Force RC HammerJaw review

[Jim85IROC]

I caved and bought a Hammerjaw when they went on sale for $130. The truck arrived last week and I've had a chance to look it over, and to use it very briefly inside.


The truck is made by HSP, and because of that, it shares a lot of simularities with other vehicles like the Redcat E10 and the Gen7. It's almost identical to the RGT Rock Hammer, though there are some minor differences.



So far, I'm pretty impressed. The truck looks like it will have some definite drawbacks to address, but my overall impression is very positive. The truck is pretty nice overall. The body looks ok, and is narrow to avoid interfering with obstacles or the tires. The interior is pretty nicely detailed, and even has a flat black finish instead of being glossy.

The track width is pretty wide, and the narrow body makes the track width appear even wider.

Quality control on decal positioning is, well, a bit lacking. :lmao:

The axle housings have a newer, more robust design than the Gen7 and RGT Rock Hammer design. The shock & link mounts appear to be very robust, as do the c-hubs up front. The plastics throughout the truck feel very good. They're not soft and flexible like Axial plastics. They don't seem like they will be brittle, but I guess time will tell. Internally the assemblies use the same plastic spools that the E10 comes with, so they will be a definite weak spot. The servo is a ridiculously slow, somewhat torquey metal geared unit, and the steering links are all metal.

The front axle assemblies use dogbone axles and they seem to have a reputation for breaking. I'm not surprised. This close-up shot shows voids in the axle itself.

The axles are my primary source of concern. The plastic spools are a cheap and easy fix. HSP and Redcat sell the 180009 aluminum lockers are plentiful and cheap. The bigger problem is these dogbones. They are apparently fragile, they limit steering angle, and they're hard to get. I'm going to need to source some alternate parts here. There's got to be some dogbones out there that work, but ideally, I'd like to get some Wraith CV axles and an Axial locker. I'll need to dissect my Bomber to see if those will fit.



From the bottom you can see that this utilizes a 4-link suspension with all aluminum links. The center skid is exactly the same as what's in the E10 and Gen7 trucks:

In addition to having the same skid as the E10 and Gen7, it also has the same transmission. Like those trucks, it has plastic gears and no slipper clutch. With these 2.2 tires, that could prove to be another weakness, especially if upgrading to brushless power. Fortunately, Redcat offers metal transmission gears that should be much stronger.


Underneath the body the vehicle uses a twin-vertical-plate setup much like you would see on a solid axle monster truck. The plates are aluminum and they feel really solid.

The layout is pretty well done. The motor & trans are mounted low in the center of the TVPs. The ESC/Receiver is mounted to the rear, and the battery tray is mounted up front where the weight can help with crawling.

The ESC/Receiver combo is pretty basic, but at least the truck utilizes a 3 wire servo, so upgrading that won't be a major hassle. The controller is the same one that comes with the ECX Barrage. It's nothing special, but it's got all of the throttle and steering trim adjustments that you need, and it works just fine. I did find that out of the box, the steering dual rate was all the way up at 100%, which allows the servo to push the wheels past the limitations of the dogbones. This could be one of the reasons that a lot of guys are breaking them so much.

The battery tray is forward mounted, which is nice. It does seem like it's a little high up, but it looks like there's room to move it down slightly.

Overall, I'm really pretty impressed with this truck. It's got it's shortcomings, and some of them, like the front dogbones, may be pretty major. But, I have to be honest, this truck is a lot better built than I expected for $189, and at $130, buying this is a no brainer!


Here's my video review for the truck.


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The truck is available on Amazon, as well as through Tower Hobbies or directly from Horizon:
https://www.amazon.com/gp/product/B...rc-20&linkId=efaa9ac4cca709d024c4fd84bb244059

 

[Jim85IROC]

well... I'd hoped to have some pics & running footage from the truck's first outing this weekend, but unfortunately I managed to break it before I even had the chance. There was a steep embankment that I was running the Hammerjaw and the Bomber on, and both of them took more than a few tumbles down a steep concrete drainage trench. On its last tumble, the Hammerjaw must have landed on the front tires, because the servo locked up tight and the steering won't move at all now.

Prior to that happening, I did get up the hill a couple times with it. In the loamy dirt that this hill had, the stock tires didn't work real well, and the truck could have used more wheel speed, but it did pretty well all things considered. Considering how many tumbles this truck took, so far I'm very impressed with the durability of the axles & suspension components.

Once I get the servo replaced, I'll get it back out for more abuse.

 

[smog]

Great review. Best part of the video is where you slam your fist on the tire to show how hard the foams are:ror:

I looked at this rig originally after reading a review in RCCar Action late last year. There was something about it I liked. After reading a few user reviews reporting they busted the axles on their first run I changed my mind.

Interested to see what comes of your upgrades. Thanks for posting this up Jim.

 

[Jim85IROC]

I'm not surprised that people are breaking axles. Out of the box the steering dual rate is turned up too high which causes the dogbones to bind in the cups. That's absolutely going to break parts. With that dialed back, I'll honestly be surprised if axles break with the stock tires and stock motor. Unless you get the tire bound up solid by doing something stupid, there's not enough traction and power to break the dogbones.

The axle housings themselves seem to be pretty tough. They're a nice hard plastic, and they're thick. I took some pretty nasty tumbles yesterday and other than killing the servo, nothing happened.

 

[Jim85IROC]

Last night pulled the stock servo off and performed an autopsy. All of the gears are intact, but the shaft that supports the center gears is bent, which is why the servo is locked up solid. To be honest, I'm amazed that the truck took a hard enough shot to bend that shaft and didn't cause any breakage to the chubs or even the plastic servo arm.

I did discover that this truck uses all phillips hardware except for the axles themselves, which are hex.

I replaced the stock servo with one of the DS3218 Pro servos that I recently bought. For now I'm running it on the stock esc/receiver to see how it copes. This servo is MUCH faster than the stock servo, and seems to have good torque even when powered by the stock esc/receiver. I can't wait to get it back out!

 

[fomoco]

I had the force deep woods same as the hammer jaw, I installed axial lockers, wraith universals, redcat steel tranny gears, also axial knuckles will work, the wraith universals have to be cut down an you gotta shim the axial pinion , these mods worked great gained 75 percent more steering an made the whole truck more solid, ran mine for couple months after the mods then sold it to a new guy wanting something for his son getting started in running trails, they are still running it an nothing has broke yet

 

[Shinchu]

nice! still on the fence about maybe surprising my father in law with one. he STILL hasn't bought a new rig for his second trip to proline this year. last year he had a near stock kit yeti and it gave him a bunch of problems.
he shows interest in a 2.2 style rig and this seems like a great way to get started in this type of rig.

fomoco thanks for the tips and smog i too was pulled in by the article in rc car action.

thanks for posting this and the price drop makes it even more tempting...

 

[mattfentress13]

I had the force deep woods same as the hammer jaw, I installed axial lockers, wraith universals, redcat steel tranny gears, also axial knuckles will work, the wraith universals have to be cut down an you gotta shim the axial pinion , these mods worked great gained 75 percent more steering an made the whole truck more solid, ran mine for couple months after the mods then sold it to a new guy wanting something for his son getting started in running trails, they are still running it an nothing has broke yet

Did you buy 2 sets and cut the 2 long ones? Also did you buy 2 sets of axial brand universals? Hate to spend $80 bucks just on axles but gotta pay to play I guess. Thought about cheap wraith cvds too but seems everyone prefers universals?

 

[Jim85IROC]

Hopefully I'll have some video soon, but I wanted to post an update. I finally had a chance to get the Hammer Jaw on the trails, and what a trail it was! I found an absolutely amazing crawl spot near Carlisle PA and I brought a few trucks along. I drove the Hammer Jaw back to back with my Bomber, and also had a buddy there with his Bomber so that we could do a good comparison between the Hammer Jaw and the Bomber.

Overall, the capabilities of the Hammer Jaw surprised us both. The truck was able to go pretty much anywhere that the Bombers went. For most obstacles, the truck drove very similarly to the Bombers, but on some of the more extreme obstacles, their differences became apparent, and resulted in slightly different lines being best. The Hammer Jaw has a smaller skid plate than the Bomber, and has a slightly shorter wheelbase (it may have more ground clearance too, I need to check). These differences made the Hammer Jaw less susceptible to getting hung up over obstacles. More than once I was able to drive the Hammer Jaw right over an obstacle that the Bomber would high-center on. The tires & overall grip was an area where I expected the Hammer Jaw to have a huge disadvantage. Both my Bomber and my friend's are using Rock Beast II tires with the Alien compound. I run the Rock Beast foams, and my friend runs CI foams. The Hammer Jaw is rocking the factory tires with the factory foams. These tires felt mediocre at best when I fondled them during my original review, and the foams felt like the same memory foam as the Gen8, and had the same rock-hard attributes in cooler weather. On the trail, both of those observations turned out to be false. This truck seemed to grip almost as well as the Bombers, albeit in a different way. The truck is substantially lighter in weight than our Bombers, and in warmer temps, the stock foams are much softer than they were in cooler temps, and also softer than what we have in our Bombers. The light weight with the soft foams worked great, and on rocks, these tires worked surprisingly well.

So, now that I gushed at how this $130 truck worked almost as good as our $800 & $1k Bombers, what's the down side? Frankly, not much, but there were a few negatives that I need to point out. First, the stock servo is fairly weak, but since I broke mine in a hard tumble on a prior outing, I've already replaced it with one of the no-name 20kg servos. Even that servo is fairly weak on this large tire truck, but that's likely due to current limitations of the stock ESC as much as it is the servo itself. Next is the stock lockers. During the truck's first run up the hill, the front locker stripped, which left the truck with 3-wheel drive. Unfortunately, I didn't take any video on the first run, so all of my footage shows the truck in 3-wheel drive, which required me to use the throttle to get it up the obstacles instead of the slow methodical crawling that I was able to do with all 4 wheels working. My last observation was that this vehicle was seriously underpowered compared to the Bombers, though that's not really a fair comparison. Brushless Castle motors on 3S vs a brushed can on 2S just can't compare. I run my Gen8 on 3S and it's much better, so I think the Hammer Jaw would really wake up on 3S, but that would require new ESC as well as a new stand-alone receiver.

As for durability, I was pretty impressed, aside from the stripped locker, but that's a given with those plastic spools. I already had the metal upgrade lockers, but I forgot to bring them with me. After I stripped the locker, I had to "bounce" the truck over obstacles, and nothing else broke. I was nervous about the front dogbones breaking, but I had set the steering dual/rate prior to use to avoid any binding, and they held up to the abuse.

Overall, I'm amazed at how well this truck could hang with the Bombers. This truck has proven itself worthy of upgrades. After I get this video out, I'm definitely going to upgrade the truck. I may even do a full upgrade series.

 

[Jim85IROC]

I finally got that video made that I mentioned in my previous post.

I've also had an opportunity to drive the truck alongside my Bomber on my new back yard course, which has a very different style than the crawling I did in this video. On my own course, the HammerJaw's limitations were much more obvious. The biggest problem that I encountered on my home course was a serious lack of power. I would frequently get the truck into situations where it ran out of torque and required me to give it more throttle, which upset the balance of the truck. It definitely needs a better motor & esc and 3S.

But, as I mentioned above, on smoother low-traction type rocks, I felt like the HammerJaw was very good. I just wish that I was able to get some footage before I stripped the front spool!

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[mewalsh100]

It is a pretty sharp rig. How coarse are the Philips hardware? I'd be looking to swap everything out with stainless machine screws. Like smog, I checked it out in RC Car Action. It's a bummer they did the ESC/Rx combo, but I get it - all about cost control. That said, it sounds like it's really only a good set of foams/tires away from being a pretty capable little rig- and at $130 no less!

 

[Jim85IROC]

It is a pretty sharp rig. How coarse are the Philips hardware? I'd be looking to swap everything out with stainless machine screws. Like smog, I checked it out in RC Car Action. It's a bummer they did the ESC/Rx combo, but I get it - all about cost control. That said, it sounds like it's really only a good set of foams/tires away from being a pretty capable little rig- and at $130 no less!

The philips hardware seems to be the standard fine thread, so M3 stuff should be able to swap right in. The axles are all hex already, so it's just the junk on the body that's philips.

To be honest, I was pleasantly surprised with the tires and foams when I had it out. They're not great, but I think they're better than the stuff that came in my Bomber kit. BUT, the foams are memory foams, so in colder weather, they're garbage. I'm hoping to do another Bomber vs Hammerjaw crawl comparison on my own crawler course before it gets covered in snow for the year, but I'll have to run different wheels/tires because I can't use these foams at all this time of year.

The biggest issue I've run into with this truck on my course is a lack of torque. I got the truck bound up more times than I could count, and the truck just didn't have the torque to get out of it. I had to yank the throttle, which is a great way to break parts and to get the truck out of shape. Unfortunately, because of the combined ESC/Receiver, I can't just swap in a different receiver to bump up to 3S.