Avinox Reveals its Motor Gearbox

Ranked purely on aesthetics:
1. Commencal
2. (tie) Mondraker - interesting use of a mass damper
2. (tie) Forbidden
4. Canyon
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John_likes_bikes said:
Ranked purely on aesthetics:
1. Commencal
2. (tie) Mondraker - interesting use of a mass damper
2. (tie) Forbidden
4. Canyon
View attachment 187415
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I would put the aesthetic competition the exact inverse of your ratings. Good catch on the mass damper, although pretty strange to remove unsprung mass, then add weight back!

That said, it appears that Avinox is not as far along in the process as Gobea (sp?).
 
Been meaning to do the sums on eCVT's for a while now and this was the spur I needed. Having a wide gear range really knocks the efficiency. Assuming they use latest tech in the electronics (which I think is likely for them) then it looks like 85% might be ball-park average, but it is much better at the design gearing (which it can default to when the battery is dead) than at the furthest point from there. Compared to maybe 90+% for a conventional motor and derailleur. Might explain why they are also launching a bigger battery.

I guess down the line batteries might be so much lighter that this 5% or so isn't crucial, maybe even by the time they launch it. And if the ecvt route is half a kilo lighter than the spur gear solution and you only need 200g of extra battery to make up for the efficiency (though obviously the spur gears have their own efficiency issues) then it's still a win. But a derailleur might still be the choice for properly light efficient bikes.
 
I was kinda disappointed to read that it has a 520% gear range... we really don't need that much range for MTB any more, now that we have the power and torque of modern motors.
IMO 400% range is plenty, and would surely have allowed a smaller + lighter + more efficient design.
 
Paco_Loco said:
I was kinda disappointed to read that it has a 520% gear range... we really don't need that much range for MTB any more, now that we have the power and torque of modern motors.
IMO 400% range is plenty, and would surely have allowed a smaller + lighter + more efficient design.
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We aren't privy to the decision making processes and should show some deference to those who design motor systems for a living. It's entirely possible the gains you're theorizing are so minuscule that there's more value in the wider ratio.
 
Powerslider said:
The tensioners look like a liability from here. Maybe I'm wrong and it's not as exposed as they appear? 🤔
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Tensioners are the bane of MGU and gearbox designs. I've harped on this for quite some time and its problem that needs to be solved along with the motor tech. Villeger Dynamic a couple of years back (nothing from them since) has a ECVT motor design with integrated tensioner optimized for the motor - a cool concept.

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But judging from these first entries, quite a lot of design progress is needed.
 
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Just wondering how these would peddle when the battery runs out, do you think there would be a lot of drag? Would they turn into a one speed bike until you recharged?
 
TQFreak said:
This concept has a disentangle though and it is the same disadwantage as the single speed mid-drives have like Sur-Ron or hub motors - they are efficient at one speed, at other speeds they dump more energy into heat comparing with mechanical geared electrical motors.
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This is not how e-cvt works. It uses 2 electric motors and a planetary gear to create a variable ratio between the inputs and the output. Works very well in hybrid cars, some e-CVTs were implemented around 20 years ago.

Back to eMTB space, it's interesting that a year ago, people said that Avinox M1 has a bit more drag than Bosch, for example. As a consequence, M2/M2S has lower drag seals.

I guess in the case of e-CVTs, there's no point in talking about seal drag because I guess the gearbox alone will have more drag. How you will with get past 25km/h limit with no assistance? :)

I also have another question , can you normally ride an e-CVT eMTB without main battery?
 
Stevedee said:
Just wondering how these would peddle when the battery runs out, do you think there would be a lot of drag? Would they turn into a one speed bike until you recharged?
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We had the same thought but you posted before I could see your message
:)
 
Stevedee said:
Just wondering how these would peddle when the battery runs out, do you think there would be a lot of drag? Would they turn into a one speed bike until you recharged?
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The degraded modes of the motor will depend on the design internals. The way ECVTs work is the gearing motor (not the drive motor) runs at a particular speed to set the ratio between the sun and ring gears or between the planetary and rings gears (depending on implementation). It's bit like virtually making either ring gear larger or the planetary gears smaller to increase the gear ratio. If the motor dies then what happens depends on what happens to the planetary gear when the gearing motor dies. If its nearly free-spinning then the gear ratio would tank, perhaps close to what it feels like when you would be in the granniest of granny gears. OTOH if the motor locks the planetary gears, then the sun gear would drive the ring gear (or vice versa depending on design) directly, and you probably get a very high gear ratio (but this too depends on design, based on steady state rotational speeds of both the drive motor, gear motor, and the gear sizes of the planetary setup).

Keep in mind this scenario is if the electrical harness were to completely fail. The more realistic degraded modes are when the battery drains. In this case the design should divert emergency reserve power to control system and gear motor, to keep the gearing control operational in this degraded mode. And remember the ECVT will likely divert human power to recharging the battery as well as for propelling the drive train. And if battery regen is available, rolling back down the grade will put some coulombs back in the battery. Edit: This would not be possible with the current prototypes on display.
 
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Stevedee said:
Just wondering how these would peddle when the battery runs out, do you think there would be a lot of drag? Would they turn into a one speed bike until you recharged?
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Pretty much, you can use one of the motors as a generator to power the gearing but it's likely to feel super draggy in all but the native gear (where the sun is stationary), and even then pretty bad. BUT assistance could be set to taper off as the battery gets low to mitigate this.
 
John_likes_bikes said:
You guys think it rattles?





/s
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Cute. Keep in mind there is no internal clutch to disengage the motor train from the pedal train (i.e. no float). The pedal axle is always connected to planetary system with ECVT. It would just be planetary gear backlash felt, so probably not a future glaring issue.
 
Suns_PSD said:
I think everyone should sort of chill out and just buy their current favorite bike.
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Really ???

The derailleur is the one Achilles Heel of the EMTB. I have broken ribs due to a bent cage, and the bike didn't change gear properly, and didn't climb over a boulder when I put the power down into the pedals, and I got high sided.

There is no way I'm buying a derailleured EMTB, if a good MGU exists.
 
My biggest concern is when hitting big jump lines etc I like to have a very tall gear selected so the pedals hardly move, I understand you can make custom gearing but I wonder how it feels under foot, in the auto setting, spinning at a fast cadence would be a recipe for disaster
 
When on technical trails, I would configure the bike in a 10 speed fixed gears mode, with the entire 500% ratio available. 50% ratio spacing between gears. On adventure rides, I would just use Auto cadence.

This is the beauty of this MGU. You can set the gearbox up for each ride, exactly how you want, just using the App. Something not possible with a derailleur.
 
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G-Sport said:
Rob had the unit in his hand, so it's disappointing (though understandable) that he can't give us a clue on weight. If they can get this down below 3.5kgs then that's great, under 3kg and it will be amazing for bike feel.
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Did we watch the same video? The Avinox rep says the extra weight is completely neutralized by the weight savings of the derailleur system, and you end up with the same bike weight. So just add the weight of an M2S + derailleur system, and you will have the approximate weight of this unit.
I think it’s perfect. No additional weight overall, but the weight is lower, more centered, and lower unsprung mass.

Plyphon said:
I love that on page 1 of this thread we already have a 'manual shifting is better' post. Can't make it up.
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Right?

I was going to order the PR as soon as it was available here in the US, not anymore. Keeping my Trek Rail one more year until this comes out. Thanks Avinox for letting us know in advance!

For the technical trail riding I do in southern Utah with lots of ups and downs where you have to constantly shift up and down under torque, this will be an absolute game changer.

Years ago, DJI killed the drone market. They took competitors completely out (like GoPro who released their drone when DJI released their first Mavic). They will kill the emtb market too. Shimano is dead (their motor is crap, and their derailleur is not needed anymore). Bosch will die if they don’t adapt but they have 1Y to move their butt.
And Specialized, well they can go f*** themselves, selling us $15K bikes for years now, filling their pocket because they had the best motor. At least DJI not only releases the best tech, but also at the best price.

I hate Chinese company that copy Western stuff. But I love companies that innovate, disrupt the market and the few players that were filling their pockets on the back of customers, wherever they come from.
GO DJI!!!
 
The Avinox MGU doesn’t promise to blow up just the e-bike industry, it promises to blow up the entire cycling industry or at least the mountain bike and commuter segments. Derailleurs are exposed, fragile, and inefficient.
 
zerofunds said:
My biggest concern is when hitting big jump lines etc I like to have a very tall gear selected so the pedals hardly move, I understand you can make custom gearing but I wonder how it feels under foot, in the auto setting, spinning at a fast cadence would be a recipe for disaster
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It would feel exactly like your are in a fixed gear; it's just that get to that gear 10 times faster.
 
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