Tamiya Tamtech Gear GB-02 Buggy Champ Review
29 February 2008.
My wife got me this for my birthday after I read the excellent
review on Oople.
It's a cute (roughly 1/16th scale) version of Tamiya's classic Rough Rider.
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The first thing I wanted to do was yank the buggy out of the box, but it was secured with zip ties.
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The buggy
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The chassis
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Buggy Champ and my future buggy champ.
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Size comparison. From left - Team Associated RC18T, Tamtech Gear GB-02 Buggy Champ, Team Losi Mini-T
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The rear. Despite the warning label on the motor can, I couldn't even get it warm with the stock gearing.
It's fun to drive around a confined area like a kitchen floor. When I took it to a small indoor track, I suddenly
realised how miserably slow this motor was. Time for the hop-ups...
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I swapped in my FM receiver and put some Dean plugs on the battery-to-ESC connection.
I had two sets of 3Racing Mini-T shocks lying around so I installed four rears all around.
The yellow springs came with the 3Racing Mini-T shocks and the green ones came from the Mini-T spring set.
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The 3Racing Mini-T dampers seemed decent on the table bounce test but I didn't like how they fit to the Tamiya studs.
3Racing included their own studs with their shocks but they felt a little too easy to screw into the holes so I guessed they were 2.5mm thread
instead of Tamiya's 2.6mm.
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In the end, I went out and bought Tamiya's plastic CVA shock set (40529). Despite toy grade looks, they work pretty decently. As mentioned in
the Oople review the springs are too long.
Mini-T springs look like they might fit though. Also, the provided Tamiya #200 shock oil was too soft for my liking.
I used Tamiya's #300 all around.
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The front shock shafts are only 3mm shorter than the rears. Only one type of piston is provided.
You have to be very careful with the E-clips since only one spare is provided.
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This is the Tamiya Tamtech Gear Sports Tuned SPT (40537) motor. It has a red endbell and is faster than the Non-SPT Sports Tuned (40514).
Since the buggy came with a whole bunch of plastic pinions, I stuck on the biggest one (an 18 tooth).
While it was much faster, the buggy was still not going round the carpet track as fast as I wanted.
The ESC and motor barely got warmed up after one battery pack.
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The rod on the left is the stock hingepin that holds in one of the arms. The one on the right is an outer hingepin from a TL-01 (part 53301).
As you can see the TL01 rods have the E-clips just a tiny bit further apart than the stock one, so I used these to mount the lower arms further out.
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I had to add about 1mm of spacers and shims on either side to take up the extra space and push the arms outwards. With the stock setup, you had to
bring the lower pillow ball out quite far to get some negative camber. This mod helps keep the pillow ball 1mm further into the lower arm.
Now that I had more space to play with, I also loosened the upper pillow ball by about half a turn, which I found gave me more steering lock.
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In this pic, I'm running Mini-T optional green rear springs and red fronts with the thinner preload clips all around.
The front was a bit too soft. I have now changed the front to Mini-T orange springs with no preload clips and that seems better.
I think it can handle much more speed so my search for a faster motor continues...
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I didn't like the softness of the stock servo saver, so it was time to put some beef into the steering.
The obvious option was to install this 3Racing bellcrank set. While I was at it, I put in this Hitec HS85MG.
I have also heard that the HS225MG is a good fit but they are hard to come by. The problem I have with these Hitec micro servos
is that they use an odd size M2.3 screw. I couldn't find anything like it but got some 2/56" screws, cut down to 8mm which
worked fine.
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The Tamiya pin that held in the left bellcrank was slightly too thick to fit through the 620 bearings that came with the 3Racing set. Luckily, the
pin was made of some soft metal, so I wrapped some 400 grit sandpaper around it and turned it with my hand to reduce the diameter slightly.
The pin only needed a very tiny amount of slimming down, so if you have to do this, be very careful and work slowly.
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Since the 85MG is smaller than the stock servo, I have enough space to tie up and tuck away some of the wires.
The plug is just small enough to squeeze through one of the round holes on the servo top plate. This servo is also slightly thinner than the
stock one, so the output shaft sits a little lower than it is supposed to. You could put some servo tape under the servo to correct this, but I
only thought about this after the install so I didn't bother. I just used two layers of servo tape on the top surface of the to keep it
squished in securely.
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viking252 from the one18th.com forums mentioned here that the steering
angles were all weird on the GB-01. When turning, the inner wheel that is supposed to turn more actually turns less than
the outer wheels. The 3Racing rack actually make things worse. You could put in some toe-out to help this but the buggy would be very
unstable at high speeds. What he did was mount the ball studs on the bellcrank pivot joints. This can be done if you use the GT-01 steering
setup (either Tamiya or 3Racing).
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The reason the Ackermann got worse was because the 3Racing set is an aluminium copy of the GB-01 steering setup.
The GB-02 steering cross bar is an improvement over this and has the ball studs closer together and lower.
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In the end, I went back to the original GB-02 cross bar.
My earlier assumption that the slimmer servo sits lower was wrong.
As you can see, it actually sits a little higher and puts the steering rack at a slight angle.
I suspect the ears on the side of the servo are propping it up. I'll need to file down the ears some.
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