The 2.2 Scale Revolution

The Smallest Crawler

May. 01, 2006 By Pete Bach

While the RC Crawling sport was being dominated by the big Super Crawlers, there were many custom builders that were looking for something a little different. The Super Class was the highlight at competitions and the trucks could climb and scale anything put in their path. Impressive to say the least in ability, however, a Super Class truck was lacking realism.

A typical Super Class Crawler with a long wheel base and large tires

It didn’t look scale by any means. To achieve its incredible performance, proportions forced an odd look to them. An eighteen inch wheel base is not uncommon, coupled with tires in the seven inch tall range make the trucks look strange with a 10 th scale body placed on top.

Several builders, less than two years ago, decided that they wanted a truck that could perform well on the rocks and look like the “real thing” while doing it. The problem was that an RC Crawler just couldn’t climb well without being long and low. There were not many tires to choose from for a smaller truck that were sticky and the platform would require the use of a shaft driven truck. The Clod Platform had become the desired norm for an RC Crawler and going back to a shaft driven truck would take some serious design efforts.

Many still started with Clod axles, creating rock machines that looked awesome!

A Scale and realistic looking crawler with Clod axles

Keeping the wheel base shorter kept the tires inside the wheel wells of popular Lexan bodies, such as the Proline Jeep CJ 8, and the HPI Classic Bronco.

The HPI Bronco Body
This was easily achieved by fabricating shorter links and attaching them to an already proven chassis like the UTRCRC V2. Performance was good……but certainly not great! Some entered their little scale looking crawlers into competitions, only to realize that the big Super Crawlers could traverse the course terrain with much more ease. To fair better in competitions, the builders would quickly change the configurations of their trucks and soon, the scale look would once again be lost.

The TXT-1 also lent its axles to many scale projects and proved to accomplish what many builders wanted…..scale looks. The TXT-1 axles are shaft driven and gave that little edge (for realism) by using drive shafts for power and of course the look of a 1:1 rig but combining “shafty” power and a short wheel base proved to be its demise.

A newer monster truck emerged into the RC world from Tamiya and was similar to the larger TXT-1 in design. Labeled as an 18 th scale truck, The Tamiya TLT-1 Rock Buster

The very popular TLT-1 Rock Buster by Tamiya

kit was much smaller than the oversized Super Crawler and used solid axles that seemed to be units that might be used in some new projects. Of course, the modification period occurred first, as builders redesigned the TLT-1 by cutting the chassis down and reconfigured the suspension from a cantilever set up, to a more traditional, vertical coil-over design. Most of the original parts from the TLT were used, including the transmission. The problem with the TLT transmission is that it is belt driven. A belt in a transmission? While a rubber belt tranny would work in most RC applications, rock crawling is more demanding and needs everything in its driveline to be locked! These small TLT based trucks crawled fairly well,

An early Scale 2.2 Crawler using mostly TLT-1 parts
until the obstacle was extreme enough to require huge torque. The tranny proved to be a failure as the rubber belts would simply spin on their gears.

Once again, builders went in search of more performance from their rigs but this time it was more difficult. A totally custom rig would need to be built. The biggest issues were finding the right parts from other rc trucks and to keep the weight low enough to allow a shaft driven truck to hit the rocks hard without flipping over easily. Compounding the problem was that a completely new chassis would be needed to accommodate a traditional suspension and some type of locking transmission.

It wasn’t long before an eager builder, in search of the perfect tranny, found what we had all been looking for. The Traxxas Stampede transmission was the answer!

The Traxxas Stampede transmission is perfect for the application
It was perfect, with a differential that could easily be locked with epoxy, low gearing, stout drive shafts and a mounting place for a 55 turn lathe motor. It was also easy to mount into almost any position.

The “Pede Tranny” was soon being used in almost every scale project being built but there was one common problem that was being over looked. The transmission was being mounted with the motor at its highest point. A shaft driven truck needs every bit of weight mounted to its lowest point and that is what a few new designs provided. The “Laydown” design changed performance forever! A “laydown” chassis mounts the “Pede” tranny on its side, placing the motor, which is the heaviest part of the truck, flat on the skid plate.

The Bender Customs SW2 is a perfect example of the laydown tranny design
It was brilliant! It kept the smaller trucks looking very scale and most importantly, it kept the trucks shiny side up!

Super Crawler performance from a small truck was getting closer. When the truck was complete, its wheel base was between 12 and 13 inches, tires used were about 4.5 inches tall and a 10 th scale body was used. The TLT-1 based trucks went from 18 th scale to 10 th scale during it’s transformation but still looked tiny next to its 8 th scale brother, The Super Crawler.

Finding the right tires to propel the little trucks up the rocks was the next problem. There were a few options but none that seemed to stand out. The wheels that are used in a scale project are 2.2 inches in diameter, which is now the official name of its competitive class. The 2.2 Class has several specification requirements, one of which is the use of 2.2 wheels and tires no larger than 5.5 inches. Wheel base must be a maximum of 12.5 inches. Most tires that fit 2.2 wheels were made for stadium trucks and buggies… and while the current tires on the market worked fairly well, we crawlers all wanted something more dedicated and Proline Racing stepped up again as our provider of a crawler tire.

The Proline 2.2 Moab Tire
The five inch tall, 2.2 Moab tire was introduced and is now seen on well over 90% of the scale builds today. They grab, stick and claw on anything standing in the way of a 2.2 crawler!

The 2.2 Scale truck is really something to watch! Their performance is as good, if not better than a Super Crawler and much of its amazing ability is still unexplained, even by some of the resident engineers. They just work!

The ultimate 2.2 Class Crawler
Improvements made their way into each build at each competition event, such as weighted wheels and battery pack placement. Each modification improved performance and put it that much closer to being the truck of choice.

Performance is peaking in the 2.2 Class and recently, more aesthetically appealing parts have begun showing up on the market. Parts that give a totally realistic looks are now in huge demand, like the ARB snorkel, Jeep side mirrors, Warn winches(that actually work!), soft tops, half cages, roof racks and C shackles.

Small equipment for small crawlers
In most photographs, you really need to look hard as to distinguish a Radio Controlled Crawler and a full blown 1:1 crawler rig.

A very scale rig. It’s hard to tell if it is RC or 1:1

Some performance has been given up on many rigs but you can’t argue that many of these Scale 2.2 rigs have looks that are mind boggling. Sure, some of them might sit on shelves and never get driven but that concept is widely accepted in the radio controlled hobby.

Recently, another new trend has begun that emulates the 1:1 world. Most of the hard core rock crawlers tow their rigs to the trails or competitions and now….the rc rock crawlers are doing the same. Tow rigs are now a hot ticket to build or buy! Some use another crawler rig with a Peterbilt body, a few use the popular International CXT,

The RC version of the International CXT

made by New Bright and others are custom building scale rc Unimogs. Of course, you can’t tow your crawlers without a trailer and most guys are brazing them up over night and hauling in the morning. Sure….you don’t drive your RC tow rig with trailer in tact down the high way but when you pull up to your buddies in the parking lot and drive your International CXT past them with three hard core rc crawlers in tow, you’ll need a towel to wipe up the drool from the lexan! Newsletter
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