DISTANCE PIECE BGM PRO rear upper shock absorber for Vespa Smallframe / Largeframe
The spacer sits between the silent rubber on the frame and the rear shock absorber on the engine. It is an important and highly stressed link between the engine and frame. Good quality is an absolute prerequisite here, which is why BGM PRO now has its own high-quality series.
Five different spacer lengths are available from BGM PRO. These can be installed as required.
Here is a short list of which length was used ex works on which models, among others.
BGM7626 (26mm): 1962-1979 - Rally, Sprint, VLA (GL), GT, GTR, TS, SS180
BGM7635 (35mm): BGM special size as intermediate measurement
BGM7643 (43mm): 1958-1979 - VBA, VGLA/B (GL), VBB1, VNB4 (114714-), VNB5-6, VBB2 (172370-212360), GS160 (32158-), Super 125/150 (VNC/VBC)
BGM7648 (48mm): 1985- 1998 - PX Lusso
BGM7652 (52mm): 1977-1985 - PX old, PX Lusso
BUILDING BOX
With the first largeframe models (VNA, 1957), Piaggio began to further develop the modular principle. Many identical parts, such as the rear shock absorber, were intended to create a greater variety of models while at the same time reducing costs. The rear shock absorber was therefore only changed minimally over a period of almost 60 years. From 1957 to 1962, it was still produced with a length of 390 mm, then with a length of 330 mm. The shortening was necessary for the newly planned smallframe models. These were also to be equipped with the same shock absorber, despite the considerably smaller chassis. In order to be able to continue using the now quite short shock absorber in the larger vehicles, spacers were required to compensate for the overall height. This allowed Piaggio to easily achieve the required length without having to design a new shock absorber. In the smallframe models, on the other hand, it was simply used without a spacer.
LENGTH AND EFFECT
Ride height at the rear
Ground clearance between exhaust and road
Ride geometry (caster of the front fork)
Difference in height between tank and carburettor
Distance between carburettor/carburettor sump cover and frame
The height of the rear of the vehicle can be varied as required using the spacer. This is often necessary if large carburetors or large resonance exhaust systems are to be used in an oldie. It should be noted that raising the rear end can also have a strong influence on handling. The higher the rear end is raised compared to the standard position, the more nervous/twisty the handling becomes. Conversely, the scooter is more stable when the rear is lower (a keyword for further research is the so-called 'caster' on the front axle). Incidentally, in some models no spacer was used at all. This is the case, for example, with all Smallframe or PX models from 1998 onwards (here again a shock absorber with 390mm was used). Occasionally, this may also be necessary for retrofit shock absorbers that are longer than the standard counterpart.
Examples of the use of a longer distance piece
The rear of the frame is higher
The exhaust is further away from the road
The exhaust is closer to the chassis
The caster of the front wheel becomes less
The steering becomes more nervous/turny
The differential pressure between the fuel level and the carburettor is greater
Installation instructions
A common feature of all spacers is the M9 thread and the wrench size 14. An M9 spring washer is fitted between the spacer and the shock absorber.
The spacer itself is screwed directly into the upper silent block in the chassis without the spring washer.
Conclusion: Small component with an important effect on driving safety!
