Gear Cog 37 teeth, 4th gear,

Denis Innocente has been actively involved in the VESPA racing scene for over 20 years. The finest tuning items are made in small production runs and the precision just like the quality are high end. DRT stands for the Denis Racing Team and is a guarantee for race proven gear box components, based on experiences collected in Rally Sport. The racers and mechanics on the Italian sprinting scene swear by the DRT products and these high end gearbox parts are also included in the racing scooters of the SIP-STOFFI racing team.

The gear cogs are made of a tougher grade of steel and then hardened. This makes them especially suited to the more hard working environment of a performance orientated motor and also noticeably more durable. The cogs have had metal removed in certain places to reduce overall weight and are precisely manufactured and finished. They are available in larger and smaller versions than the OE PIAGGIO items so providing optimal supplementary variations to the already existing range of output shaft gear cog sizes. The gear boxes can then be much more finely tuned, providing the perfect gear ratios for every motor.

The longer first, second and third gears work well in tuned 166-177cc/ 208-120cc motor setups in combination with the standard size fourth gear and original primary driven/ clutch cog gears. For successful use of the taller fourth gear cogs that are available a stronger motor or a shorter primary driven/ clutch cog gear ratio is necessary. For the use of an even taller fourth gear to be effective, they are often included in the more torque orientated motor setups that include the POLOSSI cylinder kit for example. If you have ever been happily accelerating behind a truck on the motorway just to lose all of your power while attempting to overtake due to the extra wind resistance you will appreciate the use of the shorter fourth gear cog. DRT have even gone one shorter than was possible up till now with a fourth gear cog that has just 37 teeth. This one comes in an even better steel which is robust and flexible at the same time.

Conclusion: If you are into sprint and/ or circuit racing on VESPAs there is no logical way around these conversion output shaft gear cogs. Even longer distance touring riders have quickly learned the benefits of an improved transmission ratio setup.

SIP-TIP: Do not forget to order a new cruciform, selector rod and fresh gear box oil when replacing the gear cogs on your output shaft. The SIP spacers allow elimination of any unnecessarily large end float clearances.

SIP man Robert, Kissing, 07.11.2011: “I've put the DRT 1st, 2nd and 3rd gears into my powerful 210cc motor. I can accelerate up to about 120km/h in 3rd. I've still got the original 4th gear cog in there at the moment but seeing as the engine has a sufficient amount of power this item will soon be upgraded...”

gearwheel (secondary transmission) PX/ T5:

art.-no.: 40432900, 4th gear DRT PX/PX Lusso/ T5 Z 37

art.-no.:  22322900, 4th gear  PIAGGIO, PX Lusso/ T5 Z 36

art.-no.:  88120000, 4th gear  PIAGGIO PX Lusso/ T5 Z 35 (standard)

art.-no.: 40432900, 4th gear  DRT PX/PX Lusso/ T5 Z 37

art.-no.:  17812400, 4th gear  PIAGGIO PX -`84 Z 36

art.-no.:  15280700, 4th gear PIAGGIO PX -`84 Z 35 (standard)

following gear transmission ratios are possible for Vespa 177cc - 220cc:

? (2,62) 24-63 MALOSSI 4th gearZ36 > very long

? (2,78) 23-64 POLINI 4th gear Z36 > long

? (2,62) 24-63 MALOSSI 4th gear Z37 DRT

? (2,82) 23-65 4th gear Z36 > long

? (2,78) 23-64 POLINI 4th gear Z37 DRT

? (2,82) 23-65 4th gear Z37 DRT > perfect

? (3,04) 22-67 4th gear Z35

? (3,09) 22-68 4th gear Z35

? (3,04) 22-67 4th gear Z36 > short