Hey everybody! Today I’d like to talk about a question that gets asked a lot by newbies, and something that even the seasoned RCers often ignore or forget when advising others; the proper first upgrade(s) for an RTR (Ready to Run) RC. This article’s a bit of a monster, so you may want to grab a cup of coffee or tea or even something stronger. 😉
Recent history has shown us that the mainstream (let’s say ‘less hard-core racing’ manufacturers) prefer to serve up RTRs with often minimalist specs to get them working out of the box, under the business philosophy that they can tempt you later to upgrade, simultaneously providing the main revenue stream for a model; spares and options/hop-ups. This is a double-edged sword both for the manufacturer and the consumer. Most consumers want something they can take out of the box and run with straight away. Usually these people also want quality, but don’t want to pay for it either at point of sale, or down the line. The manufacturer is then left with the dilemma of product placement and targeting specific consumer groups.
(an Arrma RTR transmitter and receiver combo. Image courtesy and copyright Arrma RC)
The consumers also face similar dilemmas. As an experienced hobbyist with radio gear and electronics literally falling off my storage shelves, I prefer not to buy RTR at all, and select my own electrics/tires/etc. and therefore don’t want to pay even one penny more for the cheap style radio and electrics supplied with many RTRs, so my preference is that they employ the cheapest of the cheap radio gear. At least I’m not paying more for something I don’t need, right? But then there’s the consumers who want the RTRs, and don’t want to then spend hundreds of dollars on necessary upgrades, or at least not straight away. The manufacturers have a difficult balance to strike, and definitely tend to err toward the ‘give cheap for attractive pricing, make money on upgrades down the line’ strategy.
You might say this is a somewhat sly policy, and in some cases it is, but more often it’s sensible, as well as good for the hobby. How is it good for the hobby? Well, if you are that guy who bought the RTR with no intention or expectation of spending more money down the line, you are in the wrong hobby. You should just head down to Toys R Us and pick up a Knight Rider for 30 bucks. By the same token, if you are coming into the hobby with real intentions of making it a hobby, working on and maintaining your car, a cheap RTR will force you to learn quickly where its weak spots are and also generally how the machines work; a definite prerequisite for someone who expects to get the most out of this hobby. Look at it as a way to weed-out those who don’t have the staying power.
Lastly on the subject of RTR specs, we have to accept that supplying cheaply specced RTRs is in fact ‘just good business’. Good business doesn’t have to mean that the consumer is getting fleeced and the manufacturer reaps the rewards (though that sometimes is the case), we all must remember that what is good for the manufacturer is often good for us. A struggling manufacturer will have fewer resources available for proper R&D, licensing fees (so they can use real life bodies that we all love), and ultimately manufacturing quality. So at the end of the day, it serves YOU to make your favourite RC maker richer.
There are some exceptions to this which I won’t go into in detail in this article, but one of them is bearings. It is my opinion that there aren’t enough supplied in RTRs (still don’t often see ballraced steering parts even on high end models), and the replacements are far more costly than they need to be. Order bearings from bearing suppliers, not RC companies, for much better pricing, and order them in quantity.
No, RTRs are here to stay and they are what they are for specific and logical reasons. They WILL need to be upgraded, in many cases sooner rather than later. Now, having had that little rant about bearings, you probably expect me to push those as the first upgrades, and sure enough, it’s a good place to start. Especially if your model is one of the super cheap ones and you have mostly bushings throughout the vehicle. If this is the case, then you should definitely consider bearings as the first upgrade. Thankfully, since shortly after the Tamiya days, bearings are supplied in most of the critical areas these days (wheels, drivetrain, gearboxes) on most models.
Image courtesy and copyright Boca Bearings
Contrary to some popular beliefs, stock bearings are also largely ‘good enough’. You don’t need to replace stock bearings for better quality ones. I’m not an advocate of buying ceramic or carbide bearings unless you are a sponsored racer. I’m specifically talking about adding bearings where they are not supplied. I already mentioned one key area where bearings are beneficial and rare in RTRs and that is the steering system. Swapping out the brass or plastic bushings in the steering system is an improvement across the board, it reduces steering slop, providing finer steering control, and makes the whole system silky smooth, allowing your servo to put more of its torque and speed into actually turning the car, rather than fighting the friction of the system. Sometimes this can make a profound difference to the handling of the car, making the steering much stronger and faster. However, while ballracing the steering system is a highly advisable thing to do, it’s not that high on the list of first upgrades, at least not until those bushings are starting to wear out.
If you asked many RC owners what single modification affects the way an RTR model drives and handles the most positively, you’d get a few different answers. A lot would say tires, and they’d be right, but we are working on the assumption that the tires are ok for at least one surface the operator has available, so what next…shocks? Some would surely say big bore shocks for off road cars, some others might say sway bars, particularly for on-road cars. The smart few will ask you first what kind of servo you’ve got. While many RTR radio sets (provided they are 2.4ghz) are often adequate for basic control, some lack End Point Adjustment which is arguably the only and most important radio setting you actually need, and often the trims aren’t very good. The lack of EPA is less of an issue on RTR models, because the usually cheap and under-spec steering servos don’t generate enough force to damage themselves or the model if the setup isn’t perfect, but that lack of grunt is what has earned them their prized spot in this article as the most recommended first upgrade to an RTR model. Upgrade your steering servos folks.
(A high spec servo, image courtesy and copyright Team Associated)
Some basics about steering servos first…The faster a model is travelling, the harder the steering servo has to work against the force of the spinning wheels and the friction of the surface to change the direction of the car. This is amplified by increasing the weight of the RC and/or its tires.
A servo is basically a small motor with a gearbox attached to multiply the torque provided by said motor. The gearboxes are often called reducers, as they reduce speed and convert some of that speed into torque. Torque (expressed in ounce-inches (oz/in) or kilogram centimetres (kg/cm)) is the primary specification we judge servos on and literally defines how ‘strong’ in the simplest terms, a servo is. Speed is a very important consideration too, but if the required torque isn’t there, all the speed in the world would be useless. The names of the units give you a good way to visualise how the servo uses its torque. For example, the more commonly seen unit, ounce-inches or ‘oz/in’, means that the servo, if attached to an immovable object with its arm parallel to the horizon, could lift ‘x’ number of ounces vertically on a 1 inch lever.
In the example of a 1/8th RC, going from a 90oz/in servo to a decent 160oz/in+ will absolutely transform the way the model feels to drive. Immediately it will turn more positively, respond more predictably, and generally give you the feeling that you are better in control of the car, the importance of which cannot be understated, as that’s where the driver confidence comes from. It’s also the first step in tuning the handling of a car. There isn’t much point trying to make the car turn better using suspension geometry or better shocks if the servo isn’t actually capable of doing what’s asked of it…
Above: various servos, the largest being an Oddified Tonegawa PS-050, one of the most powerful servos available, capable of lifting a grown man on a 1″ lever. I use it in my FG Monster Beetle Pro. 😉 The middle servo is a typical quarterscale servo (for 1/5 and 1/4 scale models); the Multiplex Rhino, and the right hand servo is a standard size DS1015 similar to the one pictured above but from an older batch.
When we mention the speed of a servo, we mean how quickly (the length of time in seconds) the servo can go through a 60 degree arc (this is usually the metric, and unless otherwise stated, it’s assumed to be 60 degrees). Typical values for this at the cheaper end of the spectrum can be 0.20 to 0.30 seconds, and at the higher end, some really crazy lightweight racing servos can swap sides in 0.05 of a second and less. The difference is staggering between a .30 servo and 0.10 servos, although it may not sound like much. With a faster servo you will be able to more effectively and subtly shift the weight of the car, as well as make switching corners such as fast chicanes much more easily and at much greater speed. It’s particularly important on a racetrack to be able to change direction quickly, for overtaking and for taking fast chicanes; your lap times can be severely limited if you can’t take a chicane at full speed because the servo can’t lock to lock fast enough.
A quick note on the cons of excessive servo speed…there is always a case for faster equals better, for reasons already mentioned, but be aware of your limits (as Dirty Harry once said “A man’s gotta know his limitations”) and the limits of your equipment. If you don’t ever take a visit to a race track and have no specific need to get used to a servo with ferocious speed, and you don’t have a radio which can be adjusted to make use of that speed, you will find that you are more comfortable, and therefore most confident (again, don’t underestimate this) with servos around a certain speed. For a true beginner with an RTR radio (and therefore no advanced radio settings such as EPA, Dual Rate and Exponential), going faster than a certain speed is likely to be highly detrimental, causing the pilot to constantly over-correct or simply over-input, making all important consistency that much more difficult. The detrimental effects of very fast servos can (and are) addressed by using professional level radios to give them specific behaviours. Personally, I stick to around 0.10 to 0.15. Going faster without compensating using advanced radio settings generally makes my driving twitchier and worse.
Before I close out, I briefly mentioned earlier that the lack of EPA (End Point Adjustment) on some RTR radios (thankfully this is getting better in recent years, with most RTR radios having this feature) is not such a huge deal when the servo is weak, what about now that we have upgraded it? Well, I’m going to have to say yes, all of a sudden this does become a huge deal. But hopefully, if you care enough to upgrade the servo, the extra expense of a novice level radio set with the basic settings and perhaps a memory for more than one model, will not break your bank.
To address those who might be saying “yeh Foxy, easy for you to say, go and buy a great servo, but I’m on a tight budget, I can’t go around spending 100 bucks on servos!”, here are a few recommendations for different models aimed at more modest budgets.
For 2wd 1/10th buggy and short course: 80-120oz/in. Hitec 625MG is a decent choice (5625MG for the digital, it’s a little faster and a little stronger but a little more expensive too).
For 4wd 1/10th buggy and short course: 100 to 160oz-in depending on weight of the model, the Hitec 645mg is a good economical choice but is kinda slow. Again the digital 5645mg is a better choice and still won’t break the bank.
For 1/8th buggy 160oz/ins will get the job done, though more is preferable. For truggy as well as Monster Truck, ideally 200 oz/in or more.
(The popular Hitec 5645mg. Image courtesy and copyright Hitec RCD)
Admittedly, at the 1/8th break, the required servos start to get kinda expensive for the good ones but don’t ever be fooled into thinking you need one of the insane torque servos, 300oz/in plus. They are just luxury overkill, I’ve had no application yet that actually required more than about 200oz/in (except comp crawlers of course), that includes truggies on and off the track, even the Savage XL. All were fine with Ace DS1015s (now sold as Team Associated XP DS1015), one of my all-time favourite servos with perfect specs at 200oz/in and 0.10s to 60 degrees. I’ve never had a single issue with any of the 7 or 8 that have passed through my hands, I use them in everything.
As briefly mentioned earlier, once you have a good servo, you need to properly consider end point adjustment and a potential radio upgrade, and while that is starting to add up, a radio upgrade is an investment for the future. If you really love the hobby from the start, consider getting one sooner rather than later, its nice to always use your own radio for all your models instead of having to get used to each manufacturers radios every time you switch cars, and the features are a real bonus too. A very good budget radio upgrade option is the Futaba 3PRKA at about 60 bucks. It doesn’t have multiple model memory which is unfortunate, but with dials for EPA and trims, you can set them quickly and effectively when switching models. For only a little more, the Futaba 3PL has all the features you need to begin a racing career.
(Futaba 3PL, an excellent step up from RTR radios, image courtesy and copyright Futaba RC)
Finally (promise, lol), I guess I have to say something about the low cost options from the warehouse outlets such as HobbyKing and HobbyPartz, so here goes; my experience with cheap servos while admittedly not extensive has been a bit of a lottery. A friend and I even had some catch fire. Others will say they have used cheap servos with no issues. Your mileage, as they say, may vary. They are at least cheap enough to give them a shot, just be prepared for model repairs if they do fail at a critical moment.
If you made it this far, I’m impressed, thanks for your time, and I welcome your comments below.