What stops faster "Car VS bike" - debate

[Griffin]

Forum Sponsor

The Chevy Tahoe may be 4X heavier then a smart for two, but it also has 4X larger brakes....So it makes perfect sense, you cant only look at the weight of the car, you have to take into account all factors.....vehicle weight, type and size of brakes, size of wheels (diameter and width)....

Do a big brake kit on that smartfortwo and it will out brake your whole list...

This kit would knock alot of braking distance off a smart car

To Mike from Canmore - In answer to your post - What he said above.

Weight is a major factor. So is contact patch size. So is quality of rubber. So is quality of brakes. My point was that more rubber on the ground is not the determining factor. If it was, as was pointed out by more than me, a transport truck would out brake everything else on the road.

You know what? They DON'T!!

 

[BrianZ]

The Chevy Tahoe may be 4X heavier then a smart for two, but it also has 4X larger brakes....So it makes perfect sense, you cant only look at the weight of the car, you have to take into account all factors.....vehicle weight, type and size of brakes, size of wheels (diameter and width)....

Do a big brake kit on that smartfortwo and it will out brake your whole list...

This kit would knock alot of braking distance off a smart car

I doubt that kit would make any difference in the Smart car's stopping distance. The size of the brake rotors, pads and calipers are not a factor as long as they are capable of locking the wheels. The difference is in the contact patch, tire compound, weight and ABS performance. Bigger calipers and pads will reduce fade, but in a single panic stop they won't make any difference. My old 1976 Pinto could lock up all 4 wheels without much effort.

I supect the Smart car's ABS/stability system has something to do with the poor stopping distance.

 

[Brian P]

I suspect the Smart's skinny low-rolling-resistance tires have something to do with it, too.

Vehicles with very short wheelbases have a lot of weight transfer during braking, which doesn't help matters, but the Smart's rear engine should offset that. But the front tires are really really skinny on those.

 

[mike.from.canmore]

I doubt that kit would make any difference in the Smart car's stopping distance. The size of the brake rotors, pads and calipers are not a factor as long as they are capable of locking the wheels. The difference is in the contact patch, tire compound, weight and ABS performance. Bigger calipers and pads will reduce fade, but in a single panic stop they won't make any difference. My old 1976 Pinto could lock up all 4 wheels without much effort.

I supect the Smart car's ABS/stability system has something to do with the poor stopping distance.

thank you for adding some logic.


I've driven a smart car, and the brake are MORE THAN ADEQUATE to stop the car one time in any panic situation. Larger brakes will only let you stop more times repeatedly.



Right from stoptech..

http://www.stoptech.com/tech_info/faqs.shtml

A bigger pad means better braking, right?

A bigger pad of the same compound in the same location as a smaller pad will not yield shorter stopping distances. The amount of pressure applied, pad friction coefficient, and the diameter on the rotor at which that pressure is applied, determine the torque reaction, or stopping force. A bigger pad does not apply more pressure, only the same pressure over a bigger area. Where the size of the pad matters is in terms of heat capacity and wear rate. A larger pad will absorb more initial heat (less thermal shock), and have better wear characteristics (longer pad life). The technical page of our web site has several articles discussing brake dynamics: http://www.stoptech.com/tech_info/tech_white_papers.shtml

Also from the same link

Why do I need a big brake upgrade?

Modern stock brake systems, for the most part, work well for a single 60-0 or 80-0 stop, and average daily street driving. The typical performance enthusiast will quickly push the stock brake system beyond its capabilities. Driving style and other performance modifications such as increased horsepower, tire and suspension upgrades quickly add up to overpowering stock brakes. A big brake kit will provide increased heat capacity, which means substantially more resistance to brake fade and caliper distortion with multiple stops from high speed. A firmer pedal due to stronger and stiffer components, as well as better modulation characteristics under threshold braking are also typical with a properly balanced brake upgrade.

JohnnyP636, you don't seriously believe that big brake kits reduce stopping distances do you? - come on man!

 

[mike.from.canmore]

I suspect the Smart's skinny low-rolling-resistance tires have something to do with it, too.

Vehicles with very short wheelbases have a lot of weight transfer during braking, which doesn't help matters, but the Smart's rear engine should offset that. But the front tires are really really skinny on those.

yup...

The friction offered by the tires DOES affect stopping distances.



brake size - does not (as long as the brakes are capable of more friction than the tires)

Virtually all cars on the road can lock their brakes - smart car can easily lock it's brakes.

 

[JohnnyP636]

I doubt that kit would make any difference in the Smart car's stopping distance. The size of the brake rotors, pads and calipers are not a factor as long as they are capable of locking the wheels. The difference is in the contact patch, tire compound, weight and ABS performance. Bigger calipers and pads will reduce fade, but in a single panic stop they won't make any difference. My old 1976 Pinto could lock up all 4 wheels without much effort.

I supect the Smart car's ABS/stability system has something to do with the poor stopping distance.

Well then you've never upgraded brakes on something that could use better brakes....Simple as that....When your brakes are weak, fade, or have a crappuy feel from OEM, an upgraded caliper/rotor/lines/fluid all makes a difference in stopping power/distance....

I rented a trail bike last week that had drum brakes F/R, it would not stop for 2 blocks when you hammered both brakes.....Upgrading to a better brake system would help alot...Im sure of it

Now if where talking about cars that come with good brakes already, then thats a totally different story.....Some cars come stock with Brembo calipers...So like I was saying there are too many variables, not only in the vehicle weight, but also in the design, size, and quality of the brake components on said car/bike...

 

[mike.from.canmore]

To Mike from Canmore - In answer to your post - What he said above.

Weight is a major factor. So is contact patch size. So is quality of rubber. So is quality of brakes. My point was that more rubber on the ground is not the determining factor. If it was, as was pointed out by more than me, a transport truck would out brake everything else on the road.

You know what? They DON'T!!

I think you might be somewhat surprised just how fast a transport truck can stop. The air brakes are not nearly as responsive as hydraulic brakes, making threshold braking nearly impossible. I'm not aware of any Air brake ABS technology!

You have NO data regarding this - neither do I... so why are we talking about transports?

 

[JohnnyP636]

JohnnyP636, you don't seriously believe that big brake kits reduce stopping distances do you? - come on man!

If the car or bikes brakes suck from OEM then yes.....Have you ever upgraded your brakes? rotors? master? calipers? pads? On a car or bike that could have used some better brakes?

 

[mike.from.canmore]

I rented a trail bike last week that had drum brakes F/R, it would not stop for 2 blocks when you hammered both brakes.....Upgrading to a better brake system would help alot...Im sure of it

Right... that bike, in it original form - the brakes could NOT offer more friction than the tires could with the road. This is completely NOT relavent to this debate - unless you think that the average car with average brakes can't lock the brake in a panic situation...

And if you do think that, then you must also think that ABS is useless on dry roads cause the car don't have enough braking force to reach lockup anyway, rending the ABS useless - since a lockup is impossible.



My opinion - just about every car on the road (not old classic cars with 4 wheel drums) do in fact have enough braking power to lock the brakes one time during a panic stop from 100 - we agree on that right?

 

[Red_Liner740]

I think you might be somewhat surprised just how fast a transport truck can stop. The air brakes are not nearly as responsive as hydraulic brakes, making threshold braking nearly impossible. I'm not aware of any Air brake ABS technology!

You have NO data regarding this - neither do I... so why are we talking about transports?

i can attest to that. Air brakes are VERY hard to modulate, but they also stop quickly! and the truck (not 18wheeler) had ABS....that thing shed of speed like nothing, once u got the brake pressure right... i guess kinda like a bike? too much pressure and u lock up, not enough and you dont stop as well

 

[mike.from.canmore]

If the car or bikes brakes suck from OEM then yes.....Have you ever upgraded your brakes? rotors? master? calipers? pads? On a car or bike that could have used some better brakes?

Yes.. and everything you said about improving the feel, fade, performance is 100% correct - but not the stopping distance.


Big brakes are better - yes. But the ONE TIME stopping distance is not affected.


the feel, and the amount of fade after repeated slow downs, the firmness, etc.. all get improved.


You can make brakes so good an powerfull that 1/4lb of force would cause a lockup... but the vehicle isn't gonna stop any faster.... the friction of the tire to the ground is still the limiting factor.

 

[mike.from.canmore]

i can attest to that. Air brakes are VERY hard to modulate, but they also stop quickly! and the truck (not 18wheeler) had ABS....that thing shed of speed like nothing, once u got the brake pressure right... i guess kinda like a bike? too much pressure and u lock up, not enough and you dont stop as well

So you are confirming that weight is not an issue?

 

[JohnnyP636]

Right... that bike, in it original form - the brakes could NOT offer more friction than the tires could with the road. This is completely NOT relavent to this debate - unless you think that the average car with average brakes can't lock the brake in a panic situation...

And if you do think that, then you must also think that ABS is useless on dry roads cause the car don't have enough braking force to reach lockup anyway, rending the ABS useless - since a lockup is impossible.



My opinion - just about every car on the road (not old classic cars with 4 wheel drums) do in fact have enough braking power to lock the brakes one time during a panic stop from 100 - we agree on that right?

Yes but if youve ever upgrade a brake system before, youd realize that it can do much more then just give you more locking power....Bigger rotors give you more modulation without locking and stay cooler......Key word here is "CAN" and this all depends on the car in question......Ive driven some cars with some ****** brakes....Something as simple as cheap pads, can make a difference in stopping

I just dont see the relevance of comparing a smart cars stopping distance to a Tahoe or even a bike...They are so different from each other your not really proving anything even if one stops faster then the other...Its kind of a silly comparison IMO cause they are so different

 

[mma01]

JohnnyP636, you don't seriously believe that big brake kits reduce stopping distances do you? - come on man!

Maximum braking effort is achieved right before wheel lock up. Yes, almost any stock braking system can lock up the wheel. The advantage of a multi piston, big brake system over the typical fixed caliper, single piston stock system beyond fade resistance is in braking feel and the ability to modulate the brakes right up to the point of lock up more easily, which translates into shorter braking distances.

 

[mike.from.canmore]

If the car or bikes brakes suck from OEM then yes.....Have you ever upgraded your brakes? rotors? master? calipers? pads? On a car or bike that could have used some better brakes?

YES - all those things make it EASIER to stop, but they don't shorten the stopping distances.

if you apply more braking force - won't your bike endo/stoppie/flipover - rather than stop quicker? You are familiar with stunting? (that was sarcastic - I've seen you, and you are quite good, Amazing even - no question about that.)

 

[mike.from.canmore]

Maximum braking effort is achieved right before wheel lock up. Yes, almost any stock braking system can lock up the wheel. The advantage of a multi piston, big brake system over the typical fixed caliper, single piston stock system beyond fade resistance is in braking feel and the ability to modulate the brakes right up to the point of lock up more easily, which translates into shorter braking distances.

Actually...you said it yourself. It translates into being easier to reach thresh hold braking - not better thresh hold braking.

I am gonna argue that thresh hold braking can be done with OEM brakes - just not as easily as with BETTER brakes. Still possible though.


Like I said. better brakes = easier stopping/less effort + more repeat stops, less fade, better feel.



We are so off topic. We're supposed to be debating cars VS bikes. Not big brakes VS small brakes on the same car/bike.

 

[JohnnyP636]

YES - all those things make it EASIER to stop, but they don't shorten the stopping distances.

if you apply more braking force - won't your bike endo/stoppie/flipover - rather than stop quicker? You are familiar with stunting? (that was sarcastic - I've seen you, and you are quite good, Amazing even - no question about that.)

Stoppies dont really relate to this, because when you do them properly its much more then just braking hard....Your body movement and shifting of weight to pop up a stoppie and the balancing act while rolling, has just as much to do with it, as the brake control does....

I could be wrong but I truely believe I can stop faster on my bike with upgraded brakes, then I could on it when it had stock rubber lines and crappy OEM fluid....For stock its just too spongy for me to brake at potential....On the flip side I use a Brembo and Magura 19x20 masters which most people just cant use. As they have a very firm feel with little travel, which if your not used to it will lead to you locking up the front...

I dont trust these comparison tests run buy humans either, there is too much room for error in the riders or drivers timing I think....Even if you average it out over a few runs, what if the rider has better reaction time then the driver or vise versa

 

[mike.from.canmore]

rubber lines and crappy OEM fluid....

The lines, surely change the feel, but is there really a difference in the fluid for ONE single stop? I know the OEM fluid boils easily, but its still hydraulic oil, and considered non compressible.

With many stops, no doubt RBF takes the heat better, but when things are cool, I don't think the OEM fluid will boil/cause fade with one single stop!

 

[mike.from.canmore]

Stoppies dont really relate to this, because when you do them properly its much more then just braking hard....Your body movement and shifting of weight to pop up a stoppie and the balancing act while rolling, has just as much to do with it, as the brake control does...

Doing them and making them look good, as you do, requires more than just brake force...

But simple squeezing till the rear end lifts just requires a squeeze.
Many sportbikes are limited in brakign BECAUSE of their light weight. they could stop faster if they could keep the rear down.

Just like the title of this article states.
If you can do a stoppie ...
you CANNOT stop as quickly as others

By: James R. Davis

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

 

[mike.from.canmore]

Looking at the poll results right now...

Amazing.. Almost a 50/50 split.


67 people think an average car stops faster.
64 people think an average bike stops faster.

Amazing how far from a consensus we are. Imagine we were all on a jury together.


Equally puzzling is...

Of the 64 people who votes for the average bike.
Most of them think a bike WITHOUT ABS is best

Of the 67 people who voted for the average car
Most of them think a car WITH ABS is best


not a trend in sight.

Forum Sponsor