French Hummer as Crawler

[Charles M 135]

This topic is about the target to transform my Hummer as a Crawler. 

 

As I've said  in my presentation, i've tried to make Crawler Session with my Stock KongHead, but with open diff, stock tires, torque tuned and Tble02s that not good enough. 

Take too much money to transform my Konghead into a Crawler, and i've just bought a Hummer without any destiny ( no project for him, just love this model i was young )

By now, I decided to restore and transform my Hummer. I've got some clue by other member to what i need to make.

 

[Charles M 135]

First of all, I've start to clean diff. After download the Manual, I've discover that Hummer get Rear Ball Bearing differential ( close to the TA03 diff option ),  at front that be a classic gear differential. 

 

I see,  we can block easily a gear diff in adding some gear ( satellite of other gear diff ). That great,  i've got some gear diff from my TA03. 

For crawler i think, it's a good idea to get some blocked diff.

How much  gear i need to add ?  Just one ?  Or three to get some balance rotary parts ?  

 

And after that, what is the best, to put  Ball diff at the front, or a second block diff ? 

 

Thanks in advance. 

 

[Mad Ax 10130]

I would put the ball diff in the front.  You can tighten it up to get some limited slip action while still retaining some diff action to help in tighter corners or on high-grip surfaces.

Then lock the rear diff using any method - an extra gear will stop any diff action and be easily reversible, 2-part epoxy glue works but is permanent, hot glue would probably work well and be removable if you wanted to restore the diff later.  Or you could use sticky putty (like Blue Tac) pressed between the diff to give a limited slip action.  You'll want quite a lot as you want it to be fully locked.

[87lc2 2833]

I use the gear diffs in my Hummers front and rear with a gear locked in place.  MadAx's idea of a tight ball diff in front will work as well if you dont want to go fully locked.  These can be very capable on the trail with a custom chassis.  You can do anything else you want with them, but if you use the stock bathtub chassis it will not perform well.

Here are a couple custom chassis TA01 Hummers I've built, use them all the time and they perform great:

https://www.tamiyaclub.com/showroom_model.asp?cid=136575&id=49562

https://www.tamiyaclub.com/showroom_model.asp?cid=136576&id=49562

[Charles M 135]

19 hours ago, Mad Ax said:

I would put the ball diff in the front.  You can tighten it up to get some limited slip action while still retaining some diff action to help in tighter corners or on high-grip surfaces.

Then lock the rear diff using any method - an extra gear will stop any diff action and be easily reversible, 2-part epoxy glue works but is permanent, hot glue would probably work well and be removable if you wanted to restore the diff later.  Or you could use sticky putty (like Blue Tac) pressed between the diff to give a limited slip action.  You'll want quite a lot as you want it to be fully locked.

Just done today : Ball Diff at the front with full tighten it up and i add 1 gear on the gear rear diff to block it. I can't add 3 gears ( 6 in total ) into the diff. 

I keep in mind other solution that @Mad Ax give to me.  

(I will try to never touch original parts to put as original if needed.)

 

In addition, i've replaced, and put Ball Bearing everywhere. Clean and put new Lithium grease into gear. 

[Charles M 135]

14 hours ago, 87lc2 said:

I use the gear diffs in my Hummers front and rear with a gear locked in place.  MadAx's idea of a tight ball diff in front will work as well if you dont want to go fully locked.  These can be very capable on the trail with a custom chassis.  You can do anything else you want with them, but if you use the stock bathtub chassis it will not perform well.

Here are a couple custom chassis TA01 Hummers I've built, use them all the time and they perform great:

https://www.tamiyaclub.com/showroom_model.asp?cid=136575&id=49562

https://www.tamiyaclub.com/showroom_model.asp?cid=136576&id=49562

Thanks @87lc2 , that real showroom. 

@J@mes have already give me the link of your work when i spoke about my Hummer into my Presentation of Charles

You make so great stuff. I've look the TA01 Chassis frame , and for me , the rear cell and front cell aren't at the same height ( upper fixation )  That work well for you, no angle on the drive shaft ? 

[Charles M 135]

I'm planned to design a chassis frame for this crawler version. Some inspiration of @87lc2 model, some Top Force Chassis Frame and mirrored Bathtub ! 

To get more Clearance, i need to put Electronic parts over the upper deck.

 

That can be the localisation of  parts with mirrored bathtub. 

 

If i've start with a upper deck as Top Force,  I've printed some parts to place the a deck  J3 / J4 / J11 / J7

 

But when I put Front Cell and Rear Cell alongside, the drive shaft alignment isn't good.  

 

If some people have Top Force picture from the side can be helpfull to know if the upper plate is horizontal or not. 

 

 

[Charles M 135]

I've asked to a friend about the alignement. 

 

That definitely not parallel between the drive shaft and the upper frame. 

Somebody  can give me the mesure/dimension of the upper plate ?  Thanks in advance. 

[Teddy Ruckspin 2]

I found this on another build thread, hope it helps

[Teddy Ruckspin 2]

I recommend if you haven't already that you change the alloy gears and the standard pinion to a steel one,  and the idler gear and spur gear in the rear gearbox to plastic ones from the TA02 , the standard ones are really soft and the ruin the gear box.

[blofeld 63]

sorry to hijack but @Charles M can you measure the length of the body mounts D11 as they are NLA as far as I can see and i am going to have to modify some others. 

 

Chassis idea looks very interesting..

[Charles M 135]

On 2/24/2021 at 12:16 PM, blofeld said:

sorry to hijack but @Charles M can you measure the length of the body mounts D11 as they are NLA as far as I can see and i am going to have to modify some others. 

 

Chassis idea looks very interesting..

@blofeld, please find below some dimension. Sorry for that poor drawing.  ( all are in Millimeter ) 

 

 

[blofeld 63]

Fantastic Thankyou so much indeed!

[Charles M 135]

2 minutes ago, blofeld said:

Fantastic Thankyou so much indeed!

if you need some more mesurement, feel free to ask. 

[Charles M 135]

On 2/22/2021 at 2:31 PM, Teddy Ruckspin said:

I recommend if you haven't already that you change the alloy gears and the standard pinion to a steel one,  and the idler gear and spur gear in the rear gearbox to plastic ones from the TA02 , the standard ones are really soft and the ruin the gear box.

I've got some spare parts come from other cars. 

@Teddy Ruckspin,  that's these parts on the left with metal insert into the main gear ? 

 

[Teddy Ruckspin 2]

yep, those ones need replacing , both of the aluminium ones