I guess it was inevitable. From the second I saw my first 1.9 scale crawler I knew I would eventually build one of my own, the only question was when. Although I was apprehensive at the thought of cutting up our AX10 project truck, possibly ruining a good thing, with all of the aftermarket upgrades available for the truck I knew it would make the perfect platform for this project. Meet the latest iteration of Project Scorpion, Project Blazer?
Part 6 – 1.9 Conversion
Here is a picture of Project Scorpion from when you last saw her. She was a mostly stock 2.2 competition style crawler. The truck was impressive right out of the box and with a few easy mods it was an excellent crawler.
I guess I should mention for those who aren’t used to the lingo that 1.9 and 2.2 refer to the size of the wheels in inches. So basically what we’re doing is running a smaller wheel and tire combo which results in a more scale appearing truck. Of course with the reduction in tire size comes a loss in crawling ability. You may ask yourself why anyone would want to lose crawling ability but for some (like myself) its just more interesting to run a scale appearing truck which is more challenging on the rocks. It is also a good solution for those who don’t have a massive rock wall to climb.
The first thing we needed to do is decide what parts we would need to convert this awesome truck into a 1.9 scale rig. For me it all started when I stumbled upon a ProLine 1980 Chevy K5 Blazer body in a local hobby shop. I started imagining what kind of setup I’d like to run with that body and the next thing I knew I was online placing orders for everything.
I knew from the get go that the stock AX10 chassis just wouldn’t cut it. I needed something more scale. There are actually quite a few options but I chose one of the easiest and cheapest routes, the TCS X-Trail. The X-trail chassis was designed to allow you to swap out your stock chassis to a more scale platform as simply as possible.
Here is the basic X-Trail chassis assembled. The Xtrail itself actually only consists of two black anodized aluminum side plates which you combine with various stock parts to make up a complete chassis.
Here is a shot of one of the x-trail side plates.
Another shot of the chassis side rail…
The next most important item to select, which some may say is the most important part of any crawler, are the wheels and tires. We considered various combinations and eventually settled for RC4WD Rock Stompers mounted on good ol’ HPI stock car wheels. It may sound weird that we’re mounting truck tires on stock car wheels but the reality is that the HPI stockcar rim is a commonly used wheel for rigs like this because of their resemblance to full size steel truck wheels.
Here is the tire/wheel combo all mounted and balanced. OK, maybe not balanced but you get the point. The Rock Stompers came with foam inserts which was a nice touch but as you’ll read later we opted not to use them.
If you read the previous editions of Project Scorpion you may have noticed that we opted to run a plain jane Futaba S3003 servo. Obviously that wasn’t the best servo choice for a rock crawler but when you’re trying to save every dime it can be made to work. This time however we decided to go with something that has a little more power, a Hitec HS-645MG. At 4.8 volts the 645MG puts out 101 oz/in of torque which is more than twice as strong as the standard Futaba servo we were using previously. The metal gears don’t hurt either.
One last thing we needed to decide was which shocks to use. The X-trail chassis was designed so you can use the stock AX10 shocks but since we wanted something a little more scale we looked elsewhere. RC4WD has an excellent set of shocks made just for this situation but at $60 for a set of four we felt they were a little out of our price range. Instead we chose to go a different route. We found a set of Tamiya High Lift shocks on ebay, removed the purple/red anodizing with oven cleaner, and painted them white. The result? A surprisingly scale appearing set of shocks for just $15.
Here’s another picture of the High Lift shocks painted white. At first we thought we would use these in stock configuration but eventually opted to remove the stock springs altogether and run them in a droop configuration. That allowed the truck to sit lower for a lower center of gravity and better looks.
Thats it, I think its time to start assembling our parts and see what we come up with. The first thing you’ll need to do is disassemble the AX10 and clean everything up. We decided that the green anodizing on the stock part just wasn’t going to cut it. In this situation we could have bought a set of anodized parts straight from Axial in the color of our choice but since this is still supposed to be a budget build we decided to get out our trusty can of oven cleaner out once again and paint the parts ourselves. After stripping off the green anodizing we spray painted all of the parts flat black. It definitely won’t be as durable as anodizing or powder coating but it was a quick, cheap, and simple solution.
After getting everything cleaned up the next step was to start building the truck. All of the parts from the AX10 easily swap over to the Xtrail chassis with few modifications or custom parts needed. Here is a picture of the chassis assembled with the stock axles.
Another picture of the chassis with the axles…
The Xtrail was originally intended to be run with the servo mounted on the axle just like the stock AX10. Unfortunately the axle mounted servo just doesn’t cut it when it comes to scale looks so what is one to do? Mount it on the frame! All we had to do was drill one hole, and with the help of the stock servo mounts we had our servo mounted on the left front frame rail. The only custom part needed for this setup was a custom length steering link which we fabricated from aluminum rod.
To mount the HPI stockcar wheels on this truck you need to file down the lip on the stock wheel hubs. Sorry for the blurry pic…
Here is the chassis assembled with the wheels and tires mounted.
Another with the wheels and tires…
From the top…
With the body mocked up…
With the transmission and electronics installed. We chose to keep all of the electronics we originally used for this project. After many runs in mud and water the waterproof LRP ESC is still working great and the Integy lathe motor is hard to beat.
We wanted to point out one of the flaws with the Xtrail chassis and that is the battery mount. It is almost like they never intended you to use a battery in this thing, no instructions on where to mount it, nothing. After doing some searching on google we found a quick and simple solution which is to use the stock battery mounting plate running perpendicular to the chassis held in place with nothing more than a pair of plain old servo mounts. Electronics…. Again it seemed as though TCS never planned for this sort of thing. To mount our electronics we wound up making a small mounting plate out of aluminum which we then bolted to our new battery mount.
Here is our custom made steering link. There are two ways of going about making a link like this. The first method, which we chose, is to using aluminum rod which you then drill and tap each end to mount the end links. On the other hand an easier solution is to use threaded rod and aluminum tube. You just create the link with the threaded rod until you get it how you like and then cover the threaded rod with aluminum tubing.
The Rock Stompers and High Lift shocks installed…
Thats it, here is Project Blazer…um…Scorpion ready to rock. Check out that sweet Pro-Line Blazer body!
I have to admit that I was very nervous about how the truck would perform in this configuration. The combo of the smaller tires and lower chassis made me think it would be lousy on the rocks. Boy was I wrong! Granted this truck will never beat a hard core rock crawler, but then again it was never meant to. With that said it performs amazingly well. After taking it for a quick run on the rocks we did notice that the tires seemed to be much too hard for this application. Like we said earlier RC4WD included foam inserts with these tires but even after removing them the tires were still too stiff to get enough flex for optimum traction. We may have to look into other tire choices in the near future. Other than the tires we felt the truck performed great. Believe it or not due to the lower chassis, shorter shocks, and lower battery mounting location I think this truck actually has a lower center of gravity than the stock AX10.
As you can see from the photos below we also built a custom tube bumper for this truck which really finish up its looks but in reality the bumper gets hung up more than not. Again that may be another thing we’ll have to look into in the near future.
I hope you enjoyed this build series. Now go check out the rest of the pics!
Here she is with the custom tube bumper. Sorry for the blown out picture.