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Old 08-04-2012, 01:48 PM   #991
mfgc2310
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Quote:
Originally Posted by daq7 View Post
Yeah if you build the integration to determine the center of mass of the system, I am sure you can demonstrate mathematically beyond doubt that the center of gravity goes up. What is important is that your body does not have to lean with the bike in order to turn. Not having to rotate the mass of your upper body makes the rotational inertia of the bike somewhat lower.

Your cog gets farther from the ground or from where the tires make contact with the ground. However your weight can now press down on either the left or right side creating a moment that can be used to keep the bike vertical while going around a corner.

If you stand on both pegs equally at all times may as well just stay on the seat.

The best way to do it is to stay just on the seat holding the bike with your legs and knees while all the weight is on the pegs using the balls of your feet.

The main reason to stand is to move your weight far forward or backward and to accomodate extreme movement of the bike.

It is incorrect to say standing lowers your cog.
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Old 08-04-2012, 03:26 PM   #992
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Ah, not really. When you stand on the pegs, the COG raises but the mass of the rider is bearing lower on the bike. This means the bike is significantly more 'tossable'. The difference in a light bike, is enormous.

Try it on a lighter bike - say one weighing 350 lbs or less. Try quickly changing the bike along the longitudinal axis. Now stand with your ass slightly above the seat and do it again. You will see a difference for sure.

The difference on a battleship bike will be less because the rider's weight is less a percentage than on a lighter bike. You will find that trials bikes have no real saddle because in that sort of event, you need a good deal of bike English (tossing).
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Old 08-05-2012, 06:58 AM   #993
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Originally Posted by slide View Post
Ah, not really. When you stand on the pegs, the COG raises but the mass of the rider is bearing lower on the bike.
...Aaaaaand, we're off!.....
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Old 08-05-2012, 07:02 AM   #994
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Originally Posted by thistle66 View Post
...Aaaaaand, we're off!.....
.. lol .. yeah .. oil .. tires .. and physics ..

.. all good for a rollicking good conversation ..
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Old 08-05-2012, 07:27 AM   #995
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ROFL .. good point ..
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Old 08-05-2012, 11:43 AM   #996
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Question

Quote:
Originally Posted by DAKEZ View Post
All right, I keep seeing advice to ride in the dirt first. I have no clue what to do on a dirt bike. I've seen a few of them on the atv trails but I wouldn't know how to go through those big puddles that block the trail or the really bumpy stuff. I'm 5'3" and not much of a wild rider :) so just looking at how high the dirt bike seats are is kind of intimidating.

I just checked on craigslist and it looks like I could get a kids dirt bike 50-80cc for about $500. Would that be worth it, giving me the experience on dirt that would help me as a n00b, or would it only be worth the belly laughing to anyone who would see me? I'm assuming I shouldn't use my street bike gear because it would get very dirty.

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Old 08-05-2012, 12:55 PM   #997
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Originally Posted by thistle66 View Post
...Aaaaaand, we're off!.....
Maybe we could slip an oil thread in too while we're at it.....
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Old 08-06-2012, 04:48 AM   #998
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Originally Posted by swann View Post
So, advice on a dirt bike for my situation?
Something you're comfortable with. A kids' bike will be closer to your size, and if that's what it takes to get you confidently out and learning more technique, that's the way to go. You'll know later on if you are ready to go up to something bigger. Plus, the price sounds great.

One of the strangest secrets of anything with motors is that a lot of times, the smallest ones are the most fun.

BTW - good on you for gearing up and taking it all seriously. You'll have fun and being a chicken isn't the end of the world. Taking your personal risk threshhold seriously is a good way to have fun and still live as much as you can. It sounds like your hubby might have had a good scare once and never got over it. Keep safe and learn as much as you can and maybe he'll come around for you one of these days.
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Old 08-06-2012, 05:26 AM   #999
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Originally Posted by swann View Post
All right, I keep seeing advice to ride in the dirt first. I have no clue what to do on a dirt bike. I've seen a few of them on the atv trails but I wouldn't know how to go through those big puddles that block the trail or the really bumpy stuff. I'm 5'3" and not much of a wild rider :) so just looking at how high the dirt bike seats are is kind of intimidating.

I just checked on craigslist and it looks like I could get a kids dirt bike 50-80cc for about $500. Would that be worth it, giving me the experience on dirt that would help me as a n00b, or would it only be worth the belly laughing to anyone who would see me? I'm assuming I shouldn't use my street bike gear because it would get very dirty.
Dirt riding if you are starting out as an adult is dangerous beyond belief. The guys who advise this all started out as kids or teens & have this odd belief they are better street riders due to that. Even if true, the many falls they took as flex boned children (needed to learn dirt) will leave an adult crippled and crippled quickly.

It's not the size of the bike. It's when you bounce your body off a bunch of rocks at 30 mph is where the damage occurs.
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Old 08-06-2012, 08:42 AM   #1000
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Originally Posted by slide View Post
Dirt riding if you are starting out as an adult is dangerous beyond belief.
not true.

i know a number of people who started dirt riding as adults and have suffered no injuries more serious than minor buises.

just don't ride over your head.

Quote:
The guys who advise this all started out as kids or teens & have this odd belief they are better street riders due to that. Even if true, the many falls they took as flex boned children (needed to learn dirt) will leave an adult crippled and crippled quickly.
only if you insist on riding over your head.

and, btw, there is absolutely no question that dirt riding makes one a better all around rider...including on the street.

Quote:
It's when you bounce your body off a bunch of rocks at 30 mph is where the damage occurs.
so don't do that. you shouldn't be riding 30mph over rocks until you are ready to ride 30mph over rocks.
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Old 08-06-2012, 09:14 AM   #1001
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Originally Posted by DAKEZ View Post
It really is that simple. :
Brilliant, boys. Don't ride a course until you can. Just skip over the learning / falling part which teaches you can ride a course and instead proceed directly to the all knowing all seeing stage.

Gee, am I sick of those who claim dirt skills mean squat on the pavement. It's not proved and can't be proved yet constantly promoted here by those broken souls who have 'paid their dues' in smashed collar bones and crippled knees.
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Old 08-06-2012, 10:05 AM   #1002
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Old 08-06-2012, 10:14 AM   #1003
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fall on the sand eat a mouth full of dirt, is alway better than a motionless concrete (dead) stop. when you lose control, alway target your body's trajectory to the soft spot. oh, sorry this is a newbie thread ride carefully then
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Old 08-06-2012, 11:22 AM   #1004
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Originally Posted by slide View Post
Brilliant, boys. Don't ride a course until you can. Just skip over the learning / falling part which teaches you can ride a course and instead proceed directly to the all knowing all seeing stage.
what the heck are you talking about?

lemme guess...you don't know what you are talking about.

develop dirt skills progressively. don't start out in rocks. don't start out at 30mph. start out slowly on soft dirt/grass. "crash" (i.e., drop the bike and step off of it in the process). get back up (if you even fell down) completely unharmed and repeat until no more crashing.

then move onto tougher terrain...at slow speeds. crash. get back up completely unharmed--er, well, except maybe a bruised ego--and repeat.

step up the difficulty of the terrain and speed in small increments as you feel comfortable. eventually, and it doesn't really take all that long, you will be riding over terrain you thought impossible at speeds you thought ludicrous safely.

(or, maybe you won't...maybe you'll decide at some point you don't want to tackle anything more challenging or add any more speed. but, you still will have gained skills and knowledge that will help you on the street.)

i've seen more than one adult who never rode as a kid learn to ride dirtbikes this way...and become quite competent at it without injuring themselves.

(i've also seen people learn to ride dirt by riding way over their heads. that works well actually...until you have to spend 2 months not riding. "crashing" is part of dirt riding...but injuries do not have to be.)

Quote:
Gee, am I sick of those who claim dirt skills mean squat on the pavement. It's not proved and can't be proved yet constantly promoted here by those broken souls who have 'paid their dues' in smashed collar bones and crippled knees.
zero smashed collar bones or crippled knees for me. no broken soul for me. yet, i somehow have managed to become a competent dirt bike rider. and those skills have saved me on the street a few times.

the street is more like dirt than it is like a track. the track is clean with predictable traction. the street is not. the track does not have potholes, bumps, etc. the track is very predictable. the street is not--you don't know what is going to happen on the street just like you don't know what lies ahead on that trail you've never ridden (or that you have ridden, but not since the last storm, etc.). dirt teaches you balance and precise control at very slow speeds, how to maneuver the bike in very tight spaces, etc. etc. etc. etc.

being able to react quickly and well to loss of traction, unexpected events, etc. are very valuable street skills...and dirt riding (at least woods riding) teaches you those and allows (even forces you) to practice them over and over again.

there is absolutely ZERO question that dirt skills help on the street. none whatsoever.

if you are afraid to ride dirt, or just don't want to for whatever reason, that's cool. but don't try to discourage others from it so that you have some company.

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Old 08-06-2012, 11:28 AM   #1005
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Originally Posted by superslomo View Post
Yeah. You should always clean, or never clean. You should lube every time you fill the tank, or never, or get a scottoiler, or they are awful messes.

When cleaning, your should always use kerosene. Or never use kerosene. Or always use wd40. Or never use wd40. Or use simple green. Or use a specialty degreaser. Or don't.

When lubing, you should only use wax. Or only use dupont teflon. Or only use 75w90 gear oil. Or only use old motor oil you have lying around. Or only use boeshield. Or only use atf. Or use nothing.

As long as you follow all of these rules, your chain will last for a period of time, at which point it won't last any longer.

You have my word.

Also, new riders should only use the one most perfect motor oil.
Got it.
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