Stuff About Springs
People often believe that spring rate and preload spacers do the same thing. Springs are measured in spring rate, which is how much force the spring will exhert at a certain amount of compression. This is usually measured in In/Lbs for RCs. Many people think that adding preload to a softer spring makes it the same as a stiffer spring. This is wrong. For a hypothetical example, Say you have a spring that is 5 in/lbs, and another that is 10, both being 4 inches long on the same vehicle. If you add 1 inch of preload, the 5 "/lb spring can now hold up the same weight as the 10 in/lbs spring. Now the part that confuses people is spring compression. Although they may seem as stiff, a 5 in/lb spring will still compress much softer at only 5 in/lbs. Add another inch to it(a small bump), you have 15 lbs of pressure resisting the movement. Add an inch to a 10 in/lbs, and you now have 20 lbs of resistance. Go up to 4 inches, the 5 in/lb will have 20 lbs of resistance and the 10 will have 40. In a summary, preload spacers add ride height, stiffer springs add more resistance. Now that you know what i mean you will see the various things i ramble about in the lower sections.
Rock Crawling - Although i havent done much hardcore crawling, ive done enough of it plus a lot of reseacrh to learn some good stuff. rock crawling is about going slow, but sometimes you just have to gun it. The Instant centrifugal force of the tires causes the truck to launch forward, sometimes freeing you, or sometimes getting you more stuck(you decide if it will work). Also facing a step-shaped object or stairs, if you peg it then let off to about 1/2 throttle, the tires hit the face and have enough traction for a split second to move up the stairs/rock/object, and not flip you over. Also if you are high-centered, a full throttle reverse to forward shot will cause the truck to move, maybe enough to get the tires onto something. Also many people believe suspension should be as lightly sprung and damped as possible when rock crawling, which is false. If you encounter a dip, the tire will just drop in if the springs are wimpy. If your shocks have low weight oil it will cause excesive hopping, which instantly robs you of all traction. And if the truck is encountering a high-angle ascent, soft springs will allow the motors to flex the chassis over if they are mounted sideways(txt-1, x-factor), aka torque flex. Stiff springs will want to stop your vehicle from articulating, which in writing sounds like bad thing, but it keeps your tires hooked up well, and traction is better to have then extreme flexiness. And more articulation is not always better. You want your springs stiff enough to allow about 8-9 inches or so depending on how wide it is, any more and your tires wont be able to grab well. Also lock up your diff, lower as much weight as possible, and soften your tires with wd-40 untill they barely hold up the truck. Also narrowing your rims helps out.
Mud - Mud basically sucks. Its easy to get stuck in, and it doesnt come off after your through it. But it can be fun. if you are going to drive through it more than occasionally and need to know what to use, ive learned a lot about it. First of all, cover everything you can, espcially your nitro/electric motors, esc, any exposed gears, and servos. Mud and water are like napalm and gasoline, it burns just as bad, but it stays there. You also need pretty stiff suspension in the mud. Soft suspension wont dig your tires in if you high center. paddles work here, but deep, agressive square treads work best, such as imex g-hawgs or stock juggernaught tires. You need them to be skinny as well. Mud needs to be dug into, not floated upon. If you start getting stuck, start sawing the wheels left and right and gun it. This alows the front tires (and rear if you use 4ws) to grab some fresh mud and they might pull you out. If your truck has tough gears, forward to reverse full throttle blasts may jerk the truck violently enough to get it unstuck. Nitro loses this advantage. Also, keep your front ride height higher than your rear. It may make your truck look retarted, but it works. If you can move a lot of weight around, keep it about 60 rear/40 front.
Sand - If your truck is prepped for sand(similar to mud, but bearings and shocks must be maintained), sand can be fun. Unlike mud, you need soft suspension and large floaty tires(stock clod, monster pirate), or if there smaller (t-maxx size) use paddles, if you use panther style paddles, put them on backwards, especially with 2wd.. A note on power, Use a smaller clutch bell/pinion than your used to, and with electric use the motor you have with the most torque(usually the stock one). Sand is hard on motors, it takes a lot of low-end power to go through. Also unlike mud, if you start getting stuck increase throttle. There is no going through sand if you dig in, you can just hope to propel enough sand for it to work like thrust. In sand try to get as much weight in the back as possible. You need your front end to float over the sand and let the back tires do the pushing.
Hill Climbing - I am talking about the sandy/dirty, super-steep nearly vertical kind of hills as seen on TV in iceland, Not shallow ones that you can walk up on foot. This was the hardest setup ive done. It takes lots of traction, but good bump handling, and articulation to keep the tires hooked up over dips, small rocks and uneven hill faces. Also finding a good weight balance point is crucial to having a good hill climber. You need a good balance between traction and anti-rolling with your weight. I have a 5 cell sub-c reciever pack that i use as a moveable weight. For suspension, you need to experiment with rear shock fluids. The front is simple, use the softest springs and shock oil you can find that will hold your truck up over bumps. The rear is hard. Too stiff of an oil and you will not get good hookup on bumpy stuff, and too soft and it will squat down too easily and roll over. for springs you need semi soft springs and enough preload spacers to keep ride height maxed at the rear. On my monster Pirate climber I found the stock springs are good on the back, and yellow kyosho mad force springs on the front work well. Wth your engine just slide the tuned pipe onto the header so there is about 1/8 inch of overlap, this gives you good mid range power. You may think you need a lot of torque but your well into the power band by the time you get to the steep stuff. Another thing that helps is drilling your clutch shoes. I drilled a 1/8th hole in the middle of my shoes, and another 1/16th hole at the end. This makes low end throttle control.... well, pack up and leave. It will just grab then let go inconsistently and make the truck jerk around at low speed. But it helps when your motor can rev up to about 4k rpms before it starts to engage, and it really lets you put some power to the ground at low speeds. If you have enough power to make it up the hill without dropping too far into the slipage point, you have a good setup. If you find the clutch starts slipping excesivley, gear down a tooth or 2 on your clutch bell, or lighten your vehicle. Use a high power motor/s if your going electric, you need to obtain maximum speed on the shallower parts of the hills to get up the top, Because the ammount of throttle you can use at the very top is quite limited. |
