SIP complete tapered steering bearing race kit, Lambretta: without chrome ring
Modern bearing technology for vintage Lambretta steering columns.
The steering head bearings are an important set of components which ensure the stability of the front suspension and riding safety. If the steering on any scooter shows signs of directional instability or becomes kind of vague, then this is usually caused by defective or worn steering head bearings.
Safe and stable steering
More precise steering
Extended service period
The standard bearing configuration found on vintage Lambretta scooters is not exactly state-of-the-art. Unfortunately, adequate replacements are also hard to find these days. Often the upper and lower bearings are badly matched, which results in the forks becoming loose or resistant to steering input. These items are also produced using inferior materials or are badly produced. This results in their rapid failure and all too often must then be replaced.
The solution from SIP:
Nowadays motorcycle manufacturers use tapered roller bearings for the front suspension. This type of steering head bearing can withstand much greater forces and allow a freer operation of the steering when under load. They are capable of holding the forks or steering column more solidly and are also automatically centered during assembly due to their conical construction. As a result of these advantages they provide a noticeably improved steering and also have a provide a longer service interval. A small specialist firm from Bavaria in Germany called V2 Edelstahl have taken on this issue and found an ideal solution to use this type of bearing on vintage Vespa models! We got in touch with V2 Edelstahl and are now also able to offer this practical update for Lambretta models!
The lower bearing:
The 32908 rated tapered roller bearing provides the basis for this upgrade. Its inner ring fits the Lambretta forks exactly and the upper bearing cup is replaced by a specially conceived type made from tough EC80 steel alloy for the Lambretta frame. To keep the bearing compact, it is not provided with a shoulder to keep it in position. Instead it must be fixed a thread-lock or center-punch. This is also treated to protect against wear and corrosion. Their outer diameter and form is identical to the types found on the original scooter models. A gasket ring with a rubber lip is also fitted to prevent dirt and moisture contaminating the bearing assembly. It is only 2.5mm taller than the original bearing.
Warning: Remember to put the narrow dust cover on the fork under the bearing. Unlike the original, it is not clamped by the bearing on the fork. From the outside it encloses the lower / inner bearing shell.
The upper bearing:
A tapered roller bearing was purposely avoided to fix the top of the steering assembly/forks due to their larger dimensions being impossible in this position. This solution however also brings some welcome improvements over the original type. The bearing itself is an encapsulated inclined ball-bearing which is fully capable of accepting the forces involved while remaining very durable. It is held in position by the original fixing nut, guaranteeing an optimal operation of the steering column or forks. The fixing nut can be held in place with thread-locking liquid and/or a lock washer. This leaves it with a slightly smaller height of 20mm, rather than the ORIGINAL versions 21.5mm. The total height of the assembly can be then adjusted using nuts, washers and spacers from the standard set up.
Conclusion: An essential upgrade for all outdated steering head bearings!
The Best Set Up – Our SIP – TIP:
The right grease (#M7615375B) is necessary for the correct fitting of the lower bearing.
The upper bearing is ideally adjusted/tightened using the correct tool (#BU5420).
Lower bearing mounting tool (#16029000).