Traxxas Funco Pro Scale Replica

Stock is as the vehicle ships. Calculated is worked from the stock figures on this page rather than stored beside them, so the two cannot drift apart. Derived is worked out from gear tooth counts the maker publishes rather than printed as a ratio; the notes below say how. The top speed is kinematic: an ideal no-load RPM with no slip and no loss under load, so a real car is slower. Speed gearing is the taller set that ships in the box but is not fitted; swapping it in is the owner's job, and the car runs hotter on it. The maker advertises 50 mph, which is their own claim on their own conditions.

Gearing parts

Tooth counts are the ones in the specifications above. Pitch is given as metric module (Mod 1, Mod 0.8) or diametral pitch (32P, 48P). They are different standards and are not interchangeable, even where the numbers look close. Bore is the pinion’s hole, listed separately from the motor shaft (5 mm on the stock motor). Gearing in the box is supplied, not fitted: the fitted set is what the figures and the calculators use. Linked part numbers go to the maker's or official distributor's page for that part.

How these numbers were settled

The product page prints 'Overall Drive Ratio: 16.4:1 (21/50 motor pinion and spur gear)', and Traxxas's X-Series gearing chart marks the 21T pinion on the 50T spur as the included stock gearing.

• The same chart and the manual's gearing table (p. 28) list a 19T pinion for wet sand and a 23T pinion on a 46T spur for high speed as optional gearing included in the box.
• The transmission exploded view shows an 11-tooth gear on the spur shaft driving a 35-tooth gear, then a 15-tooth top gear driving a 32-tooth differential gear through an idler, which works out at 6.79 after the spur and 16.16 overall, within 2% of the printed 16.4.
• The manual's formula, spur divided by pinion times 8.11, is the X-Maxx figure and would give 19.3, which does not fit the tooth counts or the speed table, so it is not used.
• The manual's gearing table gives 50 mph on the stock gears, 45 mph with the 19T pinion and 55 mph with the 23T and 46T set; the stock claim is about 97% of the no-load speed on two 4S packs.
• The rear paddle tire is 7.5 in (191 mm) and the front arrow-pattern tire 6.8 in (173 mm); the rear sets the ground speed on this rear-drive car.
• There is no fraction scale; Traxxas lists it as X-Series.

Documents

• ManualOwner's manual, 109076-4, R03 (Traxxas PDF) (opens in a new tab)Gearing p. 28
• Gearing chartX-Series gearing chart, Pro Scale Sand Car (Traxxas page) (opens in a new tab)109076-4 table
• Parts listParts list, 109076-4 (Traxxas PDF) (opens in a new tab)Spur gears & pinion gears
• Exploded viewExploded view, transmission assembly (Traxxas JPG) (opens in a new tab)

Sources

• funco-pro-scale-replica-109…traxxas.com (opens in a new tab)
• x-series-gearingtraxxas.com (opens in a new tab)
• Manual (PDF)traxxas.com (opens in a new tab)
• Manual (PDF)traxxas.com (opens in a new tab)
• 109076-4_X-Truck%20Funco_TQ…traxxas.com (opens in a new tab)
• 6493x-21-tooth-pinion-gear-…traxxas.com (opens in a new tab)
• 6448r-50-tooth-wide-face-st…traxxas.com (opens in a new tab)
• 6481x-23-tooth-pinion-gear-…traxxas.com (opens in a new tab)
• 6447r-46-tooth-wide-face-st…traxxas.com (opens in a new tab)

Every figure on this page traces to one of these. Where they disagreed, the note above says which was used and why.

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