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K.O.M.'s Newbie Comp Build Project Overview: I have been in and out of the R/C hobby for going on 20 years now. After my longest hiatus yet, not touching or building a car in the past 2 years, I'm now hooked again and that's thanks to rock crawlers. It started with a Losi Micro Crawler at the beginning of the year, soon followed by an SCX-10, and just recently, an AX-10. I thought that I wouldn't be too involved into competitions and had originally planned to build my AX-10 into a tube-framed rock racer. I know that what I'm going to do is not anything new or ground-breaking, but what I do plan on doing is explaining why I am adding a modification and doing a before and after test with video if possible. So, without any further delay: Started with an AX-10 kit that I was going to sell to get an RC4WD tuber, but decided otherwise: http://i966.photobucket.com/albums/a...e/CIMG3949.jpg As you can see from the photo above, I've already reached the limitations of the stock Pro-Line Hammer M2 tires. I've started star-cutting the foams to get a bit more flex out of the tire, and even went as far as star cutting some really old Trinity super-soft memory foam. It has helped a bit, but I've just found that the Hammers, at least the M2 compound, is too stiff for the rocks around here. http://i966.photobucket.com/albums/a...e/CIMG3952.jpg I took the crawler on a hiking and camping trip to Yosemite about a week after I bought it. After less than 5 minutes playing on a rock that had an incline of 35 degrees, I heard what amounted to a bunch of small twigs snapping. It was the dogbone disentegrating first, followed by the c-hub cracking at the screw hole as the remnants of the dogbone took it out. What you see above is a new Golden Horizon aluminum C-Hub and an Axial Universal Joint Kit. That's it for the start of this build. Parts and Prices so far: AX10 ARTR $240 Spektrum DX3E $100 Integy Prospeed Brushless System w/program card $95 Hitec 645 Servo $35 Golden Horizons Alloy C-Hub $20 Axial Universal Joints $32 The Bottom Line: $522 |
What tires are you going to run now? You'd also do good to pick up some new knuckles. The stock ones are guaranteed to break. "thumbsup" |
A quick Q and A with myself as to why I chose to start with the equipment level that I did. Q: Why an AX10 ARTR? Why not wait for the XR10? A: The AX10 has the widest array of parts available out of any crawler. Period. I figure that anything that I will comp will break something, so why not have the advantage of being able to run down to the hobbyshop instead of being out of comission for a week? As for the XR10, that's still a ways off and I may get that as my first MOA, but I want to learn and setup a shafty so that a) I can get crawling right away and b) know the limitations of said shafty so that I know where I can pick up the slack with the MOA. Q: Why the electronics package that you have? Isn't that a little "cheap?" A: I needed a 3ch. radio if I ever wanted to add a dig function in the forseeable future, so again, the Spektrum was chosen because of a combo of price and parts availability. The Hitec 645 is about the minimum anyone would want to run on a crawler @ 6v w/ 133oz./in. of torque(I found out after crunching the gears on a stock Spektrum servo). I went with the Integy, purely on price and the promise of no/little maintenance to the motor. Q: Why haven't you thrown an X, Y, or Z upgrade in there already? A: I do have a bunch of stuff already purchased, but I want to be a bit methodical and do things one at a time so I know how they will change how the rig drives--regardless of proven things that people are already doing here on the forums. I want to know for MY own edification. |
Unscientific tire test I think Duuuuuuuuude might be telepathic as he knows where I'm going with this next. The unanimous choice seems to be Hot Bodies Rovers in the White Compound. Less unanimous is the type of foam. So, based on my prior experience with Rovers and short foams in the past, I went with some generic Hobbytown oversize memory foam and cut them down to the width I liked until I got the tire flex I wanted, while not folding over on side-hills and wadding up on high traction areas. Had some time to do a very unscientific tire test. Here's a vid below: http://www.vimeo.com/11842683 Parts and prices so far: From previous update $522 HB Rovers (x2) $32 Generic Foam (x2) $30 Lead Sticky weights $3.50 The bottom line: $587.50 |
Good for you for wanting to learn stuff instead of just slapping something together and crying 'cause it don't work right. "thumbsup" |
Some Free/Low Cost Mods Free/Cheap Mods that make a difference for the crawler's performance. First and foremost, clean up your wiring. I've seen a few people's runs cut short by the servo, esc, or battery wire getting caught by either the spur/pinion gear, sandwiched beween a link, or snagged by a rock. It won't cost you more than just a few zip-ties and an eye for detail. Here's how I cleaned up my wiring. Notice no electronic wires in the middle section where the motor/tranny live. Also notice that I have removed the aluminum battery plate-hey, since people are being anal about being weight placed up high, every little bit counts. Battery, esc, and receiver are all mounted on the upper 3-link using lexan sheets cut to fit and zip-tied to the links. Also notice that I flipped the tranny to help with torque twist (note: it's a flip, not a mirror, since the spur/pinion is now facing the front of the crawler, I did this to offset the added weight in the front tires--it would flip if I suddenly let off the throttle on the same grade that I can climb): http://i966.photobucket.com/albums/a...0/CIMG3995.jpg http://i966.photobucket.com/albums/a...0/CIMG3982.jpg Now that I have the crawler climbing up stuff in excess of 65 degrees, torque twist is a bit of an issue. Part of it is addressed by the motor placement, the other is through cross-balancing the springs on the car. In this case, I just added an extra pre-load spacer on the left-rear of the rig to push the front-right down. http://i966.photobucket.com/albums/a...0/CIMG3983.jpg If you notice the steering on a stock AX10, there is a bit of toe-in and negative Ackermann (inside wheel steers shallower than the outside wheel). The means the crawler has a tendency to understeer. While I can't fully eliminate the negative Ackermann, this is due to the knuckle geometry, I can add some toe-out to reduce the negative Ackermann to close to neutral with the cost of a few small washers. Before-Notice toe-in and inside wheel not steering as sharply as outside wheel: http://i966.photobucket.com/albums/a...0/CIMG3976.jpg http://i966.photobucket.com/albums/a...0/CIMG3975.jpg After-Notice slight toe-out and inside wheel steering sharper, almost the same angle as outside wheel: http://i966.photobucket.com/albums/a...0/CIMG3978.jpg http://i966.photobucket.com/albums/a...0/CIMG3977.jpg The actual mod, cheap, and effective: http://i966.photobucket.com/albums/a...0/CIMG3979.jpg http://i966.photobucket.com/albums/a...0/CIMG3980.jpg Drove the crawler in the house, and it can drive a circle about 6 inches smaller in diameter than stock. It's midnight and I really need to finish some AutoCad and Solidworks drawings for my project, so I'm signing off. Parts and prices so far: From Previous Updates $587.50 Bag of washers $0.75 The bottom line: $588.25 |
Looks good, another 'freebie or cheap tip' is to flip the screw and nut over on the knuckle ;-) Helps prevent annoying hangups that the nut can cause 8) Best is a "button head" screw but if you want to use what you got, the stock philips works :ror: |
great post I only hope to tweak out my AX10 to this level... I appreciate the detail that you go into on this issue. I think that is what I enjoy most about the hobby. Simple and effective tweaks that make it 100% more fun. I could do 1:1, but it would cost 1:100 times more. (money, time, etc.) :mrgreen: |
im surprised you still have th stock drive shafts and broke a dog bone! Ive never broke a dog bone (not saying they cant) in any of the axials I run or seen run |
Slipper Clutch and Body Trimming Thanks everyone for the encouragement and additional tips. Time for an update. Since the last time I broke parts, I figured that I needed a slipper clutch as the "weak point" in the drivetrain. I have it set so I can bind-up any wheel and just barely have the crawler flip itself over before it slips. Without any outside interference (me), I have found that situations have to be really ugly before the slipper will disengage--usually have to have a wheel or two wedged in a hole or crack. I would consider this part "free" for me because I swapped it from another AX10 tranny from a project. http://i966.photobucket.com/albums/a...e/CIMG3953.jpg Part of the reason I went with the taller, 5.5" tires, is to be able to flip the crawler over from its roof under its own power. To do that, I simply drilled 1/4" holes 1/2" higher than the stock body holes to effectively lower the body. Before: http://i966.photobucket.com/albums/a...0/CIMG3984.jpg After: http://i966.photobucket.com/albums/a...0/CIMG3989.jpg Before: http://i966.photobucket.com/albums/a...0/CIMG3985.jpg After: http://i966.photobucket.com/albums/a...0/CIMG3990.jpg After the body lowering, I noticed that it is much easier to flip the rig back on its wheels, however, the tires rub when at the extreme ends of articulation and steering. The lower part of the body would now also get hung up on the rocks. Some body trimming was required to alleviate the tire rub and body drag problem. http://i966.photobucket.com/albums/a...0/CIMG3992.jpg http://i966.photobucket.com/albums/a...0/CIMG3991.jpg http://i966.photobucket.com/albums/a...0/CIMG3993.jpg http://i966.photobucket.com/albums/a...0/CIMG3994.jpg That's it for this update. Parts and prices so far: From previous update: $588.25 Slipper Clutch: Free from another project 8) ($27.00 if bought separately) Body Trimming: Free The bottom line: $588.25 |
Slipper clutches are for sissies and scalers. Get a good set of outputs and driveshafts and there won't be many issues unless you just get plain stupid. "thumbsup" |
I agree with dude, only little girls wear slippers. |
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NOT NICE....I could crawl circles around with mine...:shock: Jk...my dad updated my slipper to a slash style and I have never had any issues.....40T and a three cell"thumbsup" |
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This thread will quickly become a favorite for other new drivers. It's quite apparent that you're methodical and purpose driven which will serve you and those who read your posts well. I like the fact that you are keeping a running tally along with the list of mods; quick access to that info will assist others in making decisions on upgrades. Welcome back, and just so you're aware, you're also going to end up with a Short Course truck...it's inevitable :mrgreen: |
Shocks and small details. I appreciate everyone's concern for my masculinity ;-). I'll stick with the slipper for now as I get a feel for what I can/can't power over. Since installing, I've gradually tightened the spring as the pads break in, and it has come in handy as I learn a few things about line selection. Since I'll finally be able to make a weekly practice comp at the local Hobbytown, I figured I'll make a couple more changes. I was pretty happy with the rig so far, but it seems that there were still a few, small things left that I could do to get it ready. SHOCKS: The stock AX10 ARTR is pretty stiffly sprung. Axial should know, they packaged it with the stiffest springs in their line. While this might be ok for someone running a heavier 6-cell stick pack on the stock battery location, it limits the crawler a bit in more challenging situations. I ordered the "medium" springs, but that still was too stiff. Looking at some of the competitive shafty builds as well as some of the course designs, it seems that I should just quit trying to make the stock length shocks work and go with something that's already proven. My concurrent project requires a droop setup, so I just "traded" again from that project and obtained Axial's shorter, threaded plastic bodied, "comp" shocks. The shocks have the softest springs with one spring being stiffer on the left-rear of the rig to combat torque twist. Note that I also installed the shorter rod end for an even lower ride height. http://i966.photobucket.com/albums/a...0/CIMG3998.jpg Ride Height Before: http://i966.photobucket.com/albums/a...0/CIMG3996.jpg Ride Height After: http://i966.photobucket.com/albums/a...0/CIMG4004.jpg Roof Height Before: http://i966.photobucket.com/albums/a...0/CIMG3990.jpg Roof Height After http://i966.photobucket.com/albums/a...0/CIMG4003.jpg LINKS: With the new shocks, and a short test run, I noticed that the suspension was binding. I cycled the chassis up and down a few times and noticed that the lower links were contacting the shock spring collars at 75% travel. I just swapped postion between the shock and lower links at the axle and, voila, problem solved. In all of Axial's manuals, it is shown with this type of interference. IMPORTANT NOTE: I had a BTA kit on my other AX10, and tried to do the same mod there. I didn't have a chance to take pictures, but mounting Axial's BTA kit with the links/shocks mounted in the new orientation will cause some interference with the alloy BTA drag/servo link hitting the shock body--it seems that the BTA was designed with the crappy stock mounting setup--a shame really, and now I know why some folks are not using the Axial BTA or are having trouble with that kit. Before: http://i966.photobucket.com/albums/a...0/CIMG3997.jpg After: http://i966.photobucket.com/albums/a...0/CIMG3999.jpg MORE BODY TRIMMING With the lower ride height, the body and body post was snagging on some tight gaps that the crawler was more than capable of squeezing through. Also, the front of the body was hitting the servo, preventing a smooth front end flex in some situations. Before: http://i966.photobucket.com/albums/a...0/CIMG4001.jpg After: http://i966.photobucket.com/albums/a...0/CIMG4002.jpg Front Body Trim: http://i966.photobucket.com/albums/a...0/CIMG4005.jpg Parts and prices so far: From previous update: $588.25 Axial Plastic Comp Shocks: Free ($82 for two pairs for the alloy version) Link/shoc mount swap: Free Body Trimming: Free The Bottom Line: $588.25 |
Poser shots! Changed Tires: http://i966.photobucket.com/albums/a...0/CIMG3984.jpg Lowered Body: http://i966.photobucket.com/albums/a...0/CIMG3989.jpg Shorter shocks: Low, lean and mean. Tires are above the plane of the front/rear body panels for easier flips. http://i966.photobucket.com/albums/a...0/CIMG4006.jpg The obligatory flex shots: http://i966.photobucket.com/albums/a...0/CIMG4007.jpg http://i966.photobucket.com/albums/a...0/CIMG4008.jpg http://i966.photobucket.com/albums/a...0/CIMG4009.jpg Measuring "flex": http://i966.photobucket.com/albums/a...0/CIMG4010.jpg 50 degrees--can actually get up to 70, but I limited the shock travel to this level because I didn't want to get it bound up and not be able to drive out. http://i966.photobucket.com/albums/a...0/CIMG4011.jpg |
I really appreciate this thread. I have only had my crawler about a month. I have an ax10 mods include axle battery pack, mip driveshafts, twin force shocks, Panther Cougars with solder weight in front. And as of yesterday rear 4-link using stock straight lowers as uppers and putting them in the factory body mount hole. http://c3.ac-images.myspacecdn.com/i...3b5316fd4e.jpg http://c4.ac-images.myspacecdn.com/i...050858843f.jpg bout to go do the steering mod now and see how I like it. |
Nice build and post. Thanks for putting the info you have learned out there so other people can learn as well. "thumbsup" If you want to run a slipper clutch then have at it do not let some D-bag tell you it's for sissys. :flipoff: |
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