Fresh Meat's CR-01
 

My first crawler - still a work in progress ;)

Electronics:

Radio - Futaba 3PM (setup for both 2 and 4 wheel steering) in a Traxxas slash waterproof box.
ESC - Mtroniks Viper 20 (already waterproof :D - but no drag brake :cry:)
Front Servo - Integy c22435mg
Rear Servo - Hitec 645
Everything else is stock for now.

Suspension is all stock for now (stock shocks have not leaked at all yet) - with Jia's mod on the rear. I am still not getting full rear flex yet.

Would I be better off removing the canti's and just using the shocks. Should I add internal spring (pen spring with fuel tubing mod)? What about shock oil?

Parts in the mail:
Junfac heavy duty steering rods, skid plate and front servo plate.

Parts that I will be getting soon (don't tell my wife ;):
Teken FXR crawler combo
or
Novak Rooster crawler combo




Here it is:
http://i442.photobucket.com/albums/q...Front_Flex.jpg

Rear Flex:
http://i442.photobucket.com/albums/q.../Rear_Flex.jpg

Top Shot - body off, not sure where to mount the power switch yet.
http://i442.photobucket.com/albums/q...at/Top_off.jpg

Side shot - body off:
http://i442.photobucket.com/albums/q.../Side_shot.jpg

Sweet! Wish mine looked that new again LOL! The best place to mount the switch is between the rear body posts but depending where you mount you esc. ;)

You did a wicked job on that body, nice work!

Don't worry about the flex till you get it moving I say. You can't really experience all the movement it has until you get it out on the rocks. You'll get it in some situations where it will flex plenty.

I just bought some new shock oil, 45wt, just to see what happens, it was only like 3 bucks.

Looks great. I'm starting to consider actually going back to the canti arrangement, having had little success in any configuration I've used recently.

I'll be interested to see how your Integy servo copes. The one I bought had smoke coming out of it within 5 minutes of my turning my AX-10 on! On the kitchen floor!

Let's see some action pics.

BTW, I put my power switch on the rear crossbrace. I just have to reach up under the rear body to turn it on and off. You can see it here in this picture, the little orange square just behind the body post.

http://i38.photobucket.com/albums/e1...r/DSC_9674.jpg

I don't run the shocks like that anymore though, its back to the cantilever. Keeping it real with Tamiya

That's a good idea - thanks for the suggestion.

I will have to wait until I pick up my new ESC before I make any permanent modifications :).

Little Moab
 

Update:

I picked up a Tekin FXR Crawler Combo 55T TT2102 from a local hobby shop. My Junfac items arrived on Friday as well.

I drove down to a place called Little Moab with my son on Saturday (on the south west side of Utah Lake) and broke it in - which is to say I explored the limitations inherent in my current setup ;-)

First some action shots (with my 10 year old son driving)

http://i442.photobucket.com/albums/q...ittleMoab9.jpg

http://i442.photobucket.com/albums/q...ittleMoab8.jpg

http://i442.photobucket.com/albums/q...ittleMoab7.jpg

http://i442.photobucket.com/albums/q...ittleMoab6.jpg

http://i442.photobucket.com/albums/q...ittleMoab5.jpg

http://i442.photobucket.com/albums/q...ittleMoab4.jpg

http://i442.photobucket.com/albums/q...ittleMoab2.jpg

http://i442.photobucket.com/albums/q...ittleMoab1.jpg

http://i442.photobucket.com/albums/q...IttleMoab3.jpg

And a little video
http://www.youtube.com/watch?v=ylPjK_PmdwY

First Run Post Mortem
 

Suspension limitations.... My high COG really seems to be exaggerated by the sloppiness in the cantilever design. I would be slowly climbing over an obstacle and the body would unexpectedly shift from one side to the other causing my rig to roll. I am not ready to toss the cantilever setup just yet, but I would like to find a way to reduce or eliminate the slop.

Droop... I was really having a difficult time climbing up the crack, I couldn't get through certain sections because I did not have enough droop. Is there any way to increase droop without ditching the cantilever setup?

Tire limitations... the stock tires do very well on packed dirt (look at the first climb on the video) - but they do not grip very well on smooth rock (second clip of video - I initially tried climbing to the left but was just spinning). I will be taking this rig down to Moab next month so I will need to pickup some tires that grip better on sandstone.

High COG I don't want to do too much here, I will probably get a battery plate and mount the battery up on the front axle. I will also need to add some weights to the wheels.


The front servo (Integy c22435mg) held up very well - this thing is solid. The rear servo (Hitek 645) actually stripped a gear. I will replace the gear and see if this was just a fluke. I think that I would like to try running the front servo with a BEC

The Tekin FS R and 55 turn motor are great. Lots of usable torque (see first climb on video). That being said, I need to make a couple of adjustments.. 1) I need to increase the drag brake a bit. This should be pretty easy, I just need to decipher the cryptic instructions in the manual :) 2) I need to make an adjustment so I can go into reverse a little faster. I found myself going up a steep incline a couple of times and could see that I was about to tip backwards. I would try to reverse to keep from rolling, but it would just brake initially and not reverse and I ended up rolling over backwards. :-(

As for 2 wheel steering vs 4 wheel steering - I generally would just use 2 wheel steering. The only time that I would switch over to 4 wheel steering was when I needed to make tight turns.

Well I zip-tied the cantilevers and that did indeed get rid of all of the slop in the suspension.

I am still messing around with the rear shock mounting points to see if I can find a spot where I can get full articulation without the cantilevers flipping (locking) when they are fully extended.

Glad to hear the zip-tie trick worked for you "thumbsup"

http://www.rccrawler.com/forum/tamiya-cr-01/149113-cantilever-tweaks.html

Nice!

I had the issue of my linkages flipping backwards when I first got my CR-01. It hasn't done it since I changed up my suspension and then put it back to the cantilever set up. The only thing I have different now than when I first got it is aluminum shocks and I put the hard (blue) springs in front and medium (yellow) in the rear. Also I have the soft stabilizer up front where originally I had none, in back is still the medium bar. I don't know what it is, but they haven't flipped in months now. It still flexes really well. A little less than orginally. I can tell because some areas I drive the rig does the 3 wheel thing occasionally where before it would be completely twisted up but all 4 on the ground. I had almost forgotten that it happens until I saw you brought it up happening to yours.


The weights definitely help offset the top heaviness. They also get you some more traction down. When its time for new tires (soon) I'm going to add a bit more weight and see what happens. Would like to try the new Tamiya tires, I think they are called Cliff Crawlers.

Yes it works great, I can't wait to take it back out and see if it helps with control (at the limits). It's been the easiest and least expensive mod so far 8-)

I put in 4 oz in each front wheel, just messing around in the house it seemed to help. I might go ahead and add 4 more oz to each since I added more weight to front bumper to test it and it was even better. Do you think having 8 oz in each front tire is going to be to much? Adding weight to bumper area just squishes the chassis down to far, great for COG I guess but would rather find another way to keep wheel planted.
-Jeephead

I don't think the weight in the wheels will hurt. I have 6oz in each front now. You just have to have a strong enough servo to turn that weight on the rocks or you servo will be toast. I've seen my servo struggle a few times if the rig was in an awkward spot and I was trying to turn the wheels. It doesnt happen often though.

Ok cool, Yeah my servos claim 170 oz of torque but that assumes that I am running a separate receiver battery. Could plug one in I suppose and figure out how to set up ESC/Receiver. What are you running for weight in the rear? I have 2 oz in each only because that was what I had left over. Ha!

nice hoping mine shows up today worse then a kid in the candy store where the hell is the mail man

I have none in the rear wheels currently. I do need something though, its really light in the ass on downhill crawls

I think that I will start with 4oz on each front and 2oz on the rears. I have also seen my servo struggle at times. Of the two servo's that I am running the Integy is a lot stronger than the Hitek 645. I may end up getting an even stronger servo for the front and move the Integy servo to the rear (and move the Hitek to my rally car). I have found that even when I have the rear servo locked if I back into something it will move on me. The Integy servo however will not budge unless I tell it too :) (I suppose that may just be digital vs analog).

While I am adding weights to my tires I will also need to trim my foam's. Is there a good how-to that anyone can point me to? (Or maybe I will just pick up some proline flat iron tires with memory foam)

Looks good man! It's cool to see another local CR-01. I've got two of them myself...maybe I should make a thread showing them off some time...:D

Thanks - it's been a lot of fun. You should create a thread with pics and specs. I always like to see what other people are doing.

I picked up some Proline Flat Iron's yesterday (along with some stick-on weights). I really like the scale look of these tires ; I hear that they perform pretty well too.