This is a discussion on Emergency Braking Question within the The Training Ground - New Riders! forums, part of the General Forums category; Originally Posted by emrah Following distance. One Mississippi... Two Mississippi... Three Mississippi... Emrah ...that's my rule too.......
Following distance is crucial for safe riding IMO. It is very, very rare that I'm not at least two seconds back from the vehicle in front of me, no matter what the speed is. You have to give yourself time to react. The greater the speed, the further behind that vehicle you should be.
As for practicing stoppies (even small ones) to learn the edge of front brake control, I don't recommend it. I think there's too fine a line between a stoppie and a front wheel lock that could result in a highside. Practice hard braking using both brakes and try to keep some weight back on the rear wheel.
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The two second rule can be a problem in traffic as far as following distances are concerned - leave a gap and someone will try to get into it.
What we teach is therefore slightly different. At speeds below 30 mph we allow 1 foot for each mph of speed. That's 2/3rds of a second, which is the time it takes to perceive a hazzard, evaluate it, and react. Put simply, if the car in front hits its brakes, it'll take you 2/3rds of a second before you're actually squeezing yours. That means that you have to depend on your brakes being at least as good as that car's. Below 30 mph in the dry, they usually are.
At 30 mph, 30 feet is about 2 full car lengths. The actual total stopping distance including reacton time is around 75 feet, or 5 car lengths, and the 2 second time is 88 feet, or six car lengths - not practical in moderate or heavier traffic. Newbies are still advised to use the 2 second rule, with the result that it becomes ignored because of its sometime impracticability, and the ignoring is maintained at higher speeds. There's a paper to be written there.
Above 30 mph we teach 1 yard for every mph over the first 30. The effect of this is to gradually increase the gap in terms of time so that at highway speeds you're just about following the 2 second rule.
This has been worked out over the years as reasonable compromise between safety and managing the traffic. I'm not going to suggest this for anyone who's uncomfortable with it. Always double those distances in the wet, and if there's no traffic allow at least 2 seconds anyway - more if you can.
As the 2 second rule is mostly ignored by other road users, trying to keep to it in traffic can result in you being regularly cut up in a way that is more dangerous than reducing your following distance. No firm advice from anyone on this point. You just have to play it by ear.
There are defensive strategies to compensate for the reduced following distances. The major one is to position the bike so that you'll pass to the side of the vehicle immediately in front. It's also important to watch what's happening several vehicles ahead - that's why high level brakelights are pretty much standard - but don't concentrate 5 cars ahead to the extent that you're not watching the car immediately in front as well - that's the one that you'll hit.
On the stoppie issue, I simply mean that if you've done a few under controlled conditions, then if you panic and do an inadvertant stoppie on the road you know what's happening and how to recover. I'm not advocating using stoppies for on the road braking. Far too much risk of a front wheel lock up. I should also have made it clear that if you do practise them, don't hold it to a stop. Once you're up, let the front go and bring the bike back down before coming to a stop.
I have had situations when using the throttle with a change in direction rather than the brake would have been a better choice, always be aware of everything around you, so if you have to make that choice, its not a guess.
Ever been coming up to a railroad track driving a gage when you notice the red light is on to stop and you dont know if it just came on or you hadn't noticed it, so you stop as quick as possible ?
Acceleration, swerving, or a combination of both are options for avoiding hitting something. You just choose the most appropriate from your toolbox of techniques. It's just that this thread was about braking.
i thought the subject was about what caused his bike to wobble.
I sure am not going to keep a safety tip about how to avoid a collision to myself as I am sure that most riders will have a hard time avoiding the reflex of braking, I did not going into how to maneuver but just to say that sometimes braking is not the best choice, and that my friend is on the subject of braking.
Last edited by john56; 12-25-08 at 01:40 PM.
Wobble under braking.
Then it went a bit off track, if you'll excuse the pun.
I agree that braking isn't always the best choice. That's what I said.
mos def practice the emergency braking, but also remember that target fixation is really bad! keeping the mind clear and leaving an out i.e. following distance is very important. no matter what the traffic is u MUST have a safe following distance! remember those guys are bigger than u and if the want that spot, there is NOTHING u can do to stop them! and around here, the leo's tend to side on the cager!
u did unload the rear tire and it was swervin on u. but ur natural reaction saved ur butt! thats a good thing. when u put the load back on the rear tire and kept the pressure on the rear brake it straightened itself out! again, good job! sounds like natural talent to me!!!
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if the bike is new to you there is one thing that may explain the wobble. If your front suspension is not set properly and if your are too heavy for the springs. Your severe breaking may have pushed the bikes rake agle back to the point were the caster was 0 or negative. in that case the front end will be very suseptible to wobbeling.
proper suspension setup is key for optimal braking
Most bikes still don't have much in the way of adjustable front suspension, and most bikes maintain a positive caster even with the forks bottomed. Of course, if you've raised the rear of the bike.......
That said, fork dive can cause instability under heavy braking. Dropping the yolks so that the forks protrude is a common cause.
does ever take your eyes off the road while riding in traffic most of my friends have wrecked while traveling at slow speeds lookin at chics cars etc so stay focused i use about 4 to 5 missisippi when i am in traffic just in case you never know who or what is going to stop or pop out in front of you,also dont ever let anyone tell you I DONT EVER USE MY REAR BRAKE thats about the most retarded crap,learn to use both brakes together ,pay attention and ride safe
Personally I watch the traffic rather than the road, but you do need to stay focussed. Nobody's saying use the rear brake on its own except when coming to a controlled stop in the last few yards. That doesn't apply to emergency braking.
4 or 5 mississppi is just impractical in real traffic. It leaves a big gap - about 180 feet or 12 car lengths at 30 mph. 30 mph is 44 feet per second. Leave a gap anywhere near that big and someone will try to fill it. It's a good guide for riding at illegal speeds on near empty roads though.
UK advice as given in Roadcraft, the police rider training manual, is to allow about 1 foot of following distance for each mph of speed up to 30 mph. As reaction time, in terms of perceiving a hazzard, deciding on appropriate action, and performing that action - hitting the brakes by reflex in this case - takes 2/3rd of a second, you're following on the edge of your reaction time so braking control must be instinctive and your brakes have to be as good as the car you're about to rear end.
At higher speeds we advise 1 yard (or meter ) for each mph of speed. That gives you time to react and stop and is close to the 2 second rule. At illegal speeds, allow 4 or 5 seconds, because other traffic won't be expecting or making due allowance for your speed.
Last edited by williamr; 02-10-09 at 03:24 AM.
The "distance per mile per hour" formula was abandoned in the US, mostly because it is tough to judge distance accurately, but counting from a fixed object is relatively easy.
I haven't read this whole thread, but as far as stability when braking goes, try applying the rear brake a half second before the front, which will cause the bike to hunker down a bit. Of course, in an emergency, you won't have that kind of time. Another trick is to squeeze the tank with your knees to minimize having your body weight pressing on the handlebars.
An easier way is to use one car length per 10 mph of speed. That's easy to judge until your speeds start to get seriously illegal.
The proper action to take when you feel that is to release the rear break ... you have 1-4s depending on conditions before you low-side if you don't release the rear brake...
Keep in mind that a locked up wheel provides very little in the way of stopping force so it is always better to release and then re-apply the brake when it's locked up as the time for the release and re-apply will shorten the stopping distance over just trying to ride out the locked wheel (and possibly low-siding). Releasing the brake will cause the tire to start spinning again, it will also restore gyroscopic stability forces caused by the tire spinning (which are not present when a tire is locked up).
This is, also, the principle behind anti-lock brakes that will release the tire and re-apply brakes, then release again. If you mimic this behavior you will be maximizing the stopping force relative to the coefficient of static friction which is by far and away the strongest force when it comes to pavement and roads.
The only other caveat is that it is actually quite hard to lock up the front wheel with any sort of a strong increasing squeeze on the front break. (This is different then a sudden abrupt squeeze on the front which can cause a stoppie).