monoshock setup?

[amamet]

I have a project im about to start.  I plan on building a monoshock Tonti racer with a frame that has the lowers removed.  the frame I have is one of the uber Tonti frames from guzzitech purchased off ebay recently.    I still need to get the mono shock swingarm.  my question is: is the one he sells the correct way to brace the swingarm?  I've seen 2 types, one where the shock brace is welded to the swingarm where it bolts to the rear hub (thats like the one he sells) and others where the brace bolts to the stud that used to attach the shock.  just wondering if anyone out there has done this and knows which is preferred
thx
allen

[Turin]

This set up looks good to me.

I don't know if there are enough of them out there to get a real comparison/discussion, at least on this forum.

[amamet]

yup, thats the guzzitech one,  I guess some people don't want to put all the stress on the 4 8mm bolts that hold the hub to the swing arm.  the others I've seen have the shock brace trail back to shock stud thats on the hub itself

[pyoungbl]

I'd call Ed Milich and get his opinion.  Ed is an engineer by education and experience.  He also races V7s and has built up a mono shock for his race bikes. 
more info here:  http://guzzipower.com/


At one time Ed and Todd were in business together so I'd expect to see some overlap on products.

Peter Y.

[amamet]

im sure your right Peter.  being that my last engineering class was in '86 id trust his skills over mine.  I guess there really isn't  as much stress being put on the 4 bolts that I seem to think there may be

[Turin]

The pick I posted was the one that Ed sells. Check out here  http://guzzipower.com/store/Frame.html

[Antietam Classic Cycle]

This is for sale in Cornwall, UK. 

[Idontwantapickle]

Since the original swing arm design put the suspension unit attachment on the rear drive unit I would say that the mono shock version that attaches at that point would be preferred. I would be reluctant to test the stress tolerance of the rear drive mount “in the field” given the consequences.
On another note, given the effort of modification why not just go ahead and make it a floater and eliminate the torque reaction?
Hunter

[73eldorado]

This is how I did the conversion, worked well on a very rough racetrack.

[huub]

on a cafe or race bike it probably doesnt matter,
but on a heavily used bike the rear drive casing breaks when overloaded.
happened to my monshocked V65TT a couple of times.
but it was used off road most of the time
even when braced the drive box is a weak spot.

[pete roper]

The CARC box, which uses a reactive arm so the stresses on the mounting bolts/studs would be substantially less, uses 4 X 10mm bolts to attach the box to the swingarm rather than 8mm studs.

Just sayin’......

[Huzo]

This set up looks good to me.

I don't know if there are enough of them out there to get a real comparison/discussion, at least on this forum.

I'll just toss a couple in here.
The points where the brace attaches to the swingarm, should be as close as possible to the pivot axis and rear axle centre.
The one in the shot is a little lacking in that regard, but may have enough redundancy to be ok.
Dunno.
Also, the diagonal braces are surplus to requirement.

[Huzo]

This is how I did the conversion, worked well on a very rough racetrack.

From my point of view, you have it covered Eldorado.
It can be seen that you have placed the front down Tube above the pivot axis and the rearward facing strut close to the axle centre.
Essentially there should be a triangular relationship between the rear axle, top monoshock mount and swingarm pivot axis, your setup reflects this.
Also you're protecting the bevelbox/swingarm Tube joint from bending loads.

[pressureangle]

If I was racing it, I'd support the drive. It adds no difficulty.

[huub]

you can add a lot of stiffness by adding a 8 mm plate , welded to the outside of the swingarm , and bolt it up with rear axle.

[pauldaytona]

For comfort floating is more important. Here a Dynotec.de solution.