The rear hub nut needs a lot of torque (120lb or 162Nm) Somehow over the years I’ve got by, but with a lot of stretching required. There’s a couple of ways to hold the hub still while you tighten the hub to its correct torque.
Jamming a brick against the back wheel and getting someone to sit on the Lambretta is one way. A foot on the brake pedal is another.
To make things easier, there’s been some tools made available. Welding a couple of bars to a wheel rim has been done by some.
JB Fabrication has made a rear hub holder that does the job. Small and compact and for me a welcome addition to my tool collection.
You can purchase the Hub Holder from JB Fabrications Facebook page here.