DK's Rock Force Build

[dkingston]

Well I guess it is time to show mine.

Here is where I am at right now:

Rock Force 2.2
Panther Tires - Stock Wheels
Integy 55T Motor / 23T pinion
HighSpeed Gearset
Mamba Max
Trinity 3S Lipo
Futaba FASST 3PKS
(2) Hobbico CS 170 Servos (Hitech Rebrand)
Kyosho Dig


As for setup I have done a couple things different.

In the rear I have swapped the upper and lower links. The uppers are longer and got the RF to 12.5 inch WB. Additionally, I triangulated the lowers using spacers. This required me to flatten out the back side of the skid and that seems to be ok. This reduced the axle swing significantly. It also clocked the rear axle some which is not bad IMHO, it gets the dig servo arm a bit out of the way (not like I think it would hit but while jumping rocks I did land on it and it broke). The rear lower links are mounted in the top hole on the axle.



For the shocks in the rear I am in the lower rear most hole on the chassis and springs fully compressed. Ride height is cinched at 2 5/8". This setup for the shocks at this ride height allows for the piston to rest almost exactly mid stroke so it has as much downtravel as it does up travel. The dig still has the fuel tubing as I am happy with that setup for now.



Radio and battery placement is pretty much stock. I did however mount the receiver along side the battery to allow for better wiring.




I dont have the obligatory flex shot but a soda can can fit under the tires.

As for the front, it is nearly stock. I will be working on getting a bit more articulation from the front but I want to test where it is now a little more.



Side shot. You can see by extending it to the rear it is about at a 55/45 which I am finding to be fairly negligible for this rig. (note, that picture is actually at a hair above 2 3/4. The links in the rear are now level)

One of the characteristics of the rig stock was that it really wanted to carry the front right tire on incline climbs. Adjusting the anti-squat helped a bunch.

Here is a video of a couple climbs I made today with this setup.

http://www.youtube.com/watch?v=k8uLN3xVZi4


- David

[EeePee]

Originally Posted by dkingston

One of the characteristics of the rig stock was that it really wanted to carry the front right tire on incline climbs. Adjusting the anti-squat helped a bunch.

Looks pretty good Dave. Though, mine still pretty much built from the book doesn't really carry a tire. Ohhhh yeah, I had a lot of weight in my front Vanquish wheels. So then, I wonder if it's the major preloading of the springs, and the increased angle of the shocks. I do think they went a little too soft on the kit's springs.

Which way is your rear axle clocked? Is it leaning down in the front now?

[dkingston]

Originally Posted by EeePee

Which way is your rear axle clocked? Is it leaning down in the front now?

It is down in the front.


- David

[Gatekeeper]

Pretty sweet video

[BILLYGOAT]

looks great dave . where are your links mounted to the axle . it appears to be in the top hole. i may play with the rear link trick . first comp is sunday and i think shes ready.

[dkingston]

Good catch, the rear lower links are mounted in the top hole on the axle

Good luck on Sunday!


- David

[dkingston]

Originally Posted by Gatekeeper

Pretty sweet video

Thanks, Autsin... means a lot coming from you! Now if I only had your skill...


- David

[JOOTZ]

+1 on the vid, this will be a very informative build thread to follow, am now counting down the days till i get my hands on the rockforce

[ktmkurt]

Nice vid the Rockforce seemed to climb very well with just a little
modding you did. I haven't got a crawler yet and had my mind set
on an Axial but, crap now I am so confused LOL. I have always
liked Kyosho. Decisions, decisions!

[dkingston]

Originally Posted by ktmkurt

Nice vid the Rockforce seemed to climb very well with just a little
modding you did. I haven't got a crawler yet and had my mind set
on an Axial but, crap now I am so confused LOL. I have always
liked Kyosho. Decisions, decisions!

Thank you for your comments. I know it is tough, there are a lot of great choices now and in the near future.

The Axial is a very capable rig and I am sure you would like it a lot. Tons of aftermarket support and a wealth of experience here on the forums.

What Kyosho has to offer is unprecedented durability in crawling along with some innovations that make it truly unique. I think that is you decide on Kyosho you will be very happy you did. As I and others are finding out, minor tweaks and adjustment in setup make the rig a very capable crawler. As we progress into more elaborate modifications I believe the sky is truly the limit with the Kyosho.



- David

[dezmoon]

Originally Posted by dkingston

Thank you for your comments. I know it is tough, there are a lot of great choices now and in the near future.

The Axial is a very capable rig and I am sure you would like it a lot. Tons of aftermarket support and a wealth of experience here on the forums.

What Kyosho has to offer is unprecedented durability in crawling along with some innovations that make it truly unique. I think that is you decide on Kyosho you will be very happy you did. As I and others are finding out, minor tweaks and adjustment in setup make the rig a very capable crawler. As we progress into more elaborate modifications I believe the sky is truly the limit with the Kyosho.



- David

i couldnt agree more,,,this rig continues to impress me,,

[dkingston]

Chassis Cinching/Limiting Straps

One of the features of the Rock Force that I have to admit, didn't excite me much until now was the cinch strap to limit downtravel. With the other rigs I have run I had just placed fuel tubing under the piston to achieve the same thing, or so I thought.

Yes, as advertised, just changing the length of the zip tie was faster and more convenient in setting downtravel. But what I found was that by cinching with the strap in the center of the axle as shown below, the axle was still free to articulate, pivoting on the axis with the strap.



With the fuel tubing trick that was it, the shock limited any further downtravel (articulation) on each side. Now, chassis height hasn't changed and the suspension can cycle fully as seen below.



What is cool, I can run 56mm chassis height (just a hair under 2.5") and still get the articulation I want.

Setting the ride height where I wanted with the limiting strap then mounting the shock so at rest the piston was as close to mid-stoke as possible. This allowed the suspension cycle to have as much downtravel on each side as uptravel. It was so easy to do with the limiting straps.

What is even better, as advertised if I want to adjust the height all I have to do is replace or tighten the existing zip tie! Dialed.

One caveat, the zip ties that come with the kit are too small IMHO. In the video above, I snapped the rear strap making that vertical climb. As you can see in my pictures above I am now using a heavier one. It is a tight fit getting it through the hole on the axle but the additional "stout" is worth it.

Did they do this on purpose or was this an unintended side effect? I don't know and honestly I am happy with it either way.


- David

[JOOTZ]

where does one go to buy the spurs and pinions for the rockforce. if i were to use the tekin FXR/55T esc&motor combo what is the preferable spur and pinion combination ? and would 3S lipo be good ? TIA

[dave56bug]

Spur gears are or used to be standard fit, so the ones with the multiple ball bearing holes will or should fit, you'll need 48p such as:

http://www3.towerhobbies.com/cgi-bin...?&I=LXS457&P=7

looks like it would fit:

http://www3.towerhobbies.com/cgi-bin...?&I=LXD247&P=7

and any 48p pinion will fit:

http://www3.towerhobbies.com/cgi-bin...?&I=LXEX23&P=7

http://www3.towerhobbies.com/cgi-bin...?&I=LXEX28&P=7

Tamiyas 48p stuff is metric 48p wich will not mesh nicely so dont use those.

[dkingston]

Good links.

The Kyosho spur gears are identical to the Kimbrough. Any Kimbrough or Associated (which is Kimbrough also) will work.


- David

[4wdmt]

Guys, quick question. How much do you think the gain in speed if you changed the stock pinion and spur of the kit into that 25t RR pinion and 78t kimbrough spur dave56bug posted.

Also...the speed if you have the 25t/78t combo but with the HS gear set.

Thank you.

[dkingston]

Originally Posted by 4wdmt

Guys, quick question. How much do you think the gain in speed if you changed the stock pinion and spur of the kit into that 25t RR pinion and 78t kimbrough spur dave56bug posted.

Also...the speed if you have the 25t/78t combo but with the HS gear set.

Thank you.

The stock (with LowSpeed gearset) is at 143.33:1 ratio. with a 25 and 78 it will take you to 93.6:1. A significant change but is it enough? You tell us!

Here is a chart that will help you out.

General Rock Force 2.2 Info


- David

[4wdmt]

Thanks David.

With that raio (93.6:1), how much is that in mph?

[dkingston]

Originally Posted by 4wdmt

Thanks David.

With that raio (93.6:1), how much is that in mph?

1,000,000,000!

Actually that would depend on a couple other things, rpm, 2s or 2S battery then tire size...

Currently I am running a 56.09:1 and it is fast enough for me. Some would want even faster!

I would try it and see for yourself.


- David

[4wdmt]

YUP. If ever, that will be my plan. Gear it up and see how fast an RF can go.