Cen Gst based 6x6

[lincpimp]

Ok, time to do another 6x6...

Actually I am getting ahead of myself, but I am waiting on parts to fix the other 10 builds I have so why not start another build!!!

So I just received a cc 2028 motor. Big and powerful looking. I would take a pic but everyone knows what it looks like.

I also have a hydra hv18 boat esc. Got it from Mike via BB16, he used this esc in his baja (when he developed the baja conversion kit?) and had no isses with it. So I figure it should be ok. I have 10s of 3200 30c flightpower lipos, and a few 1/4 scale servos to choose from for steering.

So my plan is to get a NIB Gst off ebay, sell the offending nitro crap and radio gear. Should be able to get a roller for around 250-300 that way.

I will make a new rear skid plate, with an extension to hold the lower bace that the tvps mount to. That way I can make another, shorter, set of tvps to will connect with another complete gst rear section (bulks, diff, arms, etc).

Keep in mind that the gst is alot like the savage, tvp design. The bulks are multi piece, which allows me to easily add the necessary parts to attach a pair of tvps to the rear of the existing truck.

Now here is the fun part:

I plan to make a mod 1.5 transmission (kinda like the kershaw savvy center drive) that will sit between the center and rear bulks. The pinion will likely face the rear so the motor can get closer to the center of the truck.

The trans will be made up of two plates, that will attach to the new tvps. I will use 8mm shafts, and 2 30t spurs,1 15t pinion and 1 12t pinion. This will give me enough reduction to get mid 40s with the 2028 on 10s and the 2.8 reduction given by the cen diffs. I will run the big cen tires, as the are just too cool!

I would do a std spur and pinion, but the size of the spur would be wider than the tvps, and I would like to keep the individual gear ratios closer to 2:1 to cut down on wear. I will be using plastic spurs, but they should be strong enough.

The gear arrangement is: 12t pinion on motor driving a 30t spur that shares a shaft with the 15t pinion that drives a 30t spur on an output shaft that will go to the center and rear diffs. All mod 1.5 to handle the power and give enough spacing to clear the motor. I have not decided if I should run a solid output shaft directly to the pinion on the diffs, or use some sort of dogbone/cvd. The entire assy from bottom of the output spur to the top of the motor can will be close to 5". I could stagger it some to reduce height, but I want the motor centered, as it weighs alot. And I have a limited width between the tvps to work with. Not exactly sure on the dimension but it look to be close to the savvy width.

Now I will have to use mech brakes, so I plan to leave the stock trans in there and use the stock brakes. I will likely remove the unused internal gears. The mech brakes are supposed to be pretty good on these trucks, we will see. I may go with a 1/4 scale servo for the brakes too. Also, the stock center driveshafts will be left to power the front diff, for true 6 wheel drive.

Batteries will go where the nitro engine used to be, on a custom battery tray. Not sure where the esc will end up, maybe on the side of the tvp behind the center bulk.

I will have to make a pass thru diff. Looking at the pics the cen may have a plastic diff case, or it may be al. Might get a machined pass thru case made, or plastic weld one together like i have done before. A fair amount of load will be going thru this diff, so an al case may be mandatory.

I have to do some measuring, but I guess this truck will end up with a 26" wheelbase. Figuring I want about 4" between the rear tires and they are 7.5" diameter. Overall length will be about 3 feet. Stock the gst weighs 17lbs, so I figure th 6x6 will end up around 25lbs.

Thoughts?