PTI Goliath Stretch Project

[sweetdiesel]

For my winter project I wanted to try stretching out the Goliath to make it a dedicated crawler. I got most of my ideas from the guys at one18th.com. I'm about 1/4 finished with what I want to do. Here are some progress pics.

Current wheelbase is right around 8 inches, when I'm done it should be about 10.
The wheels are HPI super star rears. They come with hex adapters which fit the wheel pins of the Goliath perfectly. The tires are 2.2 masher 2000s. I'm not sure if I want to stick with the revo cants or forgo the cants altogether and mount the shocks directly to the axles. I'll also flip the front and rear diffs so the battery is over the steering axle for more weight over the front tires. It should help it climb a little bit.

I'm going to mount the skid plate about 10mm rearward. Rear skid is on the way also. Eventually I'm make it RWS soon as I can figure out how to activate the rear on demand with the 3rd channel of my 3PK.

Stock steering set-up sucks on the Goliath, I bent up a revo rear toe link to 128mm and took off the servo saver. Now it steers more sharply and evenly left to right.

The 4 links are all traxxas, 121mm lower and 95mm upper, with a RC10T4 cvd. I'm working on a one piece mount which will relocate the steering servo to the top of the axle and also mount the upper links closer together on the axle with the rod ends in a vertical position. The way they lay flat right now hinders their movement.

Once I stretch the rear and get the links worked out I think I can get close to 90 degrees articulation. I'll be adding a 6 cell pack, better esc, and a lathe motor for more torque. I plan on running as small a pinion as possible, looking for a 12t right now. The radio plate and battery tray will also be aluminum. Once I play around with it a bit I'm going to try and improve on the side chassis plates. They look fugly!

Well...hope you enjoy the pics, so far this has been a fun little build.

 

[supersavage]

That looks good sd...I've been toying with a small scale crawler project. That might get me off my arse!

 

[MyJeep]

I see Revo rockers

Hey SD, do you have any problem on the axle? Mine is binding like a bi*ch. I almost gave up on that project.

 

[sweetdiesel]

What part of the axle is binding? I had to shave quite a bit from the the inner halves of the axles to keep the dogbones from binding. Also on the second batch of trucks there are addendums to the instructions that said to not install the nut cover onto the screw that tightens the diffs. That will also cause the dogbones to bind.

I forgot to add that I have locked both diffs with TC3 solid axles.

And yes those are revo rockers, though I'm not sure if I am going to stick with a cantilever suspension.

 

[sweetdiesel]

Yep, sorry thats what I meant. Me engrish not too good tonight lol.

 

[MyJeep]

Where can you get TC3 solid axles for cheap. I looked and they are going for 23-25 bucks a pop.

The side chassis plate does sucks.

This is what I did (cheap quick fix) and the PTI has been sitting in a box for the last 3 months.

::: What happened to the previous post ????

 

[sweetdiesel]

I got them at my LHS for around $24 ea. Tower has them for 22.79.

Nice job on the side chassis, is that real carbon fiber? I was thinking of making something more organic looking out of aluminum with milled out sections like the clod crawler kits.

 

[joey]

its looking good Sd! keep up the work and post more pics...

 

[ImBroken]

Lookin good SD... I'm still debating on how far I want to go with the Goliath build.... lol
I bought an IRS TC3 Spool for the rear, and figured I'd keep the front a ball for better steering... BUT... after seeing your build, you got me thinkin again.... lol
Looks really nice man...

 

[ImBroken]

Hey MyJeep, what shocks are you using? I'm looking to pick up a set of Al. shocks for mine. I thought I read somewhere that people were using TMaxx shocks.

 

[nitrost]

looks good and i got those same orange cups

 

[ZANDOR]

Dam SD looks nice so far..

 

[4u2nv]

Looks good man! Nice work! Just curious, how long is the wheel base when its stock?

 

[savagelover12]

google is your friend

http://www.ptiracing.net/index2.htm

its says 8 inches

 

[Tweak]

hehe. Never seen vids of crawlers in action. that thing was pullin' a gravedigger all over that Mini-Z Ass. sweet.

 

[MaxxRunner]

SD I have just done your steering upgrade ,what a difference! In your earlier post you said a new lathe motor for more torque, what are these and where do you get them? I have been thinking of the Novak brushless system for the E-maxx do you think that would be a good choice? Also I have updated to 6 cell 3300mah sub c packs.

 

[sweetdiesel]

Most everyone I know is using the team integy lathe motor in their crawlers. It's basically a 55t motor that is low speed and high torque. They are inexpensive at around $20 each.

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXKUG5

If you decide to go with this motor I suggest you also get a smaller pinion gear, robinson racing makes one in 48 pitch 12T that costs about $4 at your LHS. The smaller pinion will give you additional torque.

You should do fine with the 6c pack, that's one of my next upgrades.

 

[MaxxRunner]

Thanks for the info and the link. Out of stock right now hopefully I can get one soon. Do you have any more pics of your upgrades?

 

[MaxxRunner]

SD thought of another question about the lathe motor. Do you need to have a speed controller that is specific to that turn of a motor? I am currently using the electronics out of a trashed Duratrax Evader the controller is a Duratrax Sprint. What do you think will I be OK if I change to this lathe motor? Also what size pinnion would yo use if you used the stock Goliath motor to get more low end. Also will taller tires give me more low end or is it the other way around?

 

[sweetdiesel]

This is my first electric since the days of mechanical speed controls so I am no expert when it comes to choosing the appropriate ESC. The first cheap speed control I used in the Goliath had sluggish acceleration and horrible brakes. I replaced it with an LRP runner with reverse and accelration was much smoother, and it seemed like more power was getting to the motor. I have no experience with the Sprint ESC. I hope someone can chime in and educate us.

Any pinion that is smaller than the stock one (IIRC it's an 18 tooth) will give you more low end torque at the cost of lower top speed. I suggested the 12 tooth 48 pitch pinion because that was the smallest I could find. Adding taller tires will give you less low end torque but a higher top speed and more ground clearance.