The following are the proposed M-Chassis (Mini) rules put forward by Hawke's Bay Radio Controlled Car Club as a 2019 NZRCA Remit. The "M-Chassis Concept"
demonstration class at the 2019 North Island EP On-Road champs will follow these new proposed rules.
A22.1 - Any Tamiya M-Chassis kit - including models M02, M03, M04, M05, M06, M07, M08. This includes kits with "R", "Ra". and "PRO" in their title.
A22.2 - Cars must be assembled as per the instruction manual and no chassis modifications or chassis lightening is allowed; except for minor grinding on the M07 for clearance of the brushless motor wire tabs.
A22.3 - No power train/diff modifications are allowed.
A22.4 - A minimum weight limit of 1230g (with battery & transponder) will apply.
A22.5 - The ride height of all cars will be minimum of 6mm. This will be measured by rolling the car over an NZRCA approved gauge after the scrutineer has compressed the car’s suspension.
A22.6 - Only genuine Tamiya replacement parts designed for that particular chassis can be used, with the exception of the following hop ups:
a. Standard ball bearing kit (no ceramic bearings).
b. Sway bar kit.
c. Tamiya High Torque Servo Saver and any aftermarket alloy servo horn specifically made to fit the Tamiya High Torque Servo Saver.
d. M-Chassis reinforced gear set Tamiya part number 54277.
e. Any after-market Touring Car shocks and spring set.
f. Alloy wheel hexes, with a maximum thickness of 5mm.
g. Universal Swing Shaft, including Double-Carden type drive-shafts.
h. Hardened motor pinion - 16, 17, 18, 19, & 20 tooth only.
i. Any brand of motor heatsink is permitted as long as they attach to the motor in such a manner as to not be considered a structural component of the car.
j. 3Racing 7075 Aluminium Side Stiffener 2 pcs for Tamiya M07 – these are required to provide the necessary clearance of the brushless motor wire tabs.
A22.7 - No other hop-up parts, including (but not limited to) the following are allowed:
a. Any optional high-speed gear sets, gear adapters, or ball diffs.
b. Alloy or after-market steering rack.
c. FRP/graphite or alloy shock towers.
Basically - if it’s not on the “allowed” list - it’s not allowed.
A22.8 - Only 16, 17, 18, 19 or 20 tooth pinions to be used.
A22.9 - Body Shells - Only Body shells (from any manufacturer) specifically designed for M-Chassis with a wheelbase of 210/225/239mm can be used
A22.10 - Spec Tyre & Wheel combo - Only RIDE 60mm SC36m Pre-Glued Rubber Tire 2 pcs w/ White Rim for 1/10 M-Chassis Part #26300 are allowed.
A22.11 - Drilling extra vent holes in the wheels is illegal.
A22.12 - Spec Motor and ESC - Hobbywing Justock ESC/17.5t Motor COMBO. #XR10-JS5-G2.
a. Only permitted motors are unmodified Hobbywing 17.5t (PN 30408006). Motors to be from the Combo Kit #XR10-JS5-G2.
b. A stock motor run at 8 volts unloaded must draw no more than 1.7 amps. Any motor which draws close to the maximum allowable current (1.7amps) be subjected to a timing test to ensure it has no more than 35Deg timing.
c. The battery plug may be changed, however no other component/s relating to the speed controller may be altered.
d. The motor wire bullet plugs must be used without modification.
A22.14 - Only batteries as per Rule A10 may be used. Modifying the chassis to fit batteries is not permitted.
Reasoning
The current M-chassis rules have been in place - largely unchanged - for a couple of decades. Support for the class has dropped significantly in recent years.
There are new chassis available - the M07 and now the M08 - with a different spec (ie no electronics, motor or body in the kit).
With this in mind, Hawke's Bay has been running the class at club level with its own updated set of rules for the last 18 months. Essentially, allowing the M07 to race
using a spec brushless ESC/Motor – for all cars, not just the M07. Plus, opening up the body rules and returning to 60 diameter tires.
Numbers have climbed from 4 or 5 cars to at least 15, and the fun factor has returned. In many ways this has been a runaway success at our club attracting some of the largest fields.
The racing has been close. A good driver with an M03 or M05 can still win (and often do).
However, the M07 is a much nicer car to drive and is keeping newbies happy – something you couldn’t say about any of the previous models. The result is better buy-in; racers are sticking with the class as opposed to buying an
M03/M05, hating it’s driving characteristics and leaving the class.
The Brushless system has also leveled the playing field. Bench testing shows the tolerances of the system are much closer than the old silvercan.
There is virtually no difference in several units that were tested. The racing has confirmed this. Important to note: The brushless system is no faster (or slower) than a good silvercan, so that aspect hasn’t changed.
The Hobbywing system we are using has been adopted by other clubs, so a large number of racers are already using it. It’s well priced, readily available from several sources and has proven to be robust.
We have no reports of faulty units. Being a popular spec system in Asia, the factory tells us they will be manufactured to the same spec for some time.
Plus – the M07 comes without a Motor/ESC – meaning you have to buy something. It wouldn’t make sense to continue buying a silvercan system. The technology is out of date.
It did make perfect sense to use what was in the box when it came with the kit. But it doesn’t appear that Tamiya are going to release the M07 (or M08) with a Motor/ESC and body.
There are a couple of hop-up options included in our remit. This is intended to allow all M-Chassis cars reach a similar spec, regardless of age or model.
We realise this is a significant leap from previous rules but after 18 months of trialling – it’s certainly worked at our club. Perhaps rather than drip-feed these changes over several years it’s time to bite the bullet and move on.
Also of Note: We didn’t put forward this remit at last year’s AGM, even though at that point we had been running to this revised set of rules for some time.
This has allowed plenty of time to iron out any issues (in fact there have been none) and for other clubs to either trial it or come and race at HBRC to see for themselves.
We regularly attract out-of-town drivers and they appear to be as happy & supportive of the change as much as HB locals.
During this time, we have made a hard copy flier freely available and the same info can be found on our website. The trial has not been done in secret.
