newbie looking to make a 4 wheel steer xr10

[jari]

Hi every one, A little over one year ago I started converting rc cars to become autonomous. Through that I leaned a lot about different types of RC cars and the one thing that stuck out about crawlers is that they are are the most capable of of overcoming any obstacle in their way (besides water).

Looking at crawlers it seems Two me that a moa 4wd 4ws crawler has the most ability at over coming obstacles so that is the route I plane on taking. I choose the XR10 over the berg because to me it seams that the axial is cheeper and has a large following (ie more hop ups). For now I don’t plan on upgrading the hardware instead just geting what is needed to make the XR10 a 4ws.

What I have decided to spend a lot on is the electronics as it will save a lot of money in the long run to get the best posible so I don'y have to upgrade in the future. I would appreciate comments on It there is a cheeper place to get each component or a better alternatives to what I have listed.


(2) Holmes Hobbies 35t matched pare
Holmes Hobbies $119.99
(2) Tekin fxr
Holmes Hobbies $172.80

(2) Futaba BLS157HV Servo
Ready Heli $299.98


(1) XR10
Tower Hobbies $219.99
(1) Tekin Hotwire interface
Tower Hobbies $31.99
(1) Futaba 6ex rx/tx
Tower Hobbies $199.98
(1) Castle Creations BEC
Tower Hobbies $21.99
(1) Castle Creations USB Link
Tower Hobbies $21.99


(2) Hyperion G3 EX 11.1v 3s 1600mAh 45c/90c Lipo
rcdude $83.90
(1) Hyperion EOS 0606i 6s 6A AC/DC Charger
rcdude $109.95


(1) VP .6 Caliber SST Weight Set
Vanquisher products $15.99

total $1298.55

This of course leaves out shipping costs.

I have been unable to find a suppler for the robotronic servos that every one is recommending and would like some advice for alternatives. I also am completely over whelmed by the shear quantity of choice of wheels and foams and would appreciate suggestions. I mainly plan on running this on rocky beaches and river beds if that helps.

I am also leaving out all the parts I need to make the xr10 a four wheel steer as I am still combing over the manual to mak sure I have a comprehensive list. after I make a comprehensive list of all I will need I plan to watch e-bay for a few weeks to see if I can get any thing for cheeper.

Sorry for the wall of text and thanks for in advance for any advice you can give.

P.S. I have no planes of going comp crawling which is why I plan on doing 4ws.

[articzap]

You'll need a second front axle housing, second front end upper link mount, chubs, knuckles, steering linkage, servo mount, and axle half shafts.

That should be everything you need extra to put a front axle in the back so you can have 4ws.

EDIT: and youll need the cross shaft for the transmission.

[aaronlecain]

Awesome. I am not the only one going for rear steering.

The rear axil housing will work for you. You just need the universal axle shafts, C-hubs, Knuckles, servo, horn, servo mounts, bearings for the knuckles and steering links.

[jari]

Thanks aaronecain, I thought that the housings had different widths and I would have to gett a second front axel. Is it just the knuckles that make the diference in width?

looking at aarolecain’s photo I’ve made a list of parts that appear to allow for the conversion to 4ws.

screws:
axa115: http://www3.towerhobbies.com/cgi-bin...?&I=LXYKX3&P=Z
$2.50
axa433: http://www3.towerhobbies.com/cgi-bin...?&I=LXYYP6&P=Z
$2.50
axa117: http://www3.towerhobbies.com/cgi-bin...?&I=LXYKX4&P=Z
$2.50


ax30450: http://www3.towerhobbies.com/cgi-bin...?&I=LXSAR9&P=Z
$5.99

bearrings
axa1230: http://www3.towerhobbies.com/cgi-bin...?&I=LXSAW5&P=Z
$5.99
axa1218: http://www3.towerhobbies.com/cgi-bin...?&I=LXSAW1&P=Z
$4.89

flanged balls
axa1331: http://www3.towerhobbies.com/cgi-bin...?&I=LXSAX3&P=Z
$4.89

link ends
ax80005: http://www3.towerhobbies.com/cgi-bin...?&I=LXSAT0&P=Z
$6.39

servo mount I think it will work
ax80063: http://www3.towerhobbies.com/cgi-bin...?&I=LXAASA&P=Z
$7.79

steering knuckles
ax80061: http://www3.towerhobbies.com/cgi-bin...?&I=LXAARY&P=Z
$10.59

hub carriers
ax80062: http://www3.towerhobbies.com/cgi-bin...?&I=LXAARZ&P=Z
$6.79

universal shaft set
ax30563: http://www3.towerhobbies.com/cgi-bin...?&I=LXAARM&P=Z
$37.99

I am missing the longer screw that connectors the steering link for the servo link and the right/left wheel connection together, as well as the components used in the middle of the links advice on the size I would need would be appreciated.

[aaronlecain]

You are correct the steering setup is what makes the width. I made up a linkage out of some spacers that I got from a local hobby shop. the only thing that I can't do is adjust the length but it is close enough for me.

the servo mounts you listed will work as that is what I used.

I believe you only need the larger bearing set as the bearings in the rear axle hubs should be the same. double check the part number as I don't have the manual infront of me.

[avoidsthelight]

out of curiosity...what are you doing making them autonomus? what is the end result?

[jari]

Thanks for pointing out the extra bearings Aaronlcain.

Avoidsthelight, to make the rc cars autonomous I use a lot of sensors (lidar, cameras, gyroscopes ...) and use a micro controller and computer to proses the information. see snowbots.ca for my robotics teams blog and here is a youtube video of the robot I made last year with a e-maxx chassis: http://www.youtube.com/watch?v=zSlzDRCHV8E

This year I will be using a gumstix board instead of a netbook (it uses the same processor as a smart phone) that will be small enough to fit in a crawler.

[jcboof]

One big thing you don't want to forget is axle upgrades. The XR is a great crawler, but the stock axles are plagued with problems. Vanquish products makes a lot of upgrades for the axles.
Aluminum knuckes, c hubs, motor plates, gear boxes, and link mounts As far as gears go, RC4WD makes a hardened gear set. You are looking at another $400.00 for these upgrades. Are they all completely necessary? No, but some if them are. If you are investing that much money in everything else, it would be wise to invest in the axle upgrades as well.

An XR10 is one of the most expensive crawlers to build. A berg IS cheaper to build. Most guys with fully built XRs have around $1500-1600 into just the truck itself not including the radio and receiver.

[jari]

I have released that fully upgrading an xr10 will make it extremely expensive I plan on doing that more gradually as components break and I get more money, for now I just want to concentrate on getting the best electronics. I also want to make some components like the chassis my self. As second year mechanical engineering student going into Mechatronics next year it will be hard to resist designing upgrades my self.