Axial SMT10 Project

Page 3: Upgrades!

Here is the first pile of upgrades I bought. I intended this to be the only list, but I was hilariously wrong. The first thing to decide on was a power system. I like the new SMART telemetry system from Spektrum so I thought I would get the same system that is in my Lost Lasernut. I ordered the set shown which came with a 1900kV motor that I thought was correct. It was not. Turns out they also have a 1/8 scale 1900kV motor and that's what I got. It won't fit even if I thought the chassis could handle the power. You can't return motors so I am stuck with it until I find a home for it. I ordered the correct motor separately. The picture on the right shows the correct motor (upper) with the 1/8 scale motor (lower). The aluminum link braces shown on the left were intended to be for the lower links but are actually for the upper links so I needed more of those as well. The King shock bodies were at least correct, but I ended up with shock problems too.

The picture on the left shows the installation of the new power system. The 130A ESC fit very nicely and was even able to be bolted down. The motor is hidden beneath but can be seen in the image on the right. I also decided that while I had the transmission open, I should probably upgrade to a steel spur gear. I intend to run this model on 4s so it needs all the strength it can get. The battery compartment wasn't tall enough for my 4s battery so I made some minor mods to make it fit.

There are a lot of changes shown in this picture (old on left, new on right). Can you spot them all? First, I added aluminum link reinforcements to both the upper and lower links. I also changed out the shock caps and spring collars to look like King shocks. The brackets which connect the links to the axle have also been changed to machined aluminum. I've added a sway bar to the front axle to keep it from rolling over so much when the front end lifts off the ground. I also added an aluminum servo mount. This is probably the least necessary of the mods, but I thought it completed the look. I like the color Axial uses for their anodization.

There are some additional changes at the rear. The springs were much too soft which resulted in massive body roll under power. Stock rear springs have a rate of 1.32 lbs/in. I tried swapping the front springs (2.78 lbs/in) to the rear and adding the maximum preload and it was still not enough. Body roll was still enough to cause the body to scrape the tires under power, and now the front end was way too soft. I moved the stiffer springs back to the front and looked for options.

I checked the offerings from Axial, but even the stiffest 90mm replacements were not much different (3.01 lbs/in). Instead I decided to go for some 54mm 3.4 lbs/in springs. By doubling them up they'll be a little long but that allows me to back off on the preload. The springs are shown installed in series in the picture. This worked out very well. The central guiding collar was actually a spare part in the kit so I didn't need to buy them.

I destroyed the first body immediately by doing wheelies and catching the rear bumper on the ground. I found this very nice wheelie bar on eBay which bolts right on. Sadly, it is really designed to be used in conjunction with the stock tires. With my much larger tires, it is not far enough back so the truck lifts further than I'd like and is still susceptible to flipping over. It's still an improvement though.

I checked the wheelie bar after the first run and somehow this happened (see image on left). It shouldn't be possible for the bracket to wear since the roller stands proud of it, but it went ahead and happened anyway. I replaced the brackets, then decided to solve the problem by using larger diameter rollers. I found some nice wheelie bar rollers from Traxxas but they were out of stock for months so I had to wait a long time. Once I finally got them, the next issue was that the wheelie bar used Imperial units while the bearings on the wheels were metric. I had to use my drill press to oversize the stopped holes in the aluminum wheels and install 1/4" ID bearings. It all fit well enough once I got it all modified and installed. Then I tried doing some wheelies and immediately stripped out the rear differential gears (the picture on the right shows the rear diff cover off while I was investigating). Sigh. I need to rethink this model.

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