An idea is born
By John Hallman
It seems as if the craze for rock crawling is becoming more popular with each
day, growing up with off road vehicles such as monster trucks, stadium trucks or just your simple cross-country trail vehicle. Now,
more than ever when you look at an off road magazine or search on the web, the coverage of "Rock Crawling" is definitely expanding not just in the real vehicle world either. There are many enthusiasts in the RC world doing this as well.
In the RC industry, there are many platforms that are being used to create these "radio controlled" versions. I have always been an avid off-road enthusiast, and since the demand for RC rock crawlers has become more popular I decided to take one of our platforms and produce a competitive crawler. I had heard of
some customers taking our TLT-1 and converting it into very capable rock
crawlers, but had not seen many pictures or had done any research on the web. Since I grew up with the famous Clod Buster and its many possible conversions, I
had an idea of how to achieve this.
My first vehicle I used specifically converted was a Clod Buster. This required 2 motors and 2 battery
packs which required the use of a special type of speed control. The truck was efficient and impressive when it came to handling, however I was not totally satisfied with the run time or the time it took to recharge,
and its weight when lugging it around. What I needed was something a little lighter, smaller and something that
would run on one battery and one motor. It wasn't long after the TLT-1 came
to mind. I had shelved this project some time ago, but when I heard about some of the conversions being created I decided take another look at it. Without concerns about losing my once stock TLT-1 to an impressive rock crawler, I started tearing it apart and using whatever I had lying around the garage. I had completed this project in one morning, except for working out a few imperfections. My maiden voyage with this vehicle was more than impressive and I soon forgot
that it used to be a 1/18 scale Mini R/C truck.
Overall, after having several different types of RC rock crawlers, this one has probably received the most attention and is by far my favorite to date. With this sport growing more each day, I feel that the TLT-1 is a great platform to expand on and definitely has great potential to become a very competitive rock crawler.
Assembling the first TLT-1 Crawler
Starting with a complete assembled TLT-1 kit, the front and rear axles need to be removed from the chassis. To gain the needed out-drive length and the need to lock the center diff it will be necessary to build a TA04 gear diff (see parts list) and lock the planetary gears with CA glue, epoxy, or silly putty. The chassis will need to be pulled apart and remove the center ball diff replacing with the locked gear diff.
At this point I Installed the carbon chassis plates (#53729) along with the aluminum gear case motor mount
(#53777), this helped in shifting the weight to a lower center of gravity, as well as helping with cosmetic appearance of the truck.
I decided to use a stock silver can motor since the necessity for speed is not needed and this clearly allows for longer run time. Since this truck is designed for low speed rock crawling it seems to work well with a lower gear ratio than stock, to achieve this I used a 19T pinion gear and kit spur gear.
During assembly and testing I tried using cantilevers from a TXT but did not notice a big enough difference to keep them on. The only difference that I noticed was that the TXT cantilevers were bulky and seemed out of place on the truck. The truck performed better with stock cantilevers so I decided to keep the stock settings and go with the blue aluminum cantilevers
(#53711) for cosmetic appearance.
If using the hop up option oil filled dampers, the 3x5mm (A4) spacer that's included on parts trees "A" will need to be added onto the shock shaft between the shock body and the spring retainer as shown on page 15, step 24 of the TLT-1 assembly manual. The length of the shocks after assembled will need to be 91mm at full extension and 70.5mm when fully compressed.
On both front and rear axles, the 4 link suspension rods and cantilever suspension rods will need to be removed. The front axle will need to be disassembled and the internals of the front differential will need to be locked by using CA glue, epoxy, or silly putty. The rear axle will need to be disassembled and the internals of the rear differential will need to be packed with anti wear grease. During reassembly of both axles, the upper suspension stay mount (BJ1) will need to be turned around so the 4-link mounting hole will now be facing away from the chassis instead of towards the chassis; this mounting hole is no longer needed.
With the removed 4link rods and cantilever rods, the lower 4-link rods (3x57mm threaded shaft) will need to be saved and the upper 4-link rods (3x45mm threaded shaft) and the cantilever suspension rods (3x23mm threaded shaft) can be "ditched". The 3x57mm threaded shafts will now be the cantilever suspension rods and will use the same ball end adjusters as the previous link rods. The length of the rods between the adjusters needs to be at 40mm. Using the TNX turnbuckle shafts, the new 4-link rods will need to be made by using the same ball end adjusters as before with all eight rods having a length of 78mm per rod measured between the adjusters.
All the new 4-link rods will be mounted to the chassis in the stock locations. The main changes are with the upper 4-link mounting location to the axle as well as the cantilever mounting location to the axle. The only hole used will be the center hole that is directly over the 3x10mm tapping screws holding (BJ1) to the axle. The upper 4-link rod will slide into the suspension stay mount (BJ1) and the cantilever rod will mount onto the side of the suspension stay mount on the outside facing the out drive, or wheel. A 3x20mm machine screw will then be installed through both ball collars and suspension stay, securing it by using a 3mm flange nut (BB5). Before installing the center drive shafts
(#9805551), each out drive will need a rubber o-ring slid into it; this will prevent the center drive shafts from falling out during operation. The axle can be shifted to slide the center drive shafts into the out drives. After the drive shafts are installed the bottom 4-link suspension rod can be re-attached to the axle in the stock location.
For using Tamiya brand tires, we found that the tire and wheel combo from the rear of the Wild Willy 2 is best suitable without having to go to an after market tire. To make the tires softer it is suggested that a 1/4 inch hole (or even 2 holes) should be drilled into the wheel. After doing so it is highly suggested that the tires are glued onto the wheels to keep from slipping.
For bodies, there are several to choose from that give the truck a "scale" look. The Chevy S10 body and the Ford F150 body, (both from the stadium truck kits) fit well onto the chassis but require some modification to prevent tire-rub during articulation. The best fit so far has been the Wild Dagger body,
since it needs very little modification to fit the chassis and prevent tire-rub.
When rock crawling, the steering can get into a bind at times when wedged between rocks, I saw the need for a high torque steering servo. Installing the TP-3010 servo used for the steering on the TNX definitely helped with this. Also using the high torque servo saver helped with the amount of throw for the steering. To use the high torque servo saver there are some modifications that will need to be done. The ball connector will need to be mounted onto the center hole as usual and the other two holes will need to trimmed to keep from hitting the bumper. Actually if facing the servo saver, only the right side will need to be trimmed. It may be possible to mount the ball connector into the far right side hole to avoid having to trim the servo saver.
While using the tires and wheels from the Wild Willy 2 keeps everything Tamiya; I found that using Pro-Line tires increased the performance of the truck to a level far beyond what the "Willy" tires can offer. The Pro-Line tires I used were the "Dirt Works" that are mounted on 2.2inch rims from the Twin Detonator
(#0440024). With the Pro-Line tires, drilling holes in the wheels is not necessary. The stock inserts that are included with the tires are too stiff, and running the tires without inserts is too soft. I am using foam inserts that can be found in Pro-Line 2.2 inch 1/10th scale buggy rear tires such as the "Hole Shots" or "Square Fuzzies". Trinity "Bomb One" inserts for the 1/10th scale buggies are the same size and can be purchased separately. This allows the tire to be soft but not go totally flat.
After constantly changing wheels and tires to find the right tire set-up, I noticed the plastic hex wheel hubs were getting worn and would stay in the wheel when the wheel was removed, sometimes causing the hub pin to fall out. To cure this problem I installed a set of the aluminum clamp hubs to make changing wheels easier. This turned out to be the final touches need to finish this truly fun project.
If you're interested and would like a full list of the parts used for this conversion, please send an email to Tamiya America's Customer Service at
us_support@tamiya.com and request a parts list for the TLT-1 Rock Crawler Conversion.