Re: 49 standard 8 touring

Posted by BigKev On 2009/10/19 12:11:13

I would imagine that the hub and drum are riveted together because of the forces in play during braking. The drum is transferring all the sheering and torsional force to the hub, and to the axel via those rivets. The lug bolts hold the tire to the hub, and probably provide another layer of mechanical connection between the drum and the hub. On most two-piece drum/hubs that I have seen if they are not riveted, then the are bolted together, and safety wired.

On more modern style drums, it usually cast as one solid piece which then is held on by the wheel studs and lug nuts.

Perhaps the other reason it has so many connection points (rivets and lug bolts) is because of the thickness (or lack thereof) of the mating surfaces between the hub and the drum.