My Mods for Crawler King so it can crawl

[Jeep-Power]

As anyone who has driven a crawler before driving a Crawler King (CK), I quickly found out the CK can't crawl.

1st things first: The steering, it doesn't. Servo On axle (SOA) works well and was a no-brainer. The trick is mounting the servo. A quick trial shows the HPI servo was gutless-- I settled on a used Traxxas 2075 I had in the parts bin. It's waterproof (always a nice feature) and it has relatively high torque (around 100 Oz).

This was the hardest thing to do.

Thanks to HndsWthtShdws for posting the template!



I re-used the stock HPI servo saver because the 2075 has plastic gears. I drilled it out to the size of one of the HPI pivot screws so it would pivot freely on the shaft of the screw.


Drilled a hole in the stock tie rod. I used the servo saver as a guide. I know it's a bit hack, but the tie rod is SUPER flexible, so it easily allows for any up & down movement of the pivot point. The steering now works 400% better then the stock 'system'.





NOTE-- in order to mount the servo here-- I had to move the upper control arm mount back. I did this by flipping the axle bracket. I shimmed it off the axle a hair with nylon washers. All this required that I cut about 3/8" off the end of the control 'wishbone' and then drilled the hole deeper. A washer was put on the outside to prevent the ball joint from pulling through.



The gearing was next--

THe OEM setup was a 90/21 tooth count with 48 pitch gears. That comes out to a 4.285 : 1 gear ratio. The parts bin had a Traxxas 66 tooth 32 pitch spur gear that I had to drill (using the OEM spur as a guide) to fit the hub. The parts bin also had a 8 tooth 32 pitch pinion. The 66/8 combo gives us a 8.25 : 1 gear ratio -- NICE! No more motor stall and MUCH more control in climbing-- woohoo!



Lasty was the tires. They were hard as a rock! My Chisels (I bought hem used, so I am not sure what foam is in them) flex like mad and have a bit of sidewall bulge even when the rig is not moving. These tirese looked like they had 35PSI in them & rode that way too! I was surprised to find that the rims were already vented. So what could be the problem? I took one apart and found that the foam was very stiff. OHHHH-- this is why folks cut thir foams! I went alittle easier than this on the first, and it wasn't flexable enough-- so I got more agressive with the rest. This is the last foam I cut.
OEM


half way done


done & they flex great!




I have to say the OEM shocks/springs are set up pretty well. This thing flexes great & is surprisingly stable! I drove it into place here and drove out of it. Note the reat tire compression... that's the way I like it.


Detail shot of the servo clearance in above shot.


I only have one crawler and it's a tuber. It is really cool to see a Jeep crawling around-- looks so much more like the real thing!

[savagefromthesprings]

sweet mod man! did you buy the optional gear reduction thing? Mine is so dang touchy with the throttle (ready to flip with a tiny bit more throttle). Have you tried to do anything with the rear steer? I unbolted the thing on the rear axle, and the wheels pivot just as much as the front does!

[Jeep-Power]

Originally Posted by savagefromthesprings

sweet mod man! did you buy the optional gear reduction thing? Mine is so dang touchy with the throttle (ready to flip with a tiny bit more throttle). Have you tried to do anything with the rear steer? I unbolted the thing on the rear axle, and the wheels pivot just as much as the front does!

Thanks.

yeah, it is touchy as hell-- backflips-r-us!

No, I didn't buy it, I just had the 66T 32 pitch spur & 8T 32 pitch pinion in my spare parts. I'm pretty sure the 66T Spur came off a Traxxas rig, because that is what the lot of parts I got the gears in, came from. I can say that I don't think a spur that is much larger than this 66T will fit. There is only a 1/16" between the frame sides & the gear teeth. If you can get your hands on a 67, 68, 69 tooth spur-- go for it. The deeper gears will be great.

Didn't even think of rear-steer, as my buddy only has a 2 channel radio, I didn't have another servo, & we were looking to keep this thing as simple as possible. I did think about making a rear tie-rod that was more rigid, but the OEM one does seem to hold up and work fine, despite how flexible it is. IT actually flexes enough to allow the tires to do a little 'torque-steering' of their own. The verdict is out on if this helps or hurts...

[fernando]

Good job stepping up your rig's rock crawling game.

[savagefromthesprings]

finished moving my servo and doing my rear steer setup.. also did several other mods, such as getting rid of battery tray and lowering center of gravity ALOT. will post more pics later. Your post inspired me to move the servo, and then the other mods started coming..

[Jeep-Power]

Originally Posted by savagefromthesprings

... did several other mods, such as getting rid of battery tray and lowering center of gravity ALOT. will post more pics later. Your post inspired me to move the servo, and then the other mods started coming...

Sweet-- I'm glad to hear that!

Please post up pics of the battery move. I know this rig can use a lower center of gravity!

[Kitty]

i have used the reduction gear box,and it's doing his job very whell,worth buying

[slowride1]

dont use the reduction with a 55 turn it is like slow mo

[slowride1]

if some one wants one i mite do some tradeing on something i have a bran new one ran for about 1 min

[Kitty]

i know but im not rushing anywhere,in my country we do not have any competition so it's just for my fun

[Jeep-Power]

My buddy put a Novak Rooster Crawler ESC in it and loves the drag brake-- the last piece to making this thing a decent crawler.

[skullking]

Originally Posted by Jeep-Power

My buddy put a Novak Rooster Crawler ESC in it and loves the drag brake-- the last piece to making this thing a decent crawler.

I just got a rooster for my Crawler King. Mine just does a slow roll, not very good drag brake. Does not hold a Position when climbing. Is this what your buddies does???

[HndsWthtShdws]

Whoa, trippy. Just browsing and saw something really familiar. Your welcome.

[Jeep-Power]

Originally Posted by skullking

I just got a rooster for my Crawler King. Mine just does a slow roll, not very good drag brake. Does not hold a Position when climbing. Is this what your buddies does???

no-- it holds like crazy-- will actually endo if you are not careful about letting up on full throttle, when going down a decent slope.

Be sure to set it up exactly as the instructions say-

[sobe164]

How dose that stearing set up for for you? Dose it give you full radious of turning?

[Jeep-Power]

It works great-- that is to say, at the very least, it works many times better than the stock steering.

It has a compatible turning radius to a stock AX-10 or the like. Don't quote me on that, 'cause he has it now and I haven't' seen or used it in months. All I can say is it make it alot more fun to drive.

With a metal-gear high torque servo and a little longer servo arm, I'm sure there might be even more steering angle to be had.

[sobe164]

im working on trying to figure out how to make mine have good stearing radious. I want to do the dual link up front like every one else has. So to say the least. I will be buying the stuff hopefully this comming week. and im going to do the adjustment to where my servo clears the 3 link on top of the axial like you did useing washers.

[philtSF505]

so i add these this week to mine does a lil better, for this is my first, crawler

JR z590 steering servo
120 mm spring shocks
96t 48p spur gear (ckrc)
13t losi pinion gear
67 ranger body

so far so good slowed it way down and the next thing is to cut the foams.
like how you did that

[Jeep-Power]

Got pics? I will love to see it, please! Sobe164-- you too!

Originally Posted by philtSF505

so i add these this week to mine does a lil better, for this is my first, crawler

JR z590 steering servo
120 mm spring shocks
96t 48p spur gear (ckrc)
13t losi pinion gear
67 ranger body

so far so good slowed it way down and the next thing is to cut the foams.
like how you did that

[skullking]

Originally Posted by Jeep-Power

no-- it holds like crazy-- will actually endo if you are not careful about letting up on full throttle, when going down a decent slope.

Be sure to set it up exactly as the instructions say-

Are you running it with the Stock WK Trans?

By the way Love the Servo Mod, Might have to steal that one!