Who knows stopping distance from 150 mph?

[outlawbusa]

So Tuf, a couple years ago you started to tell us about how you can read a person from the way his/her knee pucks look and where they position the puck.

It's kept me up a few nights waiting for you to elaborate on that.

Really though, I was interested in what you had to say.

Care to start the thread?

 

[THE MENACE]

A few weeks back I was at a CLOSED COURSE trying to see where I would hit the limiter. Yes I know where it is supposed to kick in....anyways.... was at 160 and a Harley pulls out in front of me a long ways out. Pounded on those brakes, but I would hazard a guess that it was in the 4-5 second range before I caught up to him. He was a good bit from the turn in yet only doing 45 MPH. So it took some serious time.... at any rate, the emergency braking from that speed is probably FAR more dangerous than running at that speed if you do not execute proper form on the bike...

:2cents:

-THE MENACE

 

[kml]

Stopping Distance =(Vehicle Speed×perception Time) + { Vehicle Speed² / [2×9.8×(Grade of ±g)] }


'bout 900 feet, assuming 1 g of traction level grade and a .65 reaction time. Assuming of course classical physics is able to give use a correct answer in this case unlike surface area vs traction where, as Tuff has correctly pointed, out it doesn't apply.



cheers
ken

ps g = standard gravity....

 

[Sky Rider]

Regardless of what the answer is, if you're going to be making an emergency stop at 150MPH there is a good chance the answer will be "too long".

 

[dadofthree]

I imagine 300 yards is gonna be close and hopefully the brakes don't fade or go away completely

I guess that would be a good time to use the rear brakes

 

[Tufbusa]

How bout a little bump here!

 

[dadofthree]

How about an answer

 

[Dookoo]

How about an answer

No kidding.

 

[Adam G]

So are you going to enlighten us to the correct answer???

 

[IG.]

How did I miss that?

I'd advise everyone to not try to stop from 150 to zero as quickly as possible in one braking attempt. There is a good chance the very top thin layer of the rotors will melt momentarily, and the melted metal will be deposited on your brake pads. This is called glazing of brake pads. As a result of that, next time you brake, it will be partial metal against your rotors instead of 100% brake pad material against your rotors. I can tell you firsthand that metal on metal does not brake well, and don't ask me how I know.

No one stops from 150 to zero as quickly as possible, however 150 to let's say 70 is a very real life scenario. It takes more distance than it seems because the kinetic energy the brakes need to burn is proportional to the square of the speed, however the actual burning off of kinetic energy is proportional to the speed and braking effort - not to the square of anything. In all the practicality knowing the distance in ft doesn't help, but looking pretty far ahead and applying the brakes as early as possible is paramount. The good thing about braking from such high speed is that a lot of braking effort could be applied to the lever without locking the front - it's when the bike slows down that the danger of locking the front is greater and therefore the braking effort should be gradually reduced.

 

[Blanca BusaLess]

Oh good grief isn't there a member here who's off tomorrow with long flat roads and a Gopro who can do this?

I don't know about distance but I've done it several times and time wise it's like 3-4 seconds.
And kml your post gave me a headache.

 

[StrtRac3r]

ps g = standard gravity....

Ha, I like that. As apposed to moon gravity.

Which brings a question that would interest me more. If you could hit 150 on the moon, and grab a handful of front brake. How many flips would you do?

 

[Tufbusa]

How did I miss that?

I'd advise everyone to not try to stop from 150 to zero as quickly as possible in one braking attempt. There is a good chance the very top thin layer of the rotors will melt momentarily, and the melted metal will be deposited on your brake pads. This is called glazing of brake pads. As a result of that, next time you brake, it will be partial metal against your rotors instead of 100% brake pad material against your rotors. I can tell you firsthand that metal on metal does not brake well, and don't ask me how I know.

No one stops from 150 to zero as quickly as possible, however 150 to let's say 70 is a very real life scenario. It takes more distance than it seems because the kinetic energy the brakes need to burn is proportional to the square of the speed, however the actual burning off of kinetic energy is proportional to the speed and braking effort - not to the square of anything. In all the practicality knowing the distance in ft doesn't help, but looking pretty far ahead and applying the brakes as early as possible is paramount. The good thing about braking from such high speed is that a lot of braking effort could be applied to the lever without locking the front - it's when the bike slows down that the danger of locking the front is greater and therefore the braking effort should be gradually reduced.

Now that's funny rite there, I don't care who you are!

 

[880jedi]

If the ability to stop from 150+ to zero is a measured thing because a brick wall is in your flight path, then yes, I'd like to know how fast this will happen. (If I do it wrong, it's going to end terribly anyway).

I'd rather focus on the ability to control an evasive mauever while bring the speedo down to normal. Decision making at that speed will probably save you more that brake material is my guess.

No, I've never measured the stopping distance, but I have practiced getting my arms back into their sockets ASAP.

 

[IG.]

Now that's funny rite there, I don't care who you are!

...And as expected - a useless one liner, which is rite to the point - which of course is pointless.

 

[black diamond busa]

...And as expected - a useless one liner, which is rite to the point - which of course is pointless.

Yea I find it kinda of funny he won't give us a ball park of where we should be at.

 

[outlawbusa]

The braking distance (in feet) of a car going V mph is given by
d%28v%29=v%5E2%2F20%2Bv v is greater or equal to 0.
how fast would the car have been traveling for a braking distance of 150feet?
round to nearest mile per hour.
:
Write it:
v%5E2%2F20%2Bv = 150
multiply by 20, results
v^2 + 20v = 20(150)
:
v^2 + 20v = 3000
:
v^2 + 20v - 3000 = 0
Solve for v using the quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

in this equation; x=v; a=1; b=20; c= -3000
v+=+%28-20+%2B-+sqrt%2820%5E2-4%2A1%2A-3000+%29%29%2F%282%2A1%29+
:
v+=+%28-20+%2B-+sqrt%28400-%28-12000%29+%29%29%2F2+
:
v+=+%28-20+%2B-+sqrt%2812400+%29%29%2F2+
Two solutions, we only want the positive solution
v+=+%28-20+%2B+111.355%29%2F2+
v = 91.355%2F2
v = 45.68 mph for a stopping distance of 150 ft
:
:
See if that flies in the original equation
d%28v%29=45.68%5E2%2F20%2B45.68
d%28v%29=2086.45%2F20%2B45.68
d%28v%29=104.32%2B45.68
d(v) = 150.00, confirms our solution

The 3rd line from the bottom devided by the second line from the top added to the 5th line from the bottom when read backwards is Tuf's "official" final answer!

 

[Blanca BusaLess]

Yea I find it kinda of funny he won't give us a ball park of where we should be at.

That's because he's never been that fast so he doesn't know.

 

[Tufbusa]

How did I miss that?

I'd advise everyone to not try to stop from 150 to zero as quickly as possible in one braking attempt. There is a good chance the very top thin layer of the rotors will melt momentarily, and the melted metal will be deposited on your brake pads. This is called glazing of brake pads. As a result of that, next time you brake, it will be partial metal against your rotors instead of 100% brake pad material against your rotors. I can tell you firsthand that metal on metal does not brake well, and don't ask me how I know.

No one stops from 150 to zero as quickly as possible, however 150 to let's say 70 is a very real life scenario. It takes more distance than it seems because the kinetic energy the brakes need to burn is proportional to the square of the speed, however the actual burning off of kinetic energy is proportional to the speed and braking effort - not to the square of anything. In all the practicality knowing the distance in ft doesn't help, but looking pretty far ahead and applying the brakes as early as possible is paramount. The good thing about braking from such high speed is that a lot of braking effort could be applied to the lever without locking the front - it's when the bike slows down that the danger of locking the front is greater and therefore the braking effort should be gradually reduced.

Now that's funny rite there, I don't care who you are!

...And as expected - a useless one liner, which is rite to the point - which of course is pointless.

Hey, I thought you were being funny. I had no idea your imaginary scenarios were meant to be serious

Next time if you expect to be taken seriously begin your post with: Now this aint no bulls--t!

 

[skydivr]

Glazing has nothing to do with the ROTOR melting...