Tamiya Bullhead

Traditional "make it look bigger than it really is by changing the perspective" shot.

Showing off the spiffy race-stripe paint scheme. Note the reflection of the American flag in the smoke stack.

The Tamiya Bullhead is pretty much the same as the infamous 4-wheel drive, 4-wheel steering Clod Buster, except for a few cosmetic differences. The most obvious difference is the towering "rig" truck body. A lot of chrome parts are on the body (and a few chromed chassis components), and some other brightly colored items are all that separate the Bullhead and Clod. Based on that, I'm sure you can guess that the only reason I chose the Bullhead over the Clod is because of the body.

History tidbit: The Clod Buster came out in 1986 or early '87 (if memory serves, anyway) and the Bullhead came out in 1990, along with a revised Clod kit. The early Clods suffered from a problem with a few easily-broken chassis components. The new Bullhead and updated Clod still have a tendency to break the chassis when you try to do normal "buggy activities"--you know, take it off big jumps. Also, the very first R/C magazine (Radio Control Model Cars, May '87, I think) my Dad bought for me had a review of the Clod Buster and a photo of it on the cover. (From when we were looking at the Grasshopper.) I must say, "wow" was pretty much my first and only thought. In hindsight, between this and the Lunchbox, monster trucks were for me. I don't know why I ever bothered with cars.

I always liked this truck for a couple of reasons. The obvious one was the size. (Does anybody remember the old Tamiya ads where the Clod was running over a Frog, Grasshopper and Hornet? You can see it at clodparts.com) The whole suspension system always interested me. Actually, how the whole thing stayed together is what interested me. After all, the gearboxes are held to the chassis with a bunch of nearly free-swinging arms. How could this work? And despite the exceptionally high center of gravity, how could it be so stable? Well, now I know.

As noted earlier, the Bullhead is a 4-wheel drive, 4-wheel steering truck. 4-wheel drive is managed with 2 gearboxes (and consequently 2 motors). 4-wheel steering is handled by 1 servo located in the middle of the truck, which pulls on some rather loose servo savers. Nonetheless, it turns the wheels without much problems. This thing towers over most other R/C cars and trucks, coming in as a cube: about 15" long, 13-1/2" wide and 14" tall.

Performance And Such

The following review is based on the "stock" performance of the truck. Performance of the truck with hop-ups and modifications is noted in that section below.

It should be no surprise that the Bullhead handles and performs nothing like any of my other buggies or trucks. Size and weight are the immediately obvious factors. The high center of gravity, extremely wide tires, short wheelbase and lots of play in the suspension definitely contribute, though.

The first time I ran it, I was surprised by the speed. Despite the weight and miscellaneous reviews I read, this truck is much faster than I thought it would be. Of course, it's nowhere near as fast as the Hummer and in a race it would be hysterical to watch it compete with a race truck like an XXT or RC10T3, but it cruises along at a very fun speed.

Handling is not what I expected. The short wheelbase means that a small bump up front is also felt in the rear. In other words, if the front is going to catch any air, so is the rear. Somehow, the truck remains upright on tight turns. You would expect that the high center of gravity and side-to-side play in the "4-link suspension" would allow enough weight to shift to make it easy to flip. But it doesn't. I can only assume that the wide tires handle the displacement well enough to keep the Bullhead right-side up.

One day when trying to go over a curb in the parking lot at work, I discovered quite the interesting feat this thing is capable of: it can be flipped, 360 degrees. I approached the curb a little faster than I should have, the front popped up in the air, fell backwards, continued to roll, then righted itself. This is most impressive, and got many "oohs and ahhs" from the crowd. The shape of the semi truck body probably makes it easy to roll like this. I doubt a Clod Buster--with the stock pickup body--is capable of this. (Can anyone comment?)

Originally, I thought the "Power/Economy" switch was kinda cool. (The "Power" mode runs the motors in parallel [for added power, with a run-time loss], while "Economy" runs them in series [longer run-time, with less power].) After a few battery packs, I decided the slightly longer run-time you get from Economy mode is definitely not worth the power loss. What's the point of having this beast if you can't run over things? I have the truck hard-wired in parallel now.

Hop-Ups And Modifications

I have snow chains on the Bullhead. Yes, snow chains. You can learn how to make your own (and see pictures), if you'd like to.

A hole in the chassis makes removing the servo arm easier.

I drilled a small hole in the side of the chassis where the steering servo is. This modification allows me to reach in with a screwdriver to unscrew the servo arm without having to take the entire truck apart just to get the steering servo out. Drill a hole in the center of the chassis, 1-1/8" up from the bottom. Of course, if you've got a dual-sevo steering setup this is a moot point.

I have replaced the mechanical speed control with my old Futaba MC210CB Electronic Speeed Control (ESC). Since I'm using the stock RS-540 motors I don't have to worry much about overheating, but I think anything more powerful would require a better ESC. When I put this in, I also re-did the wiring, eliminating the "Power/Economy" switch. Of course, the hard wiring is done up in "Power" (parallel) mode.

Suspension

The shocks that come with the kit visually complement the kit well (they're bright yellow), but they're just simple friction shocks. And we all know that friction shocks aren't smooth at all and provide very little dampening effect. So I replaced them with Associated's T-Maxx/E-Maxx set of eight oil shocks (here at Tower Hobbies). You'll need a few extra screws to add them, too.

They work fantastic and do a great job of smoothing out the ride. The truck bounces a lot less and that means the rubber is sticking to the ground better, offering more speed and control.

Lighting

Working headlights and foglights have been added. I can drive the truck at night! A receiver battery pack (4 AAs) run power through a receiver switch to the lights. The lights are intended to be run off the main battery pack (6 cells) at 7.2 volts; 4 AAs provide only 4.8 volts, resulting in slightly dimmed lights. I'll add a few extra cells later.

I intend to re-work the Juggernaut 2's five roll bar fog lamps to fit on the Bullhead's roll bar. I'd also like to add some more traditional rig lights--running lights, brake lights, etc. Eventually, this will all be controlled through the transmitter.

Steering

I have ditched my Futaba S-148 steering servo for something stronger. Tthe Futaba did an admirable job of trying to move these four big tires; but let's face it, something stronger is necessary. I replaced it with a Cirrus CS-80 2BBMG Super-Torque servo. This is a much better, albeit slightly slower (0.25 sec/60-degrees versus 0.21 sec/60-degrees response) servo. It's a much more powerful servo, though (129.86 oz/in versus 42 oz/in of torque). The extra strength of the servo is most appreciated; the speed loss isn't even noticeable. However, this servo still can't turn the wheels at a stand-still.

I plan to move up to a dual-steering servo setup eventually. A servo will be mounted between the bumper and gearbox. JPS offers some stuff to aid in this. I'm sure I'd need a digital FET servo (~200+ oz/in of torque) on each gearbox to easily turn the wheels.

What The Future Holds...

Of course I'll get a full set of bearings. I plan to get a Novak Super Rooster, Tekin Titan or something similar. (I'm open to suggestions.)

There are a great number of hop-up parts available for this and the Clod (most from ESP), and I'd like to get some of them in the future. A wheelie bar is first on that list, along with some of the stronger aluminum suspension components. I have no plans to get any of the racing chassis kits. Some winter I'm sure I'll buy one of those nifty ESP snow plows, too.

2004/08/24 Update: I really haven't played with the Bullhead much the past few years, so haven't upgraded anything. I don't know that I will, ever!

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