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V11 Geometry changes


docc
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Thanks, Paul! From the parts manuals, I found four frames: the first two are the "RedFrame"(01 400 130) and the Rosso Mandello frame of the same dimensions, but painted black ( 01 400 140). Wheelbase: 1471mm.

 

The frame of the first V11 LeMans of US2002 gave the wheelbase of 1490mm (01 400 160) was used for the LeMans, Scura, and Tenni and was coupled with front and rear subframes that had additional bracing. Did only the length change, or also the rake (castor) of the steering head?

 

2003 shows a final frame (01 400 190), but could it just be a change in paint finish without any change in geometry for the final two years of production? (Wheelbase appears to be still 1490 mm to the end).

 

Are there any dimensioned drawings of the longer frame?

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Page 2 of the brochure showing the Cafe Sport, the forks look raised up through the yolks a lot more than my Ballabio (no images in the brochure shown to confirm), does anyone know if this is a standard 'setting' of the Cafe Sport?

 

Not sure if this has any relevance to the thread but it will affect the geometry, I'm sure someone will let me know!

 

Dan

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The Workshop Manual "update 04/03" shows in the section R page 48: "Position as shown in the figure - - Ballabio/Marzocchi 32 mm, Cafe Sport/Öhlins 26 mm".  I understand this so that the forks of Ballabio should raise up 6 mm more than the forks of Cafe Sport.  The older 2002 User Manual 08/2002  (Scura year) says for Öhlins "Sliders should come out from the handle hub by about 2 mm, that is up to the first round mark on the very slider".  Now there's a big difference...  But the forks seem to be different (Cafe Sport 01490 283/Scura 01490 290).

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  • 1 month later...

After reviewing all of the literature I can find, including both Workshop Manuals, owner's manuals, promotional brochures, and period (US) magazine articles there are still only a couple things that can be said with certainty. Well, with some qualifications.  :rolleyes:

 

Throughout the V11 range, 1999-2004, there were two frames; the later ~2002-on frame is longer, but the rake, or angle, of the headset from vertical is 25˚ in all published references I have seen. (no actual "2005" serial numbers have been reported). One of the magazines reported, in 2002, an increase of 0,5˚ steering angle, but there is no reference in the official literature.

 

The swing arm did not change.

 

There have been changes in the fork plates (triple trees, or triple clamps). Reportedly, a Service Bulletin was issued sometime in 2000 that documented a more "relaxed" clamp set. It has been said that the axis of the forks was angled forward an additional 0,5˚. There have been observations that the offset of the forks (increasing trail) has also increased from the earliest versions.

 

Is there any resource we have to obtain the original Service Bulletin?

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  • 4 years later...

I have seen my first "early" 2000 V11 Sport triple clamp at the Fourteenth South'n Spine Raid; build date: 1-2000 (footgoose's sweet, black V11 Sport). . Upper triple clamp part number 01 49 3100.

 

[ My Sport's build date is 3-2000 and has the "relaxed" triples (upper clamp part # 501 452). ]

 

Quite serendipitous to have a 1997 1100Sport-i, courtesy of Pressureangle, at the South'nSpineRiad. Same upper triple part number as footgoose's early (1-2000) V11 Sport!

 

My take at this juncture from all we have been able to discern:

 

>The earliest 1999-2000 "short" spine frame (RedFrame) *may have* a 1/2º steepened head tube angle. Mounted with the earlier triple clamps of the previous generation 1100Sport, the rake *may be* 24.5 degrees and a bit dramatic for a big, tipsy girl on high heels.

 

>The triple tree change (501 452 upper) brought the geometry back to the published 25º rake.

 

>While Guzzi has never been known for a specific date for parts changeover, footgoose's 1-2000 Sport has the earlier parts and my 3-2000 has the later parts [edit: as does LuckyPhil's 2-2000 Sport.]

 

Thanks to these gentlemen for their contributions:

IMG_6429.jpg

IMG_6424.jpg

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My two cents;

There is nothing extreme, or even "tippy" about a 24.5 degree steering head angle. And relaxing that angle half a degree in and of itself is a very small difference. I would be more interested in what the different versions have for trail, if there is a difference between versions.

Also, it is not normal, or even desirable, to adjust rake by mis-machining the triple clamps. Since the steering pivot is at a given rake having triples mis-machined to give the the steering more or less rake than what is in the frames steering axis results in a rake that changes as you turn the steering assembly. A much better way to adjust steering feel and stability would be to either change the rake of the steering head and / or change the amount of offset in the triple clamps to change the amount of trail. I don't know if the different part numbers refer to triple clamps the are mis-machined so that the result is a more relaxed steering rake or it they simply are machined with slightly less offset to increase the amount of trail. Increasing the amount of trail would typically increase the stability of the bike and make it steer a little heavier. As feel is subjective, that may be what they thought was required to appeal to their customers.

I am only guessing about what they might have done or why, but I am pretty sure about how geometry works.. 

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I am only guessing about what they might have done or why . . .

Pretty sure Moto Guzzi might have also been "only guessing about what they might have been doing or why . . ."  :unsure:

 

Holding over (or "using up") the 1100 Sport clamps with the new, short RedFrame certainly may have affected trail enough to contribute to early reports of "instability", especially compared to the "typical" running-on-rails Guzzis.

 

Moto Guzzi looks to have acted early to change the perceived handling characteristics on the early RedFrame. Moving, in 2002, to introduce the longer frame, different forks/ clip-ons, wider rear wheel/tire, and extensively braced subframes along with less race oriented tires.

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I am only guessing about what they might have done or why . . .

Pretty sure Moto Guzzi might have also been "only guessing about what they might have been doing or why . . ."  :unsure:

 

Holding over (or "using up") the 1100 Sport clamps with the new, short RedFrame certainly may have affected trail enough to contribute to early reports of "instability", especially compared to the "typical" running-on-rails Guzzis.

 

Moto Guzzi looks to have acted early to change the perceived handling characteristics on the early RedFrame. Moving, in 2002, to introduce the longer frame, different forks/ clip-ons, wider rear wheel/tire, and extensively braced subframes along with less race oriented tires.

 

I remember reading an article in Road Racing World a long time ago about a guy who built a frame with adjustable steering head. He could adjust rake and trail, all the way to zero rake as I recall. He found that as long as trail was correct just about any rake could be perfectly stable. Rake does change the way a motorcycle steers, but it only makes the motorcycle less stable if trail is not properly matched to the rake. Additionally, the wife and I have owned two Buells over the years, and they tend to push the envelope of conventional wisdom. They ran something like 22 or 23 degrees of rake and were perfectly stable, without a steering damper. I even raced mine, an X1, like that. The guy in tech warned me of all the problems I was going to have running without said steering damper. But it was perfectly fine, steered beautifully. For comparison, I raced a TZ250 for a few years. That also had something like 22 degrees of rake, but without a steering damper it was near impossible to ride. I know, I tried. In fact, even with a steering damper it was a tricky bike to ride fast. You had to be careful about body movements, you could cause a wobble by shifting if you weren't careful. I let a friend ride it at a track event and he only did one session before calling it a day. It was too delicate for his brutish style.

Lastly, a related example of the effects of rake and trail can be seen in our Jeep. It has adjustable control arms, so we can in effect adjust rake and trail. If I lengthen the lower arms or shorten the upper arms it adds rake (castor) and increases trail. This results in less responsive steering but it increases the effort required to turn. Doing the opposite increases the rake of the steering axis and decreases trail. This makes the tires turn more directly in relation to direction of travel, as a result it also makes the steering more responsive and less effort is required. But too much of that results in over aggressive steering which is flighty and requires too much effort to maintain the desired direction of travel. So, in the end it is about finding the right balance of rake and trail for the desired characteristics.

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  • 1 year later...
On 1/3/2014 at 6:27 PM, docc said:

Jeez, but that was hard to find: A post by Greg Field regarding the change of triple clamps, but not just for the Rosso Mandello, but by serial number:

 

"What is meaningful is a discussion of triple clamps. Early (to frame 113032) bikes used triple clamps with 1/2 degree steeper rake. It is these that show the greatest tendency to instability, though even the later ones sometimes do, too."

 

With this clarification:

 

"I'm pretty damn sure the steering angle on the frame was unchanged from beginning through the last pre-LeMans bike. All red-colored frames have the same part number. The part number was changed for the Rosso Mandello because it is coated black. The angle change was made in the triple clamps at the frame number listed earlier."

 

And further clarification here, on post#164:

 

" The later triple clamps include a 1/2-degree of cant compared to the steering axis. These gray "canted" triple clamps were used through the end of the red-frames. In general, if your red-frame's forks have an axle nut, they also have the early non-"canted" clamps and if your red-frame has an axle that screws directly into the fork leg, it has the "canted" clamps. There is some crossover between axle-fixing arrangements and clamps, though, and Guzzi offered a kit of the "canted" clamps for people who wanted to reduce twitchiness of their early bikes, so any combination of parts is possible. Rosso Mandellos had black "canted" triple clamps. Starting with the LeMans, Guzzi again fitted non-"canted" clamps, but they were painted black."

 

And these part numbers under the upper triple clamp, again apparently not unique to the Rosso Mandello:

 

"Does it read "01493100" or "01493130" (both early) or "501452" (most late)?"

On 21 June, 2020, @Lucky Phil said ( in LeMans 1000 16" Front Wheel):

"Info there docc. Looks like my bike is the twitchiest of them all:)

Ciao "

Does this mean you actually have a set of the earliest, steeper triples, Phil? What is the build date on that frame, again?

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2 hours ago, docc said:

On 21 June, 2020, @Lucky Phil said ( in LeMans 1000 16" Front Wheel):

"Info there docc. Looks like my bike is the twitchiest of them all:)

Ciao "

Does this mean you actually have a set of the earliest, steeper triples, Phil? What is the build date on that frame, again?

Docc, there was speculation re my Sport and the half degree. With frame # 112086 it seems it falls into that group. Maybe at SSR there would be enough guys present to get a fairly accurate wheelbase comparison.. just fer kicks.

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1/2 degree?  That really seems minuscule.  I'm surprised that production tolerances are that close.  Could even a little debris in the fork clamp could count for that?  

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I'm gonna guess....  a half degree will bring the front axle 7-8 mm closer

1 hour ago, LowRyter said:

1/2 degree?  That really seems minuscule.  I'm surprised that production tolerances are the close.  Could even a little debris in the fork clamp could count for that?  

 

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48 minutes ago, footgoose said:

I'm gonna guess....  a half degree will bring the front axle 7-8 mm closer

 

a little more than a quarter inch?  

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