it is so much faster in a straight line, it has a lot more speed to wipe off to get through the corner (especially as it lacks the mechanical grip to carry the same speed through the corner as the car). Therefore rider has to be on the brakes much earlier than the car (and for example, GT-R ends up having to avoid taking the Ducati out at the corner entry)

[jono035]

I noticed a few people mentioning friction vs contact area. Strictly speaking friction doesn't change with contact area, but that is only for 2 non-deformable surfaces.

Tires deform as they come into contact with the road and loss of traction is either due to the tire tread buckling out of the way (tread shuffle) or the rubber itself not having enough shear-strength and giving way under load. In both of these cases more contact is better, although as per usual there are a heap of other factors as well...

[cowpoos]

I noticed a few people mentioning friction vs contact area. Strictly speaking friction doesn't change with contact area, but that is only for 2 non-deformable surfaces.

Errrrr do explain???

[jono035]

Errrrr do explain???

http://en.wikipedia.org/wiki/Friction

For the basic model of friction of 2 solid, dry surfaces in contact, the friction doesn't change with contact area, only with the material's coefficient of friction and the force pushing the 2 objects together.

Basically says a 1kg weight on a single block of wood will be just as easy to pull along concrete as a 1kg weight on 2 or more blocks of wood. This gets quoted a lot when talking about tires, but it doesn't apply in this case because it misses out a lot of real world factors, especially the shear-strength of the rubber involved and the fact that the tread moves sideways when comparing it to the rim while cornering.

[jono035]

Although apparently the version of 'basic friction' which I had always discounted as being too simple to be more than a rough indicator is a couple of years out of date anyway... From the Wikipedia reference:

# CORRECTED: FRICTION IS NOT CAUSED BY SURFACE ROUGHNESS

Some books point to surface roughness as the explanation of sliding friction. Surface roughness merely makes the moving surfaces bounce up and down as they move, and any energy lost in pushing the surfaces apart is regained when they fall together again. Friction is mostly caused by chemical bonding between the moving surfaces; it is caused by stickiness. Even scientists once believed this misconception, and they explained friction as being caused by "interlocking asperites", the "asperites" being microscopic bumps on surfaces. But the modern sciences of surfaces, of abrasion, and of lubrication explain sliding friction in terms of chemical bonding and "stick & slip" processes. The subject is still full of unknowns, and new discoveries await those who make surface science their profession

When thinking about friction, don't think about grains of sand on sandpaper. Instead think about sticky adhesive tape being dragged along a surface.

[rocketman1]

The one thing I have to say only once is:
Practice stopping
Practice Stopping
PRACTICE STOPPING

EVERY ONE CAN GO FAST, NOT MANY CAN REALLY STOP FAST