Last week I bought said 42082. While building the chassis, I noticed that mechanisms using part 18575 tan bevel gear 20 tooth were working a bit rough. The gears made a rattling sound, and didn't work very well. Well, they worked and did their job, but not how I expected it. I thought I was just being picky and continued on. But the more I used those gears, the more it caught my attention. Until somewhere in the superstructure I decided to compare them to the same gear but form my collection instead of set 42082.

I made a simple test setup compare the old and new gear (please note that with old I just mean the same gear but from an older set). And low and behold, the new gear worked very noticeably worse than the old one. The new one made a much harder rattling sound and it turned less smooth. It felt like it was popping into each gear (like a click hinge, but less clicky) instead of turning smoothly. The old one worked perfectly fine.

I then decided to break down the superstructure I had so far to replace all the tan bevel gears with older ones from my collection. And the result: everything worked very noticeably better, smoother and less noisy.

I find this very peculiar. How is it possible that this batch of gears I received works not as good? They seem exactly the same as all the other ones I have. I was wondering if anyone here who recently (or maybe last year even, as my set is technically a 2018 set I have no idea when it was produced) had similar issues with this gear?

I also sent a message to Lego about this btw.

I don't really build sets, but I've noticed working with this gear over the years that sometimes it seems to work smooth and sometimes it doesn't.  I could build 2 of the exact same gearbox and one would work nice and smooth while the other didn't, and that gear was usually the culprit..

 

I've noticed this mostly with the 12-tooth half-bevel tan gears. Often, when assembling a differential, I have to go through five or six gears to find three that run smoothly.

With mines it sometimes seems like the edges of the teeth are trying to grind sideways into the beams.

If you can weigh them on a scale .. report the difference !!!  but make sure the gears are brand new and not worn out when you weigh them!!! 

I just compared the old open crosshole design with the new slit one and the older one do indeed run smoother.

  On 10/5/2019 at 9:23 PM, Zerobricks said:

With mines it sometimes seems like the edges of the teeth are trying to grind sideways into the beams.

Yeah, I feel like the problematic gears from my 42082 were worst when sandwiched between two liftarms.

  On 10/5/2019 at 9:23 PM, sirslayer said:

If you can weigh them on a scale .. report the difference !!!  but make sure the gears are brand new and not worn out when you weigh them!!! 

I don't think I have a scale precise enough to measure a difference, if any.

  On 10/5/2019 at 9:28 PM, Zerobricks said:

I just compared the old open crosshole design with the new slit one and the older one do indeed run smoother.

Yeah. I compared three gears. The new ones from my set 42082, the same ones but from an older set and the old-old ones with the previous design. The oldest ones clearly worked the best. But even the older new ones (new design) (if that makes sense) worked noticeably better than the new ones from my 42082.

You need a scale that can weigh 0.001 of a gram would be good enough and maybe there is a difference in weight.. you can compare it to my database .. 

 

  On 10/5/2019 at 9:23 PM, Zerobricks said:

With mines it sometimes seems like the edges of the teeth are trying to grind sideways into the beams.

This is exactly what I am referring too.. I have also noticed while monitoring my wife building the new Defender set that the 90 degree limiting arm is ever so slightly rubbing the tan gear because the white rubber band is pulling it towards that direction.. This is something that I would have avoided by having the band on the opposite side pulling it slightly away from that gear.. Those tan gears can be quite fickle..

Looking from the side it seems the new 20 tooth gears have thicker, more angular and less rounded straight teeth.

Edited October 5, 20195 yr by Zerobricks

On close examination the teeth on the 12 tooth gears have also been changed. The axlehole is also changed to a solid, full shaped + shape.

The change on the 12 tooth gears doesn't seem to affect meshing - tested with new and old 20 tooth gear.

I changed all my new 20 tooth gears for old ones in my tiger 6x6 and the driveline works much smoother now.

Thanks for the great tip @legolijntje, I will use the new 20 tooth gears only as bewel gears and use old ones for normal meshing.

EDIT: Clutch 20 tooth gears are of a new type and have friction, especially if meshed with a clutch 16 gear.

Edited October 5, 20195 yr by Zerobricks

Wow it is a very interesting thread, I never noticed that because I just have the old ones but I will stay alert with the clutch ones, even more I am going to watch which ones I have and I will separate them.

Edited October 5, 20195 yr by jorgeopesi

  On 10/5/2019 at 10:39 PM, Zerobricks said:

On close examination the teeth on the 12 tooth gears have also been changed. The axlehole is also changed to a solid, full shaped + shape.

The change on the 12 tooth gears doesn't seem to affect meshing - tested with new and old 20 tooth gear.

I changed all my new 20 tooth gears for old ones in my tiger 6x6 and the driveline works much smoother now.

Thanks for the great tip @legolijntje, I will use the new 20 tooth gears only as bewel gears and use old ones for normal meshing.

EDIT: Clutch 20 tooth gears are of a new type and have friction, especially if meshed with a clutch 16 gear.

Haha, it wasn't meant as a tip perse but cool it worked out that way 

 

So, just to clarify/sum up a bit. I tested 3 gears:

• Old design
• New design, old batch (maybe 2 years old or so)
• New design, new batch (one from my recently purchased 42082)

The old design works best, but the new design/old batch works fine too. A little more rough than the old design one, but very much acceptable.  It's the newest one from my 42082 that works horrible. So much so (in my opinion at least) that I think lesser experienced builders would note it too. However, they probably aren't experienced enough to know that... it isn't supposed to be that way and they end up with a model that rattles and doesn't work very smoothly. Seems to me that would be a shame, since Lego Technic can work very well.

So I was wondering if I just happened to have gears from a somehow wrong batch. And if so, how widespread those gears are.

Arghl!!! the new OLD version of this gear is significantly thicker, and there are aweful burrs :(

Edited October 6, 20195 yr by Philo

TLG... If it ain't broken don't fix it..

I understand they cahaged the crosshole shape to be stronger, but why change the teeth? And to think 42099 uses two pair of these on each axle... And 42100 uses 3 or 4 on each track... And nobody noticed? Doesn't any (element) designer test what they design/build?

Edited October 6, 20195 yr by Zerobricks

Wow, these burrs really are bad. I have some fake chinese gears here and even those look a lot better 

I never realized the changes because I always used the old ones, gray gears look that much better than their tan counterparts 

 

  On 10/6/2019 at 8:40 AM, Philo said:

Arghl!!! the new version of this gear is significantly thicker, and there are aweful burrs :(

[snip]

Interesting. With the naked eye I couldn't notice any thickness differences.

What gears did you compare? The old and new design, or were they both new design with one just being older than the other? Any idea from what set/year your new (thicker) gear is?

  On 10/6/2019 at 9:11 AM, legolijntje said:

What gears did you compare? The old and new design, or were they both new design with one just being older than the other? Any idea from what set/year your new (thicker) gear is?

Old and new design. Not sure I have a new-but-not-so-much version. New comes from 42099 so really recent.

Old gears will increase their price  .

The newer 20 tooth version does feel harder and rougher.

  On 10/6/2019 at 8:45 AM, Zerobricks said:

but why change the teeth?

Honestly I don't see much change in teeth shape: new tooth

Old tooth:

Interestingly, the old gear can show burrs too, but located at the base of teeth where the new design is perfectly smooth. Different molding technique I guess...

Well I only haves sets that are from the last year or newer and so I don't have any old gears to refer from but currently the Tan gears are a bit taller then the black color gear.. I wonder if the older black gear are any bigger??? 

This brings a new twist in building and designing 

https://www.flickr.com/photos/23813430@N07/43651672695/

 

 

 

Edited October 6, 20195 yr by sirslayer

Now, I feel really confused. After disassembly of my little thickness comparison, I see that I managed to swap gears!!! the thicker, burry gear is actually the OLD one. The new is thinner and smoother (and so should work better!)

https://photos.app.goo.gl/wLmKNdyzdxLH4dFaA

First video is (part of) the superstructure of 42082 with the supplied gears. Second video is the same thing, but with old(er) gears from my collection. You might have to turn up the volume a bit, and through a video the difference is not as big as in real life, but there's clearly a difference. Less rattle and everything works very noticeably smoother.

Wow for me an important fail for TLG.