Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Mono Swing Arm - Yes Please!

Just pootling around t'internet and came across this on the Garage 56 facebook page.



The notes say:
A mono swing arm, to allow quick wheel changes. Not to mention a new spring/damper (twice the rate), and possibly a revised left hand fuel tank, if we need a fat section arm (which this is). The arm needs to sneak between the pulley and the rim, really...

Not sure if this is something they are actively developing or just a bit of blue-sky doodling...

I'd certainly be interested. Seems daft to incur several hours of workshop labour just to remove the back wheel.

Not sure how belt tension would be adjusted though...

Simple jockey pulley fixed to the new swing arm , with screw adjustment would make belt tentioning a doddle.

Yes, I guess it doesn't need to be complicated.
Simple belt tensioner

Just use an eccentric hub like most single side swingarm bikes use. Does change the ride height a bit as you adjust tension but not a great problem unless you change gearing a lot as well. Think you'd have to brace up the single shock top mounting point to take the additional loadings into the chassis. Could probably use a bike rear disk assembly but a handbrake would take some organising. Don't think I'd want the extra grip at the back that a fatter tyre would give.
Got a feeling that if they were to go ahead with it the price would be seriously painful; brace up the chassis, the new shock, new swingarm, new hub and brake assembly plus new rear wheel to suit then a new left fuel tank to accommodate the larger box section of the arm. Could pay for a lot of workshop hours!
Worst of all, all that beautifully done engineering would be completely hidden unlike doing a conversion on a bike where it is primarily a cosmetic exercise!

I would like

Not my images: The swing arm from a Polaris Slingshot. Also not my kind of 3 wheeler regardless of any engineering advantages. Looks like the fetal love child of a old Saab and a transformer.

I agree 100% about the styling but that Slingshot swingarm looks the business. Proper engineering. And we shouldn't forget that you can buy a whole Slingshot for $20,000!

Nice idea, but subject to high stresses and strains. Perhaps they'll test it to find out if it works before selling it...??

You are quite right, BunnyBoy, the back end was a poor design and when the new improved model comes along let's hope for some changes.
As you suggest, a rear mono swing-arm (used by BSA three-wheelers in 1929, albeit with a fraction of the stress), a duplex chain in an oil-bath case to replace the belt drive and a brake on the bevel-box, opposite end to the sprocket, instead of the rear wheel to reduce unsprung weight would be my on my list.