View Poll Results: Brakeless people, what's your minimum stopping distance, approximately, from ~20mph?
1m
18
28.57%
2m
3
4.76%
3m
5
7.94%
5m
6
9.52%
6m
3
4.76%
8m
7
11.11%
10m
1
1.59%
12m
0
0%
14m
11
17.46%
other
9
14.29%
Voters: 63. You may not vote on this poll
minimum skid stop distance from ~20mph
10-02-08, 12:33 PM
#51
pan y agua
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This is delusional, potentially deadly, thinking.
It takes 63 feet to stop a car from 20mph. You're not going to do any better than that skidding one tire, and much likely worse. https://www.csgnetwork.com/stopdistinfo.html
Know your limitations.
It takes 63 feet to stop a car from 20mph. You're not going to do any better than that skidding one tire, and much likely worse. https://www.csgnetwork.com/stopdistinfo.html
Know your limitations.
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
Last edited by merlinextraligh; 10-02-08 at 12:33 PM. Reason: add link
10-02-08, 12:39 PM
#52
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10-02-08, 01:13 PM
#53
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shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
10-02-08, 01:49 PM
#54
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10-02-08, 02:24 PM
#55
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This is delusional, potentially deadly, thinking.
It takes 63 feet to stop a car from 20mph. You're not going to do any better than that skidding one tire, and much likely worse. https://www.csgnetwork.com/stopdistinfo.html
Know your limitations.
It takes 63 feet to stop a car from 20mph. You're not going to do any better than that skidding one tire, and much likely worse. https://www.csgnetwork.com/stopdistinfo.html
Know your limitations.
Deadly! c'mon 20 miles on a bike is not even fast! takes me about 5 feet to come to a complete stop when I skid at 20 mph.
10-02-08, 02:42 PM
#57
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10-02-08, 02:42 PM
#58
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10-02-08, 03:04 PM
#59
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10-02-08, 03:15 PM
#60
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close. Not all of your weight is on the rear wheel to begin with. During a skid probably saying 1/3rd of your weight is on the rear wheel is incredibly optimistic so you'll take 3 times the distance that the equation would predict once you get the wheel skidding.
10-02-08, 03:16 PM
#61
Bicycle Repair Man !!!
Did anyone read the article I linked to and catch the part where a cyclist and a car will have similar stopping distances ?
I was riding my old coaster bike last summer and broadsided a car that came out of an alley... I hit the brake as soon as I saw the car and left a 20 foot skid mark but figure I needed about 25 feet to stop.
My bike was running 28 by 1 3/8 tyres so had a large contact patch and the brake on the bike was in stellar working condition... even though I had bled off most of my speed with the skid I hit the car hard enough to frag my fork.
I know I wasn't even doing 20 mph at the time and stopping distances increase exponentially as speed increases as an objects energy is calculated by multiplying mass times the velocity squared.
I use this incident as an example for my customers who are insistent that they will be okay if they don't run a brake on their new fixed gears and if that doesn't work I am always happy to take them out in the lane and see who can stop faster.
I came close to having several mishaps on my ride to the shop today as I narrowly missed getting right hooked and had another driver cut me off... I could kiss the new brake on my bike as once again, it saved my ass.
10-02-08, 03:18 PM
#62
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That's a useful anecdote to remember R.E.: stopping distance.
...and who knew that my naive post could generate so much controversy
...and who knew that my naive post could generate so much controversy
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shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
10-02-08, 03:29 PM
#64
Bicycle Repair Man !!!
mark - It was an excellent question and the thread has been quite educational.
After one gets through the physics you also have to factor in those things that will further increase stopping distances like reactions times and road conditions as the math only gives what would be considered an optimal distance.
After one gets through the physics you also have to factor in those things that will further increase stopping distances like reactions times and road conditions as the math only gives what would be considered an optimal distance.
10-02-08, 04:05 PM
#66
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mark - It was an excellent question and the thread has been quite educational.
After one gets through the physics you also have to factor in those things that will further increase stopping distances like reactions times and road conditions as the math only gives what would be considered an optimal distance.
After one gets through the physics you also have to factor in those things that will further increase stopping distances like reactions times and road conditions as the math only gives what would be considered an optimal distance.
Consider two particles, both infinitely small, having masses...
(embarrassingly, I used to be able to remember and apply this stuff)
__________________
shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
shameless POWERCRANK plug
Recommended reading for all cyclists - Cyclecraft - Effective Cycling
Condor Cycles - quite possibly the best bike shop in London
Don't run red lights, wear a helmet, use hand signals, get some cycle lights(front and rear) and, FFS, don't run red lights!
10-02-08, 04:18 PM
#67
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Im awfully tempted to get someone over here with a camera and a speedometer and prove that this distance is pretty far.
10-02-08, 04:39 PM
#68
Le Crocodile
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What about leg position? Where do you start your skids (R/L leg + o'clock position)? Can you start a skid at all positions?
Anybody that thinks that they can stop their fixed in 1 meter does not know crap about cycling. FACT.
Try it, you will be surprised at how long it takes to come to a complete stop from 20 mph.
Anybody that thinks that they can stop their fixed in 1 meter does not know crap about cycling. FACT.
Try it, you will be surprised at how long it takes to come to a complete stop from 20 mph.
10-02-08, 04:48 PM
#70
Bicycle Repair Man !!!
I am such a geek...
I just finished tuning up a Schwinn Moab that is fitted with 1.95 slicks and just installed some new Kool Stop canti pads and figured I would go out and test the brakes.
I don't have a speedo on the bike but do have a pretty good sense of speed and can hold a pretty steady cadence... I figure that I was doing 18-20 mph on each pass.
Anyways... the stopping distance when I used the rear brake and skidded (immediate lock up) was 30 feet from where the skid started to where it ended which is just under 10 metres.
When I used both brakes the stopping distance was 13 feet and I unweighted the rear wheel just enough to make it start to skid at the end of the stop... a full on panic stop would have stopped me faster but even then we are looking at a stopping distance of at least 3 meters.
It's a hot day here and the pavement was dry and clear.
I just finished tuning up a Schwinn Moab that is fitted with 1.95 slicks and just installed some new Kool Stop canti pads and figured I would go out and test the brakes.
I don't have a speedo on the bike but do have a pretty good sense of speed and can hold a pretty steady cadence... I figure that I was doing 18-20 mph on each pass.
Anyways... the stopping distance when I used the rear brake and skidded (immediate lock up) was 30 feet from where the skid started to where it ended which is just under 10 metres.
When I used both brakes the stopping distance was 13 feet and I unweighted the rear wheel just enough to make it start to skid at the end of the stop... a full on panic stop would have stopped me faster but even then we are looking at a stopping distance of at least 3 meters.
It's a hot day here and the pavement was dry and clear.
