Boom Racing BRX02 Land Rover Defender 130 HCPU Kit

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. Not applicable means the vehicle does not come with it, like the motor on a roller or the tires on a race kit, or does not have one, like a KV rating on a brushed motor. Not published means it exists but no source we could find prints it.

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. Linked part numbers go to the maker's or official distributor's page for that part.

How these numbers were settled

The kit's parts list includes a 32 pitch 12T steel pinion, and the page says pinions from 9T to 16T fit.

• The spur is the 28T 32 pitch composite gear Boom Racing names in the page's gear ratio section and sells as part BRLC7031.
• The stock tire is the 1.9in MAXGRAPPLER Gekko, printed as 3.82in x 1.26in (97x32mm).
• The axles are BRX90 PHAT units with AR44-style helical gears on a 385mm wheelbase, with a selectable 2WD/4WD transfer case.
• The BCF2 two-speed transmission's internal gearing is not published in text (the manuals are image scans), so the transmission and axle ratio and the final drive are left blank; Boom Racing says only that second gear turns about 2.2 times faster than first.
• It is a kit sold without motor, ESC or battery, so KV and cell count do not apply.

Documents

• ManualInstruction manual, BRX02 D130 chassis kit (PDF) (opens in a new tab)Spur p. 19, pinion and motor p. 41 (PDF p. 20, 42)
• Gearing chartFinal drive ratio chart, BRX02 D130 manual (PDF) (opens in a new tab)Motor step, p. 41 (PDF p. 42)

Sources

• brx02-land-rover-defender-1…boomracing.com (opens in a new tab)
• 28t-internal-spur-gear-32p-…boomracing.com (opens in a new tab)
• 32p-12t-3175mm-steel-pinion…boomracing.com (opens in a new tab)
• Manual (PDF)boomracing.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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