4th gear Long 35 teeth BGM PRO For Vespa PX PE (-1984) PX

The BGM Pro gear parts are made of ultra-solid material. For the highest stresses, the gear wheels are made of high-alloy NiCrMo case-hardening steel (20NiCrMo2-2/ AISI8620).

The excellent base material withstands even the highest engine power. The precisely defined surface hardening to 58-60HRC makes the sprockets extremely wear-resistant. Better than Piaggio goods. Always high quality. No compromises.

BETTER

Suitable for all types of use, both for tourers and racers.

With 36 teeth, one tooth less than the original 4-gear wheel of a PX200.

The connection to fourth gear is significantly improved.

FIT

Suitable for all gearboxes with a cranked shift cross. These gearboxes can be recognized by the main shaft which has a circlip in front of and behind the gear wheels. The central segment, on which the shift cross rests, is not visible on

Old PX (until 1984, crank gear): 5mm

Luxury (since 1984, flat shift cross): 6.5 mm

The central segment of the BGM gear wheels is larger (approx. 1/10mm) and therefore offers even more contact surface for the gear cross.

TIP: Ideally combined with the 64-tooth BGM Pro primary gear with longer reduction. The overall gear ratio becomes significantly longer in combination with a 24T clutch pinion, but the gear step from three to four is shorter. This means that the full power of the engine can be converted into top speed.

NOTE: The fourth gear with 36 teeth was developed by Piaggio for the 125cc models. It was built from a so-called tooth flank gearbox of the 4-speed 150/180/200cc models with 35 teeth. This technique made it possible to keep the auxiliary shaft splines identical on all models. However, a disadvantage of the 36-tooth gear is the narrower tooth base. This results when more teeth have to be accommodated on a given diameter. The narrower gear base is obviously not as stable as the 35-tooth gear, which is why Piaggio only used it in the 125cc models.

The short 36 Z gear, however, is very popular with 200cc engines with improved performance. With very sporty engine designs, the jump from gear 3 to gear 4 is too big and the engine no longer enters its power band. With today's very high torque concepts (such as Malossi Sport/MHR or Quattrini M244), this tuning trick from the 90s is still often used.

We strongly recommend using a 4-speed with 35 teeth. High Engine torque combined with a load peak (skipped gear, shifted gear, etc.) can otherwise damage a 36-tooth gear. If you still need a shorter gear step, you should achieve this by using another auxiliary shaft with fewer teeth (e.g. BGM6505 or BGM6506).