Longer lasting cush drive material available

[Guest ratchethack]

Nope. No wadin' in the ol' swamp o' confusion today. I've turned over a new leaf.

 

There's only so far off the fairway I'm inclined to go anymore chasing someone else's shanked drive.

 

I don't find the familiar croc-clamped-on-the-head-o'-the-wildebeest hat particularly fetching.

 

When you've got a tough lie like this, best give up the ball. But that's just me.

 

See y'all at the 19th hole.

[dlaing]

So, 60 foot pounds would be multiplied by 11.7589 to give us 705.534.

I know my bike with roughly 60 foot pounds of torque can't lift the front wheel without a bit of coercion.

How much more torque can we get by popping the clutch?

We know it is enough to bring the front wheel up, and I know that my bike won't wheelie from simply giving it 705 foot pounds of torque at the rear axle.

It does seem unlikely that we would have to escalate the force from 705 to 1250 just to make the front wheel come off the ground.

Assuming my 1250 number is correct, that would correspond to 106 foot pound of engine torque following the owner's manual's 11.7589 ratio.

That does seem a bit high. The true force to lift the front wheel is probably somewhere between 1250 and 705 foot pounds.

 

 

Dave, I think you should consider that a. The force at the rear wheel contact patch is generating a moment around the CG of bike and rider and b. Rear wheel torque then needs to equal this force at the contact patch times wheel radius.

 

Assume the height of the CG is 2ft, (wild guess). The force at the patch would be (1250ft-lb)/(2ft) for 625lb. The rear tire has a radius about 13", so torque at the wheel would need to be 625lbX((13/12)ft or 677ft-lb. Your 705ft-lb then puts you in wheelie land. (But this is too easy. Maybe the front wheel gets more than 250lb and/or maybe the CG is lower than 2ft.)

Thanks Troy!

That fills in a couple of major missing pieces.

Now that I think about it, of course you need to consider center of gravity and wheel diameter.

Ratchet probably knows the front wheel weight.

Center of Gravity would be very difficult to calculate.

I would guess it is a little lower than 2 ft.

We would want to assume a full tank of fuel, since we are looking for the maximum number.

But I think the result should be just a little more than 705ft-lb.

Maybe claims of throttle wheelies from the more powerful V11s is not as exaggerated as I had thought.

The best dyno charts posted here show about 75 foot pounds of torque, but I suspect that is from overly generous dynos, and typically with simple modifications people are getting about 65 foot pounds.

I think designing the wedges to "bottom out" at about 70 ft-lbs of engine torque would be ideal.

70 ft-lbs times 11.7589 equals 823.123 and 823 divided by six cushes equals 137.

So, if the wedge could be designed to produce a nice progressive curve, "bottoming out" at about 137 foot pounds, I think we would have an ideal product.

But I would not be surprised if the OEM wedges are already close to that.

Someday I may rig up a way to test the wedges.

If I can just find a socket that fits the splines and won't strip them at 137 foot pounds of torque....

[Guest ratchethack]

Well, before the testing begins for squishibility, practicability, power transmission ability and durability I would like to register my design. :D

 

 

Phil, on your behalf, I hasten to add yet more congratulatory kudos to the growing list of Forum members who've lately joined the long list of "cush drive practical engineering excellence" in the annals of Guzzi history!

 

Not that I think it's all that critical (I don't), but this is VERY close to the way I drilled mine.

 

Let's put it this way. I don't have to ask how much of an improvement this has made by now to the shifting and driveline feel of y'er Guzzi, (I assume the testing is done?) 'cause I already know.

 

But lemme ask you this:

 

Knowing how "wrong" it is to do this from all the accounts of those who haven't done it here, d'you feel guilty?

[dlaing]

Phil, on your behalf, I hasten to add yet more congratulatory kudos to the growing list of Forum members who've lately joined the long list of "cush drive practical engineering excellence" in the annals of Guzzi history!

 

Not that I think it's all that critical (I don't), but this is VERY close to the way I drilled mine.

 

Let's put it this way. I don't have to ask how much of an improvement this has made by now to the shifting and driveline feel of y'er Guzzi, (I assume the testing is done?) 'cause I already know.

 

But lemme ask you this:

 

Knowing how "wrong" it is to do this from all the accounts of those who haven't done it here, d'you feel guilty?

What do you mean, "from all the accounts"? I don't think more than one person, if even one, said it was "wrong".

I suggested that it could be improved on and that the added smoothness makes a compromise giving a vaguer since of engine response and that it might shorten the life of your splines if it turns out it is "bottoming out".

But that does not mean it is "wrong" any more than putting a hose clamp on your oil filter, or spending money on a windage plate or spend money on high compression pistons, or optimizing the fuel map beyond that of a downloaded map is "wrong".

If anyone said anything was "wrong" it was those that suggested urethane wedges were wrong!

[Phil A]

Let's put it this way. I don't have to ask how much of an improvement this has made by now to the shifting and driveline feel of y'er Guzzi, (I assume the testing is done?) 'cause I already know.

Mate, I did this to my Centauro in 2001....., so I guess that gives you some new verified durability data. These photos were taken recently while I was setting up a Centauro in England to tour Europe for 3 months two up with gear....... There is some more load/ durability data for you.

 

As soon as I rode the new bike it felt like it was solid in the rear drive compared to the one at home. Hence these photos, for the V10 site, because as I toured Europe setting up Injection systems for friends and aquaintances, I couldnt believe that not one had this (to me) basic modification done.

 

Knowing how "wrong" it is to do this from all the accounts of those who haven't done it here, d'you feel guilty?

Dont force me to take sides...... I am mostly, well this thread anyway, here for the entertainment value.

[Paul Minnaert]

I am mostly, well this thread anyway, here for the entertainment value.

 

 

I must be mistaken, but thats the only reason to be here. instead of watching my plasma( see english man tread), yes ive waited six month, I watch the forums.

[dlaing]

I must be mistaken, but thats the only reason to be here. instead of watching my plasma( see english man tread), yes ive waited six month, I watch the forums.

If you want to wait another six months, hook the computer up to the plasma.

[Guest ratchethack]

I couldnt believe that not one had this (to me) basic modification done.

Seemed incredible to me also, to discover only long after I did mine 3 years ago, that next to no one here had done it.

Mate, I did this to my Centauro in 2001...... There is some more load/ durability data for you.

Thanks for the seven-year validation points. They line up with those of many decades. But you knew that.

I am mostly, well this thread anyway, here for the entertainment value.

Moi aussi, Phil. It's purely entertainment, no question. It's the fabulously creative popular rationalizations. The intricate delusions and elaborate denials. The other-worldly astrophysics and "advanced" engineering. The wondrously imaginative mis-application of mathematics (to give any self-respecting high school math or physics teacher a conniption fit). The appearance of something bordering on offense taken at the suggestion of common sense. The spectacular, great gushing fountain of wildly speculative, labyrinthine permutations of sheer folly shooting off in all directions that continues unabated -- far far beyond any and all expectations. That's why I pull up my chair, too.

 

Who could've imagined the great walloping profusion of controversy over such a thing?!

 

Certainly not moi.

 

It's like watching a never-ending slo-mo train wreck . . . I hope it never stops!

[Dan M]

I stuck one of the wedges in my door jam and started closing the door and watched as the rubber bushing wedge that is not chrome-alloy hard effortlessly mushed into a flattened out pancake.

 

I haven't been following this thread but for some reason, (boredom I suspect) I started reading from the end toward the beginning.

I have no need to go any further after reading this scientific test. I do wish though, Dave would provide door speed in feet per second, as well as width of door and if his shoulder was used in the exercise.

 

I think I'll remove my wedges and get a fat lady to step on them. This should provide even more valuable information.

[Guest ratchethack]

I haven't been following this thread but for some reason, (boredom I suspect) I started reading from the end toward the beginning.

I have no need to go any further after reading this scientific test. I do wish though, Dave would provide door speed in feet per second, as well as width of door and if his shoulder was used in the exercise.

 

I think I'll remove my wedges and get a fat lady to step on them. This should provide even more valuable information.

By Jove, I think you've discovered the true value of this thread and the one prior, Dan.

 

Junk Science at its Classic Best

[macguzzi]

By Jove, I think you've discovered the true value of this thread and the one prior, Dan.

More rubber bits

[dlaing]

Who could've imagined the great walloping profusion of controversy over such a thing?!

 

Certainly not moi.

 

It's like watching a never-ending slo-mo train wreck . . . I hope it never stops!

It all started with claims of chrome-moly hard rubber and a needless rejection of the idea of using urethane.

This thread had the usual rudeness of the usual suspects. Shameful.

I am just waiting for Ratchet to admit that he was wrong about rear axle torque.

[Guest Phil_P]

Having drilled mine some time ago, I'm happy with the results.

 

Maybe it's an attempt to validate my choice, but I don't understand why drilling would put your splines at any more risk than solid originals. My reasoning is as follows;

 

Once the holes in a drilled wedge are completely compressed out of existence (making the assumption that there is sufficient torque to achieve this), one is left with a solid wedge, which although of slightly less volume than the undrilled original, presumably has a similar force/compression curve than an undrilled original wedge, and thus we simply revert to roughly the original specification. There is no point at which the drive line can be exposed to a less cushioned system than it was in the original design. Pretty much a rising rate with quite a steep transition occurring at the point where all the holes become fully closed.

[Guest ratchethack]

I am just waiting for Ratchet to admit that he was wrong about rear axle torque.

Oh-oh. I hear that old familiar thrashing sound again. . . The splashing, thrashing, flailing sound emanating from the ol' swamp o' confusion, where reason, logic, and common sense go to die after they've been weakened by sheer neglect, sickness or mortal wound, and where the unwary and foolish venture too far, only to meet a ghastly death.

 

. . . [sigh] . . . But then, it's a natural thing. Part o' the great cycle o' life. . .

If the wheel base is about 58.66 inches and the front of the bike with rider weighs 250lbs and one can pop a wheelie, doesn't that mean that we can divide 58.66 by 12 and get roughly 5, and multiply 5 times the 250pounds we get about 1250 foot pounds of torque.

It's the familiar sound of another "short timer" wildebeest wearing the ol' croc hat. Sorry, Dave. I already gave you my best shot at pulling y'er chestnuts out o' the swamp back in post #41, but you just waded out into deeper water. After this, I wasn't inclined to wade in after you again on Monday, and I'm not inclined today, either. Remember that new leaf I turned back in post #46? It's still turned over.

 

Deep in The Swamp of Confusion,

a hungry croc prepares to have lunch

[dlaing]

Having drilled mine some time ago, I'm happy with the results.

 

Maybe it's an attempt to validate my choice, but I don't understand why drilling would put your splines at any more risk than solid originals. My reasoning is as follows;

 

Once the holes in a drilled wedge are completely compressed out of existence (making the assumption that there is sufficient torque to achieve this), one is left with a solid wedge, which although of slightly less volume than the undrilled original, presumably has a similar force/compression curve than an undrilled original wedge, and thus we simply revert to roughly the original specification. There is no point at which the drive line can be exposed to a less cushioned system than it was in the original design. Pretty much a rising rate with quite a steep transition occurring at the point where all the holes become fully closed.

If the main point of the cush is to protect the drive line, you would want to engineer the cush to absorb as much of the damaging energy as possible so that it is not transmitted to the splines, etc.

You can graph the deflection against force and show exactly how the splines are being protected.

If you only get a millimeter of deflection when you go from 50 to 60 foot pounds of ENGINE torque while in first gear, it will indicate that your drive line is not well protected when you hit the gas hard enough to lift the front wheel.

If what you say is true that you will get a rising rate until the holes close and then a steep transition, it is the steep transition and especially the end of the transition where the worst damage is likely to occur.

Ideally we want the bushings to deflect as much as possible as we approach maximum force.

The suspension analogy is that drilling the rubbers is like going with a softer spring. In general, the more you soften the springs, the smoother the ride will be over small bumps, but the large bumps will more likely cause the suspension to bottom out. The bottoming out is potentially the most damaging. If protecting the riders kidneys is the objective, the ideal spring for most bikes will be as soft as possible without bottoming out.

The same holds true for cush bushing design.

Where the analogy breaks down is that a rider will feel the greatest comfort with the ideal spring if they ride over various terrain, but the rider won't feel the bottoming out of an over-drilled bushing. They will only feel the smoothness of the less threatening impacts on the drive line.

You appear to bee attempting to use your common sense to suggest that no protection from the maximum impacts is lost.

You may be correct, but you might not be.

My common sense, and my obsevervation of how soft the rubber is leads me to believe that the bushings may in fact be too soft, in the direction of accelleration.

Maybe Guzzi bushings come in inconsitent levels of softness??? I certainly would not call mine "chrome-moly" hard.

Increased progressiveness would probably be a good thing, and drilling can increase progressiveness, but maintaining adequate firmness to prevent bottoming should be the number one design criteria.

Without testing, the ideal softness of the bushing is unknown.

Observations of smoother driveline have value, but the drilling may be compromising the life of the driveline.

Probably not a big deal when most V11s will be junked before they reach 100,000 miles. I am just defending the premise that a better bushing could be made.