why light wheels make your bike turn easier

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Awesome. Makes me wish I had studied more in school. Looks interesting to me now.
 
Ride a bicycle with heavy clincher wheels/tires then switch to lighter sew-up wheels and there will be no doubt in your mind as to the advantages of light wheels. When you're the motor, things are very clear!
 
We used to get in inner tubes or small boat or office chair and turn either way by how we twisted against the torque vector. This is partially how satellites change attitude w/o thrustors. So can't fool me i saw the b/w wheel sections change direction while spinning up and slowing down -so proof to me what little gyroscope effect yeah can ***jerk*** out of front wheel spin is *momentary only* and linearly proportional to the speed/force of the pilot or road or wind eddies > out of line with the spin momentum vector that's aligned with the axle. I've done jumps and easy to find many jumps of pilot flipping the front forks yet only a wiggle goes thru the frame and does not change lean angle nor skew bike off its straight line of ballistic flight. I've got a tri-linked isolastic Command which isloates every influence of bike behavior so no more secrets nor mystery confusion of one thing bouncing off another to show up as a resultant 3rd no one can figure out why, hehehe.
Oh yeah the other way satellites position w/o thrusters is to speed up or brake a gyro for the flywheel inertia effect.


Ugh, most everyone confuses gyroscopic precession with flywheel inertia, a whole 'nother subject and main benefit of lighter spun mass. Main reason best scooters and balloon tire elites have similar dia. wheels compromise, smaller is less hi speed stable and bigger is more flywheel inertial to start/stop spin or to tip.
http://io9.com/5792341/engineers-overtu ... le-upright

21" wheel longer foot print and flywheel effect will help hold a line on loose rough stuff off road and will help make heavy bike bike easier touring steering but will fight and hinder hot dogging paved turns. 21" tire on WM2 rims have a bit larger wider tire patch area than 19-18" though don't look like it at first glance. So it not lack of traction that messes with highway flings. They look cool on choppers though.


Above is all baby pablum for corner cripples so lets get down to what an asymmetrically compliant Watt's like linked isolastic frame neutral handler reveals for scout saucer like flings, which if ya ever really see one, they are not smooth and steady but jerky/twitchy unless standing still. In a way its actually skipping like a flat stone on water surface, but its ain't water surfaces their helical stabilizers ring flux is skipping across. But they can't hold a candle to Ms Peel's thrills as craft and occupants all in same inertial torque flux vortex so don't feel a dam thing of acceleration, pashaw. Cosmic rays are felt though, kind of like a light rain. I don't want nothing more to do with any of them as all basically renegade pirates or entertained bystanders fighting among themselves on best pranks. http://www.youtube.com/watch?v=G01DPBs3eZQ

Review the professor's set up and notice that the hung wheel gyro precession is straight steering into the turn direction and even leaning opposite away from the turn center, exactly opposite of every single description of how to turn a m/c at speed, ie: turn fork away to counter steer away-opposite turning direction but it is leaning some into center of turn direction. Any bike using counter steering has to fight the gyro force that is tending exactly opposite and more so the harder-faster ya try to counter steer the turn. So gyro force hinders all cycles counter steering in "phase two" kinetic energy handling state. Hehe spin wheel fast enough and press turn and lean force hard enough and conflicts of torque leverage can lift bike horizontal on its center of gravity to then follow the tangent off the track. All m'c need some upsetting force off the straight and steady, some mc's like hobot and robots only force bars an instant to help change lean then can relieve fork pressure to just dampen into steady state, while others a constant force must be maintained to keep same turn and angle.

Everyone and their sister tends to think/feel the front tire steers the bike, pashaw no more than a rudder steers a boat or plane. All front really does is aim whole craft's flank area for the real steering force or in mc's case the rear tire profile. Think like hobot for a bit, how can forks be the key to aiming when going 7 mph ya turn em to L to steer L, yet at 12-13+ mph [w/o rear spin] same forks to L will turn ya R. We see rear tire only wheelies in tight circles and bikes w/o a fork on them go any way like a unicycle. The common denominator is the rear tire aim and/or lean. Though one cycle can use both tire flanks to thrust into center of radius so inertia of blood circulation to deal with. Even the off road maniacs with 21" fronts all say it make front easier to lift over stuff and easier to pull side ways wheelie with rear hooked in ~vertical rut. Hehe they don't depend on front to steer so much as keep stem off the ground when not thrusting enough or braking.

Yeah yeah blah blah blah on front tire camber curl inward force and cone shaped roll patch on leans and offset of front contact to one side of vertical CoG, >>> what really matters is the level of *front axle plane in relation to the forward thrust vector* of rear tire. That is if going too wimpy to lift front out of traction and say ya turn forks to the R to turn L the bike is able to pivot on tipped off level axle so can only fall to the R. Increase axle off level hinge angle and bike falls over quicker so rear lean can bite more its flank into turn force. Ie: bike tends to fold up on itself. So in reality we are dealing with a dual cross plane double hinge joint at the front. Simple as 3.141592653589793643... universal joint. just stretch the axle spacing apart using your imaging- in.
http://www.youtube.com/watch?v=R-NzQ21i ... 9CBE2504CB

Now if ya can hook up rear thrust enough the bike will fall over on its own and if not resisting the natural physics of the gyro precession of wheel to straight steer and allow forks to actually follow the road surface by aiming in same direction of the turn the axle angle off level is opposite the fold up counter steer fall over and instead allow rear thrust to unfold the stem hinge angle to lift bike up against gravity and rear tire tendency to low side on lost traction.

Steering a 'good' cycle should be as simple as saucer guidance or falling off a log, ya just think which way to go and tip forks that way to let front tire and axle level do the rest magically. If ya forks need effort to do this then oh well at some point that effort will over power up-righting forces SPAT! Wife said she'd let me watch Dr. Who on now Chow.
 
i didn't write it down but Excells in same size as steel rim are not hardly a lb or so lighter. Exelles are pretty robust though. There are lighter vintage brand rims mentioned all the time here for maybe another .5 lb less and ~double the cost. Most the tube wheels tires hub brake will be in the upper 30 lower 40 lbs. Necked down spokes can gain another few oz.
 
swooshdave said:
comnoz said:
My preference is Excel rims.

I get them from - http://www.buchananspokes.net/
Click to expand...

What is the weight difference between the stock steel rims and the Excels? Buchanans makes it sound like there isn't much.
Click to expand...

No there isn't a big difference between an Excel and a stock steel. You will notice a difference when you change however. They do make the bike feel lighter. The Excels are about bulletproof.

I will not use the lightweight aluminum wheels anymore [Sun] after jerking the spokes out of one on a rough section of track at PPIR. One time is once too many.

Now if you want a night and day difference try replacing an old pair of SR500 mag wheels with spoke wheels from a TT500. You wouldn't think it was the same bike. It almost transforms them into a decent handling motorcycle. Jim
 
The last comment that lecturer made was 'none of this is intuitive'. When I studied the vectors involved, I simply memorised the resultant for the direction of the precession of one combination of vectors. It is difficult to remember the theory behind what happens in that situation. As far as motorcycles are concerned, the gyroscope works in concert with the steering geometry. If you get it wrong it can grab you by the throat, so reducing wheel mass might not be all good. Perhaps you might end up reverse steering more, or completely lose stability ?
 
From memory, if the top of the wheel is spinning away from you, and you turn the steering to the left, the bike leans to the right . The rake and trail are set to compensate for that and keep the bike stable ? So what happens if you get a wobble and the wheel mass is wrong for the steering setup ?
 
There is no doubt the wheel mass and geometry all work together.

Not sure why but I have generally found the bikes that wobbled most where the bikes from the mid 70s through the mid 80s with heavy mag wheels. When I installed lighter wheels the wobbles were more controllable. Jim
 
I can only remember heavy mag wheels on Japanese bikes, and their handling was often on the limit of safe. I used to own a RD250LC Yamaha and I didn't like it on well worn bitumen roads where there was a longitudinal depression caused by heavy trucks. It felt very skitterish. On a racing bike there is rarely a situation where you will totally lose it due to steering geometry unless you do something stupid, as I found when I had too much yoke offset on my Seeley. In that situation I suggest wheel mass could be a factor in a crash. Too little or too much, I don't think it matters. If it is wrong, it is wrong when the handle bars disappear into a blur.
 
comnoz said:
There is no doubt the wheel mass and geometry all work together.

Not sure why but I have generally found the bikes that wobbled most where the bikes from the mid 70s through the mid 80s with heavy mag wheels. When I installed lighter wheels the wobbles were more controllable. Jim
Click to expand...

Include also frame and steering geometry in the "working together" equation....the Brits greatest error was thinking only they had it right and no one else (read Japanese) could get it right.
 
Besides the lighter versions of alloy rims being spoke nipple weak there is also alloy nipples sold that are for show queens only.
IRRC steel rims are ~ 4.5 to 5 lb, Excels about a lb less. Tubes weight ~2 lb, so most mass loss potential in our size wheels is in the tube and tire but its tricky to dangerous to try to seal a spoke rim for tubeless to stay sealed. I've never heard of any bike or car getting worse handling with lighter wheels but I suppose its possible in non-British cycles. Getting rid of spun mass pays back more performance wise than any other similar investment, if not going so small traction is lost too.

Here's automotive oriented site with spun mass calculators to play with
http://hpwizard.com/rotational-inertia.html
 
In the video the weight is placed on the axle. The demonstration doesn't address changes in the rotating mass only the effect of deflection at the axis.
Just saying.
 
It is the weight on the axle which causes the precession, i.e. the effort you put into turning the steering on your bike. If you have heavy wheels, when you reach a corner at high speed you usually unconsciously reverse steer to lay the bike over. The geometry is set up on all road bikes to make the bike stable, especially under braking. If the brake drags the bike will usually run wide in corners, due to the geometry, and a heavy wheel weight tends to maintain attitude. Fitting lighter wheels should not affect the handling except if the geometry is near the safe limit, which it is on my Seeley 850. The earliest commandos had racing steering geometry, and a few guys crashed after running over the 'cat's eyes' on UK roads. Heavier wheels might have stopped that, however Norton simply made the geometry different to make the bikes more stable. Experienced riders did not have a problem, they simply rode through their difficulties, however it caught the beginners out, and could not be left like that. Once the bike has gone into a lock to lock tank slapper, the rider must let go of the handle bars or get launched, heavier wheels are likely to increase the force with which the oscillations come through the bars. You have got to have a sense of humour to road race an old motorcycle.
 
Duh, autistic and brain injured people sure like spinning things especially gyroscopes to screw with physics reality checks.
Very Good Observation ace22 and is the reason the free hanging demo does not apply to motorcycles whose axles are not tugged up or down on one side only in a vertical plane to cause gyro torque procession in a vertical axis of rotation. If this was the way forces on fork axle were applied then the demo would have some validity on cycle handling but it does not, so demo is only good for satellites and ship guidance principles. The professor is being lazy or ignorant to imply his demo means a thing to us inline travelers but did like his vector force dance jig.

On forks the axle ends are forced in rotation that's mostly horizontal-'90' to gravity so the gyro procession forces try to tip the wheel on an imaginary pivot pointing in line with the disc of the tire plane, ie: 90' to handle bars, so about straight ahead, so any gyro force is totally restricted and absorbed easily by the fork legs unless tooth picks the gyro torque could bend, in other words same as grabbing top/bottom of tire and trying to shove top closer to one leg, ain't gonna happen and does nothing to at all to turn forks on ground or in the air.

why light wheels make your bike turn easier


What wheel and crank gyro force do do is to resist changes of lean angle, so gyro forces must be over come by fork turn to upset balance on rear patch by normal counter steer or just use body English to lean hands off so forks will road follow and straight steer automatically. To hobot this means not doing a turn so harsh bike is falling over on its own then I of course must counter steer like everyone else to over come gyro resisting the tipping side to side or in Peel's case what ever angle i let go of bars she just stayed there till a slight fork force to reset a new one. Neat gyro thing, I most notice on Peel was once angle set I could move all over bike front back, hang off or climb above it on other side, stick a leg out or stand up and hardly did nothing to the line of turn or lean until some long delay to begin to affect aim or lean.

If ya want the lightest practical wheels shop the MX and Supercross Supermotard sight$. Check out the fork flips here that are only to hit ground mostly in line not affect attitude pitch roll yaw in flight.
http://www.youtube.com/watch?v=qcUybXB50sU









http://www.youtube.com/watch?v=oHI_-hszUbQ
 
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