swingarm options?

strengthened (any need for it? in normal highway use but perhaps at heavier weights and with a pax)? or modded stock? shock mounting relocation? lengthened? custom (seen a few racing jobs)? single sided etc?

anyone sell custom swingarms?

seen bits of info here & there but interested in what folks have to say and what all is out there all around

This is one I built for my Production Racer back when I was racing it in the AMA Pro-Twins class. It didn't have the monoshock mount structure shown in this picture back then. I added that later when we used it in a Bonneville streamliner. I used a pair of tapered roller bearings on each side. Probably overkill, but it seemed like a good idea at the time.



You can just barely see it mounted on the PR in this picture.



At the time, I was running fairly wide 18" slicks, but it was also wide enough to accommodate the 17" radial slicks we used on the monoshock Norton racer. This is a picture of the bike at Daytona with the 17" wheels. Using them was a bit of a disaster, because they didn't give enough ground clearance.



I recall a company in England used to make an alloy swingarm for the Commando, but I've forgotten the name.

Ken

Normal sane thrilling fast heavy cargo flinging is not limited by swing arm flex but holding cargo stable till isolastic compression spring backs occur to induce wobble so its only stupid racer traction testing level fling downs to hi side leap backs that can put several times bike and pilot mass focused all on rear patch that swing arm can twist itself and frame up for rebounding upset or if tri-linked like Peel into incredible G forces in pure controlled glee. Factory boxed swingarm are up to sane folks excessive loading. There are a few one off Alu swingarms out there and RGM used to sell a boxed version Peel snagged from now late vender Author. But I fear even it is not up to Peel turn loads so added swash plate half way to shock mounts backed up on re-enforce Zplate mounts. I once tried to follow an ES 850 loaded with camp cargo and heavy set old fart in tight twisties to 60-70 mph spurt ups that tested my SV650 to hang with and noticed how soft aired his rear was so asked, to be told it more comfy ride and sticks better. If you can ride a sloppy swing arm Cdo like that Missouri visitor my respects to be able to use any more stability till tires leaving the surface in turns.

Kenny Dreer version


RGM disconintued version on Peel

3 monoshock variants



The one on the right is the one hobot posted pix of, totally one-off made by Kenny Dreer for the original New Norton 952 prototype

The other two were very similar to each other, built with 2 each standard swingarms, incorporating a rising rate linkage that was a simple lever pivoting on the top swingarm's original pivot point, with the bottom legs of the linkage linked to the tranny cradle centrally with spacers.

Two small tabs welded under the top frame tube just behind the web is the only mod needed on the frame, can't be seen if you want to revert to stock.

Just need to gently persuade the backside of the oil tank to clear the monoshock, also not noticeable at all (if you are gentle).

grandpaul said:

The one on the right is the one hobot posted pix of, totally one-off made by Kenny Dreer for the original New Norton 952 prototype

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Paul, I think you own the "one on the right" that has the swingarm pictured in Hobot's post. It's hard to tell from the angle of the shots, but it looks like the bearings must be carried in the cradle rather than in the forked front end of the swing arm. Can you confirm that? Does it also have an eccentrically mounted/adjustable position pivot by any chance?

nope hobot did not post photos of grandpauls mono which are rather better done than others Ive seen up close. I could hardly find Grandpauls and it wheelied in the auction shed on a demo, SOLD!

hobot said:

nope hobot did not post photos of grandpauls mono which are rather better done than others Ive seen up close. I could hardly find Grandpauls and it wheelied in the auction shed on a demo, SOLD!

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Ok Steve, do you know if the swingarm shown in your pictures has an adjustable pivot?

Kenny Dreer never involved himself in the public forums to explain much and Doug Townsend in Oregon that does know scope of details-history has been lifetime banned here after posting photos of Dreer parts that became the newbie 961. Kenny may talk to ya if can catch him anymore but apparently no adjusting sa pivot point.

Dreer quote on swing arm form this URL http://www.vintagebikeforum.org/index.php?topic=1353.0
one-off prototype box-section monoshock swingarm with big bearing conversion, and modified cradle to accommodate Spyke electric starter,

The photo that hobot posted of the silver box-section swingarm, and big-bearing cradle with e-start mount is the very unit that Kenny sold me when starting up the eventual deal for of all the parts that went into my blue monoshock bike (on the right with the 3).

The clamped lumps are simply machined bodies with an inner thread that the pivot spindle screws into, and those appurtenances are clamped into the swingarm's roots on either side. They have nifty drillings, much to hobot's delight I'm sure (but the drillings are not spaced in common with either of the typical Norton pin spanner spacings for that tool to be of any use in setting them in place).

The swingarm bearings are housed in the cradle's oversize tube, and they are not common to the steering neck bearings as I had hoped. The pivot point is not adjustable on mine, but new lumps could easily be machined, drilled, and tapped offset to accomplish that feature.

I quess noyone race level trained got to try out a mono Cdo to see if more handy or not. My impression is swing arm itself is not the weakness but isolastic rubbers and thin frame tubes are so possible a stiffer swing arm may induce wobble more, similar to better tires over powering frame vintage stability. I can no twist up a good rigid w/o them snapping out from under before useable rebound and regular Cdo twist up too easy and rebound and bound and BOUND, so be careful playing with uncontrolled fire in high winds. Not all the new hot rod cycles are mono shock, a few revert back to dual shocks but some fancy wonder cycles have asymmetric mounted shock single sided swing arm so that should really appeal to those that can not stand a normal Norton warts.