Current opinions on smooth vs toothed idlers?  

Eminent Member

Heya fellow Prusa Printers! I ordered my 2nd MK3s last week (wahoo!) and was curious on what folks think about smooth vs toothed idlers these days? I have 20-tooth ones on my current MK3s though it sounds like 16-tooth might be the better option these days (or just the smooth ones).

I found my print quality improved when switching to the toothed idlers but I upgrading the belts (to the E3D ones) at the same time. So I don't really know which one helped, though I suspect it was mostly the belts. As I understand it, Prusa now ships with better belts but still provides smooth idlers?

So I'm trying to work out if I should just stick with smooth or go ahead and buy toothed while I go through my shopping list of upgrades. Namely a sock, nickel/copper block, nickel/copper nozzle, Sunon fan. Since I won't be using an MMU on this second printer, I thought about the E3D titanium heatbreak or at least the standard heatbreak so I can more reliably with filaments like Proto Pasta.

Posted : 30/04/2020 3:48 pm
Prominent Member

I replaced the smooth wheels with new timing belt wheels to reduce the wear on the belts.
A toothed belt always feels better about working against a toothed belt wheel.

Bear MK3 with Bondtech extruder...
Posted : 03/05/2020 12:18 pm
Eminent Member

Yup that was my thought too when I added toothed idlers to my current one. Belts still look to be in awesome shape despite tons of printing.

Posted : 03/05/2020 5:14 pm
Trusted Member

There's a reason practically no printers come with toothed idlers. They're completely unnecessary for the loads and speeds any 3d printer's belts will be experiencing. Toothed vs smooth also does not affect the accuracy of the output nor somehow wear the belt more (again, in this context)

Consider - Prusa uses a genuine E3D V6 in the MK3S but doesn't bother splurging the extra $0.15 for toothed idlers?

IIRC Prusa themselves have said as such back when they started using genuine Gates belts

This post was modified 3 months ago 2 times by With_maltodextrin
Posted : 03/05/2020 6:48 pm
Noble Member

I did change mine over but the main reason was that the toothed variants had bearings on both sides whereas the stock ones only have a single centered bearing. Seems like it would have better stability since it's being run on an already slightly undersized screw and not a smooth shaft. 


Posted : 06/05/2020 6:52 pm
Eminent Member

Yeah I think my conclusion is they may not help much but probably won't hurt. I think I'd rather keep this printer as close to my current one as I can so I can expect similar prints from both, which has me thinking the toothed idlers are the way to go (for me) for consistency. Also good point about the bearings on both sides. I hadn't considered that point.

Posted : 06/05/2020 6:54 pm

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