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Just finished building the 4x4 Crawler and it was a fun build but as a remote control car it is . . . in a word . . . SLOW! 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?

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'Crawler' is a good name then... :) –  pcantin Dec 30 '12 at 16:51
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I think you need to find your own solution for the two (identical) motor blocks. There should be enough space to rebuild this with an XL motor or use other gear transmission ratios. –  BetaRide Dec 30 '12 at 18:51
    
YES! I didn't think what "crawler" really meant until after I had it put together . . . and, yeah, I've seen some videos where people are disappointed with the torque and the differentials. I have one XL motor and I'm about to order another! –  tooshel Dec 30 '12 at 22:45

3 Answers 3

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. Cheers :)

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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.

picture of portal axle swaps

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).

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You need these old school 5292 puppies ;-) 2 of them.

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. Speed or torque. They will drain your batteries for sure anyway you use it.

lego motor chart

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Why oh why did Lego get rid of them!?!? Maybe is was the un-Lego-like remote. It's funny because I remember seeing these a long time ago and when I got into Lego later I was amazed there were no real remote control cars. This is why I need to buy all the cool sets as soon as they come out! Anyway . . . I think the PF XL motor would work well too . . . my fear is that I'll break some gears but that's the price to pay for a powerful and fast "crawler". –  tooshel Dec 31 '12 at 18:13
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Oh, and another option is the PF XL motor with a gearbox so I can change speeds. sariel.pl/2011/02/2-speed-heavy-duty-linear-gearbox –  tooshel Dec 31 '12 at 18:45
    
Indeed, I love that remote, I'm so glad I actually have 2 sets. Found them on ebay at the time, pretty suspicious person selling it but hey ;-) Those motors are really awesome. –  Glenn Plas Dec 31 '12 at 18:49
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You could actually crash the car in a way big lego pieces broke in half, so it was pretty fast, we played with them at work and some couldn't handle it ;-) There is a big diff between the mechanincal power the PF XL and the RC one, but as always: lego isn't about receiving exact answers, but about posing the questions to figure out by experiment ;-) –  Glenn Plas Dec 31 '12 at 18:57

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