Sign up or log in to customize your list. Here's how it works: Anybody can ask a question The best answers are voted up and rise to the top Just finished building the 4x4 Crawler and it was a fun build but as a remote control car it is . . . in a word . . . I know it's powerful and can climb over stuff but sometimes there is nothing to crawl over and I'd rather it be faster. Are there any other gear configurations that would make it a bit more exciting? The simplest way to get different speeds is by changing the gears. The instructions get you to build it with a 12:20 gear down in the portal axles, so the easiest way to change the speed is to flip those to get 20:12. From memory that will not work because it interferes with other parts of the model. You can fit two 16 tooth gears in there instead, giving a slight speed increase. Or you can put an 8:24 gear down for even more torque (but even less speed). There two options are shown below. It's important that you keep all four wheels geared the same, otherwise you will be making the front and rear motors fight each other.
That's not great for the motors and gears, and it will drain your batteries very quickly. Deeper inside the model there is another 12:20 gear pair that you can also swap for 16:16 (two sets of this, one each end). You need these old school 5292 puppies ;-) Check a motor comparison here You're gonna have to do some after-market mods but those are very powerful , I have them from the 8366 set. But as you can see in the review, there are pro's and con's on every engine. I suggest reading it in full, it's an amazing source of information and you'll learn a lot like I did. There's a nice poster about them. It has 2 different outputs which makes it so fun to make something that can use them both. They will drain your batteries for sure anyway you use it. You can switch 4 pairs of gears on each end of the crawler (2 pairs in the portal hubs and another 2 pairs inside the gearbox infront of the motor) do this on both ends or you run the risk of broken gears or premature motor wear.
I ran 12 tooth gears all the way from the motor to my hubs for a dramatic increase in speed however the torque suffered severely, I would only recommend doing my gearing with xl motors. Sign up or log in Sign up using Google Sign up using Email and Password Post as a guest By posting your answer, you agree to the privacy policy and terms of service. Not the answer you're looking for? Browse other questions tagged technic motors set-modification or ask your own question.The Lego Group has always been reluctant to launch a Technic vehicle with an electric drive ― while various functions powered by electric motors aboard are quite common, the drive was entrusted to the builders' hands rather than motors. This approach is not without a legitimate reason: large powered Technic vehicles (as many MOC's attest) are usually complex to build, tend to be fragile, and often can't produce breathtaking performance. Being the construction perfectionists which they are, TLG obviously wanted to address these problems as much as possible before crossing this line.
But now, with 9398 they have crossed it, introducing some important new parts along the way, thus easily qualifying the set as a "Double Milestone", as mentioned in the title. Upon the ceremonial opening of the box, a familiar sight greets: a couple of bags numbered for easy assembly in two steps ― the chassis and the bodywork, with the latter requiring much less diligence and attention than the former. For a 4x4 crawler with dual live axle suspension, quad portal axles and all wheel steering (actually being a 4x4x4!), building isn't too difficult. Partly to thank for are the large, easily understood instructions with only a few parts added per step in average. There are three instruction booklets, with an additional diptych clarifying the correct orientation and positioning of mechanical parts in several building steps. Also, there are many auxiliary structures, such as beams and frames that hold the model together while under construction and are removed afterwards, and pins whose only purpose is to prevent you from inserting a part wrongly oriented (e.g. a differential).
The front and the rear axles are largely symmetric, each holding its own power motor, while the ball links keep them connected to the main chassis where the servo PF motor is located, which controls the steering through reinforced U-joints. The chassis is actually completely independent of the bodywork and can run without it ― the bodywork is attached only at the last steps. This serves its own purpose: it is intended to be released with two pins accessible behind the openable doors, and lifted to allow easy access to the battery pack. (It could have been placed in the bodywork too, but that would probably keep the Crawler's center of mass far too high for an offroad vehicle.) Building a 9398, one can notice some tricks, well-known among experienced MOCers, employed to ensure more strength than needed for the conventional models ― e.g. using two 1/2 bushes instead of a single fullsize bush for more friction. The overall result is staggering: this is certainly one of the structurally strongest models in Lego history, surviving rolling falls and quite severe offroading accidents without more than, say, losing a rear-view mirror.
And don't think it's light: with batteries, it weighs a bit over a kilogram and a half*. Overall, it is a satisfying model to build. Only once I've had a feeling I was fiddling with excessive detail, when assembling the front grille which consists of dozens of small parts. One may feel, and some have published, too, that the remotely controlled 4-wheel drive and steering, dual live-axle suspension and openable doors are a bit short list of functions for a Technic flagship. But I tend to disagree: toying with additional functions might make it more fragile, reduce its offroading performance, and detract from the idea of a good, focused vehicle which does one thing and does it well. The bodywork was also designed with strength in mind, but still it looks good too, especially since it uses some less typical colours. There are no functions here ― seats and tailgate are fixed, and steering wheel, gear lever and extra lights purely decorational. All that strength implies something else: this set is a real pain to disassemble, especially because it uses over a hundred friction axle pins, most of which are stuck into other connectors, and you will need a crater-load of patience to pluck them all out.
Important new parts, largely responsible for the amount of attention this set has received long before it hit the shelves, are the PF L and Servo motors. As you may already know, the PF L fills the gap between a M and XL motor: noticeably more powerful than the former, but smaller and more easy to mechanically integrate than the latter. This set contains two of those and I'm sure we are going to see these motors a lot in MOC's, too. Servo, which should put an end to various recentering mechanisms, simply has its axle mimic the movements of the controller (be it small, included in this set, or the large, with 7 levels in both directions), instead of rotating at the speed proportional to it. Of course, this is a perfect part for steering in any vehicle, but will find its usage for many other applications. If you're interested in technical specifications of these new motors, take a look at Philo's website ― he has painstakingly measured them and published the results. A new IR receiver has been released too, labeled "V2" at the front.
It can handle more power, required to run two PF L motors adequately on a single channel, but otherwise it behaves just like the old one. In addition, we've got a new axle with a stop and a perpendicular connector, but they aren't as spectacular introductions as the PF components. As one would expect, this is an excellent source of general Technic building material ― various beams, panels, pins, connectors, axles and similar parts are all supplied generously. Also, there is a significant amount of valuable, rare parts: beside the still über-rare new PF components, 4 large 94.8x44R tyres, 4 new triangular liftarms, 2 large ball joints, 4 portal axle housings and 2 super-hard 9.5L springs are certainly welcome to any builder's collection. There is some amount of relatively rare white parts which may also be useful. Also there are some orange parts, but far too little for building something spectacularly orange. Majority is still, however, in the familiar red-grey-black scheme. All that devotion to mechanical strength, suspension and drivetrain pays off: the Crawler is unstoppable by mere mortal obstructions.
Although the instructions carefully tell not to drive it outdoors (to keep the parts from being milled by sand and stuck by dust), if you choose to live on the edge and disobey, you will find it drives over rough outdoor terrain very well ― climbs the boardwalks and hills, bridges the gaps and consistently resists tipping over. This performance largely owes to the portal axles and a very agile suspension (e.g. easily over 10 cm displacement for a single wheel from the plane of other three), and the PF L motors that provide serious power and torque. It is not uncommon for the Crawler, being stopped dead by a wall, to actually spin the rims inside the static, blocked tyres. The large passive torque of the motors produces one more cool effect: when they are turned off during a ride, the car just stops dead in place. Since the axles are pointing slightly downward when the car is level, steering makes it lean into the curves, similar to the motorcycles. Extents of steering are not too wide, but thanks to the four wheel steering, the turning circle remained small enough for easy maneuvering.
Without the rear wheel steering, it would resemble dragging a stubborn dog around. You will have plenty of fun inventing all kinds of trials and obstacle tracks for the 9398, but make sure to have an assistant with wheelbarrow loaded with spare batteries follow you around. Faithfully following the image of the offroaders, its fuel consumption is not extremely economical. With lots of torque available onboard, it shouldn't be a problem for 9398 to carry extra weight, probably added or rebuilt at the rear, behind the cabin. Also, it should be able to pull some load or a trailer, at least not on very steep ascents. Furthermore, since the bodywork serves no mechanical function and can be simply detached from the chassis that does all the work, it can just as easily receive any other type of custom bodywork, as long as it can attach more or less to it. In fact, a B-model truck follows this approach. The chassis itself is less prone to modifications ― it is built very tightly and mechanical parts are reinforced like a nuclear shelter.