Can a motorbike out brake a car?

**Mikkel** · 1st May 2008, 23:44

Truck tyres are pretty damn expensive - thus they run a hard compound to enable a longer tyre life. This would be part of the explanation at least.

**avgas** · 2nd May 2008, 12:05

Originally Posted by koba

right but mass of the vehicle MUST surely make a difference...

Ah now you get to the confusing parts.
Rather than me type out the static/dynamics 101 i think i may be better for you to do some research on this on you own time. Basically some key words i recommend you google would be.
Momentum
Friction
Vectors
Rotational force
Weight (g-force if you wish)
If you read these topics up till you get to the differential elements (dy/dt or "s" terms in some books in some texts) it should give you a basic understanding of why this is not so black and white.

**NighthawkNZ:Me** · 2nd May 2008, 12:13

Originally Posted by jrandom

You're not that dumb.

bwahahahhaha.. im sorry but..

**crazybigal** · 2nd May 2008, 12:30

man you talk some shit!!
2m at 60k id love to see that! you would be over the bars and flying!

Originally Posted by skidMark

Well yeah i mean i can stop a bike from 60kph in 2 metres.

That is once reacted andd actually applying brakes.

But i have been in some cars that stop pretty bloodey fast.

As in hit the brakes and its stopped. 120 kph - 0 kph in err pass, a bloodey short distance thats for sure.

**koba** · 2nd May 2008, 15:38

Originally Posted by avgas

Ah now you get to the confusing parts.
Rather than me type out the static/dynamics 101 i think i may be better for you to do some research on this on you own time. Basically some key words i recommend you google would be.
Momentum
Friction
Vectors
Rotational force
Weight (g-force if you wish)
If you read these topics up till you get to the differential elements (dy/dt or "s" terms in some books in some texts) it should give you a basic understanding of why this is not so black and white.

Im not a huge reader I may have a quick gander at some googled info but I think I need to put the motor back in my car for and interesting experiment, It has very little to do with what we are talking about but it should be interesting to objectivley test the braking distance of my two cars, a disk braked beetle and a full drum lightened beach buggy....

All this just got me thinking : I wonder which will stop quicker..

What do people think?
Which will stop in a shorter distance averaged over 3 or more goes, same day, sameish fuel load etc etc,

One is standard 1969 VW Beetle Disc brake front and I think 3 inch drums on the back
185/15 tyres (a bit shabby) on the front
205/15 Gr200 Enduros on the back.
Weight unknown, est 800kg.
while the other is

a fibreglass beach buggy with 4 wheel drums (3in Front 2 in rear I think) Sill volkswagen based, 14 inches shorter wheelbase.
165/15 tyres (nice CONTIs!) on the front,
205/15 Supercats on the back
Weight is measured 450kg without fuel or passengers.

When I am closer to getting this done (engine in the beach buggy instead of under a tarp in the driveway!) I may start a poll or somthing, may also add in some bikes and/or other cars. just for fun

**Monty69** · 2nd May 2008, 15:53

In the end, factual emergency stopping distance recordings show, cars CAN outbrake bikes. Obviouisly a 1964 vw beetle wont out brake a R1 but modern sportscars will outbrake a sportsbike by a significant margin.

**Drew** · 2nd May 2008, 16:00

It seems pretty simple to me, there are basically only two contributing factors in braking for cars, momentum/friction. A bike has three large and one smaller force to overcome, momentum/friction/gravity/mass deviation(not sure if that's the right term for it, I'm talkin about the bike trying to screw sideways once the weight comes off the rear tyre.)

**Mikkel** · 2nd May 2008, 16:05

Originally Posted by koba

One is standard 1969 VW Beetle Disc brake front and I think 3 inch drums on the back
185/15 tyres (a bit shabby) on the front
205/15 Gr200 Enduros on the back.
Weight unknown, est 800kg.

That's not a standard beetle!

The problem about mechanics is that people think they can understand them without ever having spent 30 minutes studying it. And then they get pissy and demand that you explain it to them in 5 minutes. Which you obviously can not since they don't have the necessary prerequisites - which in turn means that you suck at explaining mechanics.

Being an academic is neither gratifying nor respected these days.

I studied classical mechanics during the first year of uni - we had two 2 hour lectures, a 2 hour problem solving session and a written hand-in every week for two semesters of 13 weeks each. Then we had a couple of months to prepare for the oral exam. I got an A+ and then worked for 2 years as an assistant teacher, running a 2 hours problem solving session and correcting written hand-ins every week for 4 semesters of 13 weeks.

All that said, I shall be the first to admit I don't know everything about mechanics and that I'd be reluctant to try and solve any complex 3-dimensional problem. However, I would like to think that I have an, if only slightly, better understanding than Joe Average.

And now I think it's time to go have a beer! Another frustrating week of academia draws to a close and I'm looking forward to the weekend - not least to have my girlfriend back from her holiday.

**cowboyz** · 2nd May 2008, 16:34

Originally Posted by Mikkel

I studied classical mechanics during the first year of uni - we had two 2 hour lectures, a 2 hour problem solving session and a written hand-in every week for two semesters of 13 weeks each. Then we had a couple of months to prepare for the oral exam. I got an A+ and then worked for 2 years as an assistant teacher, running a 2 hours problem solving session and correcting written hand-ins every week for 4 semesters of 13 weeks.

Guess that makes it even more embarassing when your wrong then huh?

**Mikkel** · 2nd May 2008, 17:07

Originally Posted by cowboyz

Guess that makes it even more embarassing when your wrong then huh?

Not really. What do you do for a living if I may ask?

**The Stranger:Me** · 2nd May 2008, 17:16

Originally Posted by Mikkel

Not really. What do you do for a living if I may ask?

BWAHAHAHAHA, give it up.

**jrandom** · 2nd May 2008, 17:19

Conveying understanding to others is the true sign of having mastered a subject.

In my experience, having to make excuses for an inability to explain things clearly indicates that one doesn't quite have a grasp of what one is talking about.