Jump to content

Spineframe


Baldini

Recommended Posts

watanabetakemasa, thanks for pix. Those bits are pretty much what Guzzi added to the 02 bikes, which I've got. The bike in pix is pre 02. Will check out site later, no time just now. By the way, welcome to the site!

 

:bier: KB :sun:

I already said hi to watanabetakemasa but I also ask him if he has a short name, like Rob for Robert, or Al for Alexander or Frank for Francis or….

 

If he hasn’t, never mind. We will call him watanabetakemasa.

Link to comment
Share on other sites

Guest Jeff Kelland

The spine frame was designed by Dr. John Witner specifically for racing. It has been successfully raced which would stress it far more than any of us on the street. Perhaps the most important function of the chassis is to maintain the relationship of the steering head axis to the swing arm pivot axis. The spine frame does this particularly well. I'm no Dr. Rossi, but I can push my goose pretty hard, it doesn't exhibit any instability that I can find. I used to have a 748 duck, I was impressed by the goose's handling when I got it. I have personally seen a Scura that more than holds it's own against Japanese sportbikes, it's tires (street) are literally roasted from the efforts of it's rider, he thinks it's stable too! The only handling concerns I have are that this bike is relatively heavy, and it would seem to be a little light at the front. If somebody out there is really flexing their chassis, my hats off to them :thumbsup:

Link to comment
Share on other sites

The spine frame was designed by Dr. John Witner specifically for racing. It has been successfully raced which would stress it far more than any of us on the street. Perhaps the most important function of the chassis is to maintain the relationship of the steering head axis to the swing arm pivot axis. The spine frame does this particularly well. I'm no Dr. Rossi, but I can push my goose pretty hard, it doesn't exhibit any instability that I can find. I used to have a 748 duck, I was impressed by the goose's handling when I got it. I have personally seen a Scura that more than holds it's own against Japanese sportbikes, it's tires (street) are literally roasted from the efforts of it's rider, he thinks it's stable too! The only handling concerns I have are that this bike is relatively heavy, and it would seem to be a little light at the front. If somebody out there is really flexing their chassis, my hats off to them :thumbsup:

 

 

From what I can tell, and is rarely mentioned is that Dr John actually was "inspired" by the spine frame design from Tony Foale :P ah hem <_>

 

 

I was as a suspension seminar presented by Tony last year, and as he was going through slike after slide of various frame projects he developed over the last 40 or so years, he showed a photo of what was CLEARLY a MG Spine frame, but years before MG/Dr-John developed it, and applied to a Honda or somesuch.

 

After asking Tony, and a few others in the community, it seems that one day John Witner and someone else from Guzzi came to visit Tony, chatted about designing a new frame for them, looked around the shop, and they spotted Tony's work on what we now call the "spine frame".... and lo and behold... about a year later, the great Dr. Witner designed MG spine frame debuted. They never came back to Tony for a design, nor credited him in any way :unsure:

 

Tony was a bit miffed(according to Tony when I asked him), but not enough to really worry about it as he had moved on to other projects, which at that point the "spine frame" design was a decade old.

 

Not a big deal, but interesting. I have nothing against Dr. John of course, but I think credit is potentially partially due elsewhere.

 

Anyway, I looked at these Japanese frame parts when I first bought my 2002, and it looks like these are all really for 2001 and earlier bikes, as for the most part(at least in effect if not exact execution) all the braces being sold are what was included in the 2002+ bikes from the factory.

 

So I don't think any of them would offer much benefit, if even possible to fit, on the later bikes. Other than major re-engineering, or maybe including the transmission bracket that some early sports had, there's probably not much one can do to make the spine frame stiffer.

 

It is interesting that you mention that the Tonti frames felt stiffer in your experience though, as this is typically the opposite I've heard, and was one of the reasons the spine was developed.... to be more stiff :huh2:

 

I dunno though, as I've never ridden a Tonti, nor have the skills to push my spine frame hard enough to tell the difference... I'm quite sure :D

 

 

al

Link to comment
Share on other sites

Guest Jeff Kelland

With all due respect to Mr. Foale, whose work I certainly respect, The first large tube spine frame that I'm aware of was designed by Fritz Egli, a Swiss engineer. Perhaps Mr. Foale was inspired by Mr. Egli's frame? I'll bet if one were to research the subject, it would be possible to find even earlier examples. My point was, that the concept of a spine frame, properly designed, is an elegant engineering solution to address the problems of the loads involved in motorcycling. It works in an Egli Vincent or a Moto guzzi. As street rider's, I question that we can generate the loads necessary to flex these chassis enough to warrant worrying about it. I personally believe that I would be confronted by traction concerns long before I could wrap one of these spine frames up. Maybe if we add racing slicks and higher cornering speeds to the equation, things would be different. Don't get me wrong, I've spent plenty of time and money "improving" my bikes to deal with situations I'll never see, but the truth for me is that these "improvements" therefore become simply cosmetic. :blush:

Link to comment
Share on other sites

I agree completely Jeff :D

 

However, I have to stress that while I'm sure there are other spine frame designs that are similar and predate even Tony's design, Tony's was effectivley our spine frame, almost exactly.... before Dr John applied it to Guzzi. It was uncanny :huh:

 

al

Link to comment
Share on other sites

A Moto Guzzi will always compromize in the handling departement if the road is not very smooth, simply because of the unsprung weight of the rear differential. This, compared to full sport bikes of course.

That said, it is a fairly good handling bike, but like somebody mentioned, at high speed, the handling does get "willowy", and not as confidence inspiring and sure footed as many bikes out there.

The spine frame I feel would turn into a right wiggly monster if an engine of much more than 110rear wheel horsepower were introduced into it. But it does well with the basically stock 1100 engine capacity of 85-90bhp.

Ciao, Steve G.

Link to comment
Share on other sites

For size & weight handling's great, but on the far side it can be like riding a drunken elephant who's just had something unpleasant inserted into it's bottom. Sure you go faster on a track & stress more stuff more of the time, but it's not as simple as that. I've only raced a little at a low level but I've noticed that most race tracks are smooth with no potholes or unexpected dips & humps. You get to ride round again & again learn to deal with any odd rises or dips. There's no oncoming traffic, cowmuck, diesel etc etc etc. You can ride round a bike's inadequacies on a track, and adjust it for a quite limited set of requirements, & there's nearly always more run-off. Road bikes got to do motorways/ twisties on same settings less you're going to stop everytime to adjust. Steve maybe pointed to the main culprit on the Guzzi - the rear drive, & that held in a s/a you wouldn't see on a Jap lightweight. It was same on Tonti.

 

I just wondered if anyone else had concerned themselves with the frame. I do think that Guzzi themselves admitted some weakness when they added all the extra bracing on 02 bikes. If you look at the Dr John bikes, look at the s/a mount plates ...look like they're machined from solid ally? Compare them with the cast bits on the V11...etc. Same frame?

 

Re Foale frame. Respect to John Wittner for all he did with Tontis & spine ...but...It's not so much the concept of a spine frame...It was more like a direct copy, rear cross tube, s/a plates n'all....& no acknowledgement to Foale...hopefully Jaap's posting a photo...

 

Al...yeah I've wondered about that little bracket on trans on basis of every little helps...I'm surprised about what you heard on Tontis, To me Tonti frame feels inherently stiffer than spine. Suspension was pretty poor tho...

 

I'm not slagging the V11, mostly I love it, but things can always be got better. So...to the original question...anyone attempted to stiffen up the frame /swinging arm on a post 02 V11?

 

KB :sun:

Link to comment
Share on other sites

Guest Jeff Kelland

Hmmmmmm, not like me to add fuel to the fire, but.... the frame here looks suprisingly like a mid 60's Harley Davidson / Aermacci, sprint / road racer......, :bike: In engineering terms, adaptation and refinement.

Link to comment
Share on other sites

 

I can get the suspension adjusted better &  it could be lightened, but I was just wondering if in the long term it would be worth thinking of stiffening up the frame. I wondered if anyone had any views on/experience of this.

 

Thanks,KB :sun:

Yes do that get the suspenson adjusted up properly more importantly do the static sags and ensure the springs are rated for you. I think the current Guzzis suffer some stablity problems from the move away from true clipons to heli bars, handle bars whatever your variation is on the theme.The reduction on size of the rear wheel also probally didn't help (18-17) much better selection of tyres for the 17 though. On a bike with a already rearward wieght bias this has accentuated the problem. The only time I have possibly had something flexing on my 1100 sport was entry on the local track to whats known as the basin. Third gear 5-6000rpm down hill postive camber 180degree turn at a track day I possibly may have experinced some swingarm flex on my carbed 1100sport. Oscilating action from the rear end the latter 1100i's models they strengthened it it only ever did it once. But most definatly with properly setup springs the guzzi's get along quiet well and the V11 suspension is well ahead of what was fitted to the carbed 1100 sport.

Link to comment
Share on other sites

Oscilating action from the rear end

Murray, something like that, set the front going as well for about 20 yards, similar circumstance too - 2 sharp dips into a longish uphill lefthander. I have stronger springs, set sag etc, kept std clip ons. Generally suspension feels good, bike handles well but when it gets upset it really let's you know. I could stiffen up r shock but it's already pretty firm, pos not enough compression, too much rebound. But however good I get the suspension I think overall weight, esp rear drive box, rear weight bias & frame stiffness that'll eventually let handling down.

Thanks for your post, seems I am living in the real world.

 

:bier: KB :sun:

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...