Zentool 21E2 vs RUPES LHR21 MKiii


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I thought I'd do a little comparision between the RUPES LHR21 MKiii and the Zentool 21E2. Not alot can be found on the Zentool 21E2, nothing like the Rupes. 

Bear in mind, I haven't actually used the RUPES yet, while the Zentool has seen about 50 cars by now. It's getting abused as well.... I've only cleaned it once, even the air in-/outlets. But it's still going strong! I decided I wanted to try the RUPES LHR21 MKiii, so I bought one (at more than double the price of the Zentool 🤐). I was crazy excited to get my first RUPES, thinking it would be vast improvement over the Zentool (even though I was very happy with the Zentool).  So let's see if I was right!



I got the Zentool from The Rag Company Europe through their business program. It cost me €260, and came with spare carbon brushes and in a box. The RUPES I bought through another retailer at the price of €639, yikes haha. It was the LUX-version though, which came with a nice bag and lots of goodies. Without the goodies it would have been €489. No spare carbon brushes though, but an allen Key for the backing plate. A definite win for the Zentool.


To me, the Zentool has the nicer case moulding. Sometimes I need to grab the center section of the polisher, which is a more ergonomic shape on the Zentool. I do like RUPES' materials more though, and it looks sexier as well. The speed dial on the RUPES is WAY better, since it's bigger. It means I can use anti-vibration gloves on the RUPES but not on the Zentool.

Rupes speed dial


Zentool speed dial


The Rupes also has a gas pedal trigger, which I like, but the Zentool starts at a way lower speed than the RUPES (2000 vs 3000 on the RUPES). So it definitley needs it. 2000 OPM Is the perfect speed to use with the Lake Country Pad washer 4000. The RUPES' variable trigger doesn't really modulate very well in use. And also, it sometimes doesn't work. If I let go of the trigger and pull it again to quickly, it doesn't work. I then have to wait for the machine to slow down all the way before I can use it again. On my FLEX XFE 7-15 the variable trigger doesn't have that problem and worked great!

Zentool speed range


Rupes speed range


The backing plate on the RUPES is way nicer and holds the pads better, I feel the Zentool one doesn't grip the pads as well.  It has let go of pads for me when spinning pads to dry. All my OPT ones have become unusable as a result. As a whole, the RUPES feels like the higher quality polisher. Deciding factor being that the Zentool has a bit of play on the axis, causing a clanking noise of you move it and hold it. The RUPES is tight. 

Pad rotation

The Zentool has great pad rotation, at least when in use. On flat panels, I can run it at Speed 2 without pad stall, and if I turn it up to 3, it basically nevers stalls. When turning the pad by hand though, it's not as free spinning as my FLEX XFE 7-15, but in use, the FLEX stalls much easier. Then there's the RUPES.... I can see why people perform the 'washer mod' straight away. There's no pad rotation whatsoever lol, definately not by hand, even when free spinning it doesn't rotate before speed 2. However, the Rupes is supposed to get better over time, as the dust shroud, which drags over the backing plate wears down. I would guess this is a better design compared to the Zentool one, which has a big gap beteen the shroud and backing plate, more easily letting in debree.

Zentool dust shroud:


RUPES dust shroud:


If I lift up the dust shroud on the RUPES (sort of possible) so there is a gap, the RUPES has the far better pad rotation. So I'm thinking, with use, the RUPES pad rotation will match or exceed that of the Zentool, with a better dust shroud design to boot.


An important one to me, up front I figured the RUPES wouls win this! In a very unsientific way, I put my phone down at a certain distance and opened a dB-meter app. I then got each polisher in hand, and ran at speed 3. The RUPES ran at 85 dB average, the Zentool 81 dB. A win for the Zentool, I can use it for extended periods of time withouth hearing protection. In practice I do use hearing protection though, because why not. The RUPES I won't be able to use for long without hearing protection, that's too bad! The noise it eminates is also a more unpleasent pitched one, a bit like gears grinding. Don't know how to desribe it. The Zentool sounds smooth!


The most important one to me! Recently, the Zentool had begun to vibrate A LOT for me. I was getting sick of it! This made me want the RUPES, since this would definitly be better, right? I even use mostly RUPES pads, so couldn't be better right? Well..... I got the RUPES and Zentool side by side, and to my surprise, the Zentool felt smoother??? It actually felt crazy smooth. So in another very ubscientific test, I opened the Vibrometer app on my phone and pushed it tight on each polisher as I ran it on speed 3. The result were pretty shocking:

RUPES vibration:


Zentool vibration:


What the heck??? On both polisher I placed the pad (RUPES whool) as centred as I could. The Zentool is WAY more balanced?? Turns out, the pad I was using before, was what caused the terrible vibration. Once I used a new pad, it was a breeze! It's a good thing the RUPES has the big speed dial, because compared to the Zentool, I'm gonna need the Anti-vibration gloves! A big win for Zentool!


In my opinion, a definite win for the Zentool. Crazy how a used and abused Zentool wins from a brand new RUPES? It's cheaper and runs better. I didn't expect that really. I'm going to use the RUPES and see if it beds in or something, maybe than it will get nicer. I would like to see some improvements on the Zentool, namely a larger Speed Dial, different casing materials and a better backing plate. Oh and a variable trigger that works!

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As did I, Ron.... Bummer to be disappointed like this! It's definitely a looker, but it just doesn't work for me. I've tried to use it the last couple of days, but couldn't get to grips with it. 

In use, the noise and vibration are so much worse than the Zentool's. The Zentool I can use all day, no problem (if I don't use a broken pad lol). The RUPES annoys my ears and vibrates too bad, it really aches my arms. It's better if I use a lightweight Microfiber pad, but still not good enough. Vibration gloves don't help. Plus, nothing works as well for me as RUPES blue wool. 

I dislike the fact the RUPES starts at 3000 OPM, and that the RPM's are limited stock. When used with a pad washer, the pads stay too wet. The RUPES stalls way too easily.

So I tried the washer mod actually. Free spinning now is awesome, but the pad doesn't really get any dryer compared to the Zentool. It does seem more balanced at speed 6 though and a bit quieter. However, it generates an aweful noise when ramping down... With the washer mod I can mostly use it at speed 1. However concave or curved panels, the speed needs to drastically increase to prevent pad stall.

The Bigfoot has also started to clunk, creek and rattle. It doesn't feel as sturdy anymore.

So.... I'm gonna sell it again and stick to my Zentool! Maybe buy another one in case this one breaks haha!

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  • 4 weeks later...

So let me get back to this, since I've been really trying with the RUPES. I said I'd sell it, but wanted to try some more. I've tried the washer mod, but was unhappy with the results. I then shaved off a thinner washer, so the pad rotation matches the Zentool's. I can't seem to get it to work with the pad washer, since the pads get too heavy I suppose?  It seems to cause excessive vibration while polishing. Where the Zentool seems to like a heavier pad, the RUPES prefers a lighter one.

But I've no doubt the Zentool is the smoother machine anyhow, and has better pad rotation. In use, it feels like a rotary polisher with a slightly off-center pad, crazy smooth.

I've got a ShineMate polisher coming in, the EX620 6/21 to do another comparison. It's quite a bit cheaper than the Zentool and they also produce a cordless 21mm DA. I'm really interested in that one, so I'm hoping to like the ShineMate.  Let's see!

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I've gotten the ShineMate, and it's a good machine, especially at the price. The variable trigger works better than the Rupes', is difficult to stall, and is as balanced as the Rupes. Noise is slightly worse than the Rupes, but better grease would definitely help. The backing plate has high-quality velcro. I need to use it some more.

I still like the Zentool more, it's more balanced and makes less noise. The 2000 starting OPM is perfect and 4800 is high enough or even perfect for spin drying. I do dislike the velcro on the backing plate though. Some pads let go as soon as spindrying at speed 3, a real bummer. This wouldn't happen on the ShineMate or the RUPES. I need to get a replacement backing plate, maybe that would solve the problem.

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  • 5 weeks later...

Nice review!


Aside from the Adam's Swirl Killer 15 I use at work, Rupes is the only other long throw I've used. Very happy with them too. The Duetto is my favorite because I'm not a fan of the rotary style chassis (even when I used a rotary back in the day, I thought they were too big and bulky). 


With the Rupes, and any polisher (except the Flex 3401 maybe) can be wildly affected by the weight of the pad. For instance, when I use Rupes microfiber pads on them, they will vibrate more due to the increased weight of the pad. Rupes even had an optional backing plate available specifically for their microfiber pads, which feature a very dense foam rubber type material between the loop backing and microfiber face. 


I do like their wool pads a lot though, which are much lighter, and don't need the other plate. I don't think that plate is even available anymore!


I also run my 21 and Duetto without the washer mod. I am very diligent about making sure the backing plate is properly lubricated. One tiny dot of dielectric grease is usually sufficient. Too much grease will cause excessive drag, and kill rotation, as will not enough, or dry. 


So as of now the Rupes works fine for me.


All that being said, my favorite polisher is the original Porter Cable 7424, not the current "XP" version. It maintains rotation at lower speeds better. It's smaller and a touch lighter. It'd durable and reliable. It's incredibly easy to use. That polisher was the industry's introduction random orbital polishing at a mass level. It suffered through being used with pads that were a little big for it at 6.5", and polishes that didn't maximize it's effectiveness. When I took delivery of my first original 7424, I put a 5.5" and went to town. I've polished everything from my mom's modest Saturn Ion to Lamborghini, Bentley, McLaren, etc, etc with the humble PC where I work part time. 


Again, excellent review and comparison. Love the Flex XFE mention as well. I've been eying that one lately.

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@dlc95 reading your post, I might have overdone it with the grease on the backing plate of the 21. Nevertheless, it wouldn't have made enough of a difference to win me over! Same with the XFE, Zentool sits at first place for me, with a big lead.

I actually got a second 21e2, you know, in case the first one breaks 😋. It's just as smooth but has better free spinning and the velcro on this one is definitely better. I also got a new backing plate for my other 21e2, which seems to be better as well. We'll see how it performs with use! Sadly no Hyper Wool pads available anymore, but got some more waffle pads.

Cool read about the Porter Cable! We never got those here in The Netherlands I believe.

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Well, the new backing plate works great! It keeps a better hold of the pads, none have flung off during a day's work! It's a bit smoother in use now as well, so it seems.

Also very strange; but it kept the Rupes Blue wool pads way fluffier during use compared to the old backing plate.  Let's see how it does over time.

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