Kyosho Ultima RB6.6 Readyset

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. 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.

In our catalog, half of 1/10 buggies run between 10.3:1 and 11.5:1 on stock gearing; this one is 8.2:1. What's a normal final drive for your RC?

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.

Buying a new pinion or spur? Check what’s fitted first: Why your RC's gear specs might not add up

How these numbers were settled

The ready-to-run 2WD Ultima RB6.6 from 2017, with a brushed 15-turn G15 motor.

• Kyosho's Technical Data gives 'Gear Ratio 8.23:1' and 'Tires (F/R) φ84×28mm / φ86×43mm'; the rear tire is shown here, as the rear wheels are driven.
• The spare parts list names LA206-76 'Spur Gear (48P-76T)(ZX-5)' and UM324C 'Steel Pinion Gear (24T) 1/48 Pitch'.
• The ratio after the spur works out at 8.23 x 24 / 76 = 2.60.
• The product description says 8.45:1, which is what the optional 78T spur (LA206-78) gives with the 24T pinion; the Technical Data and the stock parts agree on 8.23.
• The G15 is a brushed motor, so there is no KV rating.
• Kyosho lists a 7.2 to 7.4V Ni-MH, Ni-Cd or Li-Po battery for the car, which is a 2S LiPo at most; the ORION 45A brushed ESC has no published cell rating of its own.
• The manual asks for a battery with a Super (Deans) plug.

Documents

• ManualInstruction manual, Ultima RB6.6 readyset (Kyosho PDF) (opens in a new tab)Battery p. 7
• Exploded viewExploded view, Ultima RB6.6 readyset (Kyosho PDF) (opens in a new tab)
• Parts listSpare and option parts list, Ultima RB6.6 readyset (Kyosho PDF) (opens in a new tab)

Sources

• 34310rc.kyosho.com (opens in a new tab)
• Manual (PDF)kyosho.com (opens in a new tab)
• 1rc.kyosho.com (opens in a new tab)
• Manual (PDF)kyosho.com (opens in a new tab)
• um324crc.kyosho.com (opens in a new tab)
• 70705rc.kyosho.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.

More from Kyosho

• Turbo Optima Mid Special
• Ultima
• Ultima Pro
• Ultima RB6.6 Kit
• Ultima RB7
• Ultima RB7.5
• Ultima RB7SS
• Ultima SB Dirt Master