Tamiya Hummer Quick Mods and Build

[subyman]

I purchased a used Tamiya Hummer from JSN (thanks, it looks great!) I've always liked the way they looked and drove in the videos and I have always wanted a Tamiya RC. JSN had a good deal and it was the XB model with everything needed, so I jumped on it.

I charged my 5000mha battery and took it out totally stock. Lets just say, it leaves much to be desired lol. It can barely climb anything and could even get stuck on wet grass. The mechanical speed controller was hilarious with its on or off power.

First thing I did was throw on some Trail Docs that I got from onespeeder. They were already on hummer wheels, so it was just a matter of bolting them on.

Next I stripped the MSC out and put in a Duratrak Ai with reverse. It isn't the most robust esc, but it is plenty for what I am going to be doing with this for now. Plus I had it laying around. I had to cut a small square out of the top of the plastic cover to fit the esc.



I took this back outside and tooled around. Much better already! It hooks up a lot better and it is actually controllable now with the esc. After a couple of minutes I checked the stock can and it was smoking hot, so was the esc. So I decided I would put in a 55t lathe to see if that would cure the problem.

I had the 55t laying around from another project so I bolted it in with a 16t gear (lowest that can be put in these without mods.) While I was in the rear of the truck I decided to lock the rear diff. This was surprisingly easy after some thought. Remove the dog bones and couplings going into the rear diff. Simply remove the rear cover containing 4 screws. Pull the diff out. Remove three small screws and open the assembly. Pull the three gears out and remove one gear. Put the one gear down into the assembly and put the two gears still attached to the 3-point mount on top of the one gear. Make sure the "jam" together. Reassemble. Check the picture below to see what I am talking about.



This method of locking the rear diff is similar to an old TLT method and works just as well while not doing any permanent modification to the assembly (plus you don't have to wait for glue to dry.)

The front tires rubbed and ground clearance was an issue in some areas. So the next thing I did was try to get some more lift out of the guy. I started at the rear of the vehicle. I removed the rear shocks to see how much travel the rear geometry would allow. I was pleasantly surprised by how far it would drop without the shocks. All that is needed is a taller shock on the back to get a lot more clearance.



I disassembled the shock as can be seen from above. Notice the small black tube that is marked in red? This was making the shock's travel roughly 3-4mm less. Take that sucker out. Now reassemble the shock. The stock springs were much too short. I had some Losi truck springs which I was going to use on my TLT crawler still in the package so I broke those out. I had to cut 2cm off of the bottom of them. I then inserted these and it was a perfect fit.



This instantly gave me a ton of clearance in the back (almost too much with the trail docs.) Next was the front suspension which is a bit more involved. I took the shocks off like before and did the same mod, except this time I did not use new springs because there is not enough travel to need them in the front. After doing the droop test again, I realized it would not be as easy as the rear. The front binds pretty fast. I found what was stopping it was a small piece of plastic in the front knuckle which was stopping against the lower A-arm. I took out the dremel and shaved that smooth. I also shaved the front A-arm. After reassembling, the dog bone was rubbing the knuckle. So I took it back apart and shaved the top portion of the knuckle where the dog bone touches. This gave me a lot more clearance in the front. New springs aren't needed because once the preload is set, there is plenty of spring left to do the work.





The final mod of the day was to get rid of the front bumper which 1.) kills the hummer's awesome ability to drive up vertical walls and 2.) rubs the tires at full lock. The bumper can not simply be taken off because it locks the bar that holds the front lower A-arms on. I removed the bumper and made a small plate out of steel that will hold the bar in place. It was only a matter of using 22gauge steel, tin snips, vise, and a drill. Works great, and looks much better as well!



So, I did a bunch of new mods and it was time to try it out. Whoa, what a difference. This thing is practically unstoppable now. The locked diff, tires, esc, suspension lift, bumper mod, and other small things I did made a world of difference.

The next thing I am looking at doing is maybe locking the front differential the same way, trying to get a bit more lift out of the front, water proofing my electronics, and then I may tackle some body modifications such as converting to a civilian hummer.

Finished with mods done for the day:







Check it out with some flat irons on it just for fun:

[66sprint6]

Thats pretty cool. First real nice 4x4 RC I had was the Tamiya Hummer. I beat the SNOT out of it, and its still around today...altho only as scrap . I had it running around at the end of 09, and could prolly fix it up and get it runnin once again, but I realized that I only have patience and focux enough for one rig and thats my SCX10. Good luck with it, keep us posted, would love to see this thing crawlin!
Matt

[SuperAwesome]

The stock dog bones break really easy on those things once you lock the diff.

Nevermind what I said about the dog bones, I thought they were the same as the ones on the S10's and such with the plastic on the ends.

[maxxa87]

I still want to get one of those to mod. They're relatively cheap too. I just really dig the 4W independent suspension.

[SuperAwesome]

After looking at this thread I actually decided to buy one. Should be a fun project.

[subyman]

Took it out again today in the rain. I haven't done any waterproofing what-so-ever except that my esc happens to be water resistant. I when through water up to the windows and it did fine. I will bag the rx and esc tomorrow just in case.

I'm thinking my next mod will be lighting. I'll try to get some outside pics of it in action tomorrow if it is nice.

SuperAwesome, go for it man. I'm glad I did. I'm enjoying it so much I have lost interest in my KoH tuber project. This thing is awesome to drive around outside, it looks so scale going over everything and it is great watching the independent suspension work. Watching the rear end squat down while powering up a hill is sweet.

[tamiyaguy6194]

im getting a tamiya hummer in a few days. its all stock with futiba radio. im going to lift it and lock both diff's like you did. im ordering some 1.9 mud slinger tires for it! im going to waterproof it all too. ill let you guys know how it turns out and some pic's

[rhom]

it looks great with the lift and tires.

[Bellvis]

Looks awesome!

I will be locking my diffs and getting better tires/wheels soon!

[tamiyaguy6194]

i ordered a tamiya hummer rtr on ebay for $120 i should be getting it in about 3 or 4 days. any advice to make it go better? im going to be mudding/trailing. how do i cut out the tires? i would like a picture of what they look like. thanks for any help/ideas

[Grasshopper]

I locked both front and rear diffs,
Put on some rock busters,
Gave it a small body lift,
Did a minor suspension lift,
put in a 65t motor.

The thing is unstoppable!

It's only weak point is the break-over angle.
It performance more than makes up for the
break-over issue.

[Mocca Master]

Excellent thread - thank you very much for the detailed walkthrough Subyman! Very appreciated since I've been thinking of doing just that - just recently rediscovered my old joy for RCs and dug out my old M1025 hummer - I'll probably modd the body and upgrade it with a lift, tires and a new motor+ LiPo battery...
Biggest problem I have is the width of new tires - I'd love a pair with a snug fit, but what I come across are often too wide to be bolted in place... Do you guys cut'n glue your own tires or do you have a tire model that would fit? I'm looking for an allround pattern - a bit wider than stock and with some more grip. Nothing extreme like mudders/soft climbers or anything like that...

Hope you can help. Again - superb work on the hummer. Serves as an inspiration to me

[Mocca Master]

So - got working on my Hummer - cleared it a bit in the back with the "Suby-method" giving it some 3-4mm extra. Modded some old Buggy tires to fit in the back - fitting well with the extra height in the back. Cleared it up inside - in the diffs etc. as well greasing everything up right and also gave it a quick paint job... the orange body looks good IMO, but the paint is a bit flaky and flawed in places due to an earlier crappy paint job from my older brother - still, I like the orange and black. Might paint the rear wheels orange as well - not sure if they are permanent. I need to make a test run hoping for the type of ride I'm after :p
Btw - think your differentials might have been switched Suby - My rear Diff is ball bearing and my front is similar to what you posted. So - I might switch 'em, locking the the front diff and throw it in the back... still, not sure if I'll let this baby be a rally car or a dirty crawler... time will tell.

Cheers,
Mocca

Here are some few pics:


Updated picture (a lot has happend... ):

[RCCrawler4000]

Thanks for a very detailed and good thread Subyman.
I have also done all the modifications you have shown.
Similar to Mocca Master I also have ball diff in the back and and 3 gear diff in the front. I was not able to fit the 3 gear diff in the back. It was to wide, so the dog bones were pushed to close to the wheels.
Kept the ball diff in the back then. Stuffed a good load of super glue in it to lock it. Hope it holds up.
Wanted to change the paint job on the body and put some paint remover on it yesterday evening. Unfortunately it also desolved some of the body details. BE CAREFUL THERE.
Hope I can save it with some sandpaper and hard work.

[Mocca Master]

Yo Crawler.

I tested different methods to remove old paint and for me I threw on a fat layer of "brown soap" - not sure what it is called in english. Some gel like old fashion soap used for scrubbing floors etc... I wrapped the body with the thick soap coating in a plastic bag - sealed it tight and left it for 24 hours.
I was able to actually rinse of a lot of the old paint. I should have left it longer or maybe do it again since the leftovers of paint is spoiling my new paintjob :(

I'm sad to hear about the diff. I was hoping that the front diff would fit in the back - I've read other posts with people doing this

On a side note I'm eagerly awaiting my Trail Doctors 1.9" I still havn't gotten a real 55t engine, but that might come - for now I'll just skid around on some dirt roads with my new LiPo battery pack.

Mocca out

UPDATE: Just as I finished writing the mailman arrived with my Trail Doctors... boy oh boy are they cool! Fits right on the hummer rims - just need to foam'n glue 'em on

[blukon98]

This makes me want one

[Mocca Master]

So - been sharing and I might as well update. I've been painting and finishing my bodywork - lots to be done still, so I'll wait with pictures until finished.

Today I wanted to finally try out the improvements with my new trail Doctors, my 3500 mAh including low voltage buzzer, my lift and improved handling.
And my, oh my does she fly. I've decided to name her "the Claw" since that is the soundtrack I plan on using in the (hopefully) upcomming movie .
Actually she moves in such a way, that I suddenly heard a strange "tack tack" sound - thought it was the rear differential that blew, but after tearing her apart this evening I found nothing (except the engine was hanging quite loose ). Then I wanted to check the dog bones and it appears it was a rear wheelbase that couldn't handle the extra grip = extra torque . Can't even tear the damed thing apart now!! I'll try with a hammer tomorrow since I don't wanna wake up my son...

Thinking of changeing the hex'es with metal ones - but I'm afraid what might blow next (notice I didn't even lock the differential yet!). Maybe I should just settle down and drive her like a crawler with a 55t engine... again - time will tell...

Picture showing the cracked wheelbase (the black ring around the bolt is not supposed to be there! ):

[Grasshopper]

When you switch the front and rear diffs, switch the CV joint & Axles too.
This will make them fit front or rear.

I got rid of my metal diff and use plastic ones front & rear, locked with silly putty.

On the body, I would have used brake fluid...

Originally Posted by RCCrawler4000

Thanks for a very detailed and good thread Subyman.

Similar to Mocca Master I also have ball diff in the back and and 3 gear diff in the front. I was not able to fit the 3 gear diff in the back. It was to wide, so the dog bones were pushed to close to the wheels.
Kept the ball diff in the back then. Stuffed a good load of super glue in it to lock it. Hope it holds up.
Wanted to change the paint job on the body and put some paint remover on it yesterday evening. Unfortunately it also desolved some of the body details. BE CAREFUL THERE.
Hope I can save it with some sandpaper and hard work.

[Mocca Master]

Thanks grasshopper!

I'll try and switch it one of these next days.

About the break fluid. I tried it but with only limited success - and it discolored the plastic. I think it works best on Lexan bodies, but I'm not sure - atleast on the hummers green plastic body it discolored it. The soap I refered to is a mild chemical just softening the paintlayers after a couple of days...

[RCCrawler4000]

Finally done sanding the body so it looks somewhat decent. Received the spray paint in flat black, desert grey, and olive green yesterday. Really looking forward to doing the paint job on this one. Got a little inspired by this: http://www.youtube.com/watch?v=XLXS10e-Rto . Hope I am not getting disappointed with the result. I will take some pictures along the way. Next thing is to get some scale jerry cans, scale tools and stuff.