CMAX #1 by new2rocks - recycled Blazer

[new2rocks]

After writing the CMAX guide and assembly instructions...
http://scalebuildersguild.com/forum/...036-CMAX-Guide
http://scalebuildersguild.com/forum/...y-Instructions

...and putting together 3 CMAX chassis (1 for an XJ, 1 for a D110 pickup, and 1 for a Blazer) in short order, with some help from my favorite tiny trucker, of course...


...there they sat without completed bodies or electronics for I-don't-particularly-care-to-admit-how-long, looking something like this:


The problem is that it takes me a long time to finish a body. Like...a really, really long time. I started on the XJ hardbody a while back, but that one needs even more than the usual amount of work due to the need to fab a floor pan and deal with a 3D printed interior. My NIP Blazer and D110 pickup bodies wouldn't require as much work, but there they sat in their boxes, unstarted, awaiting inspiration. It was getting a bit embarrassing, to be honest. So I declared this would be the summer of CMAX and got to work.

Well...sort of. As I was starting to gather my thoughts, I stumbled across a Blazer with a lousy paint job in the classifieds here:


So I jumped on it. When it arrived, I popped it on the chassis and saw just how lousy the paint job was:


Yup. Complete and utter garbage.

What to do about it? Well, I decided to try to make the most of it. First up was a set of new shoes. I happened to have a set of now discontinued raw steel 1.55 RC4WD Landies laying around, with a set of Fun Dicks looking for a home. The stock foams are mush, so I decided to experiment:


Drift tires + CI single stage foams + inside-out wheels + Fun Dicks =


Mounted up:




Now we're talking. You may have noticed the bumpers - SSD Ascender Blazer Bumper in front and RC4WD Tough Armor Blazer bumper in the rear. There's a bit of irony in that combination, but it works.

Since the point of this was to get a CMAX running ASAP, I didn't waste any time testing it out in the yard. And what better way to put it through its paces than to run it back-to-back with a TF2 Blazer:

https://youtu.be/JAo_j67EVB0

I was blown away. This thing is so stable I can throw it into a full lock turn on ashpalt at full speed (light jogging pace) without lifting a tire, much less flipping it over. Bonkers is the word that comes to mind. So much potential here. This one's going to be fun.

We're going to have some new BowHouse RC parts that will show up here this fall. And eventually, I'll get to work on the interior, but that will come later. In the meantime, I'll be using this thread to discuss various setup experiments and share some adventures. I hope you enjoy.

[new2rocks]

The first experimentation came with the axles. I originally put this together using the GCM TM8 axles:




This setup works very well. Steering is fantastic (duh). Gearing with the stock 12T LRT2 pinion and an HH Crawlmaster Pro 16T (equivalent to a 35T) on 3S was spot on for me...which is to say silky smooth at the low end but still able to pop a wheelie.

So why mess with a good thing, you ask? My biggest reason for wanting to change was to narrow the axles. The original TM8s sat at 175mm pin-to-pin (down to 173mm with the CVD update earlier this year). That width would have worked fine using a neutral offset wheel. But after seeing how the inside out Landies looked, I knew they had to stay. And that setup adds a lot of offset. Which meant I needed narrower axles to bring the tires back in.

Fortunately, the good folks at RC4WD gave me a deal I couldn't pass up on a set of the new cast K44s (approx. 170mm pin-to-pin). In case you've been hiding under a rock for the past few months, this new version of the K44 is cast instead of machined, which cuts the cost by slightly more than half. They also have a right drop front axle instead of a left drop, which is perfect for a Chevy. And they look great right out of the box:


Fitting them on a CMAX involves a little bit of adjustment to the shock mounting. The upper shock mounts for the CMAX are designed to work with shock mounts like those on the GCM TM8 that sit below the centerline of the axle both front and rear. In front, the mounts sit below the leafs on the back (diff input) side of the axle:


In the rear, the TM8 shock mounts sit below the leafs also on the rear (pumpkin side) of the axles, allowing the use of the triangulated upper mounts on the CMAX cross brace:


The shock mounting positions on the cast K44 housings are a bit different. In front, the shock mounts sit above the tube, which would have limited shock travel too much:


And in the rear, the two shock mounting positions (one above and one below the axle tube) sit to the outside of the leaf mounts, making the inverted shock position from the TM8s impossible from either of those positions. If I happened to have a set of RC4WD lower link mounts handy (say...from converting a G2 Cruiser from links to leafs), I could have used those to mount the shocks to the axles in front and rear (in the rear, the lower link mounts could be installed with the link mount dropping behind the axle instead of in front of it to enable shock mounting). But that extra set of link mounts was sitting under my Skeleton D90 (which uses the machined K44s), and I didn't care to buy entire link mounting sets (which include the upper link truss) just for the lower link mounts. So...I improvised.

In front, I moved the CMAX small shock mount back a few holes to create enough of an angle to allow the suspension to cycle fully:


That was simple enough. In the back, if I had another pair of CMAX Tiny Shock mounts handy, I could have just used those. But I didn't and wasn't patient enough to wait. So I rummaged and found a pair of rear leaf shackle mounts that I took off a TF2 (you can guess what went into their place on the TF2...). Turns out the spacing of the chassis mounting holes was perfect (nice coincidence) and the height was nearly perfect, so the only massaging to be done was getting rid of the play inside the larger than M3 hole (that bracket is designed for the TF2 shoulder bolts, which are thicker than M3 threads at the pass-through). I accidentally discovered that the tapered end of an M3 nylock nut was just the right width to eliminate that play, so I used the tapered end on either side of the shackle mount, and voila!






Let's recap for those (like LSXGMC) trying this at home. If using cast K44s or other RC4WD axles with similar mounts, your options for mounting to a CMAX include:
1. Use RC4WD lower link mounts front and rear, with the rears reversed, as your lower shock mounts
2. Get an extra set of GCM Tiny Shock Mounts for the rear, and/or
3. Improvise (as I did)

So how does the new setup work? The first thing I noticed was the gearing change. Because the RC4WD axles have more gear reduction than the Ascender-based TM8s (2.67:1 vs 1.85:1), no more wheelies. On the plus side, Bolshoi-worthy pirouettes are still just a flick of the wheel away.

I then took it out for some extended runs out at RC4WD ECSC a few weeks ago, and it did great. In fact, it landed a top-5 finish in the ultra-competitive (I'd go so far as to call it cut-throat) Class 0. And it was a blast to drive on a fun run before we all left town. Here are some pix:









Even Uncle Albert approved:


Since it's working so well as is, coming up with a more elegant solution to the shock mounts drops down on the priorities list.

[LSXGMC]

This is such a cool Blazer - excellent write-up as always.

[doubler]

Indeed. I was bored last evening watching some scale footage on youtube and I saw little ROO! He was driving what looked to be a TF2 like a boss I might add.

[new2rocks]

Originally Posted by LSXGMC

This is such a cool Blazer - excellent write-up as always.

Thank you, sir!

Originally Posted by doubler

Indeed. I was bored last evening watching some scale footage on youtube and I saw little ROO! He was driving what looked to be a TF2 like a boss I might add.

Lol...he's all business when it comes to tiny trucks.