Posted 12/11/2004 2:57 AM (#5615) Subject: Mounting a Duna sidecar to a Moto Guzzi Breva
This project has produced many questions that need answering in order to proceed. The following has been posted to Moto Guzzi lists
but as the mating of the two units includes a sidecar . . . Help:
I have embarked upon an odessy of fitting a small light sidecar to a Breva. It should fit nicely.
But odd problems present themselves with each turn in the journey.
First I obtained a V50 II for the project but the restoration on the sidecar (a '50's Duna hack) was so nice
and the V50 so rough and in need of multiple major cleanups and repairs that being offered a Breva for less
than the cost of the fixups on the V50 seemed the way to go. Then the project got interesting.
The following are excerpts from posts placed elsewhere that detail my needs in proceeding with the project.:
1. I started looking for 17" flat profile treaded tires to improve traction, braking and tire life and have
had little luck so far.
I have gotten questions about why I would want to do this in the first place. "Those tires will quickly
wear flat on the bottom anyhow so why bother?" sums up that point of view. Seems to me that "wearing flat"
wastes tire rubber quickly and leaves one in a less safe condition until accomplished.
As I understand it, on a sidecar rig the stresses on the tire are more "automotive" in nature. That is, the
vertical pressure is augmented by significant lateral force on turns and not significantly increased in
turns as is a 2 wheel motorcycle usage.
I am running automotive tires on my Moto Guzzi V11 EV/ EZS RX5 combo. As I understand it motorcycle radials
also give little lateral stiffnes. Automotive tires are built to deal with it.
Also, a tire having a flat tread has a larger contact patch at any time for greater braking capability.
Anyone have any thoughts on the above and sources for 17" flat tread tires?
2. Another alternative would be using the 18" wheels from the V50 and the Metzler Block K tires that are
mounted on them now. Would the hub of the rear wheel work with the final drive of the Breva?
3. Could the hub of the Breva or one from the spoked wheel of a Nevada be used to build a custom 15" wheel
with an automotive rim to run automotive tires as I do on my EV/EZS rig now.
4. The bike is a 400 lb. standard and has one 320mm Brembo disk on the front and a single 260mm disk on the
rear. I am trying to decide what if any additions, like an additional front disk would be advisable.
I am having a leading link fork built for it and now would be the time to provide the mounting points and
hardware for a second disk.
I know that adding another disk would probably require a new master cylinder to handle the additonal fluid
It would also mean changing the front wheel out for one that could accept twin rotors. The stock Breva wheel
is only set up for one disk.
Would the V50 front wheel accept modern Brembo rotors?
There are no provisions on the sidecar for brakes but due to its light weight it doesn't seem to be an issue.
Any thoughts or suggestions?
Thom Irwin - Los Angeles
Ursa Da Grizz - '98 EV / EZS RX5 Sidecar
Abreviator - '04 Breva w/MGC custom aluminum bodywork
Traveler - '03 Stone / Aluminum - highway cruiser
Li'l Sparky - JZR(Morgan kit car replica 3 wheeler) / '81 G5 V1000
Scooter - '04 Breva / Duna sidecar