Choosing a box stock racer
Choosing a box stock Mini 4WD for racing can be a bit of a minefield as there are several factors to consider when choosing your car.
The main rule of the class is to only use parts that are included in the kit. It’s worth noting that very special kits like the Super-XX Evo, VS Evo 1, MS Evo 1, Zenquish, Azente & the fantastic starter packs are not eligible for entry in box stock races. These kits often include a mix of option parts such as FRP or carbon plates, aluminium bearing rollers & tuned motors.
The layout of the circuit will also play a key part in choosing your box stock racer, and will influence which of the parts you choose a kit for.
The main considerations are chassis layout, wheel & tyre diameter, gear ratio, tyre compound & body type.
Chassis layout
One of the most important things in choosing your car will be which chassis layout to use, the layout of the track will mainly determine the best layout to go for, but currently here in the UK sticking to the more modern chassis like AR, MA & FM-A are a pretty safe bet. However, the very lightweight high performing VS chassis is a very good choice when it comes to high speed circuits.
Modern AR, MA & FM-A chassis are a good start.
AR chassis
The AR chassis is well suited to a more spread out circuit with less jumps as the nose of the car tends to have a steep upward angle on takeoff causing it to mostly land on it’s rear wheels, with the front end increasing the risk of a course out.
MA chassis
The MA chassis is more balanced as most of the weight is in the centre of the chassis, it also tends to have more torque due to it’s dual shaft motor. This makes the chassis a good choice for circuits with more corners.
In our experience MA chassis is a solid choice, but does seem to have more freak course outs than the other chassis we have tested.
FM-A
The FM-A is my personal favourite for box stock, though currently the choices of kits are limited.
The front mounted motor puts most of weight just behind the front wheels, making it incredibly stable on lane changes and jumps.
So far in our race meetings I’m yet to have a course out, however, the FM-A does seem to lack the speed of the AR & the torque of the MA.
Gear ratio, wheel & tyre diameter
Most modern kits only come with 1 set of gear for 1 ratio. This is usually 3.5:1 for low profile wheels & tyres or 4:1 for large diameter, these configurations offer reasonably comparable performance.
Aero Avante Black Special AR chassis (95376) has been dominating box stock at DXN races in California, but is getting harder to find.
The 26mm diameter on the low profile tyres with the 3.5:1 ratio gives them the edge on acceleration as there is less rotating mass & the rollout (distance covered by each rotation of the motor) of the transmission is lower.
The large diameter 30mm wheels & tyres, with the 4:1 gear ratio lack a little acceleration due to the extra weight, but the higher rollout gives it the edge on top-end speed. The high arch tyres often included in kits reduces the contact patch of the tyre on the track lowering friction & increasing corner speed. However, it does raise the centre of gravity making the car more prone to flipping on jumps or in the lane change.
Tyre compound
When choosing your kit the included tyres can make quiet a difference to performance. The standard compound is quite soft, though soft tyres means more grip to accelerate, unfortunately, it means the reduce the speed of the car in corners, and may bounce more over obstacles.
The Trigale Black Special MA chassis (95413) is the only current kit to include low profile low friction tyres.
Try and choose a kit with hard, super hard or even low friction tyres. Hard tyres offer better grip with less bounce, super hard are a nice balance of grip and corner speed, and the low friction tyres offer the faster cornering speed, but may reduce initial acceleration off the start.
Body type
A nice feature of some of the specials such as clear, violet or light blue, is that they include a polycarbonate body instead of the standard ABS plastic.
Gun Bluster XTO Light Blue Special FM-A (95439) has a lightweight polycarbonate body & hard low profile tyres.
These light weight bodies not only reduce the overall weight of the car, but also lower the cars centre of gravity making them more stable on obstacles such as the lane changer.
Other considerations
When building your car take your time and ensure you do not damage parts and that the transmission is nice and smooth. If you find parts are broken or shafts are bent it is ok to swap them for kit standard replacements, in the case of pinions, it’s generally seen as ok to swap the purple pinions for black reinforced ones as they suck.
Some special edition kits are supplied with a lightweight or re-enforced chassis, or a different low friction material for the rollers.
Battery voltage is a very useful tool for controlling the speed of your box stock mini 4WD racer as you can use it to lower the speed of the car if you are struggling with the lane change or slope sections.
Summary
Box stock mini 4WD racing is a good cheap way to start learning the basics of racing, and build a small collection of cars without spending lots of money.
Sometimes just going for one of the clear specials, or black specials is a good place to start, as they often tick all the boxes for a competitive box stock mini 4WD race car.
The most important aspect of box stock racing is to have fun, and sometimes this means just picking a car that you think looks cool.