What stops faster "Car VS bike" - debate

[mike.from.canmore]

Forum Sponsor

ok folks it's time i chime in. i'm a living proof that bikes stop faster than regular cars. because i did it. to do a panic stop from 120 - 0 all you had to do is go apeshit on the brakes and if you still can't make it, lean a little and self induce a rear skid/fishtail and highside yourself the last millisecond to stop and prevent yourself from a rear ending incident. :laughing8::laughing8: just make sure you are wearing gear and the bike has adequate crash protection (so you can still ride home after) sliders are useless cuz it will snap for sure and most likely destroy your frame. race rails/engine guards are where it's at. you dont even need to worry about the car behind you running you over because the highside will launch you a few ft forward and even if the car behind you can't stop in time your bike can act as a road block.


ok j/k

FYI - the car in front of you was probably stopping at about half it's potential.

 

[mike.from.canmore]

Well in your opinion weight does not matter. So why does a change in vehicle? The Jeep will have the front wheels on the brink of locking, I find the ABS to be particularly good on dry pavement... I hammered them as hard as they would go just a week or two ago on an open road, just to see what happened.

you do know ABS would increase the stopping distance right? (but allows even the most novice of drivers to retain control).


It's not the weight of your jeep, it's the coefficient of friction offered by the tires - are they off road/dual purpose tires?

Also, just cause the front were near locking, were the rear also? in a car, the rear wheels still provide braking at threshold as cars don't usually do stoppies.

 

[mr.fizz]

FYI - the car in front of you was probably stopping at about half it's potential.

there's a nice skid mark from the car... so maybe not half the potential :happy3:

 

[mike.from.canmore]

there's a nice skid mark from the car... so maybe not half the potential :happy3:

precisely..

Skidding is slowing down at no where near the max potential.

On dry pavement, when skidding, you no longer have the static coefficient of friction, you get the dynamic coefficient of friction. On dry pavement, the dynamic coefficient of friction is at least 20% less than the static.

(source = http://www.msgroup.org/Tip.aspx?Num=209&Set=199-231)

search for the words "DYNAMIC coefficient of friction"

 

[SweetOnion]

you do know ABS would increase the stopping distance right? (but allows even the most novice of drivers to retain control).


It's not the weight of your jeep, it's the coefficient of friction offered by the tires - are they off road/dual purpose tires?

Also, just cause the front were near locking, were the rear also? in a car, the rear wheels still provide braking at threshold as cars don't usually do stoppies.

Well interestingly enough, I love the Jeep as an example, because the suspension is set up in such a way that under extreme braking, the front end dives severely. The back wheels lose grip and the rear becomes very loose. It is not hard to start a power slide just by tapping the brakes and giving it the old Scandinavian Flick.

And yes, I do know all about the ABS increasing stopping distance... my previous posts will represent that.

The real idea that people need to consider is that a 4 wheeled vehicle can stop faster than a 2 wheeled vehicle. What we call "CARS" ... well that particular blend of 4 wheeled vehicle can only out brake a modern day sport bike in a very few cases...

 

[mr.fizz]

precisely..

Skidding is slowing down at no where near the max potential.

On dry pavement, when skidding, you no longer have the static coefficient of friction, you get the dynamic coefficient of friction. On dry pavement, the dynamic coefficient of friction is at least 20% less than the static.

(source = http://www.msgroup.org/Tip.aspx?Num=209&Set=199-231)

search for the words "DYNAMIC coefficient of friction"

oh ok i skidded too so it evens it out then

 

[invictus43]

The real idea that people need to consider is that a 4 wheeled vehicle can stop faster than a 2 wheeled vehicle. What we call "CARS" ... well that particular blend of 4 wheeled vehicle can only out brake a modern day sport bike in a very few cases...

I think that people who consider only the physics behind the exercise are not seeing the entire picture. Tire behaviour during dynamic conditions (dynamic does not necessarily mean only sliding..) is not well understood. Any tire engineer will tell you this. In theory, contact patch is not significant to stopping or cornering. However, the reality is somewhat different because the coefficient of friction generated by the tire is variable depending on the conditions at the interface between the road and the tire. To understand this, imagine a car cornering on bicycle-width tires. In theory, the available traction is the same as with very wide tires, but because of the interaction with the road (primarily increasing temperature as well as micro-surface interlocking) the tires will quickly lose their coefficient of friction. I believe this is what happens with the majority of passenger vehicles. Their coefficient of friction may start out similar to a bike's front tires but the loads placed on it quickly alter it's ability to maintain traction. So, while in theory, contact patch is not relevant, in reality, it is.

 

[SweetOnion]

I think that people who consider only the physics behind the exercise are not seeing the entire picture. Tire behaviour during dynamic conditions (dynamic does not necessarily mean only sliding..) is not well understood. Any tire engineer will tell you this. In theory, contact patch is not significant to stopping or cornering. However, the reality is somewhat different because the coefficient of friction generated by the tire is variable depending on the conditions at the interface between the road and the tire. To understand this, imagine a car cornering on bicycle-width tires. In theory, the available traction is the same as with very wide tires, but because of the interaction with the road (primarily increasing temperature as well as micro-surface interlocking) the tires will quickly lose their coefficient of friction. I believe this is what happens with the majority of passenger vehicles. Their coefficient of friction may start out similar to a bike's front tires but the loads placed on it quickly alter it's ability to maintain traction. So, while in theory, contact patch is not relevant, in reality, it is.

So what did you vote for??

 

[psycho44]

can't believe most people think cars can stop better than bikes.

Cars weigh a lot more hence it's like comparing a 500 pound sumo wrestler with a marathon runner. Who will stop better if both travel at the same speed?

I did say in Mr. Fizz's thread that it's all dependent on the rider's braking skills to keep the bike upright. Under perfect condition the bike will almost always brake better than a car. But again braking on a bike is heavily dependent on the rider's ability while braking in a car essentially requires just slamming on the breaks to stop the car.

 

[murf]

can't believe most people think cars can stop better than bikes.

Cars weigh a lot more hence it's like comparing a 500 pound sumo wrestler with a marathon runner. Who will stop better if both travel at the same speed?

.

the data shows that they are very close, and high performance cars can stop faster.
can you show us otherwise?

 

[murf]

From autocar back in 2004:

100mph to a standstill in seconds:

Caterham R500: 3.60
Porsche 911 GT3: 4.00
Ferrari Enzo: 4.08
Mercedes Benz SLR Mclaren: 4.22
Peugeot 206 GTi: 4.39
Aston Martin DB9: 4.42
VW Toureg V10 TDi: 4.52
Subaru Impreza WRX: 4.64
Honda Civic Type R: 4.64
Vauxhall Senator 3.0i: 5.43
Suzuki GSXR-1000: 5.63

 

[optionfa]

Guys whats faster a honda civic or 600?





























at stopping

 

[psycho44]

From autocar back in 2004:

100mph to a standstill in seconds:

Caterham R500: 3.60
Porsche 911 GT3: 4.00
Ferrari Enzo: 4.08
Mercedes Benz SLR Mclaren: 4.22
Peugeot 206 GTi: 4.39
Aston Martin DB9: 4.42
VW Toureg V10 TDi: 4.52
Subaru Impreza WRX: 4.64
Honda Civic Type R: 4.64
Vauxhall Senator 3.0i: 5.43
Suzuki GSXR-1000: 5.63

aren't these all high-end cars? For a hundred thousand dollars I'd hope it's not just for looks. So if a high performance car can stop better than a litre bike I'd say the average car won't stand a chance.

What stops better a 600 or a litre bike? Do higher cc's stop better than lower cc bikes both going at same speed? I'd guess the lower cc bike would stop better but surprise me someone.

 

[murf]

aren't these all high-end cars? For a hundred thousand dollars I'd hope it's not just for looks. So if a high performance car can stop better than a litre bike I'd say the average car won't stand a chance.

What stops better a 600 or a litre bike? Do higher cc's stop better than lower cc bikes both going at same speed? I'd guess the lower cc bike would stop better but surprise me someone.

A subaru and a civic is high end?

 

[psycho44]

A subaru and a civic is high end?

I don't know much about cars but $50k for a civic I'd say is high end.

 

[omega8]

There was some test in Top Gear a while ago. In that test the car (Lamborghini Gallardo if I recall correctly) had a shorter braking distance than the bike (Ducati 1098, again IIRC).

Taking average car from the street and an average bike from the street, I would guess that the bike would be better. But that's just my feeling. I have no data on it.

I think I have the video you are referring to, it's actually from the Fifth Gear. I can share it, but it's 20MB file. Will GTAM host the file?

 

[DY]

What stops better a 600 or a litre bike? Do higher cc's stop better than lower cc bikes both going at same speed? I'd guess the lower cc bike would stop better but surprise me someone.

engine capacities have nothing to with it. this whole debate is munt because everyone already has their own theory on how things are based on their exposure to different vehicles.

I think I have the video you are referring to, it's actually from the Fifth Gear. I can share it, but it's 20MB file. Will GTAM host the file?

its on youtube. i believe 1098 vs...lambo w/e

 

[murf]

I don't know much about cars but $50k for a civic I'd say is high end.

since you are using UK pricing lets convert the GSXR1000 UK price over to canadian, so I would say a $30000 GSXR is a high end bike as well no?

you know there is a vauxhal and a subaru in that list if it makes you feel better.

 

[Flashmonkey]

Since the OP began this thread in the hopes of having a logical, meaningful debate filled with facts...and seeing as how its kind of degenerated into a "Who would win in a race: a CBR600RR vs a turbo'd honda civic" style thread...I figured it was time for a university research paper:

http://www.egr.msu.edu/dvrl/abstracts/Olson-etal_aVA00.pdf

Behold....the abstract for a mechanical engineering graduate level research paper out of the University of Michigan discussing vehicle braking using non-linear models.

It's a little thick in the jargon...and it's hard to form any solid conclusions without seeing the entire report....but it gives a good idea of what we're up against with this topic. It's interesting to note that these models also don't seem to take into account the non-linear force transfering nature of springs and dampers...but I guess their effect on vehicle braking is debatable.

Get your geek on folks.

Edit: Yeah, that link goes right to a pdf....so it may be a little twitchy.

 

[Teal]

Hey Mike if you're so smart why don't you explain your theories to these guys, I'm sure they'll love hearing about your calculations and assumptions; "100% braking efficiency" and "tire traction the limiting factor".

http://www.brembo.com/ENG/Contact

Forum Sponsor