Gear Selector DRT, “4-gear”

h 51 mm
hardened
type: square/51mm
4-arms
Product description
The gear selector spiders, for small frame motors, made by DRT are produced using a harder grade of steel than the original items, hardened and sealed for a tough surface finish and are precisely manufactured to ensure minimal production tolerances. They can withstand larger amounts of power and torque making them ideal for performance orientated motor setups. We have two versions of this item available for 4 small frame motors with a 4-speed gear box, one with an overall diameter of 51mm and the other with a 50,2mm diameter. DRT makes no difference between and a squared off and rounded ends. A more exclusive gimmick originating from the Italian racing scene is the ‘PK STRETTA’ variation of the gear selector spider. These items are modified by DRT to eliminate radial play. This reduces gear jumping due to selection problems and also makes the gear changing mechanism more precise in use. If the outer arms are shortened just slightly this item can also be used on the earlier PV/ET3 motors.
Conclusion:
High end gear box components for performance orientated small frame motor tuning projects. -TIP : The thing that really counts during the assembly of the small frame motors output shaft is to measure precisely and adjust correspondingly the end float after the cogs have been (correctly)arranged in place on the gear cluster. Do not forget to order fresh gearbox oil for successful completion of this conversion. The suitable output shaft assembly tool (Art. No. : 63791000) makes this job a whole lot easier and quicker.
SIP community user
chup4
on Art.-No. 4043175:

The serrated edge that keeps the ball bearings in place are noticeably more defined, which prevents gear jumping effectively combined with a stronger gear selection spring and a well distanced gear box it really proves its worth when measured against the original system. Goodbye jumping gears.

ESC rider Salvatore Randazzo on Art.-No. 4043175:

The less play between the gears, the better the gear box. I’ve already set mine up successfully. Two spring races and one fall race, no jumping gears and we didn’t even use the clutch to change gear.
Differentiation of 4-speed Vespa Smallframe gear selectors. For the 4-speed engines of the Vespa Smallframe models, there are two different gear selectors that fit different gearboxes or their gearwheels. There are two characteristics that distinguish the two types of gear selectors. 1. the shape of the transition to the upper end of the selecor. The later “PK type” has a radius there, i.e. round. The earlier “V50/PV type” is angular at this point. 2. the overall height of the gear selector. The “PK type” is 50.2mm high, the “V50/PV type” is 51mm high. Today there is a whole range of manufacturers who produce gear selectors for tuning and racing purposes. Unfortunately, some suppliers no longer adhere to the classic distinguishing features. DRT, for example, no longer produces the round gear selector and CRIMAZ, for example, produces the 50.2mm gear selector in 48.8mm. Therefore, we have decided to indicate either “type round/50.2mm” or “type square/51mm” for each 4-speed smallframe gear selectors.
OEM numbers (for comparisons):
111589 (PIAGGIO)
8000000023506 – a02350 (previous: CRS 4m 51mm k175 (DRT)