Gear reduction
 

Can I fit a wheely king gear reduction unit on a Goliath with minimum
"re-engineering"

I have almost zero familiarity with the Wheely King. Is there a gear reduction unit specific to the WK? I searched around a bit and the only thing I've seen people use is the GD-600. You can use a GD-600 with minimal re-engineering. It just requires that you use a 5mm pinion, which is available from RC4WD I believe.

Hey KB...are you the same KB that suggested on one 18th.com that I
use a 1050 brushless outrunner for my VMG? If so-thanx..it worked great!... here's a link to the WK reduction...
http://www3.towerhobbies.com/cgi-bin...?&I=LXVLE9&P=7

I would just fab up a Axial tranny in place with a slipper clutch, that would be alot better.

Your welcome! :) That GRU is most likely too wide. The chassis rails are only a few millimeters widers than the motor itself. If you moved the chassis rails to the outsides of the side plates, it might fit then. Like 666 said, the Axial tranny would ultimately be your best bet for reliability, but it would definitely require you to widen the chassis quite a bit.

thanx y'all

Go with the HPI GRU. It is not very big and will easily fit in a goliath. I have one in my tuber. It has a rc10 stealth tranny and the gear reduction fit perfectly on it. Axial sucks:-P

Not really, it is one of the most durable, compact, cheapest trannys available specially made for rock crawling. Try not to knock what you have not tried.

Isn't the Axial tranny damn near a carbon copy of the stealth?

Sure is! "thumbsup"

Hey, 555, uh, I mea 666, you know I have to talk smalk about something. Seriously though, the gear reduction would bolt right up and give plenty of options for gearing. With it bolted to a tranny like my setup, it is too damm slow, even with the high rpm motor I have and a 3 cell lipo. With the pti, it should work great. And it would be cheaper than buying another tranny and mounting it to the chassis. But you know I am all about modifying and building hybrids.

to get back on task --- anybody know the dimensions?

It's slightly wider than the motor. The gear reduction is on a backing plate that attaches to the motor and hangs off one side about a quarter inch. It raises the motor up just slightly as well (from the stock mounting position on the WK tranny) to make up for the gear offset inside the unit. If I had a caliper I would measure it for you but that's the best I can do. I just put one on one of my scale rigs that use a WK tranny in an F350 chassis. I didn't snap that it was made for the stock WK and I put a 75 turn on it....... :shock: Needless to say I ended up digging through my box of parts for the old 27 turn. That thing has some serious reduction. Zero wheelspeed, but it will push my ottoman across the living room on thick pile carpet! No need for a drag brake either..... "thumbsup"

What about the RC4WD GRU that they sell for $39...anyone have one? Does it fit without modding the chassis?

The RC4WD one does fit with no mods; it's almost the exact same diameter as a 540 motor. You will have to fab up some sort of crossmember under the motor to help support it. Otherwise, the motor plate will flex out of alignment, screwing up your gear mesh.

here are some pics of my hpi gear reduction mounted in my goliath chassis. fits good. the motor plate definitely needs reinforcement with the motor out farther.
http://i301.photobucket.com/albums/n...withhpiGR2.jpg
http://i301.photobucket.com/albums/n...withhpiGR3.jpg
http://i301.photobucket.com/albums/n...piGRbottom.jpghttp://i30[IMG]http://i301.photobuck...kwithhpiGR.jpg
http://i301.photobucket.com/albums/n...ithhpiGR-1.jpg
http://i301.photobucket.com/albums/n...kwithhpiGR.jpg

hope this helps.

I wonder if the quality of the RC4WD is any better or worse than the HPI gru?

Did you do any mods to the chassis to make it fit?

Is this the one you have?
http://cgi.ebay.com/HPI-87634-Reduct...3286.m20.l1116

No mods necessary. I took my tuber apart to test fit the gru in my goliath and take those pics. I have not driven the pti with the gru because I am waiting for metal ring and pinions for the axles. I have used the gru in my tuber and it works great. I had mine too low geared, and even with a 27 turn motor, the truck was super slow. great holding on inclines. no need for drag brakes.

Looks like that is what I will do too...at half the price of the RC4WD gru, it seems like a good option.

Why are you waiting for the metal R&P's??

because I am very rough on my trucks and I will be running some wheely king Mud Thrasher tires which are big and heavy. No plastic gears for me.