Q: Who “Needs” a Steering Damper?

[luhbo]

The whole thread is nonsense. Time to close it. The only interesting thing in it are Ratch'es pix and maybe its Haikus.

How shall whatever raked triple clamps work at a production line like that? It's geometrically just impossible. They don't find the time to grease the bearings or to choose the right rear axle spacers. How should they find the time and interest to measure each framehead, choose the right amount of shims matching both clamps and frame and then carefully assemble all this? Do these shims show up in any parts catalog? Does anybody believe Guzzi would have been willing to spend the extra money for rather expensive special bored clamps? The more as a different frame would have cost nothing compared to all this silly scenario?

 

That's just science fiction, bad science fiction. Only Greg Field can make up such boring nonsense. Yes, and then stamp feets

 

Hubert

[Greg Field]

They are bored off-axis. No need for shims. Or haikus. Or demons. What the Aprilia-era Guzzi factory did was far more interesting than demons or pathetic poetry. After that, the Aprilia clowns stepped on their @#$$#! trying to put hydraulic lifters in the Cali engines and installed a single-plate clutch that self-destructed sometimes in less than 200 miles. I suppose those things made sense to you, Luhbo? Or perhaps you think they're fiction, too?

[GuzziMoto]

So you think that raking out at the triples which decreases trail is a good idea?

Dave, raking out (or in) the fork tubes in relation to the steering stem does not mean the trail changed in any way. While it is possible that the trail did change when they did this, without knowing what the trail is on a pre offset clamp bike and a post offset bike we have no way of knowing what the impact if any on trail was. They could have given the bikes more trail with the new clamps or less trail, it comes down to how they moved the fork tubes. If the wheel base stayed the same then the trail did not change. If the wheel base got longer then the trail was reduced and if the wheel base got shorter then trail was increased. The angle of the fork tubes does not directly effect trail. Trail is purely a function of how much the center of the contact patch is behind the point where the steering axis would hit the ground if it went that far.

[Greg Field]

Yes, all is fiction but what the Kool-Aid drinkers offer, which is nothing but demons and bad haiku. I think the main stabilizer needed on this forum is thorazine. Or perhaps an ice-pick lobotomy. Scratch the ice pick. For most, nature has provided.

[luhbo]

What does that mean "bored off-axis"?

In a triangle with fixed lengths you can't have just one leg differently. So shimms below the upper tripple clamp are a must if you bore them "off-axis". Just make a quick sketch on top of your workbench, it's not that difficult.

 

Hubert

[Greg Field]

It's not a triangle.

[luhbo]

Of course! What else?!?

 

Hubert

[Greg Field]

If it's not a triangle, what you say does not apply. It's not a triangle, so what you said does not apply.

[GuzziMoto]

What does that mean "bored off-axis"?

In a triangle with fixed lengths you can't have just one leg differently. So shimms below the upper tripple clamp are a must if you bore them "off-axis". Just make a quick sketch on top of your workbench, it's not that difficult.

 

Hubert

Picture the front wheel and axle staying exactly where it is (since I don't yet have anyone saying they changed the wheelbase as well) and the fork tubes get rotatedback just a little so they are at a 1/2 degree shallower rake (that is a small amount). This would move the holes in the triple clamps back a little bit (the top would move more then the lowers) and would put the bores of the holes a little off perpendicular to the clamps. No shims or changes in trail required.

Hope that helps.

[luhbo]

No guys, that makes a triangle. You must add the missing upper part in your imagination of course. Do you get the picture?

 

Ok, hold it then, and now think of all the tolerances that will stack up in this assembly. Bearing seats, height of their contact surfaces above or below the reference surfaces of the fork tube bores, distance of bearing seats in the frame, the bore diameters etc. etc.

 

Something like that will not work at an (semi- ) industrial assembly line. You can do something like that if you build bikes one by one and one per week, no problem, but you'd need shims to get the tolerances out and to get things straight. Cutting off the steering head and weld it back correctly would take less time and cost less money.

 

And G/M, like you wrote already, for what reason if they keep the wheelbase constant?

 

The raked clamps thing is nonsense made up by Greg. Hopefully he at least knows why he does such things.

 

Hubert

[Greg Field]

No guys, that makes a triangle. You must add the missing upper part in your imagination of course. Do you get the picture?

 

Ok, hold it then, and now think of all the tolerances that will stack up in this assembly. Bearing seats, height of their contact surfaces above or below the reference surfaces of the fork tube bores, distance of bearing seats in the frame, the bore diameters etc. etc.

 

Something like that will not work at an (semi- ) industrial assembly line. You can do something like that if you build bikes one by one and one per week, no problem, but you'd need shims to get the tolerances out and to get things straight. Cutting off the steering head and weld it back correctly would take less time and cost less money.

 

And G/M, like you wrote already, for what reason if they keep the wheelbase constant?

 

The raked clamps thing is nonsense made up by Greg. Hopefully he at least knows why he does such things.

 

Hubert

 

I did not make it up.

[Dan M]

Is this the right place for an argument?

[Guest ratchethack]

What does that mean "bored off-axis"?

 

In a triangle with fixed lengths you can't have just one leg differently. So shimms below the upper tripple clamp are a must if you bore them "off-axis". Just make a quick sketch on top of your workbench, it's not that difficult.

 

Hubert

Hm. OK, I’ll have a swag at this. . . Why not?

 

Amidst the usual group dork wad wrap-up now building considerable girth around the ol’ driveshaft here lately, I seem to detect a glimmer of sincere interest here.

 

Maybe another set o’ visuals would help:

 

 

Note difference in offset between top and bottom triple clamp^. The steering stem holes are drilled at the same angle, not parallel to the fork tubes. This is "off-axis" relative to "normal" forks. No shims.

 

As noted previously, chassis tuners chasing optimum performance on the track have been producing custom triple clamp sets with other than OE offset for as long as there’ve been telescopic forks. Options include adjustable offset triple clamp sets, where replaceable inserts with matching offset are used at the steering stem axis in upper and lower triple clamps. Likewise, matched sets of RAKED inserts have been fairly common. They’re bored off-axis, as noted previously. Isn’t “off-axis” fairly self-explanatory?

 

Similarly, but chasing something entirely incomprehensible to Yours Truly, the human equivalent of modern day Neanterthals have been making raked triple clamps for as long as there’ve been guys with nicotine and whatever-stained hands hanging off the ends of their full-sleeve tatt’s making metal shavings in hole in the wall metal shops bent over anything that can make repetitive mistakes in metal and/or bore a hole.

 

Now the “stupid bike”, aka “long bike” crowd may not be considered all that brilliant, as population “sub-cultures” go, with groups of a dozen or so typically sharing a hundred IQ points between them on a good day. But if there’s one thing the chopper “purists” know besides the penalty for armed robbery and drug possession in the state/country where they live, it’s RAKED TRIPLE TREES -- along with every other conceivable way to get that front end “OUT THERE”. Why this is necessary, I’ll never be capable of comprehending, but that’s just me, and I sure as hell ain’t no Rhoads scholar myself.

 

SIDE NOTE: Having observed way way too many of these latter-day "primitives” on the road, riding Great Wallopping rolling noise makers/butt jewelry abominations under assless chaps with their feet up as if they were getting some godawful rolling public gyno examination -- many dressed up in pirate costumes yet -- is all chronic behavior far beyond my humble comprehension. I’m sure the geniuses at dumbassbiker.com (yes there really is one, no surprise) would offer the wisdom of the now Classic mind-numbing Chopper Mentality universal explanation for everything that defines “the culture”: “If you have to ask, “WHY?”, you’ll NEVER get it.”

 

And so it goes. . .

 

Sure hope this helps.

[GuzziMoto]

Wow, thanks Hatchet Wack. That was actually a constructive post with real information.

There is no reason you can't build a production bike with raked (either in or out) triple clamps by the thousands. Harley I believe does it. It is no harder then building a bike with "standard" triple clamps. Mind you, I see little value in doing so, particularly if you are not building a chopper. It is not likely to improve a bike like a Guzzi. There are things that would improve a bikes stability much more then this if it needed the help. This does not mean I do not believe Guzzi did it, they have done dumber things like the hydro valve idea. I have no reason to doubt Greg in his claim that they did this and until someone actually measures some bikes to prove one way or the other I will go with what Greg said. But I do think it was a stupid idea.

Oh, and by the way. Funny thing about the effect of trail on a bike. As long as you have enough trail adding or subtracting trail make little impact on stability until you get below the threshold value where you no longer have enough. So changing the front end like dropping the front to steepen the rake (and decrease the trail) does not automatically make the bike less stable or more stable. Until you cross that threshold where you no longer have enough trail you may likely see an increase in stability due to the other effects of the action like putting more weight on the front and lowering the front ride height. This is not to say that changing trail does not effect other aspects of the bikes handling. Stability is only one thing that trail has a strong influence on. It also effects steering weight and feedback. Too much trail can be a bad thing just as too little is.

It is all about finding a balance.

[luhbo]

It's very hard, if not , under commercial aspects, impossible, to do this rake thing just because you can't keep the vertical distance between upper and lower clamps constant or as designed. Tolerances and such things you know. It's no problem as long as you have the 3 boreholes parallel to each other. If you have them tilted you've lost. There you need the shims, between the clamps, not in the top view like RH's sketch.

If you want to keep your assy line running this would mean Harakiri. For nothing. It brings no effect besides a slightly variing trail under different load conditions (wheelbase kept constant, of course).

 

....

Oh, and by the way. Funny thing about the effect of trail on a bike. As long as you have enough trail adding or subtracting trail make little impact on stability until you get below the threshold value where you no longer have enough.....

 

More trail makes a bike more prone to wobbling. You've probably watched wobbling shopping trolly wheels or maybe also the uncontrolled front wheel of a vintage sports plane. Good examples of wobble caused by trail. Remember that with a longer trail you also have bigger reaction forces which may make a steering damper indispensable because of the risk of an overshooting stabilisation (Greg's Death Wobble). Massive wheels, fenders, rifle holders, rollers and bullshit more like this at the front fork might multiply this risk.

 

Hubert