With more and more 4x4 1/10 scale Short Course trucks hitting the market it was only a matter of time until dedicated electric motors make an appearance. Tekin's Redline SC4X electric brushless motor is one of them and although (or because!) it is available for some time now we took the opportunity to put one in our Team Durango DESC410R we reviewed some time ago.
The Tekin SC5X is a 550-size electric motor meaning it sports the same diameter as a 540-size one - 36mm - but is longer in size - 66mm compared to 54mm of a 540 - which in return means a stronger magnetic field resulting in lower RPMs, more torque and reduced operating temperatures. These three characteristics tick all boxes of a perfect 4WD SC truck motor as the heavier trucks need more oomph to take off from tight corners or before taking off from jumps.
The SC4X follows the design ideas of Tekin's T8 line of 1/8 scale brushless motors with an all-T6 aluminium motor can with integrated heat sink ribs, lightened front shield and, in the case of the SC4X, a plastic motor end cap that allows for adjustable sensor timing. The sturdy motor shaft has a diameter of 5.0mm and exposed length of around 15mm ideal for most Module 1 pinion gears on the market. As most of the current 4x4 SC trucks feature a Module 1 main gear which is identical to the ones used on 1/8 scale buggies, you can easily source suitable pinion gears.
To the touch construction of the motor add a 5x16x5mm front and 1/8x3/8x5/32" rear A.B.E.C. 5 oversize bearing, both should withstand the rigours of off-road racing and bashing with not problem. The sizes also make for less need of maintenance if you clean and lube them on a regular basis. Sintered rare-earth Neodymium magnets and a 12.5mm rotor make for a strong magnetic field, keep the operation temperatures down and also maximise the efficiency of the whole set-up.
The motor comes including a 200mm sensor wire but the motor of course also is compatible with sensorless speed controllers also. We missed a manual to go with the motor or at least gearing recommendations as most of the specs and features are printed on the package but especially with the ultra-fas 4.5T motor a correct gearing is crucial. Help came in the form of Tekin's RX8 speed controller setup sheet section that fills with new setups very fast and most of them not only contain speedo settings but also motor and gearing recommendations for most of the important trucks from Team Durango, Losi, OFNA and Traxxas.
Randy Pike of Team Tekin recommends the use of Tekin's RX8 1/8 scale speed controller with the SC4X motors although we have seen similar set-ups with "1/10 scale" speedos. But as RX8 isn't too big in size and the DESC410R chassis offers plenty of space we were happy to install Tekin's flagship controller that not only offers loads of performance but also very handy menu options such as drag brake, brake strength, limiter and throttle profile to adjust the throttle and brake characteristics to your liking.
Beef-up
To make use of the brutal power of 550-size motors Team Durango recommends to convert the slipperential of the DESC410R SC truck from a slipper to a differential with the help of the #TD210031 ‘Conversion set for centre slipper-diff’. This set basically contains six gears, two cross pins and some shims to bring the centre differential to life and make the truck more controllable with high-power motors on loose and bumpy tracks - such as our test track. Instead of buying the conversion set we simply robbed the parts from our DEX410 buggy and that's why our parts don't look like new but well used. As recommended by Team Durango we filled the centre diff with 20,000 (20k) cst oil which should give a good balance between forward drive and drivability. You can of course use other oil to fine-tune the balance with thinner oils are generally better for slick and bumpy tracks while thicker oils are better suited for high-traction surfaces.
Set-up
To have a rough guide on how to set the gear ratio and speed controller, we downloaded Renaud Savoya's set-up from this year's Silver State race, a rough low to medium traction outdoor track. He used the 4.5T motor as we do with a gearing of 54/15 and adjusted the RX8 to the following settings:
Drag Brake: 0
Brake Strength: 100
Limiter: 90
Neutral Width: 5
Voltage Cutoff: 2
Motor Type: 1
Throttle Profile: 3
Below is only accessible with HotWire Software:
D2 Dual Mode: yes
Timing Advance: 85
Reverse Strength: off
Push Control: off
Track Test
For the track test, we installed both the SC4X motor and RX8 speedo into our Team Durango DESC410R truck we reviewed a while back. With the heavier components and changed drivetrain set-up we really looked forward to the test as it would be interesting to see how the changes affected the overall performance of the 4WD SC truck. 
With the recommended 15T pinion gear the 410R took off quickly, with a bit of wheel spin and very controllable despite the powerful 4.5T motor. The track surface of our test track was in the most worst condition ever as it hadn't rained for weeks making it both hard packed, slippery and sandy at the same time making it a real challenge to keep the truck where it belongs but the very drivable yet fast set-up gave us a good feeling for the throttle and also the centre differential massively helped on the rough and slippery parts of the track. Only braking lacked but this is something the centre diff is to blame for. Even thicker oil than the 20k we used may help here and should be an option if a point-and-shoot style of driving is needed or preferred. For the floating track having a less aggressive brake wasn't a problem so we stuck with the thinner oil as we felt the advantage over the rough track parts was greater than the losses "on the brakes".
The gearing recommendation of 54/15 we extracted from the team's set-up sheets proofed perfect but we adjusted the limiter two steps down (to 70) to have a less aggressive punch when coming out of tight corners. With the low ambient temperatures of around 12°C heat wasn't an issue as the RX8 speedo stayed cold to the touch and the motor never reached more that 40°C or so. With an ageing pack of 25mm 4500mAh Team Orion Carbon Saddle-Pack batteries we were able to get runtimes of around 9 minutes indicating that the SC4X can be quite power-hungry at times.
The track test also reveals that the somewhat heavy motor and speedo "can" affect the weight balance of your truck. Compared to the 540-size motor and 1/10 scale touring car controller we used before the DESC410R felt a bit heavy up front which was also indicated by a tendency to "dive" when jumping. Additional weights or Team Durango's new DESC410R rear bumper may help to get the truck back into balance but that's something that may differ from truck to truck ...
In Detail
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SC4X and RX8 The SC4X range of motors and the RX8 speed controller are the perfect bundle for 1/10 scale 4x4 "Pro4" Short Course trucks. The S4 motors are available from mind-blowing 4.5T up to milder 7.5T to suit your personal speed needs and of course the tracks you are bashing or racing on. |
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Front plate & motor screws This is important! The front plate that is screwed to the main motor case only allows for 3mm and 4mm motor screws of limited length as otherwise the screws can interfere with the motors internals! When dry fitting the motor screws in the motor mount, they should only expose around 3.0mm of thread - not more. This way you can securely fasten the motor without having to fear damages of the motor windings. |
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Technical data Team Tekin Redline SC4X - Lenght: 66mm - Diameter: 36mm - Weight: 237gr - Shaft Dimensions: 15.3mm x 5.0mm |
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Likes & Dislikes + Cool locks + Powerful + Efficient + Reliable - No manual or at least gearing recommendations supplied |
