A quick look at the Kyosho Twin Force I have been running up and down the back garden!
For those that have never heard of it, the Twin Force is a 1/8th scale electric monster truck (seen above crushing my poor Tamiya TT-01). Twin Force standing for twin motors and twin battery packs. Technically it is pretty interesting and unconventional, especially when compared to it’s main rival, the Traxxas E-Maxx.
From the side with the body on you can sort of see the solid axles that this truck runs on (shared with the Mad Force nitro truck). This was a pretty unusual setup for a truck released in 2004, with most of the other monsters on the market preferring independent wishbone suspension. These solid axles mean the the TF is a very popular base truck for crawler conversions.
The front gives a better view of the solid axle – that is a 1/8th scale buggy gear diff in there so nice and sturdy with option to upgrade. The control arms for the axle are solid as well, this does limit suspension articulation (which is both a good and bad thing as it also limits roll), crawler conversions generally change them to rods and ball ends.
The axles are supplied pre-assembled with grease in the diffs. I stripped them to check the assembly and they were spot on. I did find that one of the axles had a slight high-point when turned however that is not noticeable once assembled and probably bedded in after the first run.
Two 7.2V stick packs and two motors means a lot of cable. I have left it with the supplied Tamiya plugs for the time being.
Inside the radio box. Futaba R133F receiver and Kyosho Perfex KA-6 speed controller. The KA-6 hasn’t blown me away with its performance, braking seems pretty weak and low speed control is not the greatest, but it does the job.
One tip here – I drilled a small hole for the antenna through the side of the radio box instead of threading it out through the rear. As well as making the antenna route more direct it should reduce the risk of interference from the power wires.
Two 550-size motors drive a single spur with a slipper clutch, then CHAIN DRIVE takes the power down below. Take time assembling this area of the car, making sure everything runs freely. It is easy to overtighten and misalign parts causing unwanted friction. Correct setting of the gear mesh and slipper is important too, the pinions should have a little backlash on the spur gear, the slipper is very loose on the factory setting and will benefit from a little tightening once you have got the car running.
Down below there is a one-way drive to the front and fixed to the rear, the freewheel effect on the front axle makes this big truck turn very sharply off power, surprisingly nimble.
Better view of the solid axles and steeply angled shocks. For a very simple design with plastic bodies they make a very plush setup. I used Much-More #300 oil instead of the Kyosho mystery mix.
The steering arrangement is quite unwieldy with lots of long links, some curious angles and a very soft servo saver. You also need to find and modify a big, heavy duty servo horn to get enough travel. However it does seem to steer well on the move. Kit settings give quite a lot of toe-in, so I have shortened the wheel links to get closer to zero toe.
A high-torque servo is recommended, I am using a Futaba S3305 which is decent value at around £35 and has enough power to turn the wheels at a standstill.
Rear end just uses fixed links (they are Inferno wheel axles by the way), however you could fit steering to that end too with a little clever thinking, this is another thing the crawler people do.
What’s it like to drive? Well, the standard motors are not slow, but I wouldn’t say they are fast either. A high-voltage brushless setup would be a lot of fun, and the chassis and drivetrain look like they could handle it with ease. The solid axles don’t ride the bumps so well, so it can be a bit lively on the rougher bits – but that just adds to the smile this truck puts on your face! Crank the slipper tight and you can wheely ’til the cows come home!