What stops faster "Car VS bike" - debate

[Griffin]

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Your parents were probably the kind who sat you in front of a television to stifle any form of creative thought eh? **** man, curiosity is not a bad thing, hell it encourages technological advancement for goodness sake.

Actually no. We had INTELLIGENT conversation. We didn't discuss whether the War of 1812 would have been won by the Yanks if they had had automatic weapons or tactical nukes.

This thread is about as far from an intelligent conversation as you can get. Arguing with mis-informed and/or un-informed people that have their minds made up about matters that they haven't a clue about is stupid.

I'd be interested in this discussion if it was with some informed and intelligent people. ANyone want to way in with some actual physics on this situation and not what they can glean from youtube?


I didn't think so.

 

[V-Tom]

...I'd be interested in this discussion if it was with some informed and intelligent people. ANyone want to way in with some actual physics on this situation and not what they can glean from youtube?
...

Hey I'm game for it!

I think, though, that this really should be an easy thing to find out.. all the theory aside it should be pretty easy to take some cars and some bikes and test their stopping ability.

My suspicion is that in reality the best cars will outbrake the best bikes for the reasons I stated previously, and that the best bikes will outbrake average cars.

..Tom

 

[mma01]

My suspicion is that in reality the best cars will outbrake the best bikes for the reasons I stated previously, and that the best bikes will outbrake average cars.

..Tom

Far from being the best car, but I can bring out my friend with a bone stock 996 C2. Im willing to bet that with rear engine, big brembo brakes and sticky tires it will outbrake the average rider here piloting even the best bike.

 

[invictus43]

nope...


say your bike is 100 lbs (ease of use number).
and your current contact patch is 1 sq inch (ease of use number)

you would have a contact pressure of 100 PSI, and a contact force of 100 lbs


If you double the contact patch to 2 sq in... the contact force doesn't change, but the contact pressure drops to 50 psi.

Simply distributing the load doesn't help traction/friction.

What I'm trying to say is... the coefficient of friction is independent of contact patch.

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



Debating the tire width VS traction issue has already been done here - http://www.physicsforums.com/archive/index.php/t-330790.html

xxChrisxx knows what he's talking about on that forum.

from the above link talking about tire widths

The fact that coefficient of friction is independent of contact patch, while true, is only half the story. Mu changes depending on the conditions at any given time at the tire/road interface. An extreme example, you could put a car on bicycle tires and in theory, mu is the same. However, once you introduce high loading on the tire you're obviously going to severley alter the performance of the tire ie you'll melt it.

 

[mike.from.canmore]

The fact that coefficient of friction is independent of contact patch, while true, is only half the story. Mu changes depending on the conditions at any given time at the tire/road interface. An extreme example, you could put a car on bicycle tires and in theory, mu is the same. However, once you introduce high loading on the tire you're obviously going to severley alter the performance of the tire ie you'll melt it.

exactly

 

[mike.from.canmore]

I'd be interested in this discussion if it was with some informed and intelligent people. ANyone want to way in with some actual physics on this situation and not what they can glean from youtube?


I didn't think so.

There are a few who are genuinely participating, and it's pretty clear who they are.

Unfortunately there is no "troll" filter.


As for actual physics - there have been several posts with very useful links. Did you take my last post with a link to http://www.physicsforums.com as mere hearsay?

 

[invictus43]

There are a few who are genuinely participating, and it's pretty clear who they are.

Unfortunately there is no "troll" filter.


As for actual physics - there have been several posts with very useful links. Did you take my last post with a link to http://www.physicsforums.com as mere hearsay?

I read a great article written by one of the Michelin F1 tire guys from a few years back. It was refreshing to see him write "we don't really understand what's going on at the contact patch 100%". It's a bit of a black art I suppose.

 

[Baggsy]

Some of you people are really starting to scare me; I hope you don't work at designing braking systems.

Invoking "physics" and then talking about weight with regards to stopping distance?!?

There's some golden irony in this thread.

Anyway, I'm surprised that the car without ABS is ranked so low.

 

[mccarthy]

Some of you people are really starting to scare me; I hope you don't work at designing braking systems.

Invoking "physics" and then talking about weight with regards to stopping distance?!?

There's some golden irony in this thread.

Anyway, I'm surprised that the car without ABS is ranked so low.

This has been proven, many, many, many times.. an average bike will outbrake an average car everysingle time becuase of wieght.... a car is just too heavy, many times heavier than a bike. The heavier the vehicle the longer it takes to stop. I watched a tv show about this- they took a motorcycle, a small car, middle size, large car, and a truck... the bike won.

 

[mike.from.canmore]

This has been proven, many, many, many times.. an average bike will outbrake an average car everysingle time becuase of wieght.... a car is just too heavy, many times heavier than a bike. The heavier the vehicle the longer it takes to stop. I watched a tv show about this- they took a motorcycle, a small car, middle size, large car, and a truck... the bike won.

Oh my . Did you skip the entire thread and then just post this absolute nonsense?


Where has it been "proven, many, many, many times"?
FYI - you are presently very deep into the loosing side of the argument.

LOL - because of weight. - LOL

the VERy FIRST POST specifies that posts like yours are what we DON"T WANT.

quote from first post

posts like

"bike stops faster cause it's lighter" is generally regarded as a stupid post, cause you forgot to include a reference to a fact.

I guess we shouldn't flame you too much... as you clearly didn't even read the thread you were replying to

 

[gasgaschris]

Most cars on the market will not lock the tires instantly when you hammer on the brakes at higher speeds. By upgrading the brakes on that same car i.e. Larger rotors and stickier brake bads you will reach optimal braking faster than stock equipment therefore reducing braking distances. I don't think the same holds true for bikes because you have to give time for weight transfer in order to compress the front tire and therefore get perfect traction. My vote is for the car if both vehicles can lock the tires instantly at that givin speed.

 

[mihnea]

it's all about the relation between weight, its distribution, the area of contact with the surface and the quality of the tire AND brake efficiency...

 

[mike.from.canmore]

it's all about the relation between weight, its distribution, the area of contact with the surface and the quality of the tire AND brake efficiency...

Might as well just say..

it's all about the relationship between how fast one vehicle stops VS the other vehicle.




Weight = NOPE
Contact patch = NOPE
Quality of tire = yup
brake efficiency = Nope



so close.

 

[gasgaschris]

Might as well just say..

it's all about the relationship between how fast one vehicle stops VS the other vehicle.




Weight = NOPE
Contact patch = NOPE
Quality of tire = yup
brake efficiency = Nope



so close.

That makes sense if an average vehicle can lock the brakes instantly. But lets say you are travelling at 160km/h and you hammer the brake pedal. The tires will not lock untill say 140km/h. By upgrading the brakes, you may be able to lock the tires at say 150km/h therefore reaching maximum breaking sooner and stopping faster. So brake efficiency does play a part.

 

[Baggsy]

This has been proven, many, many, many times.. an average bike will outbrake an average car everysingle time becuase of wieght.... a car is just too heavy, many times heavier than a bike. The heavier the vehicle the longer it takes to stop. I watched a tv show about this- they took a motorcycle, a small car, middle size, large car, and a truck... the bike won.

When you discover the formula where Mass doesn't cancel out, can you please let us in on it. It might make FTL travel and teleportation possible.

That makes sense if an average vehicle can lock the brakes instantly. But lets say you are travelling at 160km/h and you hammer the brake pedal. The tires will not lock untill say 140km/h. By upgrading the brakes, you may be able to lock the tires at say 150km/h therefore reaching maximum breaking sooner and stopping faster. So brake efficiency does play a part.

But, to stop in the shortest distance possible you don't want to lock the brakes.
You want to be using the static coefficient of friction and not the dynamic one.

 

[gasgaschris]

I didn't mean that you would actually lock the tires. A car that can lock the tires faster can reach maximum braking faster. I was just using it as a reference point.

 

[mccarthy]

Oh my . Did you skip the entire thread and then just post this absolute nonsense?


Where has it been "proven, many, many, many times"?
FYI - you are presently very deep into the loosing side of the argument.

LOL - because of weight. - LOL

the VERy FIRST POST specifies that posts like yours are what we DON"T WANT.

quote from first post

I guess we shouldn't flame you too much... as you clearly didn't even read the thread you were replying to

I see your still arguing it.. its just the way it is lol. i didnt have to read the rest of the thread to understand how simple physics works... that isnt a theory. physics would definately allow a motorcycle to stop faster than a car because you can put almost all the weight on the front wheel while slowing down, you cant do that in a car, a motorcycle can do a wheelie because it has a higher power to weight ratio than a car, a motorcycle can stop faster because it has a higher center of gravity allowing more pressure to be put onto the ground by the front tire when braking. there is always some skill that changes the results, but a good motorcycle can easily stop faster than a car.


Why is this even a debate?

 

[V-Tom]

I see your still arguing it.. its just the way it is lol. i didnt have to read the rest of the thread to understand how simple physics works... that isnt a theory. physics would definately allow a motorcycle to stop faster than a car because you can put almost all the weight on the front wheel while slowing down, you cant do that in a car, a motorcycle can do a wheelie because it has a higher power to weight ratio than a car, a motorcycle can stop faster because it has a higher center of gravity allowing more pressure to be put onto the ground by the front tire when braking. there is always some skill that changes the results, but a good motorcycle can easily stop faster than a car.

Why is this even a debate?

Wow.. Do you really believe that?

Let's take your argument and apply to another aspect of driving.. cornering ability. Your argument implies that raising the centre of gravity, therefore putting more weight on the wheel on the side the G-forces seem to come from (ie: the front wheel in a stoppie, the rear wheel in acceleration, the outside wheels in a turn on a car) increases the G-Force. Perhaps you should give the Formula One engineers some lessons as I seem to recall them trying to lower the centre of gravity of F1 cars.

You argument would imply that a Van, SUV or Truck with a high centre of gravity can out-corner a sports car with a low centre of gravity since the high centre of gravity vehicle can get closer to rolling over sooner (and will roll over sooner.) I suspect that most people would agree that it simply isn't true.

..Tom

 

[mikbusa]

a motorcycle can stop faster because it has a higher center of gravity allowing more pressure to be put onto the ground by the front tire when braking

Seriously? :laughing8:

 

[mccarthy]

Wow.. Do you really believe that?

Let's take your argument and apply to another aspect of driving.. cornering ability. Your argument implies that raising the centre of gravity, therefore putting more weight on the wheel on the side the G-forces seem to come from (ie: the front wheel in a stoppie, the rear wheel in acceleration, the outside wheels in a turn on a car) increases the G-Force. Perhaps you should give the Formula One engineers some lessons as I seem to recall them trying to lower the centre of gravity of F1 cars.

..Tom

- they already understand, thats why they adjust the camber of the tires on race cars- in order to use the wieght of the vehicle to its full potential when cornering. lol your really not understanding what im saying and i dont wanna waste more time trying to break it down.

Does anyone here understand that all cars front 2 wheel do 80% of the stopping and are supplyed with 80% of the power when you apply the brakes.. does anyone here watching any kind or motorsport racing. god damnit

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