Hi guys I got my self this at the weekend and all I can say is awesome ! I've looked on YouTube at videos but not got a great idea so I thought I would ask some people that know a lot more about this then I do :) I've just ordered some new gears 8/24 what's next? Tyres ?

Cheers and my name is Tom.

@ d1ging: Welcome to Eurobricks! The 9398 4x4 Crawler set benefits a lot from different, "third-party" tires -- see this Eurobricks topic for ideas. That set also benefits from replacing the Differential Gears with 32072 "Technic Knob Wheels", as stated in this TechnicBRICKS article:

What the crawler needs is a xl motors per wheel to eliminate the diffs. Unimog tires or power puller tires would be nice too. The 4x xl motors might be a bit impossible though, maybe large motors... Could anyone do this?

one large motor per wheel? works superb, but forget the origiinal chassis

Lovely Orange Truck Video. Matches Unimog really well!

Can you not just lock them yourself the diffs?

The diffs are pretty weak if you lock them, usually the gears start slipping.

Anyone encountered the wheels stopped spinning with a "wheeeee" sound coming from the motors when the crawler got stucked? Will this situation cause any damage?

no it should not course any damage that the diff working

no it should not course any damage that the diff working

Thanks for the info!

The only mod that I made to my 9398 was to redo the portal axle gearing to make the vehicle faster for traveling around the house. The primary purpose for this truck is to chase the cat and the Lego factory setup was not effective for this purpose. Yes my crawler is still slow, but at least is has a sporting chance at cutting off the cat as she runs from me in the living room.

The only mod that I made to my 9398 was to redo the portal axle gearing to make the vehicle faster for traveling around the house. The primary purpose for this truck is to chase the cat and the Lego factory setup was not effective for this purpose. Yes my crawler is still slow, but at least is has a sporting chance at cutting off the cat as she runs from me in the living room.

I have a few sets, but no spare parts, which means I can't experiment myself. How did you make it faster, by changing the gearing in the axle, but what gears did you use?

I have a few sets, but no spare parts, which means I can't experiment myself. How did you make it faster, by changing the gearing in the axle, but what gears did you use?

I'd guess either the 12 and 20 teeth bevel gears (for 1:1.66 reduction) or 8 and 24 teeth regular gears (for 1:3 reduction). Might be that the 8 teeth regular gear is too fragile though.

Edited January 2, 201312 yr by jantjeuh

If you want maximum speed, use the gears shown on the left. If you want maximum torque, use the gears on the right:

There's another 12t/20t combo that you can replace, just before the drive goes to the uni joints.

The one with the uni joint attaches here:

You can replace these with 16t/16t or even swap the order of them (I think), gearing it up quite significantly.

The original configuration is 12:20 x 12:20 = 0.36:1

With those reversed and 16 tooth gears in the hub, it's 20:12 x 16:16 = 1.67:1

= 4.6 times as fast, with correspondingly reduced torque. Which is probably more than you need.

Edited January 2, 201312 yr by Hopey

Just assembled this set, and I'm a bit irked by the low speed. Gonna replace the L motors by XL motors, which results in increased unsprung weight, but whatever. This also requires an additional IR receiver, which leaves me with an unused IR output. So, I will also add a winch.

Edited January 2, 201312 yr by jantjeuh

Just assembled this set, and I'm a bit irked by the low speed. Gonna replace the L motors by XL motors, which results in increased unsprung weight, but whatever. This also requires an additional IR receiver, which leaves me with an unused IR output. So, I will also add a winch.

You can change the gear ratio on the portal axles to make it go faster.

with a xl motor it will go slower

Just assembled this set, and I'm a bit irked by the low speed.

By default, it's geared quite low to increase its torque, making it more able to crawl over obstacles and up inclines. If you want it to go faster (at the cost of reducing torque), it may be worth playing with the gear ratios before you do any major redesigns.

I know the XL motor is slower, but I will gear it up a bit :) That should leave me with approx. the same torque as the L motor, but with more speed (assuming the XL motor is a lot more powerful than the L motor). Then the crawler can still handle obstacles, while driving faster.

Edited January 2, 201312 yr by jantjeuh

Has anyone tried to put the RC (5292) motors into the Crawler?

Just assembled this set, and I'm a bit irked by the low speed.

I don't have this exact set, but I have the 41999 set with the same mechanics. I switched the gears at both the motor end and the universal joints for a double gear up. Without the body on the chassis flies around pretty good. However, there is a significant reduction in speed when the body is on (obviously due to the extra weight). After a few minutes of running it at full speed the overload protection kicked in and the truck just stopped. Turned it off and back on again and it worked fine.

I'll probably end up switching one of the gear ratios back to they way it was so I get a bit more torque, but it won't be as slow as if I had built it per the instructions. I'm also working on a mod in LDD that will use the XL-Motors, but since they spin slower (220 RPM vs the L-Motor at 380), I will have to gear up for more speed. I'll crunch some numbers and let you know how that plays out. Given that the XL-Motor is wider I'll have to redesign a few areas in order to fit it.

I'm having tremendouse difficulty trying to get XL-motors into this crawler. I would love to see someone put up som pictures with some ideas. I don't know what it is I have access to some goot spare parts but my mind is frozen I can't figure out how to do it. its just one of those mental blocks.

First attempt at adding an XL to the 41999. I'm sure something will have to be done with the shocks due to the increase in height, but this should get it started.

Here's the file from LDD if anyone wants to mess with it.

41999.lxf

You can't attach the shocks in the normal place with that setup...