MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.

Download Now


Differential for OpenRC F1 car.

by tahustvedt Jun 2, 2017
Download All Files

Thing Apps Enabled

Please Login to Comment

I refer to a post July 20th 2017 by "Saiteik" spider gears not meshing fully, I have same problem, should Saiteik still read this forum, would there be any possibility of sharing the STL for the 3 spider set-up? My CAD skills are not at that level!.
The 5 spider diff is reasonably free, and may be the gears would "bed in" a little but I would like to try the 3 spider.Thanks anyway

can anyone comment on whether this improves driving performance of the car?
Best regards,

I would also like to know.

Bigger parts printed fine but 5 small gears ended up squishing between fingers. Could you make those little gears in its own STL file so its faster to try again :)

Separate the parts in the slicer. I don't want to have a lot of different files of the same things because people get confused.

Do you need to put little pins though the holes in the small gears to locate them in the spur properly ?

see pic above. "Make axles from small bits of 1.75mm of filament"

Works great! For the 2017 updated version of the OpenRC F1 I just added an additional bearing on the outside of the rim to compensate for the longer axle.

Thanks so much for this. Brilliant design.


I printed this differential for my OpenRC F1 and immediately had issues with the gear meshing of the spider gears to the beveled gear hub that locks with the rim. Is anyone else having inconsistent meshing on one side? I can see 2 out of 3 mesh correctly but the other 3 are basically hitting teeth to teeth with the spider gears.

I've had the same problem so I've made some modifications. Check it out: https://www.thingiverse.com/thing:3535376

OpenRC F1 differential
by klemza

Hi, I think I have the same issue, I have printed versions on two different printers and both have the same difficulty with the drive side. I can hold the spur gear and turn the left wheel freely but the right wheel does not turn. It appears to be the bevel gear that fits inside the wheel is not meshing with the properly with the spider gears, not sure why as they turn freely enough when turning the left wheel but when the right wheel and bevel gear is driving the spider gears, they lock up.

They're not perfect, but they should mesh fine. I guess it can vary from printer to printer. When I print a diff it usually feels rough at first due to the intricacies of printing and sometimes micro plastic debris and occasional micro stringing between some teeth. I like to hold one wheel and spin the motor for a few seconds with a new diff and that usually beds them in. The ones I have on my two F1 cars feel and look well meshed.

I have tried to break them in by locking either side while having the motor rotate. I ended up chewing through one of the beveled sides (rim hub) and significantly wore down the spider gears. After further inspection I believe the problem lies with the positioning of the spider gears on the spur. I actually did a few things to correct this as I do not believe it is my printer. I have the Original Prusa i3 MK2s and printed accurate calibration cubes. I modified the rim hub to be shorter and wider near the bearing so it can grab more rim. I also changed the spur to accommodate 3 spider gears rather than 5. I believe this will reduce friction load allowing for easier slipping of the diff. I will update you on how it goes, honestly I commend you for the engineering effort done to make this diff fit in such an incredibly small area.

Did you lube the gears before running them in?

Nope, however even if I did they just didn't align so I doubt it would have been an improvement.

Just a little bit of lube will really help. They melt from the friction.

This is what it should look like. This one spins very smoothly and easily since it has been run in. There's a reason why I said they need lubrication in the instructions: https://youtu.be/OVFahlVHfgs

Is the gear that goes on the wheel side meant to slot into the gaps on the wheel rim?

Mine doesn't seem to slot inside, just seems to sit on the edges of the wheel rim.

Should it sit in more than this? https://ibb.co/mQdvFF
That's on the larger remixed wheel rim.

I didn't design that rim. If the rim doesn't have the same dimensions as the stock front rim then it won't fit.

I have the same problem! Could you please provide the link to the rims that you used? I tried using the stock front rims from Daniel's original design.

Ok, Well i'll give it another go once I've repaired a few parts

Hi! Very nice job!

Could you split the pieces in multiple files?

I'm having trouble printing some pieces...

Thank you!

Doesn't your slicer have the option to separate the pieces?

If I split it up it'll just cause confusion and make a mess of it.

Sorry. I'm new at this

I'll try the simplify3d options

Thank you!

Under the "Mesh" menu select "Separate Connected Surfaces" while the part is selected.

WOW! Thank you very much!

Well done! What is the big difference between the 40 and 46 teeth version? I assume the 40 teeth version is more suitable for a larger nozzle? What material did you use? Nylon or plain PLA?

Both are the same tooth pitch. The 46 t gear is there to provide more gear ratios to play with. One of my other things is a set of pinions for this car. If you want to slow the car down or you have a very fast motor youcan install the 46t diff and the 9t pinion and you slow it down to 56%.

Thanks for the quick reply! Do you have a recommendation for the material? Plain PLA, Colorfabb XT, a co-polyester or something else? Just did some research and it seems that nylon (even though very strong) is a bit to flexible for high torque gears.

I made all mine from PLA. I like to design my stuff so that PLA works well, if possible. That way it's going to work for everyone.

Wow, i didn't think anyone would manage to make one given the tiny space you're working with! Well done.
Will have to give this a go soon.