Mini 4WD gear ratios

 

Gear ratios in Mini 4WD are pretty easy to get your head around. It basically comes down to the smaller the number, such as 3.5:1, the higher the top speed. The higher the number, for example 4:1, the faster the acceleration.

The number 3.5 is the number of times the motor has to turn, for one revolution of the wheel.

 
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Where this gets complicated is how you combine this with your motor and tyre diameter choices. The general rule of thumb with gear ratios is to pair larger tyres with lower gear ratios, like 4:1. This will take strain off of the motor and batteries, allow the car to accelerate quickly and have a high top speed. In fact if you look at the roll out, the distance the car travels per revolution of the motor, this combination is slightly higher than 3.5:1 with low profile/medium size tyres. This is why on high speed setups you often see large and enlarged tyres on the machines.

Reducing your gear ratio when racing can also help you if you are struggling to clear some obstacles, like the lane changer or dragon back. It would mean there is less speed for the brakes to lose before the obstacle, but faster acceleration for the machines recovery after the obstacle.

For cars based on the AR, FM-A, Super-II and other prop shaft based cars, there are excellent gear sets available, that give you the full range of gear ratios for the chassis, re-enforced pinions and crown gears, a light weight prop shaft, low friction counter gear shaft and counter gear bearing.

  • #15456 JR Setting Gear Set (AR)  - also compatible with VS, Super-II, Super TZ, and Super TZ-X

  • 15516 FM-A Chassis Setting Gear Set - also compatible with Super-X and Super-XX

 
 

These are great value at around £10 for having a full range of ratios available, plus some enhancements to the transmission.

For MS and MA these sets are not available, instead you have to buy each ratio separately.

  • #15355 - JR PRO High Speed Gear Set - MS Chassis/Gear Ratio 4:1

  • #15429 - JR High Speed EX Gear Set - MS Chassis/Gear Ratio 3.7:1

  • #15349 - Super Speed Gear 3.5:1 ratio (MS Chassis)

 
 

At around £5 per set we recommend looking for a base car with a 3.5:1 gear ratio for a technical build, then buy 3.7:1 as an option. In most cases you will probably only ever use 4:1 with large diameter tyres on a speed focused build.

 
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