My latest rc car is this cryptically named I10MT which is distributed by Integy, built by River Hobby. The MT stands for Monster truck but the first thing my 7 year old said was "That's not a monster truck." I'd have to agree, it is more of like a 4wd truggy with big tires which is exactly why I was attracted to it.  Well, that and the fact that the brushless version of the kit ships with a 3S lipo battery.

A preliminary internet search turned up an identical FTX Carnage being sold in Europe but very little information on the US version which was released sometime in late 2011 as far as I could tell. It looks I was going to roll the dice. The pictures above are from the River Hobby website and the chassis looks strikingly similar to a myriad of other 4wd buggies/truggy's/monster trucks out there by various manufactures'. One feature with this iteration I really liked was how the rear tie plate attaches to the motor mount, rear differential and to a pair of outriggers near the edge of the chassis.  Most of the competing chassis designs just use a single upper brace up the middle which really doesn't do much to fight chassis flex around the motor/gear area.

If I have learned anything from these sub $200 dollar cars it's that it is cheaper in the long to pick up a second one right off the bat for use as a parts car than it is to buy parts as they break.  With that in mind I got this discounted brushed version from the Integy scratch and dent section of their website with the intention of buying a brushless version down the road if it looked like a decent car to invest some time and money into. I also ordered the optional wheelie bar.

 Two weeks passed before the car showed up in a non-descript cardboard box (the website did say there was no packaging). In the box was a very cheap looking 2 channel AM setup, an 1800mah NIMH battery and a small wall charger.

The power plant of the brushed I10Mt is a generic looking 550 motor which is connected to an ESC who's label claimed to be 2S lipo ready. I am thinking ESC's label was writing checks that it's battery connector could not cash.  Does anybody even sell a lipo with that style connector on it? We loaded up transmitter with 8 AA's, charged up the 6 cell battery the car came with and headed outside to see what the car could do.  To say the performance was a little underwhelming is an understatement.  I'd guess the max speed to be around 20mph with the wheelie bar just along for the ride. The car did corner nice but at that speed what wouldn't?

The biggest issue I noticed during the run was the steering servo arm had too much travel with no way to adjust it on the supplied radio.  At full extension the servo was causing the servo saver to pop up and full retraction the bell crank arm was hitting the servo. There might have been enough travel in the turnbuckle to shorten the arm but why was it not set properly from the factory? If you didn't know to check for it you'd be on the way to a busted servo.  Now keep in mind I didn't pay full price for this kit but I was starting to feel like I had made the wrong choice as I set the car down on the workbench after the first run. Maybe it just needed a little more onion....

So out came the anemic brushed motor and speed controller and in it's place went my Castle Creations SCT ESC and 3800kv motor. I also ripped out the AM receiver and replaced it with a 2.4GHz receiver that I bound to my Fly Sky FS-GT3B transmitter. The servo travel issue was solved by dialing back the endpoints of the servo throw on the transmitter 20%. With the new power plant plugged into my 2S 30C 5000mah Turnigy lipo I headed back outside for another go.  The car immediately put a smile on my face. Despite a top speed of only 30mph (radar verified) the car seemed way faster.  We figured it had to be the acceleration afforded by the 4wd system because it just launches hard and gets to top speed nearly instantly no matter what the surface with little to no tail wagging. The buggy is also incredibly stable despite it's tall stance. We found it near impossible to roll on the pavement even taking hard corners at full speed. Roughly 25 minutes later the buggy was back on the bench and I was already starting to think about the next modifications to make this a good basher.

The first thing that needs to be addressed is guarding the gears.  Other variations on this chassis design have gear covers but for some reason this one does not. Both the spur gear and motor set just above flush with the underside so I foresee a lower chassis plate in this cars future along with some foam panels to isolate the gears from debris.

Here is the lower chassis reinforcement plate I came up with.  The sides are bent to match the 45 degree angle of the oem chassis tub and make this piece far superior to a simple flat plate. The area under the spur gear did have to be clearanced slightly due to the gear being out of round. Every hole in the original chassis was transferred over to the reinforcement late so I could remove all parts without having to take the plate off.

Now I just need to come up with some guarding for the gears to keep dirt out. Still experimenting with foam blocks.

I also see the need for a more flexible and basher friendly bumper.  The stock bumper is rigid to the extreme with no give whatsoever. My T-Bone Racing bumper from my Desert truck nearly fits, I may drop them an e-mail in the morning and see if I can get one made with a slightly different bend and no holes. A bigger bumper would also afford some protection for the front shocks which are mounted to the front of the a-arm.

No complaints about the suspension other than the shocks seemed a little light as far as dampening goes.  I swapped out the stock oil for some 35w shock oil which made it feel much better. I could now drop it from 3 feet with no bottoming of the chassis.

The stock tires seem to hook up real well in loose dirt and grass while still allowing for power slides on asphalt. I am pretty sure my Dirt Paw tires mounted on HPI rims will work with these hexes when the time comes to try a more aggressive off road tread.

The body actually seemed a bit beefier than my Losi Desert Truck body but I still went ahead and coated the inside with Gorilla tape.

Update 1-31-12

Managed to run several battery packs thru the car and everything was running good until I ventured off-road and a stray pebble wedged between the pinion and spur gear which took out a bunch of teeth on the spur gear.  Yep, first run off road and the spur gear is toast.  As luck would have it the spur gears are backordered till March!

My foam block guarding idea wasn't working  out (too many gaps to fill) and the more I thought about it the more I am leaning towards just making my own motor mount plate with an integrated gear box.  I have a Hobby People Tempest spur gear guard #143766 on order (uses a very similar chassis), if I can adapt it great, if not I started on a plan "B" as seen above. 

The Tempest spur gear cover would not work so plan "B" was it.  Here is the new motor mount and spur gear bearing holder.  I lightened it up as much as possible but may go back and add some fins to the sides.

Slipper clutch assembly and motor installed.

The rear covers wrap around the snout on the rear differential housing.  Two pieces were used so I could remove the pinion side cover to adjust the motor, tighten the rear differential coupler, etc. The final piece is the top cover which ties into all the same points as the stock brace.  After 5 minutes testing off-road I picked up the car and turned it over and found there was about 1/8th inch of debris at the bottom of the body. None of that got into the new gear box! 

As a side bonus the whole assembly acted as a heat sink keeping the brushless motor cooler despite hard running with the 3S lipo battery.

The lower chassis plate is now rev "B". It is now .06" thick and made from 6061 which is harder than the 5052 I used for the prototype.  The sides are cut much shorter to shave some weight, I added clearance holes for a number of the screws to reduce the number of longer screws required at assembly, the nose area is narrowed up and the rear portion has some small outriggers which support the rear suspension droop set screws better (that's what I think the set screws are for).  The last change was due to discovering that the stock plastic chassis was flexing enough to allow dirt into the rear gearbox.

As you can see in the pictures above the brushless version of this truck finally showed up the other day. This one I have been messing with was an open box special which was destined to be a parts car. I think it may have been an early production tester because there are quite a few noticeable differences between the new and old one.

Some of the small changes I spotted were the rear wing was now bolted on (first one was taped and promptly fell off).  The wheel nuts are also different and there is an additional star washer under them.

Chassis changes included some new stiffening ribs up front as well as some new unused mounting holes in-line with the spur gear (future gear cover??).

The upper chassis brace is now spaced up a few millimeters by a bunch of blue spacers. This does allow them to mount the receiver on top of the steering servo and makes getting the battery in and out easier. Also noticed the brushless version has bearings on the input shaft of the gearbox where the brushed version has bushings.

When I went to heat shrink the front axle joints I was pleasantly surprised by a new design which utilizes an o-ring to retain the cross pin if the set screw should work loose. The axles in the second photo are from the first car and you can see where I melted some heat shrink tubing around the axle joint to keep the cross pin captured.  Not sure if the axle change is due to the brushless power plant, the spare parts list only show one style front axle assembly for both kits.  Upon further examination I did notice some rub marks on the smaller axles so they may not have allowed enough suspension droop before binding.

Obviously the power plant is different.  The brushless version comes with a 3000kv motor, 60 amp esc, 3S 3250mah hard case lipo battery and a 2.4ghz radio.  On 2S power the car does about 30mph which feels just about right for bashing.  By that I mean there is enough power for high speed blasts and instant acceleration with no sign of wheelies.  The 3S lipo adds another 5-8mph which makes close quarters driving a little trickier.  Still no wheelies and I actually ditched the wheelie bar since it tends to get mangled in botched landing attempts.  Maybe stickier tires would allow for more wheelie action but to be honest if I wanted to do a lot of wheelies I would just buy a Traxxas Stampede.  I definitely like the extra speed the 3S lipo allows but after about 6 runs I am averaging a breakdown roughly every other run. I have my doubts this thing can hold up to the power for an extended period of time.

One of the first breaks was due to the rear gearbox slipper coupling set screw coming loose (despite my blue loctite).  I am now using red loctite. Also lost a front brace screw, again more loctite and some new screws fixed the issue. After another run the rear shock mounting screws were pulling out of the plastic shock tower. Loctite won't fix that so I added a longer (25mm) bolt that now extends all the way thru the body post mount and capped it off with a nylock nut. Keen eyes will notice the button head screw just behind the nut in the second picture is also pulled out of the plastic a millimeter or so.

Two runs later the bolts from one of the front steering arms had pulled out of the upright (steering knuckle). It looked like there were only a few threads of the bolt engaged in the upright.  I ran a tap thru the holes to clean them up and then put a slightly longer button head bolt in which about doubled the thread engagement. 

These parts really need to be metal or have helicoil inserts in them.  I could not get a good, clear picture of the threads but it looks like the manufacturer is just using the fine thread hardware to create the threads instead of a sharpened steel tap.  To be fair my Losi Desert Truck is put together the same way but the threads are a little better due to the 4-40 hardware which is a course thread.  On the I10MT it looks like for most of the fasteners you can either substitute a longer screw and nut or add helicoils if the threads strip out. I went ahead and added helicoils to the uprights and steering knuckles knowing they would be subject to a lot of abuse.

Upon further inspection the true source of the failure looked to be the front axle joint cross pin which was sticking up nearly thru the retaining o-ring.  The set screw didn't seem loose but it definitely was not holding in the cross pin in place and since there wasn't much room for the bell of the cvd joint in the axle upright (knuckle) it looks to have popped the steering arm off. Many manufacturers use this same crappy design in their axles and drive shafts and it just doesn't' hold up to the kind of power a modern brushless system can put out.  Since these axles have a groove in them I decided to wrap a piece of bailing wire in the groove in place of the o-ring, then I TIG welded the ends of the bailing wire together.  With this setup the set screw is no longer needed to hold the cross pin. 

For axles that don't have a groove I don't see why you don't just press a sleeve on over the bell?  After debating steel, plastic or aluminum I ended up making some small steel rings so I could use bearing retaining compound to set them in place in case I needed to swap out the dogbone down the road. I made a similar setup my Losi Desert truck axles.

Update 2-11-12

Never heard back from T-bone Racing on either the new bumper design or a Desert Truck bumper without holes but I think a better solution presented itself.  The above is a Traxxas Slash 4x4 bumper (#6835) I bought to put on my Son's Stampede.   As you can see it got caught up in an experiment and never made it to the Stampede. With some trimming along the blue tape line...

...and four new holes it fit the front end of the I10MT like a glove.

The bumper not only looks nice but it is very flexible so it will give the front end some much needed energy absorption.

Update 2-22-12

6 more runs later and I have managed to break a front axle shaft, broke the mounting ears off a steering arm, swapped out the pinion which was looking mangled, broke a set of body mount posts and later the rear shock tower after landing the car on it's lid. Ended up making some aluminum shock towers to swap in for the plastic ones, not sure if I'll attempt aluminum steering arms. 

A more concerning problem is the dirt collecting inside the rear gearbox.  I noticed some dirt in there when I had the car apart to mock up the spur gear box so I used a little silicone between the differential housing and chassis to ensure a good seal. I was hoping it was just a fluke.  After a few more runs I tried swapping in the brushed motor to give it another go and discovered I needed to modify my motor mount to accommodate the bushing on the front of the motor. While I had the car apart I discovered even more debris in the rear differential housing (none in the front yet). My first thought was the chassis is flexing creating a gap between the chassis and differential housing but it seems unlikely with the reinforcing plate I added, especially considering all the bolts were tight.  The only other way I can see dirt getting in there was thru one of the wheelie bar mounting screw holes which actually went all the way thru into the housing.  However, some of the debris seemed too big to fit thru that hole (I filled it in with silicon anyways).

Oh and in case you are wondering, the brushed motor came back out after one battery pack.  It was just too painfully slow.

At this point I will say I think this car as it is priced today (roughly $169 brushed and $269 brushless) is way overpriced.  Between the glaring design flaws, constant breakages and terrible spare parts availability there are way better options out there which really is a shame. The brushless version does perform well, is fun to drive and it looks unique in a sea of short course wannabes but most people want to drive more than they wrench on their cars.  If you like to tinker you may be able to overcome some of the design flaws and make something of it like I have but it's definitely not a good basher in any sense of the word.  

For comparison: my kid breaks his Traxxas Stampede (almost) weekly.  After just a few weeks of ownership (keep in mind he's 7 and this is his first real RC car) he has destroyed a servo saver, two front bulkheads, the servo case, wheelie bar, front shock tower, front chassis brace, one shock end, two T-Bone Racing front bumpers, one a-arm, bent a hinge pin and burned up the stock brushed motor (it has run hot from day one). The saving grace is you can walk into Pep Boys (a local auto parts chain) and pick up many of those parts on a Sunday morning to get it running again, or you can buy a rolling chassis off of E-bay for roughly $35 shipped and have a majority of the commonly broken parts on hand. With the Integy I10MT it is the opposite: parts availability is severely lacking with orders from the sole source Integy taking weeks to be fulfilled. Definitely buyer beware.