Having very recently come into the hobby with no prior experience, I know first hand how daunting it can be for a novice. With this guide, I hope to break down all the terms and concepts that you need to know to get started with electric RC cars. I am far from an expert myself, but over the last few weeks I've picked up enough information that I can at least follow along with the conversations on this board. If I have made any mistakes, or if there is something you would like me to add, please let me know.
Types of Vehicles
Monster Trucks (MT): I think everybody knows what these are. Huge tires and lifted suspension. They usually aren't the fastest, which is actually good because they don't handle well at high speed. However, excellent ground clearance means they'll run over pretty much anything.
Buggy: Open wheeled with a narrow front, usually an exposed motor in back and a wing on top. Buggies have relatively low ground clearnace compared to STs and are preferred for dirt-track racing rather than going through grass and brush.
Stadium Truck (ST): Basically a buggy with a modified truck body and modified (usually higher) suspension. STs are sometimes referred to as "truggies", though there are technically some minor distinctions between the two. A good "all-around" truck that will handle well on pavement, dirt and gravel, but can still get over grass without too much difficulty.
Short Course Truck (SC): Sometimes called a CORR (Championship Off Road Racing) truck, these are usually a bit narrower than STs or buggies and the outer body is widened to cover the wheels. They usually have smaller wheels and a bit less suspension travel and ground clearance then STs. Good for pavement and dirt, but the lower body gives them some trouble with coarse gravel or high grass. The wide body has something of a "parachute effect" when taking jumps, which takes some getting used to. A new sub-category of desert trucks (DT) is emerging from the SCs with slightly smaller, more to-scale bodies and tires. These DTs do not fit into existing approved race specs, but they are a nice option for those who want a more realistic off-roader.
Rock Crawler: These are a specialized version of MT with
highly articulated suspension components. They go very slow, but they'll climb over obstacles that nothing else can handle.
Road car: There are probably several subtle sub-classes that I am unaware of, but in general, a road car is low slung with very little ground clearance. They are designed to race on asphalt or concrete, or a smooth indoor floor surface, and cannot handle uneven terrain. Their suspension is stiff with little travel, but they'll drift around corners like nobody's business.
F1: Also called indy cars, these are road-only vehicles that are set up to look like full-scale race cars with wide, exposed wheels and spoilers.
Rally car: Just as with real cars, RC rally cars bridge the gap between on-road race cars and off-road trucks. These cars don't have the ground clearance for really rough terrain, but with the proper tires they'll do well on either paved or dirt tracks.
Motors
RC motors are available as either brushed or brushless (BL).
Brushed motors are cheap and get the job done, but they are not as fast as BL. Brushed motors are rated by the number of turns (t) they use. In general, lower turns means higher speed. Most stock motors are in the 19t-30t range while high performance motors will be 5t-12t. Brushed motors have two power wires. Rebuildable brushed motors are made to easily be disassembled so that the brushes and springs can be replaced when worn out. Most cars come with non-rebuildable motors (often called "cans") which are sealed and must be replaced when they wear down.
BL motors are faster and more efficient, which means they'll run longer on a single battery charge. The trade-off is that they are significantly more expensive than brushed motors. BL motors are rated by KV, with higher ratings equaling higher max RPM. Note that "faster" is not always better, since heavy vehicles actually do better with lower KV rated motors, which don't spin as fast, but have more torque. All BL motors have three power wires. Brushless motors are available as either sensored or sensorless. Sensored motors have additional wires (as shown above) which plug into the ESC. These wires connect to sensors inside the motor and allow the ESC to know exactly what the motor is doing for better control. Sensorless motors are cheaper, but they are not as smooth running as sensored, especially at low speeds. Many sensored ESCs will also run sensorless, but not the other way around.
Electronic Speed Controls (ESC)
ESCs are the electronic devices that control how fast the motor runs - basically a digital throttle. Without getting into too much unnecessary detail, just be aware that a brushed motor requires a brushed ESC and a BL motor requires a BL ESC. Most BL ESCs have extra programmable features, like anti-lock breaking, low-voltage cutoff and signal loss protection. Brushed ESCs are rated by the number of turns (t) they support, while BL ESCs are rated by amps (A).
Gears
When people talk about changing gears or gear ratios, they're usually talking about the pinion and spur gear. The pinion is the small gear mounted on the motor itself, and the spur is the big gear that meshes with it. Making the pinion gear bigger or the spur gear smaller will lower the gear ratio, while making the pinion smaller or the spur larger will raise it. A higher gear ratio will give more power, but a lower top speed. A lower ratio will do the opposite. Both gears are rated by the number of teeth they have (t) and the pitch (angle) of the teeth (p). If you want to learn all the specific math behind gearing, I highly recommend you read
this post.
Suspension
Suspension tuning really deserves a lengthy post all to itself (in fact, many already exist), but the quick version is this: Shocks absorb up-and-down jolts to the car. The springs on the outside keep the car from slamming into the ground, and the pistons (usually filled with oil) inside the springs dampen the rebound and keep the car from bouncing off the track.
Camber is the vertical angle of the tires, and
toe is whether they point in or out.
Ackermann is the difference in steering percentage between the front wheels. For a more detailed explanation of how these (and other) factors affect handling, see
here. For the ultimate lesson in every aspect of RC car handling, [link=http://users.telenet.be/elvo/]this site[/link] is phenomenal.
Tires and Wheels
For all tire types, softer material will give better grip, but will wear out faster. All tires work better with foam inserts, which are included with most tires these days. Tires should be glued to the rims with cyanoacrylate (CA) glue. If you chose tires with an outer diameter that is much larger or smaller than your factory stock tires, you may need to change your gearing to maintain performance. Here are the main types of tires (stolen almost verbatim from
this post):
Pins: Extremely high wear on hard surfaces, low traction on hard surfaces, gives even traction in all directions, traction greatly reduced on sand.
Ribbed: Only used on the front wheels of 2-wheel-drive vehicles, good for most off-road conditions, excellent side-to-side traction.
Grooved: Medium-low wear on hard surfaces, high side-to-side traction, low traction on acceleration on sand.
Slicks: Can be made of rubber or foam, high traction on hard surfaces, gives even traction in all directions, virtually no traction off-road.
Paddle: High wear on hard surfaces (especially during acceleration), extremely good traction on sand, can drastically reduce steering on 2WD vehicles
V-Groove: Similar to slicks, but provide improved traction in wet conditions during acceleration.
X Pin: Medium-high wear on hard surfaces, relatively low traction on hard surfaces, gives even traction in all directions, traction less effected by sand.
Different types of wheels are almost purely an aesthetic choice. As long as you chose a wheel that is sized correctly for your tires and has the proper hub for your car, it's up to you what "style" you want.
Servos
The servo is the device that actuates the steering for your vehicle. It gets a signal from your receiver and moves its arm accordingly. Servos are rated for torque (oz/in) and speed (sec. per 60 degrees). Unless you make some major modifications to your vehicle, you should be fine with the stock servo or a replacement which is similarly rated.
Transmitters and Receivers
The transmitter (Tx) is the radio that you use to control your radio control vehicle. The receiver (Rx) is the little box with the antenna sticking out of it takes your radio signals and translates them into signals that the ESC and steering servo can understand. There are three main types of Tx/Rx systems, and the two components must be of the same type to work together. The older systems are AM and FM, and if those sound like the kind of "radio" that you listen to in your car, it's because they work on the same principles. Both AM and FM setups are made to work on one of several frequencies, and each of those frequencies are broken down into a handful of channels. Most AM and FM sets use removable crystals to determine the channel they work on. If you are using your vehicle near other RC cars, it is important that no two cars use the same channel, or you will interfere with each other. The third, newest, and by far the best system is Digital Spread Spectrum (DSS). These sets work on the 2.4GHz band, so many people refer to them by that number. A DSS Tx must be "bound" to a Rx, which syncs them to each other. Once bound, the Tx and Rx will communicate without noticeable interference, no matter how many other RC vehicles are near by or what type of system they use. Most DSS transmitters have extremely long ranges - so much so that you are likely to lose sight of your vehicle before the Rx loses the signal.
Every Tx is rated based on the number of channels (control channels, not to be confused with the frequency channels) it supports. Most cars only need two - one for the throttle and one for steering. Some large trucks use a third channel to lock/unlock the differential, but it's not common.
Batteries
There are two types of batteries currently used for RC cars - nickle metal hydride (NiMH) and lithium polymer (LiPo). Originally, all RC vehicles used a third type - Nickle Cadmium (NiCad) - but NiCad has been almost completely replaced by the vastly superior alternatives and few shops sell the old batteries these days. All batteries have two key ratings which you should be aware of: Voltage (V) and milliamp-hours (mAh). Voltage can be thought of as "electrical pressure". The higher the voltage, the stronger the battery is. The mAh rating tells you the capacity of the battery. The higher the rating, the longer the battery can run between recharges.
NiMH batteries are sold in packs consisting of 6 or more cells. Each cell provides 1.2V, so a 6 cell pack would be rated for 7.2V. NiMH batteries are heavier and cannot provide as much current as LiPo, but they are cheaper and less finicky. NiMH batteries are generally recommended for beginners.
LiPo batteries consist of packs containing two or more cells of 3.7V each. A two cell battery has a total voltage of 7.4V, and is usually called a "2s" pack, which stands for "2 cells in series". LiPo batteries have another rating in addition to voltage and mAh: C. The C rating is an indication of how much amperage a battery can supply. The [link=http://www.radiocontrolzone.com/showpost.php?p=2121837&postcount=2]exact calculation[/link] is not really important, just be aware that a LiPo battery with a 20c rating or higher will be sufficient for almost any stock brushed motor. If you upgrade to a higher power motor/ESC (like a 60A+ BL setup) then you should also upgrade to 30-40C packs, especially if you're using low-mAh cells. LiPos are much lighter than NiMH, and they are able to provide more current as well. The down side is that they can be more expensive, and they require more careful handling. You
must use a special LiPo charger to recharge them. LiPo batteries are very sensitive, and all the cells must be charged to the same level or you will have problems. All LiPo batteries have a 2nd, smaller connector called a "balancing connector" so that the charger can monitor and charge the cells individually. If you discharge the batteries too far (below 3V per cell), they will be damaged and cease to function properly. If you overcharge them (above 4.2V per cell), short them out, or physically damage them, they can
explode. Some manufacturers are now producing "hardcase" LiPos which, as the name implies, are enclosed in a hard plastic shell to help prevent physical damage.
Battery Chargers
A good charger is important. If your charger is slow, you'll spend more time waiting for your batteries to charge than actually driving your car. Make sure you get a charger that is capable of charging the type of batteries you will be using. Even if you're starting out with NiMH batteries, it might be a good investment to get a charger that can handle LiPos as well, so you won't have to buy a different charger if you upgrade in the future. It's hard to go wrong with something like the AC6 (shown above), which will quickly charge every type of battery you're likely to come across. It will also cycle NiMH batteries (drain them flat before charging them), which can help your batteries last longer. In any event, look for a "smart" charger with a charge rate of at least 3A.
Battery Connectors
There are a lot of different battery connectors available for RC vehicles. Though some would argue otherwise, there really isn't one "perfect" connector. Heck, if there was, we probably wouldn't have so many to chose from. Here are the ones you are most likely to see:
Deans: Until recently, these were (and still are, to some extent) the "go-to" connector for serious RC enthusiasts. They have a high current rating, they're very small, and they are not too difficult (or too easy) to connect and disconnect. The problems with Deans are that they are expensive and comparatively difficult to solder. Many companies sell "knockoff" deans connectors, which do not work nearly as well. Since few companies are honest about whether they are selling authentic deans or not, it can be hard to be sure you're getting the real deal.
XT60: These are the new connectors on the block. Debuted by Hobby King, these address the main problems with deans and EC3. The pins/plugs are permanently molded into high-temp plastic, so they should never come apart. They are easy to solder for anything up to 10AWG wire (and don't even need heat-shrink), and they're cheap. The only complaint is that because they're so new, few shops (besides HK) carry them yet.
EC3: These are a great all-around connector. They're rated to 65A, are fairly easy to solder, and they're super-cheap. The down side is that the pins/plugs must be inserted into the housing after soldering, and this can be difficult if you're using thick wire. The plastic is also thin and soft, so they have a tendency to deform at high temperatures. Some people complain that they're difficult to disconnect, but others like the fact that they fit together so securely.
Traxxas: As you might expect, these are the connectors used in Traxxas vehicles. They're not bad, but they're expensive and not particularly easy to assemble. Unless you buy a Traxxas vehicle with these already installed, you should probably just avoid them.
Tamiya: Sometimes called "standard" connectors, because for 20 years, they
were the standard. Also occasionally referred to as a "molex connector" after the company which originally designed it. Many cars still come with these connectors, even though they cannot handle much current, are difficult to disconnect, and have a tendency to melt at high temperatures. Tamiya connectors
can be crimped instead of soldered, but crimped wires have a tendency to get pulled out - especially because you really need to yank on them sometimes to get the connectors apart. These are fine for beginner setups with brushed motors and NiMH batteries, but once you go much beyond stock performance, you'll need to upgrade to something better.
Bullets: Sometimes called "banana plugs", these connectors come in various sizes and can be connected (as shown in the pic above) or separate. These are most often used to connect the ESC to the motor, but some people use them for batteries as well. Personally, I would strongly advise against it, because the female socket is often not recessed into the plastic housing. This makes them easy to short out, which is a bad thing.
Anderson Power Poles: Excellent connectors that can be reliably crimped instead of soldering. Unfortunately, their large size makes them a bit of a hassle for smaller vehicles. The connectors are somewhat expensive, and the special crimping tool costs upwards of $50. But if you can afford them and don't like to solder, they're your best bet.
Tools
You're going to need some basic tools to work on your RC vehicle. Exactly which tools you'll need will depend on what vehicle you buy, but a good all-around RC toolkit should contain the following:
[ul][*] Hex drivers (allen wrenches) in 1.5-8mm and 1/16-1/4in.[*] Hex sockets in 5-12mm (larger for large-scale lug nuts) and a driver to attach them to[*] Phillips head screw drivers in #0, #1 and #2 - a set of precision (very small) drivers would probably be helpful as well[*] A sharp utility or hobby knife and a sharp pair of scissors[*] A pair of precision needle-nose pliers[*] A wire stripper/cutter[*] Soldering gear - A 30W or higher iron, solder, and desoldering braid[*] CA (cyanoacrylate, aka super glue)
[/ul]
Some additional items that aren't strictly necessary, but might make certain tasks a lot easier:[ul][*] A hobby vise[*] [link=http://www.yourcablehookup.com/cables-helping-hands-with-magnifier-38022-p-3093.html]Extra hands[/link][*] E-clip tool[*] A Dremel or other rotary power tool[*] Needle Files
[/ul]
"What Car Should I Buy?"
It's the one question that absolutely everybody asks, and it's the one question that everybody else is sick of hearing. It's also impossible to pick one vehicle that it perfect for everybody. But if I had to try, I'd say that it's pretty hard to go wrong with a
Traxxas Stampede XL-5 2WD. It's tough as nails, waterproof, is decently quick, has a low-speed "learning mode", and you can get it with everything you need (including Tx, battery and charger) for under $200. Pretty much every hobby shop stocks TRX parts, and you can even get them at Pep Boys auto stores.
Beyond that, I'm not going to try to anticipate everybody's individual needs. I will say that no matter what your requirements, someone else has already asked for the same thing and been answered. I would highly recommend searching the forums before starting another "what should I get?" thread. As long as you buy something from one of the main manufacturers (Losi, Associated, Traxxas, Ofna, Duratrax, Tamiya, HPI), you'll probably be happy with it. Just remember, you get what you pay for - mostly. There are deals to be found, but there is a reason why the "good" brands cost more than the cheap ones. A sub-$300 1/8th scale brushless monster truck on ebay may look tempting, but the reason that a BL E-Maxx costs twice as much is because it's twice as well made. The no-name brands were not designed or built with reliability in mind, and when they do break, you'll have a hell of a time finding parts.
General Information
Faster isn't always better. If you're new to RC cars (and if you've bothered to read this far, it's safe to assume you are), then you're probably not an excellent RC driver yet. You'll have a hell of a time not running into things at low speeds, let alone at 40MPH+. Don't run out and buy the fastest car you can find, because you probably won't be able to control it, and that won't be much fun. Once you get the hang of RC driving, then you can work on
fast RC driving.
Your car will break - accept this fact. If you plan on driving at more than a walking pace on anything other than smooth blacktop, eventually you'll break something. If you're anything like me, you'll probably break something the first time you go out for some serious bashing. Don't sweat it. Most of the non-electronic parts can be replaced for only a few bucks. Don't let your fear of breaking your new toy prevent you from using it to its fullest potential.
Use the right tool for the job. If you don't have the right tool, buy it. You'll be taking your car apart and putting it back together a lot for repairs and upgrades. You do
not want to have to deal with stripped screw heads and rounded-off nuts. You can find complete sets of metric and standard hex drivers and sockets at most hardware stores, and they're not very expensive.
Bearings, bearings, bearings. If your car comes with solid bushings (many low-end ones do), then the first thing you should do is replace them with bearings. Bearing kits are cheap, improve the overall performance of your car or truck, and if you bought a RTR kit, they'll give you a good excuse to tear it apart and learn how it goes back together.
Bumpers are your friends. Even the pros crash sometimes, and beginners crash
a lot. A cheap set of big front and rear bumpers can save you a lot of money on parts replacement in the long run. Most new cars come with either tiny bumpers that don't protect much, or none at all. [link=http://t-bone-racing.com]These guys[/link] make custom bumpers for almost every make and model car and truck. They're cheap, practically indestructible, and guaranteed for life.
Racing - Look before you leap. If you want to get into organized racing, you'll want to check out the local racing organizations before you chose a car. Different tracks have different classes / requirements. If nobody else in your area runs in a particular class, it wouldn't make much sense to be in it. Go to your local track and scope it out. See what the other guys are running and get something similar (or at least competitive). If you choose a car that's popular at your track, then you will have no problem finding people to give you help and suggestions for getting the most out of it.
Don't be afraid to ask for help, but always ask correctly. First, search the forum to see if someone else has already asked the same question. If you cannot find the answer you're looking for, post your question with as much detail as you can. Be clear and specific. Post a picture of the problem if applicable. Use proper spelling, grammar, capitalization and punctuation. If you can't be bothered to ask your question the right way, then why should anybody else be bothered to answer it? If your question isn't answered right away, wait some more. Bumping your thread every hour or starting another identical one will only make people less likely to help you. And most importantly,
be polite. If someone takes the time to help you out, thank them for it.