Frame and Body
Vespa Small Frame Front Hub
Small Frame Front Hub & Forks Rebuild
This front hub is from my auto project and shows a small frame front end from a mid 70s to 80s bike. The earlier small frames had an integral hub and axle, but the newer type (like this one) have a removable front hub and separate axle. I started by taking the entire front end apart and then blasted the parts and had them painted. This page shows the reassembly including bearings, speedo drive, and front shock.
The axle on the small frame fork actually rotates inside the hub. From left to right in the shot above is the axle with one bearing fitted on the spline side, the retaining ring, the second axle bearing, and the axle nut with speedo drive.
Take the free bearing and place it in the hub from the brake shoe side. Support the hub on a block of wood and use a socket or suitable sized pipe and a hammer to drive the bearing in to the hub.
It should go all the way in beyond the threaded area inside the hub.
Then fit the retaining ring. This has two cut outs in the side to aid in tightening it. I used a metal bar with the same diameter of the hole with a pair of vice grips on it to tighten it up successfully.
Grease up the bearing well before the next step of fitting the axle.
Grease up the bearing on the axle and fit it in to the hub. Mine went in pretty easily but you may find you need to tap it in with a rubber hammer. If you use a normal hammer make sure to use a piece of wood between the axle and the hammer to protect the axle nut threads.
Once the axle is in, fit the circlip to hold everything in place.
Flip the hub over to the other side and grease and fit the axle nut with the integral speedo drive gear. Tighten this down with a socket. You can temporarily fit the front rotating hub on the axle end to allow you to get the nut tight.
Grease and fit the speedo drive...
..followed by the cover blank which can be tightened with a large flathead screwdriver. Note the small fiber gasket around the rim of the cover plate. Also fit the snap in plastic cover plate over the end of the axle.
Grease up the brake arm and push it through the hole in the hub.
Make sure the cable connector is on the same side as where the cable will run before fitting the brake shoes.
I always find it easier to fit the brake shoes as one item with the spring in place. Before fitting these fit the metal end tabs over the shoe ends and grease them lightly. To put the brake shoes in place, place one shoe over the end pivot and the other against the brake cam. Then take the other shoe and fit the end loosely to the pivot and use a screwdriver to lever it over the brake cam until it drops in to place. This may take some practice.
Lastly (and very importantly) fit the circlip over the end pivot to hold the shoes in place.
Now we can move on to the front shock. Above are the parts to the front shock. It also has a plastic piece which covers the spring itself, but I prefer the look without this piece so I left it out. The oil damper inside the shock was also left alone because it was working well.
The first step is to fit the spring. As far as I can tell there is no specific up or down to the spring.
Take the top cap and fit the large rubber bung inside it. This gives some protection if you ever bottom out the shock on the road.
Using a small flathead screwdriver, insert it in to the top of the damper shaft to stop it rotating while using a wrench to turn the cap down on the shaft. You'll need about 3/4 of an inch of thread showing to instal the shock in the forks.
Place the first larger rubber ring around the top of the fork.
Place the threaded part of the damper shaft through the shock mount and follow it with the second large rubber ring.
And finally place the large washer, lock washer, and nut on the end of the threaded rod and tighten it down. While tightening make sure the base of the shock has the hole through it in the same direction as the fork pivot hole. If the damper shaft rotates use the flathead screwdriver in the slot as before.
Moving back to the forks, fit the small needle rollers to each side of the main pivot point. Use grease to hold these in place. Also (not shown in this image) now is a good time to fit the grease nipple in the hole underneath the pivot if it has been removed.
On the hub side of the forks, fit the single O-ring and hold it in place with a dab of grease.
Carefully slide the shock and fork pivot pins their holes making sure no needle bearings drop out. This picture was taken before the brake shoe work but the idea is the same.
Fit another O-ring on the fork pivot....
...followed by the pivot link spanning between the two pins. On each pin, use a washer, lock washer and nut and tighten them down securely. The final step to the forks is to snap on the fork link cover.