Yokomo's Super Offroad SO3.0 is a 1/10 two-wheel-drive electric buggy kit, sold without motor, electronics, pinion, tires or wheels.
Its 80T spur works through a 2.6:1 gearbox, and Yokomo's chart for that spur runs from 11.56:1 with an 18T pinion to 6.93:1 with a 30T. The gear diff takes 5K oil as built. Pick a pinion from that range to suit your motor and track, then enter it in the gearing tool to see the speed it gives.
The kind of vehicle the maker sells it as. It sets what the car is built to do and which cars it is fair to compare it with.
Buggies are low, light off-road cars built for jumps and fast corners on dirt, clay or turf tracks.
Drive
Only one axle is driven, the rear on almost every 2WD RC car.
It is lighter and simpler, and it takes more throttle control on loose ground.
Power
Sold without a motor, so you choose the motor, ESC and battery yourself.
Rows that depend on the motor say so.
Build
A kit you build yourself from parts.
Most kits come without motor, ESC, servo, radio and battery, and many without tires or a painted body.
The manual lists what to add.
Scale
The maker's nominal size compared with a full-size vehicle. It works more as a class label than a measurement.
A 1/10 monster truck is far bigger than a 1/10 touring car, so compare length and weight for real size.
Part number
The maker's product number for this exact version.
A V2, a new color, or a kit instead of an RTR usually has a different number, and parts can differ between them.
Check it against your box or receipt before ordering parts.
Class
Buggy
Drive
2WD
Power
Motor not included
Build
Kit
Scale
1/10
Part number
SOR-030
Drivetrain
Pinion
The small gear on the motor shaft. Fewer teeth gear the car shorter: quicker acceleration, lower top speed and a cooler motor. More teeth do the opposite.
On a chassis sold as kits, each kit brings its own.
Spur
The large gear the pinion drives. A bigger spur with the same pinion gears the car shorter.
Pinion and spur must have the same pitch, or tooth size, to mesh.
Transmission & axle
Every reduction after the spur, multiplied together: transmission, differentials and axle gears.
It is fixed by the design; the gearing you change is the pinion and spur.
This one is worked out from the tooth counts the maker publishes.
Final drive
How many times the motor turns for one turn of the wheels. A higher number is shorter gearing: more acceleration and pulling power, less top speed.
The range comes from the maker's gearing chart for the pinions it lists.
Diff oil, rear
Silicone oil sealed inside the differential. A diff lets the wheels on one axle turn at different speeds in a corner; thicker oil makes it act more like a solid axle.
At the rear, thicker oil puts power down more evenly on loose or slippery ground; thinner oil lets the car rotate more easily through a corner.
It is graded in cSt (centistokes), a measure of thickness that means the same across brands. K means thousands, so 5K is 5,000 cSt.
Pinion
Not applicable
Spur
80TStock
Stock
Transmission & axle
2.60:1Derived
Derived
Final drive
6.93 to 11.56:1 on 30T to 18T pinionsMaker's chart
Maker's chart
Diff oil, rear
5KStock
Stock
Wheels & tires
Tire diameter
The outside diameter of the mounted tire, tread to tread. A taller tire covers more ground each turn, which gears the car taller.
Race tires wear down over a day, and a smaller tire gears the car shorter.
Tire diameter
Not applicable
Power
Motor
Motor KV is the RPM a motor turns per volt with no load.
This vehicle comes without a motor, so there is no stock KV; it depends on the one you fit.
Motor shaft
The diameter of the motor's output shaft, which a pinion's bore must match.
This vehicle comes without a motor, so it depends on the one you fit.
Battery
The highest LiPo cell count the maker rates the electronics for.
This vehicle comes without electronics, so it depends on the ESC and motor you fit.
Motor
Not applicable
Motor shaft
Not applicable
Battery
Not applicable
Performance
Theoretical top speed
It needs a motor KV, and this vehicle comes without a motor. Fit one and the calculator works it out from the motor's KV and the gearing.
Theoretical top speed
Not applicable
How to read these figures
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.
Maker’s chart is the ratios the maker prints for this chassis with the pinions it names.
How these numbers were settled
The manual's gear table for the 80T spur (Z2-SG80SDA) runs from 11.56 with an 18T pinion to 6.93 with a 30T; every cell works out to the same 2.6 after the spur (80/20 x 2.6 = 10.40), so that ratio is derived from the table rather than printed.
The Japanese text says pinions from 18T to 30T fit, the English line says 20T to 30T.
The gear diff is built with #5,000 silicone oil.
Pinion, motor, tires and wheels are bought separately.
Sources
Every figure on this page traces to one of these; where they disagreed, the note above says which was used and why. Links open in a new tab.
