Category Archives: Musings

ROAR do a backflip on 1:10 Wheels

Why do we care what is happening with some US rules? Because many AARCMCC regulations are derived from ROAR rules, and what happens there tends to have an influence around the world.

Now i never understood the controversy around the bigger 2.4 rims (diameter, not width) were banned last year be ROAR as the rules never allowed them. However the announcement today is an about face from their position in 2014 that is effective immediarely.

Now the height and width of the tyres is not changing, just the size of the rim, and a lower profile tyre will not suit all conditions, just like with 1:1 cars.

If anything i am relieved to see the rule makers moving with the times a little, although i don’t see it changing the nature if how we race much.

ROAR is introducing a rules change with immediate effect that results in 2 different wheel configurations being available as options for manufacturers and competitors: – the existing 2.2″ nominal wheels – the newer 2.4″ or 61mm nominal wheels The new rules do not include dimensions compatible with vintage style wheels as they are generally not used in ROAR sanctioned competition. Dimensions for the traditional 2.2″ wheel will be: – Mounting Bead Diameter – 2.20 inch (55.88mm) +/-.013 inch (.30mm) – Maximum Overall Diameter – 2.42 inch (61.468 mm) – Width – 1.513 inch (38.43mm) maximum Dimensions for the newer wheel style will be: – Mounting Bead Diameter – 2.380 – 2.427 inch (60.45 – 61.65 mm) – Maximum Overall Diameter – 2.571 inch (65.3 mm) – Width – 1.513 inch (38.43mm) maximum

How heavy is Lightweight?

There was some fanfare about B5M Factory Lite kit when it came out as a great, lightweight, stock class racer, and I thought what a good idea, lighter is faster! 75g lighter than the regular B5mM, fantastic!!

However something about the touted weights seemed familiar but I never looked into it.  However my recent acquisition of some 2nd hand shorty packs prompted me to think about the weight saving of these packs as well as the punch provided by them as they are MUCH newer than my existing packs. So I thought I would re look at the B5M and it’s lighteright sibling.

While official weights have not been published, I have seen the B5M noted as weighing 1342g without a battery or weights by a user online, so a Factory Lite should be around 1267g.  So I took the battery out of my DEX210 (details here of what it is fitted with) and it came in at 1312g. Ok, it has an alloy chassis, not plastic, gear diff,  steel driveshafts, still a slipper clutch, transponder fitted etc etc. Now minimum buggy weight under the AARCMCC regulations is 1500g, so anything under that really is a pointless saving. So with a battery fitted I weighed in at 1600g, a little on the weighty side of things.  However with the new shorty fitted there was a 75g saving in weight, an uncannily similar figure from higher up the page bringing me down to 1525, not bad all in all I think for somebody who isn’t a truly serious racer.

So all that weight saving is pointless?  well, no not at all.  Yes, you still have to be over 1500g, and my buggy can loose a little weight (much like it’s driver), but with a shorty battery as the weight saving instead of in the kit, it means I have the flexibility to move the battery around to help tune the handling of the buggy, something that made a big difference on my first night of running the new shorty batteries.  Mind you, with a lightweight buggy you can add weights to tune the performance, but i’m too lazy to mess around with those, and it’s just another part that I need to buy!

Are you getting the battery that you paid for?

It has been interesting seeing the capacity and C rating of Lipo batteries rise and rise of late, and I have always wondered how long that increase was sustainable on the currently available technology.  Now it looks like SMC may have answered that for me!

Superior Matching Concepts, or SMC, is a brand of battery that I was shown by then fellow racer Scott Guyatt as a good bang for your buck battery much akin to the Intellect batteries I am/was running at the time.  I am afraid I am yet to buy any, but I am in need of some younger batteries so whey are moving up the list in priority and these are at the top of the list.

However a post on their facebook page today caught my attention so I thought I would re-post it for our readers to see. The complete statement is included below.


I’m making this post to try and help educate everyone about how crazy the Lipo ratings have become and are pretty much useless. I know most of you will appreciate this post and some will think I’m just using this to promote SMC but this is really to open some eyes.

First let me explain the fact that their is no true C rate testing standards. Some factories use mAh retention and others use heat and voltage curve to determine the C rate. Every factory knows the C rate of their cells based on one of these 2 methods of C rate testing.

When I started testing and buying Lipos 8 years ago the C rates were 10 to 20C for car packs. At that time the factories were giving true C rates based on their testing method for C rate. Within a few years C rates doubled but this was just marketing to try and sell more packs and make more money. Now 8 years later it’s even crazier with some outrageous C rate claims and mAh has also started to increase on the labels but not on the cells. In my opinion 80% or more of the packs being sold in car market today have a true C rate of 15 to 25C using the heat and voltage curve method for C rate testing. Using the mAh retention you can add 5C. There are some 30C and 35C packs available but these are very rare and cost more to make.

C rate is the amp rate at which the cell/pack can be discharged at. So a 5000-20C can do 100amps. A 7200-20C can do 144 amps and so on. IR(Internal Resistance) is directly related to a cells ability to handle amp loads. So it’s not possible for a pack to have higher C rate and higher IR. This means a 7200-20C has to be lower in IR than a 5000-20C. The size of the cell also limits it’s mAh or C rate/IR. In car packs with hard cases we’re limited by the size of the case. This means if you want to increase mAh you must increase IR or vice versa. A 7200-25C will have higher IR than a 6000-35C. The 7200 will be able to do 180 amps and the 6000 will be able to do 210 amps. Only way the 6000 can provide more amps is to have lower IR.

Now that we know this if true C ratings would exist the consumer/racer would be able to know what pack better suits his needs. Unfortunately this isn’t the case so there really is no way for the customer/racer to know. SMC is no different than others as we also use inflated C rates as we have no choice. If we would use true C rates we would be out of business. What we do try and do that is different is make sure that our ratings mean something. For example our 5000-40C will have higher IR than our 5000-50C and so on.

Here is something that I find interesting and frustrating at the same time. Some of our competitors buying the same packs we do offer them with higher ratings. This leads to some customers buying these higher priced packs instead of ours. Here are 2 examples. The 4400-60C shorty which we sell for 29.95 is being offered as a 4600-90C at 44.95 and it’s the exact same pack that we offer. The 7200-60C-2S pack we offer for 39.95 is being offered as a 7600-75C for 64.95.

Something else interesting is that a customer who bought one of our 5000-40C-2S packs at 24.95 compared it to a 5450-120C-2S pack at 129.99 and told me that our 40C pack ran longer and faster in the same vehicle and the 120C pack was new to make a fair comparison.

Now that we know C rates are all made up and it’s actually getting a bit ridiculous to claim even higher C rates it seems like in the past few years mAh is now what is being inflated. Recently I tested a 7000-1S pack that only put out 6222mAh. I will admit some of our packs also have a bit lower mAh than claimed but this is due to the model being improved to provide lower IR. If you drop the IR the mAh drops.

I hope this post can help some of you not fall for all the BS and hype and don’t be surprised if SMC starts releasing higher rated packs to try and keep up as it’s very frustrating to under rate our packs and lose sales.


Source: https://www.facebook.com/smcracing?fref=nf
Website: http://www.smc-racing.net/
Australian Stockist: http://www.coast2coastrc.com.au/

2015 IFMAR Off Road Worlds at Yatabe on Astro Turf?

There has been quite a bit of discussion among some media, on Facebook and on RC tech about the possibility of the 2015 World EP Off Road Championships at Yatabe being run on Astro Turf as it is currently configured.

Neobuggy are calling it astrogate –  http://www.neobuggy.net/2014/12/01/2015-ifmar-yatabe-worlds-astrogate/
RCTech forums – http://www.rctech.net/forum/electric-off-road/849776-2015-offroad-worlds-astro.html

Interesting though much of the feedback has been overwhelmingly negative towards the idea which surprises me a little I have to say, certainly I have seen some very heated debate on Facebook varying from support to horror and threats of drivers pulling out. . Neobuggy suggested that some manufacturers have been working on new models if it eventuates, and certainly the Hot Bodies (HB) team members appear to have been testing a lot on the similar high traction surface of carpet of late.  The way it is worded almost sounds like it is scandalous though, because there aren’t any manufacturers that have cars suited to those conditions!  Oh, wait, that’s not right! The B5M exists for precisely these conditions, Schumacher has a number of models suited to high traction as does Team Durango and TLR. Ok, maybe not specifically for those conditions, but designs that work well on this type of surfaces and are commonly raced on those surfaces in various parts of the world. Let’s not forget the current trend for sugared surfaces as well which offers almost ridiculous levels of grip and very heavy tyre wear.

I have seen comments from all off road should be on dirt through to it’s just touring cars with big wheels, and whilst I personally disagree, I doubt this post will change many minds other than for me to vent about it a little and put across my point of view. However I have seen dirt tracks with far fewer “off road obstacles” than many of the astro turf tracks that I have seen around the place. Have a look at the video below of Yatabe and tell me that it is boring or even lacking in challenging features?

There has been the suggestion that it would be unfair for the drivers who race on dirt all the time and have no astro setups.  My first thought was that they have been missing out, but how is it any different for a racer used to racing indoors and on carpet or turf coming to race on a dirt track, how is that any less fair?  and you will always have locals with a certain level of experience with the surface and conditions in a local area. It is no different to a loose dirt track vs a sugared high traction track? The same argument can be applied to the suggestion that you need to buy a car for the astro conditions, but if you already race on astro, the same applies to going to race on dirt.

Personally, I race on a carpet and astro turf track.  I race a buggy that can be configured for anything from loose dirt through to high grip carpet and everything in between.  I enjoy the different challenges racing on this surface brings, but it is not as easy as it sounds.  I actually have used the phrase “Too much grip” a number of times when referring to my setup. The surface is not 100% the same everywhere with some areas wearing out, some areas blackening up with rubber down, and other areas are quite bumpy because of the layering of carpet.  I took some photos at a recent event and the layering of the carpet alone was putting the wheels of most cars in the air. As far as looking after the surface it is much easier than dirt to look after as we are indoors so no rain to need to cancel race days (unlike most Tasmanian clubs), it is easy to change the configuration of the track and in our case, we have to be out of the shed for at least 4 weeks a year so that the owners of the site can use it (so dirt simply is not an option for us).

IMG_5420
A stadium track over a “flat” corner into the main straight at Launceston R/C in Tasmania, Australia.

At the end of the day, it is about seeing which driver makes the most of the equipment that they have, at the location they are racing to see who is first across the line at the end of the day.  The challenges along the way is what makes it interesting and exciting.  If that means adapting to a new tyre, a new track, a new car or a new radio, that is all part of the challenges that you need to overcome. I don’t see how a different colored surface changes that much, perhaps some drivers are worried that they loose an edge being unfamiliar with the conditions, surface or track?  Only time will tell the outcome, but I really can’t understand what all the noise is about!

Aussie RC’s 1 Year Anniversary

Has it really been a year since the first post on Aussie RC? Well not quite, technically that’s Wednesday the 3rd, but the first was when I started working on the main blog and facebook page before making the first post.

I had always read Red RC, Bigsquid RC, Neobuggy, Red RC and other RC news websites around the world to keep up to date with what happens, but I was somewhat dejected to not find any sites that had news specific to Australian races, clubs and news.  So I started one myself to see how hard it was to do. The internet, facebook and the likes has made it much simpler to disseminate news with our website feeding to our facebook page which in turn feeds to our twitter profile.

To date www.aussierc.wordpress.com has racked up in excess of 18,000 views since our inception, with some of the most highly viewed posts surprising me at times.  On facebook we have almost 750 likes at the time of writing and steadily increasing in number.

Some of the interesting posts that have recorded the highest views (in order) have been Do we need to modernise how we race?, 1/4 Scale Grave Digger, the Kyosho FO-XX VE and coming in at no.1 What 2wd Buggy for 2014.

I would like to thank me those who have emailed in news to us at aussierc@outlook.com, or through the feedback page of the site.  I would like to thank those that have helped contribute towards the site, and remind you all that we are always looking for people to help and contribute.

So onwards and upwards to bigger and better things for what remains of 2014, and the year 2015 to come!

What would you have for a Radio Control Christmas?

I am a dreamer at the best of times, my Christmas wish list is as long as your arm and it isn’t even December yet! But I thought I would see what RC item you would have under your Christmas tree if money was no object.

Personally I would have trouble choosing, from Crawlers to Scalers, Drift and Rally cars through to Race Trucks, I think I could name a desirable car in each category just about! So then I thought, well why not write an open letter to Santa!

Basher
For bashing you have to have something big, powerful and robust. A lot of vehicles fit that description, but for me it has to be electric, so that narrows it a bit.  Yes i’m a HPI fanboy so the list has to include the Savage Flux, which is a bashing classic in any guise. The Trophy Truggy Flux also appeals to me for it’s now and fast look, while still clearly being built to take a flogging.  The Axial Yeti XL is a big, quick and less common vehicle, and is very tempting. However money no object the clear winner in my book is the biggest of them all, the RTR Baja 5B Flux. Big, Powerful, impressive and fast.  Ok, no noise, but the trade off is less annoyed neighbors or beachgoers wherever you are bashing, and no fuel to lug around.
http://www.hpiracing.com/en/kit/107684

Crawler
An SCX10 is what most of you probably expect to see here, but you would be wrong, I have to say that the Vaterra K5 Blazer Ascender RTR. The body is something a little different, the platform looks strong and flexible, and as always with me, it’s a little different to what everybody else is doing.
http://www.vaterrarc.com/Products/Default.aspx?ProdId=VTR03014

Scaler
Until a few weeks ago this would have simply been the Gelande 2 D90 from RC4wd, however RC4wd threw me for a spin recently with the release of the Gelande 2 D110.  Let’s face it, the only thing better than a Land Rover Defender, is another Land Rover defender (yes, I suspect I bleed green).

http://store.rc4wd.com/Gelande-II-D110-Truck-Kit-With-Hard-Body_p_4326.html

Drift
I have had a HPI Sprint 2 in the past, and i’d probably go back to one for drifting.  I am loving the orange BMW M3 body that comes with the Sprint 2 Flux, so I’d probably say that model with some drift tyres!

http://www.hpiracing.com/en/kit/112862

Rally
There are a few more rally platforms out there this Christmas as compared with the last, so there is a lot more choice, but ironically I would go with one that was available last Christmas, the HPI WR8 Flux.  Even more so since they released a Subaru Impreza body for the WR8. I preferred the Rally liveries over the Ken Block one (despite being a fan of KB), but they have been discontinued.  I hear the Rally purists crying why not a Tamiya XV-01, well I already have one of those!
http://www.hpiracing.com/en/kit/112715

Racing
So my racing fleet has seen a serious shakeup this season with the addition of a 2wd Buggy, and the replacement of the SCT with a new one (under construction). 8th and 5th scale I would never get a chance, so a 4wd buggy I think would be the item on the wish list, and whilst I like the Team Durango DEX410V4, I like the design of the HB D413 even better, making it my pick for a new car for racing.
http://www.hpiracing.com/en/kit/112723

Other Equipment
In the “Other Equipment” category I think I would have to ask Santa really nicely for a new Radio. While I love my DX2.0 it’s getting a little long in the tooth and only has a 2 model memory and limited compatible receivers.  So I think that the DX4S or DX4C would look very good in my pit bag. (The spektrum website was unavailable at the time of writing so no link)

Other
With money no object, the Other category is fairly broad, but I think something airborne would be in order, and by something I think I would have to pick the Walkera Scout X4 Quadcopter.  With a retractable undercarriage, programmable gps, camera with transmission back to the radio for FPV and a host of fabulous features including a “follow me” mode, it would be a fantastic toy to play with and work with. You can even fit two motors and rotors to each army making it an X8 for heavier loads. With a 25 minute flight time, this is on fantastic piece of equipment which looks fabulous in the grey finish it is available in.
http://www.walkera.com/en/showgoods.php?id=2742

Pro teams Wax and Wane

It seems to be a roller coaster for many of the Professional RC racing teams at the moment while the silly season driver changes are happening, and Team Durango and HPI/HB are two who seem to be at opposite ends of the spectrum.

HB (Hot Bodies) seems to be increasing their number of drivers exponentially signing Reno Savoya and David Ronnefalk and confirming contract extensions for Ty Tessmann (they would be mad not to), Andy Moore, Tanner Stees, JJ Wang and Teemu Leino.  This really takes HPI/HB form a fairly small team, to a fairly large one with some bug name drivers.

On the other hand, after announcing that it was dissolving it’s professional team, Team Durano’s drivers have all headed off to greener pastures with the exception of Travis Amezcua who was announced as the TD North American Technical Representative. I had to go and look at the release to see precisely what that meant, but it looks to be in line with the theme of strengthening local support, notably “Travis will be traveling from his SoCal base, around the US, bringing expert track-side support to local club racers and Team Durango fans.” So TD are focusing on you, the local racer instead of it’s professional team.  A good thing for the local racer but will it work long term? Let’s look at Traxxas, the No.1 selling RC brand and their professional team, except that they don’t have one do they, they focus on what you the consumer wants.  So while some are saying that TD’s decision is insane, there is not only a precedent, but a successful one.  Another paragraph of the press release caught my eye as well:

Travis will work closely with our newly appointed, Champaign based, Hobbico Field Communications Manager, Brad Brucker, in the US. This new support team for Northern America will allow our fans to gain race-day support, whilst also feeding back important ideas and issues to our design engineers

Travis will also be scouting for new talent, in all racing classes, allowing us to build a base of local racers who will contribute to how we design new race machines.

Expect to see these guys travelling across the US to meet as many of you as they can at your local events.

Stay tuned for more news on how your local racing scene will benefit from regionally appointed Team Durango Trackside Representatives very soon.

So reading between the lines, the change comes after Team Durango was sold to Hobbico.

Also i would say that we will see more local Team Durango Technical/Trackside Representatives, which lines up with the rumors we are hearing from other quarters.  We will probably also see more drivers with minor sponsorships in busy areas as well, anther plus for average joe racer at the local track.

Source: http://www.team-durango.com/blog/2014/11/21/team-durango-%E2%80%93-strengthening-local-support/
Source: https://www.hpiracing.com/en/news

Racing Lines No.217 Out Now

IMAG0325

This month’s Racing Lines is a good one I have to say, although a slightly different physical print than the last editions.

In between the covers you will find articles on LRP at the ETS season final, an interview with Shane Van Gisbergen of V8 Supercars and RC racing fame, a look back at some cars of the past from AYK, a look at the Latrax V8 Supercar, a review of the Team Associated RC10 1993 Worlds Car re release and of course the reports from the latest major Australian RC races around the country.

One article that caught my attention was Scott Guyatt’s article titled Get a Grip. It’s well worth a read and it examines the latest fad of high traction surfaces such as sugared off road tracks that simply eat tyres.  Whilst I don’t often have the opportunity to race on dirt I have to agree that I don’t think high traction, heavily prepared surfaces are the best thing for the RC Racing Scene on the whole.  Now I have to confess, my regular racing haunt is a high traction carpet surface, not because we were looking for high traction, but because the concrete in the shed we race on is too slippery to race anything.  Also the carpet can be removed when the site owners need the venue for other events.  I never thought I would hear myself saying that I have too much grip at any RC track, but it was a phrase I have used on many an occasion now that the track is almost 100% carpet.    Have a read of Scott’s article, and let us know what you think, but personally, I 100% agree that at a local level, it’s not good for the hobby I love.

Driving Etiquette

All too often we see poor driver etiquette on the racing track.  Now I don’t mean bad driving from somebody who is learning or having a bad day, I mean poor driver etiquette.  Now you wouldn’t think that etiquette, a code of behavior that defines expectations of social behavior,  would have a place on a racetrack, but on a R/C racetrack it is very important.  Why?  Because without it races would degrade into a demolition derby.  Yes, there are rules in place to black flag poor driving and poor sportsmanship, but it goes deeper than that.  Let’s not forget that Racing Etiquette also extends to marshaling as well as you will see further down the page. Good, bad and inbetween, all drivers need to be reminded about etiquette at times.

Now this is something that you would expect would disappear from a race in the heat of the moment, but even at the highest levels of competition it is still not only desirable, but expected of drivers. Now I am no expert on the topic, although I try my best, so I defer to regular racer, and Racing Lines columnist Scott Guyatt who wrote the following piece on the website of my local club when he was a member.  I have not edited out the references to my local club, the piece is not mine to tamper with, but it gives a good overview of the etiquette behind Radio Control Car Racing.

As we continue to grow as a club, and learn our way around the R/C hobby, perhaps it’s time to think a little about ethics for R/C racers.

R/C is like any sport in that there are some guidelines which enable all of us to enjoy our hobby more.  Here’s a few that we want to encourage at Launceston R/C:

Driving:

R/C is essentially a non contact sport.  For sure there will be racing accidents (like there are in any motor sport), but we’re not doing demolition derby.  The intent is to race cleanly, to pass cleanly, without crashing other driver’s off the track.

If you’re trying to pass another car, the responsibility lies with you to make it a clean pass. For sure push, probe, look for opportunities, but the car in front has the right to their racing line, and you have the responsibility to wait for the opportunity.

If you do crash into a car while trying to pass, racing ethics are to wait until the car you’ve hit is back on track and back in front of you (even if you have to wait for a marshall to intervene).

If you’re lapping the car in front, all the same rules apply – it’s your responsibility to find a clean way past.

The difference here is that if you are the car being lapped, it’s also your responsibility to make space for the car trying to find a way past.  V8 Supercars and F1 have blue flags to tell  drivers that they’re being lapped. We depend on each other to do that job – and the commentator and race-system will help let you know.  Letting a lapping car by is better for both of you than racing against them and trying to keep them behind.

The track boundaries are there to mark the race track. If you accidentally cut across a corner (even if it’s as the result of an accident that’s not your fault) you need to drive back to where you came from, or at the very least to wait to ensure you don’t get an undue advantage.

Driver Behaviour

R/C racing is a unique motorsport in that we stand side-by-side while we race.  If you’re in a V8 supercar, or a sprint-car you can yell and curse as much as you like, and nobody can hear you (except maybe your pit crew on the radio!).  If you start yelling and cursing on the Driver’s Stand at Launceston R/C, everybody can hear you.  Abuse of drivers, officials and marshalls is just plain unacceptable.  We discourage bad language so that we can keep Launceston R/C a great place to race for families of all ages.

Marshalling

It’s a standard system in R/C all over the world that you marshall immediately after you race. If you run two classes, you marshall twice.  We all make mistakes on the race track, and we all want to be marshalled quickly and efficiently – so each of us needs to take that approach to marshalling.

Within the bounds of your physical capability (remembering that some of you are nearly as old as me, and we don’t move so fast!), marshall well.  Watch your part of the track. Get to crashed cars as quickly as you safely can, put them back on the track as quickly (and safely) as you can.

Much as we all like to chat about our race, have a drink, something to eat etc, while we are marshalling just isn’t the time for those things. Marshall the way you want to be marshalled.  Fast and safe.

Those are just a few of the ethics of R/C, of making your club an enjoyable place to go racing.  Now, its over to you….

If you think this doesn’t happen at the highest levels, think again.  Have a look at the footage below of a 1:5 Touring Car Championship final from 2010 as covered by RC Racing TV.  In the first two minutes there are a number of occasions where front runners pause and allow the car that they have crashed into retake their position before continuing.  THAT is the kind of racing I love to see.  I’m not saying that clubs around the country aren’t teaching it, we all forget sometimes,  however i’ve also seen top drivers conveniently forget when they are frustrated by slower drivers.

Roar makes changes to EP Off Road Chassis Rules

In the US, there was some conjecture about battery packs at last year’s EP Off Road world championships.  You see the ROAR regulations state that to be eligible a car must be able to take a full size battery, and some vehicles were not being raced with full size batteries.  In the case of the Hot Bodies D413 Buggy, it was being run with a shorty battery rather than a full size, or saddle pack.  At the time the argument was that it was simply in a different configuration, and that the car could be configured with a saddle pack.  The new Team Associated B44.3 is much the same in it’s multiple battery configurations.  A similar situation exists with many 2wd vehicles as well,he Losi 22 in mid motor configuration comes to mind as being a very tight fit for a standard battery pack. Now ROAR has amended the rule to allow vehicles that are able to take both batteries, whereas before the wording was a little ambiguous.

Who do we care in Australia, well to a fair extent we don’t as racing in Australia is governed by AARCMCC (Association of Australian Radio Control Model Car Clubs) and our rules simply give some maximum physical dimensions, minimum weights, 2wd must be the rear two wheels driven only, 4wd can be 4wd or 2wd / front wheel drive, batteries must be legal and transmissions single speed only.  More simple and straightforward to understand.  Why you might care is because the ROAR regulations do effect the design of the cars that we race here in Australia.

How does the ROAR rule read now, see below.

Rule 8.2.3
All chassis (including optional/aftermarket) in all electric classes (except those specifically noted) MUST accept batteries up to the maximum dimensions allowed for its application. Chassis must have at least 1 standard configuration (standard configuration to be saddle or stick pack) to fit a battery of maximum dimensions for that class or it will not be considered legal, and the racer will be disqualified. Foam blocks/spacers are permitted to help secure any size battery in its position. Electronics may also be located within the battery area when “shorty” or smaller legal batteries are used, provided that “permanent” mounts for the aforementioned don’t preclude the installation of full size battery or saddle pack of maximum dimensions. The only exception is 1/8 off-road where it’s common to use two battery packs to achieve the maximum 4S configuration, or to use a single 4S battery, which has a different specification. Only under these circumstances will the fitting of either configuration be considered legal, but the production chassis must still conform to batteries of the maximum allowable dimensions. Should a question arise as to whether the chassis will accept a full size pack it will be up to the racer to prove that the chassis meets all requirements.
Similar clarification was illustrated by ROAR recently when they reiterated that 2.4 tyres were not legal for buggy, only the approved 2.2 tyres.  Not sure why this was an issue at the race because 2.4 tyres have never been legal despite many manufactures producing tyres and rims in the size, but ROAR did a much better job of letting people know than the debacle that was the Trinity D3.5 17.5 motor was deemed illegal.  Again, in Australia we simply have a maximum allowed width with no minimum.
So for all of you that whinge and moan that AARCMCC and it’s regulations suck, have a closer look at our rules vs those of ROAR and EFRA and you will see that our regulations are simpler, more logical, and not all that bad after all!
Source: http://www.liverc.com/news/announcements/8169-The_long_and_the_short_of_ROAR%27s_new_chassis_rule/