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New LEGO Technic differential from the 42109 Top Gear Rally Car – test & comparison

New LEGO Technic differential from the 42109 Top Gear Rally Car – test & comparison


what’s up guys this is Balazs from RacingBrick I hope you have a lovely holiday season and you got tons of Lego to build
yesterday I published my review video about the brand-new LEGO Technic 42109 App-Controlled Top Gear rally car if you did not see it yet then click on the
link above one of the main, or I could say probably the only highlight of the
set is the brand new differential that looks quite exciting in this video we’ll
take a closer look and compare it to the previous generations a quick look at the
differential itself as you can see there are two separate parts one of them is a
red 28 tooth double bevel gear and the other one is a barrel-shaped housing that
holds five of the single bevel 12 tooth gears before going into the details let’s
start with a little history lesson there were three previous generations of the
differentials for lego technic the oldest one was also a 28 tooth differential gear but it had a very different look if we compare it to the red gear part of the
new differential the number of teeth matches and their size is roughly the
same originally it came with the old type 14 tooth small gears but it also works with the newer 12 tooth gears – it was possible to drive it with both parallel
and perpendicular gears the next generation was again very
different it had two different sized gears at the two ends the bigger one has
24 teeth, the smaller one only has 16 both ends can be connected to the driving
rings and the extension rings locking the differential since it does not have bevel gears it
can only be driven by parallel gears the last generation before the new one
is the differential we know very well from the previous years it’s only three
studs long compared to the older ones which are four studs long it fits well in the 5×7 frame it needs
three twelve tooth gears inside to operate it can only be driven by a
perpendicular bevel gear now let’s get back to the newest version as you can
see there are no pegs to hold the gears inside one of them goes to the bottom
through this hole on the side the next 3 needs to be slided in these slots and
the last one goes on to the top the red gear clicks on the assembly and it is
held together by small clips it is not very easy to disassemble I noticed that the proper placement of
the gears inside is very important if you don’t pay attention is possible to
complete the assembly and insert the axles in both ends but they won’t turn
it is really important to verify this during building otherwise you need to go back
and disassemble a lot of things so this is how the new and the previous
differential look in a 5×7 frame side-by-side the main difference
is the size of the driving gear and the gear ratio if it is driven from the same
direction due to the size difference the new differential requires a faster input
to maintain a similar output speed I guess this fits for the new Powered Up
motors especially the XL one which is almost 2 times faster as the old XL
motor for me it seems that there’s a little more room for play with the
smaller driving gear but the difference is not that significant as you see it is
possible to drive the new differential with a perpendicular bevel gear and it is
also possible to drive it with a parallel one just like we saw with the
Top Gear rally car about the disassembly the clips are holding the two parts
together firmly it is not very easy to take them apart you need to push one of
the small clips to separate the two pieces you might want to ask if the newer one
requires more power to turn as it has more gears inside and possibly more
friction I fixed one output and we’ll try to spin the other one to see if
there is any difference as you can see the new one actually
seems to have a smoother operation and it spins more if I fix both outputs we
can see how much play does the gears allow if I compare them the new one
seems to allow a little bit more probably due to the smaller driver gear I have only this single piece of the new
differential at the moment coming from the Top Gear rally car so I won’t risk a
very heavy-duty stress test but I will try something to see if there is any
difference based on my non-scientific approach both differentials can be
forced to slip but the newer one requires a significantly higher force
with the older version it was possible to force the inner gears to jump out
this won’t happen with the new one as always use common sense and don’t
overload the differentials at the end of the day it is only plastic and it can be
easily damaged here you can see that even the 5×7 frame has marks where the axle went through so it definitely required a much higher force to make it slip
this new differential can be also connected to the driving rings so it is
possible to lock the differential here is a very simple setup it is obviously
very weak but it can show you the possibilities one final bonus point for the new
differential when you remove the axles from the old one the small gears always
fall out instantly and you can try to find them on the carpet with the new one
you won’t have this issue anymore gears are locked inside securely so I’m
looking forward to see what opportunities will have with the new
differential for me the biggest new feature is the fact that it can be
driven with both parallel and perpendicular gears it gives a bigger
freedom in building with a more flexible motor placement let me know in the
comments what you think about it and how you are planning to use it if you like
this video then please give it a thumbs up you can also subscribe and tap the
notification bell if you want to see more Technic reviews and other LEGO RCvideos, see you next time bye bye

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21 thoughts on “New LEGO Technic differential from the 42109 Top Gear Rally Car – test & comparison

  1. Great run through! Thank you. I was looking at it earlier wondering what all the pros were. Really looking forward to seeing how this one is used

  2. Also, with the idle-gear forces now symmetric and distributed over 3 gears instead of 1, and supported by the smooth circular ridges of the bevel gears instead of the points of the cross-axle holes, this should run a lot smoother under load, too.

  3. hey racingbrick,i have little question,it's not related to this video but,anyway,im 12 and I have build the 42110 (Land Rover Defender) in bout…. 12h not continuous,is that a good mark? I lost some pieces and I have the cracking issue,but, I have the 1st high and 1st and 2nd low gears work perfectly.so,I wanted to now,what do u think bout the 12h mark of time

  4. Just the fact I don't have to fiddle trying to keep the 5 12-tooth gears in place while adding the axles is big plus. The previous version was a nightmare for my fat sausage fingers.

  5. Thanks so much for the great review as usual. I had recently built the Mack truck and it was constantly “leaking” gears when my daughter plays around with it. I can’t wait to get my hands on this new differential to retrofit the truck with it. Thanks again.

  6. 4l old differentials are still the best for me, they have a lot of pros and very few cons compared to others…i don't have the last one and seems a good version of the previous one, the engagement seems better and can be driven directly by a motor in parallel which is the most efficient solution…the old one, over this, has another driving ring both lockable, lot of gear up and down ratios possible, new 9l frames are perfect for a lockable one, and most of all the driving axles completely penetrate the satellite gears with possibility to insert a 1l cyilindric spacer at the center of the diff: perfect! i'm afraid the new ones don't have this peculiarity and internal beavel gears are poorly engaged into driving axles like in the previous diff…i imagine you have only one and you don't wanna stress it too much!

  7. Great review. I’m gonna buy two of them when they come out because like you said, it’s a pain to find them on carpet. And I work in my room, which has carpet. Liked the vid!!

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