You are here:
WebshopVespa Smal...TuningHigh End R...Gear Cog 51 teeth, 3rd gear,
 Your Shopping Cart
Your shopping cart is empty.
calculate shipping Live! Shipping Costs Calculation
 Your Notepads
notepad icon  Please login to use the Notepads.
webshop icon All Webshop
Your Scooter
Show only articles for selected scooter.
Most Popular Articles

SIP EuroFlat Banner
prev Pictures may look differentnext

Gear Cog 51 teeth, 3rd gear,

DRT "4-gear PK" for Vespa
50 S 3°/Special V5B3T 3°/V5B4T
2°/SR (D)/100 2°/125 PV 2°
/ET3 2°/PK50/S/SS/XL/2/FL
/PK80-125 S/PK125/ETS/N//XL
Ø 104,5 mm, h 10 mm, mid
section: 4,2mm, "short 3rd

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.


Well coordinated gear ratios helps your motor deliver its power more smoothly and constantly and can be decisive over a win or loss in a racing situation. It is almost an art, to be able to set your gearing up to remain within the power-band every time you change up to another gear. 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 will appreciate the use of the shorter fourth gear cog.


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 cog teeth are straight cut, CNC machined and have had metal removed to lower the overall weight.


Helpful hint: If your motor has enough power to give you the impression you could still change up a gear while travelling at top speed, than you could probably do with a taller 4th gear. If the gap between 3rd and 4th gears seems a little too wide, than a shorter top gear will probably help.


Conclusion: These DRT gear cogs are essential for all serious racers and sprinters. Rally going scooterists have also learnt the benefits of top quality adjustable gear box ratios.


SIP-TIP: If you want to raise the ratio of your gear box start with the primary drive gears.  Never forget to order a new gear selector cruciform (at best the DRT item) and fresh gear box oil.  Last but not least the SIP gear box shaft assembly spacers help you find the ideal output shaft assembly end float for safe and enduring use of your motor.


Depending on your motor type there are the following gear cogs available:

DRT 'PK 4-gears'

Suitable for : VESPA 50 S 3°/Special V5B3T 3°/V5B4T 2°/SR (D)/100 2°/125 PV 2°/ET3 2°/PK50/S/SS/XL/2/FL/PK80-125 S/PK125/ETS/N//XL/XL2.

The 'PK 4-gears' is the most commonly used type of gearbox set up in performance orientated small frame motors. All four-geared small frame models produced since around 1976 are factory equipped with this gearbox type.

The 'ROVIGO' tall 1st gear is renowned for its excellent acceleration qualities, ideal in both sprint and circuit racing, due to its cog ratio being very close to that of the 2nd gear so minimizing the gap between them. The extra tall 1st gear in combination with an even taller 2nd also ensure an ideal gearbox set-up for sprint and circuit racing.

The short 2nd and 3rd gears are excellent especially when used in combination with the DRT input shaft assemblies. (The third gear cog with 51 cog teeth does not work in combination with the DRT SINCRO Replica or Sincro input shafts). If you want to use the third gear with 51 cog teeth the OE PIAGGIO input shaft will have to be used.

The RSP 3rd gear cog with 49 teeth is delivered with a specially modified gear selector spider produced by DRT. This package stands out with its extremely low production tolerances and was designed specifically for high end motors with a cubic capacity of over 140cc and a power output of between 30 and 40 PS. It is ideal in combination with either the OE PIAGGIO input shaft or the high end DRT items coupled with a shorter 3rd gear on the output shaft.

It can be difficult to bridge the gap in ratios between 3rd and 4th gears. In case travelling two-up (with luggage), going up a mountain pass or even overtaking on the motorway is becoming increasingly frustrating, DRT have-in combination with their very own input shaft assemblies- the answer. If the width of your power band does not allow you to bridge the gap between 3rd and 4th gears, then you can consider the use of a shorter 4th gear or the recently produced new input shaft assembly, developed to address this very problem, produced by DRT. The PARMA shortened 4th gear cog can be used in combination with a DRT input shaft assembly. The use of this high end item also enables even finer gearbox ratio tuning possibilities than can be achieved with the OE PIAGGIO items.

OEM Numbers (for the purpose of comparison)  ICs 3° z^z51 163/A ap alternat 4043315 (DRT)

Customers also searched for this article with:  gearcog, Gear wheel

icon explos Spare Parts Catalogue
This article can be found in the following exploded drawings ... go Go to Exploded Drawings!
40431770 $105.18
40431730 $106.10
40431710 $106.10
15011500 $3.33
4043165A $50.74
Our Alternatives
for this item
40434945 $155.92
40431680 $100.57
Customers choice
might interest you...
40431710 $106.10
40431730 $106.10
40431770 $105.18
40431620 $105.18

580g / piece
Stock on hand   Amount

  • facebook
    • Share on Facebook!
  • twitter
    • Send a tweet on Twitter!

Pages(s) 467 to open.
Catalog Preview Page
Product forums
icon scootermodels This product fits the following models
divider Producer/Model divider cc divider Type divider Engine divider Yr. of Const. divider Extra
VESPA 50 S 50 V5SA1T 2T AC `63-`84 69444 ->
VESPA 50 Special 50 V5B3T 2T AC '75-'83 (A) 228069 ->(w/o speed liwith)
VESPA 50 Special 50 V5B3T 2T AC '75-'83 94315 ->
VESPA 50 Special Elestart 50 V5B4T 2T AC '75-'76 1514 ->
VESPA 50 SR / Sprinter 50 V5SS2T 2T AC `71-`79 10380 -> (D)
VESPA 100 (UK) / 100 Sport (US) 100 V9B1T 2T AC `78-`90 50001 ->
VESPA 125 Primavera 125 VMA2T 2T AC `67-`83 0150203 ->
VESPA 125 Primavera ET3 125 VMB1T 2T AC `76-`90 8161 ->
VESPA PK 50 50 V5X1T 2T AC `82-`84
VESPA PK 50 S / Elestart 50 V5X2T 2T AC `82-`84
VESPA PK 50 S Lusso / Elestart 50 V5X2T 2T AC `85-`88
VESPA PK 50 SS / Elestart 50 V5S1T 2T AC `83-`86
VESPA PK 50 XL / Elestart 50 V5X3T 2T AC `85-`90
VESPA PK 50 XL FL 50 V5N1T 2T AC `90-
VESPA PK 50 XL2 / Elestart 50 V5X3T 2T AC `90-
VESPA PK 80 S / Elestart 80 V8X5T 2T AC `82-`86
VESPA PK 80 S Lusso / Elestart 80 V8X5T 2T AC `85-`88
VESPA PK100 S / Elestart 100 V9X1T 2T AC `82-`84 4gear
VESPA PK125 125 VMX1T 2T AC `82-`85
VESPA PK125 ETS / Elestart 125 VMS1T 2T AC `84-`85
VESPA PK125 N NUOVO (FL) 125 VMX7T 2T AC `90-`91
VESPA PK125 S / Elestart 125 VMX5T 2T AC `82-`84
VESPA PK125 XL / Elestart 125 VMX6T 2T AC `86-`90
VESPA PK125 XL2 125 VMX6T 2T AC `90-

Legend: Quantity In Stock

This article is in stock and ready to be shipped immediately. Our warehouse is fully stocked.
This article is in stock. This item is in stock in sufficient quantity.
This article will soon be sold out. This item will be sold out soon.
This item is ordered by us especially for you. Deliverytime might take more than 3 weeks. You cannot cancel this order any more. This item needs to be ordered especially for you. The expected delivery time is about 3 weeks.
This article is currently not available but will be back in stock soon. This item is currently not available but will be back in stock soon.
This article is currently not available. This item is currently not available. You can order it nevertheless. The expected delivery time is about 3 weeks.