MS2 vs M2 Motor Rattle and other Intangibles

[slickrock]

There's been a whole lot of reviews discussing the performance superlatives of the M2S motor, as the flagship successor to the M1. Yet there's been pray little chatter about the base M2 motor. It seems even the base model of a number of bike makers only offer the M2S, and those few that do don't put them on test with the influencers. What we do know is the motor internals (both motor and transmission) are not the same - IOW the M2 is not a nerfed M2S, but rather a different motor build. While the spec side-by-side spec differences have been laid clearly, what is less clear are the intangible experiential differences of riding the two sequentially. I had the opportunity of doing so at Sea Otter, and wanted to share my contemporaneous anecdotal notes:

1. Uphill Noise: The M2 sounded quieter in volume and less intrusive in timbre compared to other non-Avinox motors I tested that day (Bosch Gen5, Mahle, Rivian ALSO), which is I guess is still a feat. The M2S, however, seemed to be in a different valence altogether. While I have not tested that latest TQ or Maxon motors that would most likely temper my surprisal, I was indeed surprised by the soft sound of the M2S.
2. Downhill Noise: The M2 has the dreaded rattle, at least with the base PR I test, and it was sensed at the motor internally rather than from some loose attachment or cable. I was blown away when I tested two bikes with the M2S, both of which were noiseless on the chunky downhils. Among other things, that additional spring loaded mesh gear setup with the M2S banished the one of the chief complaints of the the M1.
3. Motor Refinement (Pedal Feel): It was really hard to get the pedal feel of the M2S out of my head. It had the polished feel of a multi-generational motor. Backlash, slack pedal engagement, that sense of gears meshing was just not there, or at least not making itself felt. The M2 felt more workman like, you can feel the gears, but for some than could give the heavy duty sense of a truck vs sport car.
4. Power Refinement: Here I feel the M2 had more equal footing compared to the M2S (both in 800Wh and 700Wh setups), and as expected leagues beyond the non-Avinonox motors I tested that day. Once you get to this level of power, it's more about how the power is delivered than how much. I tried multiple modes on the MTB test tracks, which a lot of loose gravel and silt, and the bikes delivered copious power with without losing traction. I would blow past other folks demoing ebikes from the other motor makers and it felt like a cheat code. I've ridden over-powered Bafang motors, and it's just not fun in an, bucking, unbridled way. All that power on the M2 felt just as controllable as the M2S, and that's probably chalked up to the similar/same firmware. On the flats or grinding fire roads, the differences were more apparent among the M2, M2S-800, and M2S-700, with the difference between the former 2 starker than the latter 2. The 700 was off the chain and the only motor to best it that day was the Rivian/ALSO. The M2 and M2S never "felt "overpowered beyond rider + bike abilities, even though they are over-powered.

I would say if you not sensitive to motor rattle or the more felt sense of the motor at the pedals, then the budget-minded M2 is good choice if you want a bike that is part the Avinox ecosystem. The M2S, however, put me into another headspace. The lack of rattle and highly attenuated motor noise, and elevated motor and power refinement, overwhelmed the personality of every bike that it was attached to. I rode a PX and Teewing Flux, and I'm struggling to pen out the differences. I rode the venerable Yeti LTE that day as well, and as good as the bike's suspension is, all I could think about was what this bike would be like with an M2S.

 

[Roughshod]

Thanks @slickrock helpful feedback, it's annoying about the lack of proper coverage of any M2 motors.

 

[xtraman122]

Good to hear, I wish I had the opportunity to demo the PX and Flux back to back like that. One of those two will be my next bike, but I’m still undecided on which… I’d like the extra travel of the Flux but I’m not sure I actually need it. The lighter, shorter travel PX is probably all I need for my riding…

 

[HandsomeDanNZ]

The lighter, shorter travel PX is probably all I need for my riding…

I think this is likely true for about 90% of us, but we all tell ourselves that more is better.

 

[Astro66]

I think this is likely true for about 90% of us, but we all tell ourselves that more is better.

Unless you do like me and have one of each .........

Regarding the OP. The differences between the M2S and M2 will be subtle. So I think it will come down to the kinematics and suspension of the bike, the motor is installed on.

If the Teewing Flux was sold with the M2 motor. I would have still not hesitated to buy it. I'm glad it has the M2S, because it's lighter, quieter and has more advanced components. But there is no way the extra 200watts of peak power, or extra torque would have swayed me.

I'm all about choice. Having your Turbo Mode set up with a Ludicrous power setup, is better to have, than not have. You can always choose not to use it. But perhaps you will find a climb you cannot clear, and this mode unlocks it. More options is always better.

 

[HandsomeDanNZ]

Unless you do like me and have one of each .........

We aren't all living off of royalties from our many piano albums, Liberace!

 

[TheKaiser]

On the flats or grinding fire roads, the differences were more apparent among the M2, M2S-800, and M2S-700, with the difference between the former 2 starker than the latter 2. The 700 was off the chain and the only motor to best it that day was the Rivian/ALSO. The M2 and M2S never "felt "overpowered beyond rider + bike abilities, even though they are over-powered.​

Agreed that the M2 is underreported, so it is great to hear your side by side review. I have seen mixed reports on the M2 rattle situation, so maybe it is kind of like the M1 where depending on the individual motor and bike it might be more noticeable or not. Regarding what you wrote above, I am curious about the comparison of the M2S-800 and the M2S-700. I assume we're talking about the Teewing being the 800 bike, so I guess being capped at 1300w vs the 1500w of the 700 on the Amflow PX makes a real difference. Also interesting to note that the 800w Removable battery on the new PR is supposed to be able to do 1500w (although only for a 30sec boost mode), so it is sort of in between the 800 internal you rode and the 700. Do you imagine that power level is something you would use for more than 30sec at a time, or do you think that having access to it in a 30sec boost would effectively make the removable 800 equal to the 700 for practical purposes?

 

[slickrock]

...
Regarding what you wrote above, I am curious about the comparison of the M2S-800 and the M2S-700. I assume we're talking about the Teewing being the 800 bike, so I guess being capped at 1300w vs the 1500w of the 700 on the Amflow PX makes a real difference. Also interesting to note that the 800w Removable battery on the new PR is supposed to be able to do 1500w (although only for a 30sec boost mode), so it is sort of in between the 800 internal you rode and the 700. Do you imagine that power level is something you would use for more than 30sec at a time, or do you think that having access to it in a 30sec boost would effectively make the removable 800 equal to the 700 for practical purposes?

1. The differences between the 700 and 800 can be felt, but more likely under direct comparison than in outright capability.
2. But once accustomed to all that power, I would not want the motor to derate. For this reason and if the initial motor tests are to be believed, the 700 is the more important choice, although I did not get to the point where the 800 derated and the M2 derate is much less than the M1.
3. The 30 sec boost mode was more stark with M2S over the M2. The 700/800 boost modes were somewhat silly unless on pavement or smooth fireroad. Or for the highly impatient.
4. The M2S is so refined and powerful on technical uphills, I have to rethink the riding experience. It's like technical uphills are now like technical downhills. Less overrun is needed as you have a lot more momentum to negotiate the uphill chunk. I hate to admit it, once I get a taste of that controlled power, I'm now spoiled. it was a bad idea to test a Gen 5 CX after this motor.

 

[Astro66]

It's like technical uphills are now like technical downhills.

I have copped so much flak from MTB purists over making the same comment. But this motor does change your entire outlook on what you want to ride.

I went to a very expensive Bike Park for 3 days. And found myself only using the uplift and gravity trails, one of the three days of riding. I just wanted to tackle some climbs and not just downhill, and you weren't allowed to climb up on the gravity trails. So we went and rode some adventure trails for 2 of the days.

 

[dadeadduck]

Can anyone comment on the M2 resistance with the motor off?

Its doesn't bother me with EMTB, but a gravel avinox the resistance when off is really important.

 

[slickrock]

Can anyone comment on the M2 resistance with the motor off?

Its doesn't bother me with EMTB, but a gravel avinox the resistance when off is really important.

Didn't even think about it. Huge omission on my testing. When I was at the Bosch booth they were going on about Gen 5's motor-off feel and low resistance in comparison Avinox (though I wasn't sure if they were referring to the M1 or the M2/S) -that should have triggered something in my brain when I tested the PX. Oh well.

 

[luna87824]

We aren't all living off of royalties from our many piano albums, Liberace!

 

[dadeadduck]

Didn't even think about it. Huge omission on my testing. When I was at the Bosch booth they were going on about Gen 5's motor-off feel and low resistance in comparison Avinox (though I wasn't sure if they were referring to the M1 or the M2/S) -that should have triggered something in my brain when I tested the PX. Oh well.

To be fair, it's not really needed on MTB.

@Velduro UK do the Phantom, it currently has the M1, but it's coming with M2 soon (M2S is Valduro MTB only). Resistance needs to be non-existant for

Didn't even think about it. Huge omission on my testing. When I was at the Bosch booth they were going on about Gen 5's motor-off feel and low resistance in comparison Avinox (though I wasn't sure if they were referring to the M1 or the M2/S) -that should have triggered something in my brain when I tested the PX. Oh well.

It's understandable, doesn't matter for MTB.

For gravel (or for me) it needs to be non existent. @Velduro UK Phantom currently the only Avinox Gravel, is M2 only. The Specialized 1.2 motor is great for this, it'll be interesting to see if the Avinox can usefully be used off now.

 

[Roughshod]

I'm also interested in the unpowered resistance. I think both the M2 and M2S are meant to have 41% less unpowered drag iirc.

Both motors are listed as "low" for pedaling resistance on the Avinox site while they have the M1 as moderate.

Not seen any actual numbers for this anywhere or how all 3 motors compare to others on the market.

 

[Roughshod]

Did a bit more digging to see if I could find any figures. Unfortunately not but e-mountain bike magazine have got some titbits from different articles.

Their 11 motor roundup for best 2026 motor has a section where they talk about idle resistance where they've measured unpowered torque (this was pre M2 motors). Unfortunately they don't appear to have actually published the figures that were measured that I've been able to find.

However they did have this section in their M2 test article:

Efficiency of the new Avinox M2S
Another key aspect is efficiency. Our measurements show an average efficiency of 81% for both the M2 and M2S, with values ranging from 78.4% to 84.4%. That might not sound like a huge gap at first, but compared to the previous Avinox M1 and especially to other motors we’ve tested, it’s anything but marginal. The efficiency window of modern eMTB drives is quite narrow, with most systems from our motor group test sitting between 77% and 79%. Even a single percentage point is a significant step forward. The Avinox M1 achieved an average efficiency of 78% (74.1% to 79.4%) in our test, meaning the new M2 and M2S run a full 3 percentage points more efficiently at 81%. Chapeau.

Idle torque of the new Avinox M2S
Less obvious but still relevant in practice is idle torque, an area where the Avinox M1 delivered comparatively modest results in our test last autumn. To provide context, we also include the corresponding power loss at a cadence of 75 rpm. The M1 recorded 0.75 Nm / 5.89 W at the time. With the newer system, the picture is more nuanced. The Avinox M2S from the PR Carbon Pro measured 0.67 Nm / 5.26 W ahead of the DEKRA test, dropping to just 0.55 Nm / 4.32 W afterwards. That equates to roughly 73% of the M1’s resistance and represents a clear step forward. The PX Carbon Pro, however, recorded 0.75 Nm / 5.89 W, placing it exactly on par with the outgoing M1. This suggests that idle torque is influenced not only by the motor’s fundamental design, but also by factors such as seal break-in and the behaviour of the clutch or freewheel mechanism. Variations in preload from freewheel springs or roller clutches can have a measurable impact on the result.

The broader takeaway stands: when riding unassisted, the Avinox is not the most free-spinning motor on the market and tends to demand a touch more effort than rival systems.

They've only mentioned the M2S for the idle torque but that's bound to be the better of the two new motors and it doesn't sound like it's a clear cut better option than the original M1 when it comes to unpowered drag. I took a look at some of their other motor specific articles and there doesn't seem to be any consistency regarding publishing idle resistance figures.

I included the motor efficiency bit as well as I thought that was interesting and not many other reviewers are going to have access to actually measure in a lab.

 

[J_A_N_G]

Among other things, that additional spring loaded mesh gear setup with the M2S banished the one of the chief complaints of the the M1.​

Is this thin black second gear made of plastic ?

How durable is it ?

Will the rattle return once it is worn out ?

 

[Suns_PSD]

The black toothed ring doesn't carry any of the motor torque, just serves to keep the main gear that does the work preloaded, even when not pedaling or receiving forces from the opposite direction from chain tug. Hence it removes the rattle.
It's just a little spring that works in all gears.

 

[Winford]

I had the opportunity of doing so at Sea Otter,

Ive heard those bikes were not set up well, and were getting trashed. There is a setting that probably was not turned off or on that was causing such. I run an amflow site with 17,800 members with another fella, and so far no ill complaints yet about M2 rattling.

 

[Winford]

Not seen any actual numbers for this anywhere or how all 3 motors compare to others on the market.

Me neither. And the reports I have seen on the M1 have all been wrong. The resistance on the pedal at a very slow rpm is not the same at higher speeds when you are fighting the rotation inertia of all the gears inside. I did a mile home once with a dead battery and it was quite the chore, more than any BS number people have been throwing out. Hopefully as you said the M2 and S have much less than M1.

 

[ozzybmx]

Nice review/information and well written

 

[Scott_123]

My M1 has 1,270 miles. I live in the Southwest desert where we ride downhill over lava rock. If there is ever a surface that will provide a rattle in an electric drive train it is lava rock. I actually have to take attention away from the riding and listen as close as I can to determine if I hear a rattle. I do hear a very slight rattle but to be honest I can’t tell if it’s coming from the motor or some cabling/wiring below the Avinox screen. I’ve even tried to do a peddle stroke on the downhill to see if it stops. My assessment is the rattle is so slight I can’t even determine it’s origin. There are plenty of noises going on a chunky downhill section and I simply can’t understand why people are so fixated on having a completely silent MTB riding experience?

If you want noise my wife’s Bosch SX delivers in spades.

 

[slickrock]

Ive heard those bikes were not set up well, and were getting trashed. There is a setting that probably was not turned off or on that was causing such. I run an amflow site with 17,800 members with another fella, and so far no ill complaints yet about M2 rattling.

In comparing the M2S and M2 with hours of each other, the difference was there, perhaps more noticeable because I had brethren to compare it to. All the Amflow bikes were in heavy rotation and I tested on the 3rd day of the event, so this would be better test for rattle as wear-in would have already occurred. It could have been anecdotal in just that bike, but the fact that Avinox has an additional mesh preload gear in the M2S explicitly points to a solution against a known problem. And a solution that worked based on my testing.

 

[Redlemon]

My M1 has 1,270 miles. I live in the Southwest desert where we ride downhill over lava rock. If there is ever a surface that will provide a rattle in an electric drive train it is lava rock. I actually have to take attention away from the riding and listen as close as I can to determine if I hear a rattle. I do hear a very slight rattle but to be honest I can’t tell if it’s coming from the motor or some cabling/wiring below the Avinox screen. I’ve even tried to do a peddle stroke on the downhill to see if it stops. My assessment is the rattle is so slight I can’t even determine it’s origin. There are plenty of noises going on a chunky downhill section and I simply can’t understand why people are so fixated on having a completely silent MTB riding experience?

If you want noise my wife’s Bosch SX delivers in spades.

Any noise is a distraction for me, my attention is shifting to that specific noise and I can definitely lose confidence in my bike.

M2 motor should be rattle free, that's a major let down and this shouldn't be a premium feature.

I would go Bosch before having to hear that clacking all the way down.

 

[ptkatoomer]

Not really motor related but:
I was also at Sea Otter and this was my first chance to ride the Amflow/Avinox bike. While the motor was amazing I felt the geo and suspension wasn't on par with either the Santa cruz Vala and the Pivot Sl that I rode there as well. I know these bikes weren't set up specifically for me but it did make me think I'd want a more established brand that was running that motor.
Sure wish I could have ridden the Mondraker ...

 

[slickrock]

Not really motor related but:
I was also at Sea Otter and this was my first chance to ride the Amflow/Avinox bike. While the motor was amazing I felt the geo and suspension wasn't on par with either the Santa cruz Vala and the Pivot Sl that I rode there as well. I know these bikes weren't set up specifically for me but it did make me think I'd want a more established brand that was running that motor.
Sure wish I could have ridden the Mondraker ...

I feel at this point Amflow is an established brand now, Just not a prestige brand. Tried twice to test the AMP'd but kept getting squeezed out of scheduling a ride. The good thing is that you have wide choice as to what bike you want with that motor (funny that's it's got to this point). One thing I came away with brief demo testing is just how much the experience is dependent on bike fitting and suspension setup. Luckily I was primarily focussed on testing motor versions, so rideability took second fiddle. And I didn't have much choice - The Teewind Flux had an over-spring coil shock for my weight and backing it out can only do so much. Next time I'm bringing a shock pump for air shock setups. The best suspension setup I rode that day was oddly enough the Rivian/ALSO TM-B. It was somehow well-turned from the get go.

 

[Fangs2k]

I’ve formed the impression that the M2 is an evolution of the M1, hence why perhaps some of them still rattle like some of the M1 motors did? It would make sense that’s why the M2S is what’s getting reviewed the most?

The M2S seems to have had quite some development changes going on from watching the various videos, along with the batteries obviously.

To be fair, this is classic DJI (and not meant as a derogatory thing before anybody feels the need to get spikey!) they release a new iteration of ‘a thing’ as well as another one that is warmed up tech based on the ‘old’ thing.

Makes sense from a development costs point of view, and keeps those who want to be on the upgrade treadmill something to buy.

I’m in the camp where motor rattle (such as it is) either doesn’t occur on my rides as I’m predominantly a trail rider, or on the gnarlier trails I sometimes ride there’s so much other noise and stuff going on that it doesn’t really enter my conscience.

 

[Thomas46]

I have tested a Mondraker Zendit with the M2S Motor and the motor had quite a noticeable rattle. I am wondering if I got a faulty motor or if dji didn’t fix the rattle problem completely. The motor is really quiet but the TQ hpr 60 has still much lower noise levels.

 

[AirKuhl]

My Pivot Ampd is pretty much silent downhill, the loudest sound is the radial tires on the rocks.

 

[mhueschen]

has anyone experienced a "coupling" of the chainring and cranks during overrun on the M2S? I got my DreadE recently and notice that when I stop pedaling and the motor overruns (even on lowest setting, which is what I use), the cranks are torqued forwards along w/ the chainring.

I find this awkward and it requires me to brace slightly to resist the torque, if I want to keep my pedals level.

the bike is brand new and has very few miles on it, so I'm wondering if this is just a seals-esque issue which will go away with wear.

on the Druid CorE M1, I never experienced this, even when the bike was brand new. overrun never torqued my cranks.

 

[Plyphon]

has anyone experienced a "coupling" of the chainring and cranks during overrun on the M2S? I got my DreadE recently and notice that when I stop pedaling and the motor overruns (even on lowest setting, which is what I use), the cranks are torqued forwards along w/ the chainring.

I find this awkward and it requires me to brace slightly to resist the torque, if I want to keep my pedals level.

the bike is brand new and has very few miles on it, so I'm wondering if this is just a seals-esque issue which will go away with wear.

on the Druid CorE M1, I never experienced this, even when the bike was brand new. overrun never torqued my cranks.

The motor can move the sproket/chain independently of the cranks - that's how smooth shift works, but also how overrun works.

I'm unsure what it is you're feeling - but perhaps there is some tolerances there that will loosen. I'm surprised you can even feel it, tbh.