Author Topic: Sport-lowrider bike (Read 977 times)

NUKE · « **Reply #15 on:** October 04, 2002, 08:09:08 PM »

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Yes. Probably not as much as you, Nuke. I haven't ridden anything in years. But... don't you think that some of the instability of motorcycles is a direct result of the added weight of the rider perched on top

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Cool Pic Sandman!

I agree that stability is sacrificed by the weight of the rider perched on it. However, stability and maneuverability are two different things.

A stable aircraft will fly straight and level, yet will not turn as well as a less "stable" aircraft.

If you want a stable bike, plan on going straight most of the time.

To turn a bike, you need to counter the centrifical force of the wheels ( like you are doing in that pic)

easymo · « **Reply #16 on:** October 04, 2002, 08:20:13 PM »

"A stable aircraft will fly straight and level, yet will not turn as well as a less "stable" aircraft. "

How this could relate to airplanes, even remotely, is beyond me. With bikes its all a matter of rake, and trail.

SaburoS · « **Reply #17 on:** October 04, 2002, 08:50:21 PM »

Leaning one's body to go fast in a turn (say one is racing on an on road track) is for traction, not for the turn. By leaning over (hanging off the bike as one can see roadracers do), one allows the bike to be a bit more upright (to maintain the tire's footprint, read increased traction) than one that does not hang off the bike.
Shifting your weight over to turn is actually counter-productive as the bike counters that motion (Newton's Third Law of Motion, Action and Reaction) as the rider is a counter weight to the bike in those circumstances. Racers turn fast by a snap counter steering into a turn that forces the center of gravity to shift and snap the bike into a lean. The racers are hanging off the bike for the traction they need in a turn to maintain traction of the tires, not for the turning.
For cruising, the bike with the lower center of gravity should be more stable as one doesn't have to hang off the bike in turns at non-race speeds.
BTW, one needs to counter the gyro-scopic effect of the wheels/tires, not the motor.

SaburoS · « **Reply #18 on:** October 04, 2002, 08:55:52 PM »

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Originally posted by NUKE
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Have you ever riden a motorcycle? You have to shift your weight if you want to turn. You can only turn the front wheel at very low speed.

If you cant assert your weight at higher speed, the bike will just want to keep going straight. You could run right off the road if you are not able to shift the cg of the bike fast enough.

Shifting you and the bike at speed is far more efficient to snap counter-steer into a turn rather than leaning over (you'll be fighting the bike to lean over rather than letting the bike lean you over.) By acting as one unit and allowing the bike to do the 'leaning' work, you'll cut faster turns.

easymo · « **Reply #19 on:** October 04, 2002, 10:55:02 PM »

LOL. That works real good, right up to the point you hit that patch of loose sand.

SaburoS · « **Reply #20 on:** October 05, 2002, 04:42:07 AM »

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Originally posted by easymo
LOL. That works real good, right up to the point you hit that patch of loose sand.

....or oil, or anti-freeze, etc.

Not healthy for the motorcyclist no matter how you lean it over in a turn... or are you saying that one that tries to force the lean by shifting body weight alone magically has more traction?
LOL! You ARE funny.

capt. apathy · « **Reply #21 on:** October 05, 2002, 08:54:54 AM »

please someone post a video of a bike hitting a corner at speed without leaning into the turn. even this low C of G bike. if you look at the pic sandman posted you can see that the rider has shifted his bellybutton clear off the seat. there's no info on how fast he is going but I've seen conventional frame designs race at very high speed and have took quite a few corners at high speed myself and I've never had to actually climb out of the saddle to take a corner. I've leaned way out there so the peds are almost touching the ground but never had to drop my bellybutton over the side to get the thing to lean far enough. this bike doesn't apear to hit the corner any different than any other bike. the rider just looks like he's working harder to make it perform.

Lizard3 · « **Reply #22 on:** October 05, 2002, 09:21:19 AM »

Subaru has it right. The lean has nothing to do with getting the bike to turn. Getting the bike to turn is done with the handle bars. In a right hand turn, you turn the front wheel ever so slightly to the left, causing the bike to fall to the right, you turn the wheel back to the right to keep it from going all the way over and more to the right to bring it up straight again.

Have you not ever on a long trip hung off of one side or the other while going straight down the road just to relieve some butt pain?

You guys are funny.

Staga · « **Reply #23 on:** October 05, 2002, 10:37:31 AM »

Driver turns front-wheel to left if he wants to turn the bike right. When bike leans to the right after that the frontwheels right side has smaller spinning radius than the center of the wheel, making bike turn.
Easy isn't it

Staga · « **Reply #24 on:** October 05, 2002, 10:39:28 AM »

hmm I'm wondering if it would be too cold weather to borrow my friend's Moto-Guzzi for a small ride...

capt. apathy · « **Reply #25 on:** October 05, 2002, 12:50:27 PM »

lizard, read your own post. you just explained how you can use stearing to help get the bike to lean so you can turn. your own post states how the leaning is nescasary to turn. if it was the stearing that causes the bike to turn why do you stear left (while leaning right) to go right at high speed, but stear right to go right at low speed?

NUKE · « **Reply #26 on:** October 05, 2002, 12:56:31 PM »

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Subaru has it right. The lean has nothing to do with getting the bike to turn. Getting the bike to turn is done with the handle bars. In a right hand turn, you turn the front wheel ever so slightly to the left, causing the bike to fall to the right, you turn the wheel back to the right to keep it from going all the way over and more to the right to bring it up straight again.

Ever take a passenger who refuses to lean into the turns? You can hardly turn the bike! In fact , the passenger can turn the bike and they arent touching the bars.

Shifting your weight has everything to do with turning.

Every see someone ride without hands, yet turn?

easymo · « **Reply #27 on:** October 05, 2002, 01:48:47 PM »

http://www.montreal4ever.com/performance_riding.htm

Its not mentioned here, but the gyro phenomenon will also create "weight". When you are in mid air, if you are going to land nose down, you can rev the motor, and the spinning rear tire will cause the butt end to lower.

BTW. The lack of knowledge, in this thread, of something as basic as cornering, is what is funny.

Lizard3 · « **Reply #28 on:** October 06, 2002, 02:28:56 AM »

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Originally posted by capt. apathy
lizard, read your own post. you just explained how you can use stearing to help get the bike to lean so you can turn. your own post states how the leaning is nescasary to turn. if it was the stearing that causes the bike to turn why do you stear left (while leaning right) to go right at high speed, but stear right to go right at low speed?

Leaning the bike, not you. You can put on a seatbelt, a back brace and a cervical collar and still ride and turn a bike.

Lizard3 · « **Reply #29 on:** October 06, 2002, 02:35:13 AM »

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Originally posted by NUKE

Ever take a passenger who refuses to lean into the turns? You can hardly turn the bike! In fact , the passenger can turn the bike and they arent touching the bars.

Shifting your weight has everything to do with turning.

Every see someone ride without hands, yet turn?

Yes, those passengers were the good ones. The ones that tried to lean into or out of every corner got told to stop. All the leaning screwed up the balance of the bike. It made for much wobbley turns. Leaning may increase or decrease your rate of turn, but isn't necessary.