VehiclesHobao Hyper MTX

Hobao Hyper MTX

1/8 scale · monster truck · HB-MTXE

Final drive: 21.75:1
Tire: 182mm

Open in Top Speedsourced

Specifications

Last modified Sep 25, 2026

Spec	Value	Basis
Drivetrain
Pinion	15TStock	Stock
Spur	45TStock	Stock
Transmission & axle	7.25:1Derived	Derived
Spur ÷ pinion	3.000:1Calculated	Calculated
Final drive	21.75:1Stock	Stock
Wheels & tires
Tire diameter	182mmStock	Stock
Rollout	26.3mm per motor turnCalculated	Calculated
Wheel hex	17 mmStock	Stock
Power
Motor	Not applicable
Motor shaft	Not applicable
Battery	Not applicable
Performance
Theoretical top speed	Not applicable
Chassis
Weight	6.4 kg (14.1 lb)Stock	Stock
Length	635 mm25 inStock	Stock
Width	495 mm19.5 inStock	Stock
Height	290 mm11.4 inStock	Stock
Wheelbase	396 mm15.6 inStock	Stock
Diff oil, front	5KStock	Stock
Diff oil, center	7KStock	Stock
Diff oil, rear	5KStock	Stock
Vehicle
Part number	HB-MTXE
Scale	1/8
Class	Monster truck

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.

Gearing parts

Pinion and spur parts for the Hobao Hyper MTX: fitted, and optional gearing supplied in the box
Component	Teeth	Pitch	Bore	Part number
Fitted at the factory
Pinion	15T	Mod 1	5 mm	89325 (opens in a new tab)
Spur	45T	Mod 1	Not applicable	94089 (opens in a new tab)

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

Hobao's page lists a 15T motor gear, a 36T spur and 9T/29T differential gears, but the 36T gear sits on the center differential and is not the gear the pinion drives.

The manual (steps 39 to 44) and its parts list show the 15T motor gear (89325) driving a 45T spur (94089) on a gear axle, whose 16T gear (94088) turns the 36T center differential gear (94091N).
The front and rear differentials use a 29T crown gear and a 9T pinion (94001N, 94002N).
That makes the ratio after the spur 7.25:1 (36/16 x 29/9) and the total 21.75:1, worked out from the tooth counts, since Hobao prints no ratio.
Hobao's tire drawing gives the tire as 182mm tall and 98mm wide.
The ARR comes without motor, speed control, servo or radio.
Hobao's page and its distributors list the 15T motor gear with the ARR, and the exploded view marks only the motor and speed control as optional.
The manual fills the front and rear differentials with 5000 silicone oil and the center differential with 7000.
The shock oil is marked 500 with no unit, so it is left blank.
Hobao's dimension drawing gives 6400g without saying how the truck is equipped.
The RTR version (HB-MTXE-C150BU) adds a 2000KV motor and a 150A speed control.

Documents

ManualHyper MTX instruction manual (Hobao USA PDF) (opens in a new tab)Center gearbox and motor steps 39-44, pp. 15-17
Exploded viewHyper MTX exploded view (Hobao USA PDF) (opens in a new tab)
Parts listParts list, in the Hyper MTX manual (Hobao USA PDF) (opens in a new tab)pp. 23-26

Sources

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