vozizm
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posted March 04, 2003 12:30 PM
Just a Question
if i'm going 20 mph how many feet will it take for me to stop?... stock brakes pads.....
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Megabyte
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posted March 04, 2003 12:57 PM
quote:
if i'm going 20 mph how many feet will it take for me to stop?... stock brakes pads.....
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EastBayDave
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posted March 04, 2003 01:49 PM
About 35...unless you do a stoppie & land on your head! 
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vozizm
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posted March 04, 2003 02:19 PM
damn...35ft....thats far..... 
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ZX12Girl
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posted March 04, 2003 05:41 PM
quote:
One, your right one
Bahahahahahahaha!!:d Always a smartass in the bunch!!! Too funny!!!! 
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slug
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Out in search of my mind...
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posted March 04, 2003 07:22 PM
man he got it first...i woulda gone with both, one jammed in front tyre (a la BMX) and the other dragging behind......
   
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redelk
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posted March 04, 2003 09:16 PM
 Edited By: redelk on 4 Mar 2003 21:18
This is from a UK motorcycle safety site. Though it is just an "average", most folks tend to forget about the "thinking" part. This is the time from when you realize you need to brake to the moment you actually start applying the brakes.
Thinking / Braking = Stopping
30 mph - 30 feet / 45 feet = 75 feet
50 mph - 50 feet / 125 feet = 175 feet
70 mph - 70 feet / 245 feet = 315 feet
I've always said that a good sportbike has the braking distances similar to a BMW... station wagon (comparing 60-0 distances). While wondering how a 12R would actually do in such a "panic" stop, I ran across this website that has a fairly "simple" formula to figure braking distance.
http://www.msgroup.org/TIP034.html
It isn't specific to the 12R, but what I like most about it is that it is "real world". It talks about the average time it takes to recognize a threat, as well as the time it takes in deciding to react to it (note: actual braking has not started yet).
These are factors commonly overlooked when talking about stopping a bike. The distances a bike can stop at are irrelevant until you actually apply the brakes. One thing is for sure, when that dog runs out in front of you, these factors will NOT be overlooked. It will just determine if YOU are dead or not.
There is also a link to similar topic (they're actually related to each other) at the top of the page.
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There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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redelk
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posted March 04, 2003 09:40 PM
Edited By: redelk on 4 Mar 2003 21:43
For those that don't want to read though the whole link, here's a "condensed version...
To determine how long it will take to stop assuming a constant rate of deceleration, divide the starting velocity (in fps) by the rate of deceleration.
60 MPH = 88 fps. (fps=1.467 * MPH)
If the deceleration rate is 20 fpsps, then stopping time = 88/20 = 4.4 seconds. Since there is a 1 second delay in hitting the brakes (recognition and reaction time), the total time to stop is 5.4 seconds.
Note: experienced racers can attain a deceleration rate of up to 32 fpsps (1.0g). Traffic engineers figure that the average driver of a car can stop at a rate 15 fpsps. This is on dry pavement.
To determine how far the distance of travel while braking, take 1/2 the starting velocity and multiply the result by the stopping time (calculate the average speed and multiply by the time moving).
.5 * 88 * 4.4 = 193.6 feet
Since the distance traveled is 88 feet before braking starts, add that to 193.6 feet for a total of 281.6 feet.
Assuming a deceleration rate of 32 fpsps (1g), it would calculate a braking stop time of 2.75 seconds (88/32). Distance traveled now is calculated to be 121 feet (ignoring the 88 feet traveled before applying the brakes).
To calculate the distance using deceleration rates using "serious" math:
x = x0 + (v0 * t) - (1/2 * a * t²)
x = distance traveled (feet)
x0 = starting distance (feet - i.e. recognition/reaction distance of 88 feet)
v0 = initial velocity (feet per second)
t = stopping time (seconds)
a = deceleration rate (feet per second per second)
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There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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Ninjaman12R
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posted March 05, 2003 05:32 AM
Sherm Sherm Sherm,,,,,,,
Never let it be said that you don't "Break it down" because you definitely do. Interesting topic BTW.
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What we're dealin' with here is a complete lack of respect for the law.
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redelk
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posted March 05, 2003 05:18 PM
Edited By: redelk on 5 Mar 2003 17:22
Let's make it even scarier...
Let's say you are doing 170 mph and you could brake at a 1g (32 fpsps)rate. The braking distance by ITSELF is 973 feet (7.8 seconds). That's longer the THREE football feilds! You can add another 250 feet for just the addional one second of reaction time!
Since most of use are not currently racing in the AMA Superbike series, but feel that we are "good brakers", we'll say the we could brake at a rate of 0.75g (24 fpsps). Doing the same 170 mph, the braking distance would be a whopping 1222 feet (10.4 very long seconds). That FOUR football fields.
Again, you'd need to add on the 250 for reaction time. That OVER a quarter of a mile! Even at 100 mph, it'd take almost 450 feet to stop (+147 feet of reaction time).
Even if we could brake at a rate of 1.3g, it would still take almost 750 feet to stop from 170 (not counting the dreaded "reaction time" distance - making it just shy of 1000 feet). At 100 mph, it would be 259 feet (400+ feet including reaction time).
For those of us who do not drag race, have someone stand at the other end of a quarter mile and take a long look on how far away it really is, You'll be quite surprised.
Almost anyone can whack the throttle, but how many can stop their bike in the shortest possible distance. Some of us (myself included) might want to think about testing their "high speed stops", the next time they are practicing their "high speed gos".
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There are only three sports: bullfighting, motor racing, and mountaineering; all the rest are merely games.
-Ernest Hemingway
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