[MOD] 9398 Limited slip diff (friction)

[Void_S]

Hello everybody! I'm a newbie here, but Lego Technic was a part of my live many years ago.

Recently it turns that that we meet again and I'm ready to discover or invent something new for me.

About several months ago I got the well-known 9398 Crawler - amazing flagman model with a lot of pro and cons (I believe that many spears and axes were broken, so I'll skip the long list).

The main disadvantage is differentials (also known as diffs) that makes the off-road or crawling ability so close to zero. A common recommendation is to get rid of them by replacing by the knobs. It works, but I faced another issue then: now it can't go on a flat surfaces. Really, now the rear axle tries to pull the vehicle ignoring the forward one and broke the axels or suspension.

As solution I remembered the limited slip differential based on the 20-tooth clutch gears: add the one more axle between the left and right wheels that has one (or two if necessary) clutch gear. It allows to have some difference between the wheels rotation angle, but in the same time provides some friction that prevents the free rotation. I remember that I saw it at somebody's MOC, so I will add the credits a bit later.

 

Let me don't bush around and provide the my receipt (sorry for the quality, it was a phone):

1. The additional axle. 9L axle with two 20t gears, normal one and clutch, and connectors. Plus 2L beam to reinforce the connection (you'll see it later).

2. Place where to mount it. You'll need to remove the 11L beam from the steering arms add this assembly.

3. Mounted.

4. Now let's move the 2L red beam to lock the connection.

5. The result! Completely mounted and covered by two 3x5 Bent beams (instead of two 3L beams at the original model). 

As summary, I have to say that now it works fine everywhere (limited only by Crawler's design) and requires a minor changes for the original model.

That's all so far, hope that it still actual since the model is relatively old.

Edited November 12, 2016 by Void_S

[Myers Lego Technic]

That's not a limited slip differential, but the opposite, which forces the tires to move the same sped on either side of the differential unless the resistance is strong enough, which really defies the purpose of a differential. 

[Void_S]

6 hours ago, Myers Lego Technic said:

That's not a limited slip differential, but the opposite, which forces the tires to move the same sped on either side of the differential unless the resistance is strong enough, which really defies the purpose of a differential. 

Well, yes, I agree: it's a mistake but so common here, so I used this term. Really it's kind of differential with high friction or something around it 

Scheme is very poor and can not stop the wheel than doesn't have sufficient grip, but still able to force the other wheel to move slightly. But on other hand it's so simple and performance is acceptable and that's why I decided to share it. Anyway we can't fit the torsen differential (true limited slip diff) here unless the 1L worm gear is released (2017 is coming ) 

Edited November 13, 2016 by Void_S