Custom Chassis Tamiya Hummer (TA01)

[87lc2 2659]

I wanted to share my latest modification for the TA01/02 chassis.  It's definitely been done before, but it seems everyone does it differently so why not post up for others to see.  The main reason for this modification is to get rid of the original tub chassis and use a single plate to gain ground clearance.  I have quite a few M1025 Hummers and the one thing they are lacking is ground clearance, they most commonly end up being high centered when trying to do any real crawling.  I have done this before using 3mm thick acrylic, but wanted to do something different this time and ended up using 2mm thick carbon fiber plate.  It is extremely strong and easy to work with.  It cuts easily with a rotary tool, and drills nicely with sharp bits (sharp bits are critical to effectively drilling real carbon, with dull bits you'll be sitting there all day.

The first few photos are of my first attempt at this using the acrylic material.  It works extremely well and gave the clearance needed, but I thought the carbon would give a nicer look and also be much stronger with less thickness.  I still run this truck as is, works great.

[87lc2 2659]

Here is a photo in comparison with a stick chassis Hummer, you can clearly see the clearance gained by raising the chassis up into the body.

[87lc2 2659]

Some more photos of the M1025, really love this truck.  Run it on the trails almost every weekend.  Last photo is next to my fathers Cross HC6, amazing vehicle.

[87lc2 2659]

[87lc2 2659]

Now on to the new chassis.  As I said in the first post, it started as a 200mm x 300mm carbon fiber sheet purchased from Amazon (~$20USD).  I used a thin piece of lexan to make a template for the diff mounting positions using the stock tub, then laid it over the sheet and got to cutting/drilling.  With the left over material I made a battery/electronics tray mounted about 1.25" above the main plate using aluminum tube threaded for M4 hardware.   Even when using carbon fiber, you must brace the front & rear diff lower mounting points.  For the rear I made an angled skid plate that serves a few purposes; brace the chassis, protect the motor, help slide the truck over obstacles.  For the front I simply used aluminum flat stock bent to shape.  this not only braces the chassis but protects the steering linkage.

The other challenge is steering.  I originally made a drag link setup, but it was a bit bulky and ended up scrapping it.  Turns out in this case simpler was better.  I made a hole in the chassis plate for the servo arm to drop through and simply connected a link from the arm to each wheel.  Traditionally drag link setups work better (especially on monster trucks like I'm used to building), but it turns out this setup is absolutely perfect for this truck.  It turns easily, smoothly, and equally well in both directions.  My M1025 Hummer has been running this setup for over a year and not one issue.  I use a high torque waterproof servo and heavy duty links threaded for M3 hardware and have not had an issue yet, even when submerged over the hood in water.

While not necessary, I also made quite a few other modifications to the chassis/suspension to make it a legitimate crawler.  As I said earlier, I'm out on the trails every weekend through dirt, mud, water, rocks, etc. and the Hummer rarely gets stuck or is unable to navigate an obstacle.  It's obviously not as capable as an SCX10, Ascender, TRX-4, but it holds its own and since its a Tamiya its much cooler.  People always laugh when I bring it on the trail, but that ends pretty quickly when I stay right with them for most of the trail.

Both diffs are locked, running an 65t brushed motor w/18t pinion and HW 1080 Crawler ESC on 2S Lipo.  Springs are from an Axial SCX10 to give max travel and ride height.  Front and rear control arms are the shorter versions from a TA02 (This is mostly for looks, I hate how the stock Hummer a-arms make the tires stick out of the body).  Front knuckles are from a TL01 (stock TA knuckles will not work with my steering setup, I needed the TL01 straight steering arm attachments) and rear uprights are from a TL01 as well (to keep 0 degrees of toe in, dont like the toe-in with stock uprights).  Made camber links for the rear so I can adjust camber.  Wheels are from the TRX-4 tactical and tires are 1.9 RC4WD Mud Thrashers.  I think that's about it, but there may be other little things I dont remember at the moment.  The black on the bottom of the chassis & skid are just matte black vinyl to protect the carbon.  Really happy with how it came out, even better than the first one.  Can't wait to get it out on the trail.

 

[Juggular 4961]

Wow, that's some major work you've done there.  

I always thought putting a rally car chassis in Hummer wasn't such a great idea.  You've taken care of that yourself.  

I am impressed.   The floor where the servo is mounted, that's mostly empty?  I guess the shaft running through it makes it mostly unusable? 

I have a feeling I don't want to tackle this with a handheld drill, and a hand-saw.  Maybe I should do it with an acrylic board, and attach the carbon just to strengthen.  

 

[87lc2 2659]

On to the body.  I wanted to try something different as I already have a few of the M1025 military style bodies.  I bought a few of the toy-grade Nikko Hummer hard bodies from Ebay to see how they would look.  They're definitely not as scale as the Tamiya body, but they really dont look too bad once you remove the decals and do a bit of detailing.  They also match the wheelbase well enough.  I added LEDs and custom Hummer decals to make it look a bit better.  Also used wire to make actual hood slings as they come solid on the Nikko body.  Made the tonneau cover using black vinyl material I found at a local craft store and the mirrors are from the Tamiya Hummer body.  The green body will be my runner on the trails, looks decent enough for now.  For the other body I bought, I'm going to use the back cap to make a station wagon version.  So far I've just filled in all of the unnecessary holes and painted it red.  Need some more time on this one.

[87lc2 2659]

The red one...still a lot to do, but its painted.  Going to add windows to this one rather than the blacked out windows on the green Hummer.

[87lc2 2659]

3 minutes ago, Juggular said:

Wow, that's some major work you've done there.  

I always thought putting a rally car chassis in Hummer wasn't such a great idea.  You've taken care of that yourself.  

I am impressed.   The floor where the servo is mounted, that's mostly empty?  I guess the shaft running through it makes it mostly unusable? 

I have a feeling I don't want to tackle this with a handheld drill, and a hand-saw.  Maybe I should do it with an acrylic board, and attach the carbon just to strengthen.  

 

Yup, its wide open under there due to the shaft.  The main reason I made the raised tray was to keep the battery/electronics as dry as possible.  I run through deep mud/water often so the higher the better.   I did both of these using hand tools and a Dremel rotary.  Would be nice to have a drill press and other fancy tools, but not necessary.  To be honest, working with the carbon was easier than the first time around with the acrylic plate.  The carbon cuts easier & cleaner.   It is a lot harder to drill, but as long as you have sharp bits and drill a small pilot hole first it drills easily.

I wanted the Tamiya Hummer since I was a kid and finally bought my first one last year.  Needless to say I was extremely underwhelmed by the performance of it is stock form.  I like that they used independent suspension like the real Hummer and wasn't about to give up on it.  It really does perform extremely well for what it is, people are shocked when then see it run.  If you're looking to do this yourself let me know if you have any questions, more than happy to help or take any photos you need.  It's a pretty simple build and costs almost nothing in materials.

[Charles M 135]

Nice job, sadly pictures are not available :-( 

[Mad Ax 9306]

I think I missed this thread first time around, I have a stick-chassis hummer that I acquired in a trade some years back, I keep meaning to dig it out and do a custom chassis job.

@87lc2 I'd love to see the pics if you still have them  

[87lc2 2659]

8 hours ago, Mad Ax said:

I think I missed this thread first time around, I have a stick-chassis hummer that I acquired in a trade some years back, I keep meaning to dig it out and do a custom chassis job.

@87lc2 I'd love to see the pics if you still have them  

Hey @Mad Ax I still have both of my Hummers in the Showroom:

1st chassis I built was from thick acrylic plate - https://www.tamiyaclub.com/showroom_model.asp?cid=136575&id=49562

2nd was from carbon fiber - https://www.tamiyaclub.com/showroom_model.asp?cid=136576&id=49562

 

Both work really well, but I don't use them much anymore.  Funny this thread came back around today, I finally caved and purchased the HG P415 this morning.  I'm a huge H1 fan and ever since the HG came out I've wanted one but they're a bit expensive.  Found a good deal on one and bought it this morning.  It's a black wagon civilian version and should be here in a few days.  I'll start a thread when it arrives along with comparison photos to the Tamiya Hummer for size reference. 

[Mad Ax 9306]

@87lc2 thanks for sharing, that's awesome!  I like your take on the flat chassis, I was planning something similar on mine.  I think I've pulled mine apart 3 or 4 times to start work and always end up doing something else instead, but this would be a great low-budget project for me this year as I already have most of what I need to get started  

[87lc2 2659]

4 hours ago, Mad Ax said:

@87lc2 thanks for sharing, that's awesome!  I like your take on the flat chassis, I was planning something similar on mine.  I think I've pulled mine apart 3 or 4 times to start work and always end up doing something else instead, but this would be a great low-budget project for me this year as I already have most of what I need to get started  

Thank you!  Yes, it totally transforms the TA01 chassis and makes it quite capable.  I haven't had them out in a while, but I've have them out on the trails a lot in the past and they do really well.  Still not as capable as a 4-link truck but they've really surprised me at times.  I'd say they can do 80% of what a typical crawler can do with the high clearance chassis.  Also cheap as you said, just material cost.  

I have been meaning to rework one of them with an Axial 3 gear trans mounted in the center of the chassis but haven't gotten around to it.  I don't like the motor hanging low since I run in water a lot (have gone through a lot of motors in these).  Won't really help with more clearance as the gearbox will still be hanging low but will gear the truck down a lot and get the motor out of harms way. 

[Mad Ax 9306]

Ooh, a center motor installation - now there's a thought!

A few years ago I went to a local crawler event and took a long a friend who didn't have any RC cars.  I hadn't yet built my Class 1 Toyota at that point, and my CC01s were out of action for some reason, so all I had to lend him was the Hummer.  I'd acquired it as a "custom build stick chassis conversion" - it turned out to be two bits of aluminium U-channel badly screwed together with a servo hanging out into the weeds, but I taped a battery pack to it, stuck in a Novak FiftyFive crawler motor and a cheap servo and took it along to the event.  It only had the stock Tamiya tyres, no fancy crawler rubber, but it fared surprisingly well.  We had to tow it a lot over the bigger rocks and more technical terrain, but it had the benefit of high wheel speed, and if it couldn't get over an obstacle with torque and finesse it could often do it with brute speed and ignorance.

We gave the body a serious battering and a couple of parts fell off and had to be recovered, but it survived the day, got to the end of the course and earned the deserved admiration of the rest of the group.

I'm excited to get this one going again now

[87lc2 2659]

16 minutes ago, Mad Ax said:

Ooh, a center motor installation - now there's a thought!

A few years ago I went to a local crawler event and took a long a friend who didn't have any RC cars.  I hadn't yet built my Class 1 Toyota at that point, and my CC01s were out of action for some reason, so all I had to lend him was the Hummer.  I'd acquired it as a "custom build stick chassis conversion" - it turned out to be two bits of aluminium U-channel badly screwed together with a servo hanging out into the weeds, but I taped a battery pack to it, stuck in a Novak FiftyFive crawler motor and a cheap servo and took it along to the event.  It only had the stock Tamiya tyres, no fancy crawler rubber, but it fared surprisingly well.  We had to tow it a lot over the bigger rocks and more technical terrain, but it had the benefit of high wheel speed, and if it couldn't get over an obstacle with torque and finesse it could often do it with brute speed and ignorance.

We gave the body a serious battering and a couple of parts fell off and had to be recovered, but it survived the day, got to the end of the course and earned the deserved admiration of the rest of the group.

I'm excited to get this one going again now

Glad I could inspire you to get working on it, excited to see how it turns out.  Sounds like a good time was had at that event.  I always enjoyed taking these out against SCX10s, TRX4s, and the like because it was such a challenge and felt great when it could follow right in their paths.  The center trans has been in my head since I built the first custom chassis, but just haven't gotten around to it.  I'll have to figure new mounting for the battery since the upper tray will be gone but that's not a huge deal.  I can just run shorty packs if I have to, but I prefer to run full size packs when out on the trail for run time and weight reasons.  

It's funny you mention the wheel speed of the Hummer as well.  Even with a 65t 540 in these trucks they still have a lot of wheel speed since the gearbox is geared so high.  I definitley had to use brute force in this truck more often than other crawlers where I prefer to use finesse.  Similar to a real H1 actually.  With the TT-4 system in the real trucks you really just floor it and the truck goes over obstacles, a lot different than a technical crawler.  My dad had a 96 H1 Wagon a while back and ever since I've been in love with them, really cool piece of engineering.  I'll get one someday, but they're getting quite expensive these days. 

There's one other main difference between the two that I built - The one with the original body is using short arms from a TA02, the one with the civilian body is using the stock Hummer long arms.  The truck with the long arms does perform better, but I used the short arms under the stock body to keep the wheels inside the wheel wells, I think they stick out too far stock. 

This is a totally different beast, but have you seen my 1/6 scale H1 built from a narrowed and stretched Summit?  2-speed trans with remote locking diffs and huge, this thing is an absolute animal and still looks like an H1 with the 4-wheel independent suspension.  I have yet to get this stuck anywhere.  Tires are about 6" tall and runs a Dewalt 820 brushed motor - https://www.tamiyaclub.com/showroom_model.asp?cid=136663&id=49562

[Mad Ax 9306]

2 hours ago, 87lc2 said:

This is a totally different beast, but have you seen my 1/6 scale H1 built from a narrowed and stretched Summit?

No, I didn't see that - but I have now!  I'm not too good at keeping up with the showrooms.  It's a great looking thing - top work!

[87lc2 2659]

30 minutes ago, Mad Ax said:

No, I didn't see that - but I have now!  I'm not too good at keeping up with the showrooms.  It's a great looking thing - top work!

Yea, I try to look at new entries but rarely go back and look at older stuff unless I'm researching a particular model.  Whenever I do I find interesting stuff.