MXUS 3KW HUB - FRAME OPTIONS

I'm looking at building a second ebike to replace my hardtail, I'm running a 48v 17.5ah battery, a 35a controller and 1500w hub.

My next build I'm going to run a 72v 20ah capable of 60a continuous with a 60a controller and MXUS 3kw rear hub.

It must be a full suspension and not the enduro ebike type frame. The MXUS is considerably fatter than my current little hub and specs say I'd need 142mm dropouts. I don't trust this and think I'd probably require 150mm after seeing some videos.

Anyone have experience with this hub? Any full suspension recommendations? I've seen Vortecks on YouTube fit one to a Voodoo Canzo 19" frame which I believe has 157mm rear dropout.

Are there any other donor bike options?

There are too many options to list here. There are threads already filled with suitable fs frames.

Ideally, you need a Downhill bike because most of them have a swing arm wide enough, and they are equipped with good suspension and brake components. Preferably, it will be an old one because they are very expansive when new, and recent DH bikes are not as robust as older ones.

MartyMcfly1 said:

Anyone have experience with this hub?

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Lots. Most of the references to MXUS in posts in the last several years refer to this series of motors, so a search on MXUS will bring you lots of information, most of which will be relevant to this motor.

Sometimes its' called "3kw", whcih is only true in a 20" wheel--in a bigger wheel its' really about 2kw; see the main MXUS 3Kw v1 v2 v3 thread for one discussion on that. And I think 3Kw is more like a max it can handle, rather than what it can do all day long without sweating.

Sometiems it's called the 450x series, where the x is the winding number.

Sometiems it's called the XF40-45H series (referring to the number on the cover).

Personally, with two of them in different versions, I think they suck, build-quality-wise. Shorted windings to stator laminations, easily-broken axles, bearing issues, hall sensor issues, etc, and I'm not even using them nearly to their rated power levels, and have never overheated them (not even close). :/ (neither did their previous owners)

I'd much rather use a QSMotors QS205 50H for 3Kw, because it can do that all day long and ask for more. QSMotors build quality is better than MXUS, from all the internal pics I've seen posted of either, plus my own personal experiences of each. The 205 I have here is used, from someone else that broke the axles off after using at several times it's rated power with poorly-mating torque arms. So I don't hold that against it. :lol:

MartyMcfly1 said:

My next build I'm going to run a 72v 20ah capable of 60a continuous with a 60a controller and MXUS 3kw rear hub.

It must be a full suspension and not the enduro ebike type frame.

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If you give us full and complete detailed information on your intended usage, riding style, required range at required speed, terrain, weather, riding conditions, etc., we can better help you pick the parts you need to do the job you want the bike to do.

Otherwise you're going to get recommendations that suit(ed) the people that recommend them, but may not suit your needs.

Amber, what do you mean the MXUS is only 2kw on larger wheels?

If I'm feeding 72v at 60A, that's 4,320w regardless of wheel size? On a smaller wheel it would have quicker acceleration of course and lower top end speed...but it would still draw the same wattage?

I've found a hardtail to be a bit of a bone shaker at speeds and I'd like rear suspension to help with comfort. I don't go offroad and I am content with hub drive.

Any suggestions are welcomed, as I'm finding it difficult to find a frame which has ample space to mount a battery + tucked away shock + correct dropouts for hub + rear dropouts wide enough width.

I did search to help me find suitable options, but most people have these on the enduro bike/ stealth bomber style frames. Can't find any others.

motors are rated for continuous power. We can feed them many times that rated power for short acceleration bursts, but the continuous power demand must be kept within rated limits. The larger the wheel, the less a motor has a chance to dissipate the heat and the more power is required for equal speed/load, thus we have to be conservative with large wheels, and higher power can be fed to a motor that is laced in a small wheel.

I agree that a QS205h50 can be fed much higher power than a Muxxus 3k even though their rated power is the same. The difference is in the testing procedures of those manufacturers, because motors are not tested by an independent lab in China.

Check for Downhill bikes 2002 to 2010, preferably with bolt-on dropouts. They are the stiffest and the easier to build. Forget about frame triangle space, because the best frames to build have none. They have a big shock right in the middle of a very small triangle. Then batteries must be mounted outside of the triangle: down tube, top tube, fork crown...

Here is a frame that I like very much for an example. I have built my best ever street bike on it:

MartyMcfly1 said:

Amber, what do you mean the MXUS is only 2kw on larger wheels?

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Can overheat if run higher continously. Check the mentioned thread, it has some discussion (there's ohter places too).

If I'm feeding 72v at 60A, that's 4,320w regardless of wheel size?

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The actual power drawn will depend on actual conditions and any other system limitations, but if you have a controller with a 60A max current limit, that is on a 72v (average) battery, then that's the average max wattage it would be able to provide, yes.

On a smaller wheel it would have quicker acceleration of course and lower top end speed...but it would still draw the same wattage?

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I recommend going to http://ebikes.ca/tools/simulator.html and reading the entire page so you know what everything is and how to use it. Then setup the same system with different wheel sizes, and use them under conditions that will draw max power, and look at the overheat times on each (lower right corner of chart below the graph). You can see how wheel size and other conditions will affect the abilty of a motor to handle a certain amount of power.

I've found a hardtail to be a bit of a bone shaker at speeds

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What speeds, under what specific conditions, with what riding style?

I ask because each of those things changes what you can / should do to fix the problem.

The reason I asked for detailed info before (which hasn't been provided yet) is to help you solve the problems and make a bike that does what you want it to do.

It will be on flat terrain, which can be bumpy, which is why I want full suspension. Larger tyres and reduced pressure doesn't cut it. I haven't opted for a sprung seat post either.

I'd like the battery inside the frame, it will be a triangle battery. I don't mind mounting the controller outside of the frame.

Range required, 10-15 miles at most.

Weather conditions - dry.

Speed - 30mph average. With the ability to reach high 40's.

Any frame suggestions with wide rear dropouts? If you can link me to any threads etc where someone has mounted a MXUS 3kw into a full suspension frame that would also be appreciated.

Edit: would a Giant Trance / Giant Anthem fit a mxus 3k? Difficult to find axle spacing online...

Well, this post may be missing some details vs the long version I just lost when Jelly pawed the back button on the keyboard trying to let me know she's very neglected.

Let's try again now that she's happier:

MartyMcfly1 said:

It will be on flat terrain, which can be bumpy,

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What does "bumpy" mean in this case, exactly? If it's a paved road with multi-inch deep potholes and/or asphalt waves inches high from the cars/trucks braking and accelerating, it's going to need a much better suspension than a few small rocks or sticks laying in the road or on a paved or even gravel bike path.

I'd like the battery inside the frame, it will be a triangle battery. I don't mind mounting the controller outside of the frame.

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I haven't seen many good-suspension bikes that have a useful triangle space--most of them use the triangle, or a significant part of it, for some of the suspension components (or they just use a narrow-shaped frame, or curved, etc).

Range required, 10-15 miles at most.

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At what speed, and riding style/conditions? It takes more power to go faster, or to acclerate quickly, climb hills, repeatedly stop/start in traffic, etc. A battery that may get you 15 miles with typical pedal speeds and bike path conditions may only get you 5 miles at car speeds in traffic.

Speed - 30mph average. With the ability to reach high 40's.

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With a heavy hubmotor wheel instead of a light bicycle wheel, many (most? all?) bicycle suspensions won't react nearly as fast, so faster speeds are going to be a harsher ride. Tunable suspensions will help, it might require replacing the shock(s) that come with the bike to make it good. MadRhino would be the one to help with that.

Any frame suggestions with wide rear dropouts? If you can link me to any threads etc where someone has mounted a MXUS 3kw into a full suspension frame that would also be appreciated.

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If you only want bicycle-looking bicycles, its' a tougher look. Even tougher since the wider stuff is probably not using the typical 10mm axle that hubmotors need dropouts for to mount in, so you end up having to make torque plates to bolt to the existing dropouts to actually hold the axle. (the actual dropouts are likely for thru-axles and the like, which wont' work with the average hubmotor).

This post
https://endless-sphere.com/forums/viewtopic.php?f=3&t=108852&p=1593116&hilit=MXUS+3kw+full+suspension+frame#p1593116
says this:

My hub bike is a specialized big hit with a mxus 3kw motor and 2" of wheelbase extension in the custom dropouts.

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so there's one frame it will fit in...but I dont' know what year he used, or what his custom dropouts look like so you can make some.

Edit: would a Giant Trance / Giant Anthem fit a mxus 3k?

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There's some stuff about the anthem in these posts
https://endless-sphere.com/forums/search.php?keywords=Giant+Anthem+mxus&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
but I haven't read them all. This one
https://endless-sphere.com/forums/viewtopic.php?f=3&t=96133&p=1409439&hilit=Giant+Anthem+mxus#p1409439
says

If I was to use the Mac 4kg motor or a 2-3 kg motor I would look for a Anthem,
However
If I had the DD MXUS 3000 I would get a Giant Trance / Glory / Reign , instead of the Anthem.

Do you have the MXUS laced into a 26 inch rim ?

Other options are the Specialized Enduro , Big Hit , Demo 8 , FSR .

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This thread talks about a pretty old anthem
https://endless-sphere.com/forums/viewtopic.php?f=6&t=43388&p=702489&hilit=Giant+Anthem+mxus#p632834

Difficult to find axle spacing online...

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If it helps, the official term is OLD (Over Locknut Dimension); sometimes called dropout spacing.

Oh, and here's the big MXUS 3kw thread if it helps any
https://endless-sphere.com/forums/viewtopic.php?f=2&t=92101

MartyMcfly1 said:

Edit: would a Giant Trance / Giant Anthem fit a mxus 3k? Difficult to find axle spacing online...

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The Giant website is a good source for specs, but hard to navigate. What year are you looking at? Earlier models have 26" wheels, but they moved to 27.5 and 29. Dropout spacing vary as well (older quick release with 135mm and 142mm spacing, before switching to thru axles and 145mm+). I've been thinking about an Anthem with a MXUS 3kW, but something in the 2012 vintage, with the straighter tubes to fit a triangle pack, but likely a single speed freewheel so it can fit into 135mm. I don't need high speeds, but like hard acceleration, so it should work fine for my riding. If you're riding over high speed bumps, the shock is going to pack up with that amount of weight.

https://www.giant-bicycles.com/us/anthem-27dot5-3-2014

Every major bike manufacturers are listing dropout spacing in their DH frames spec, or the rear hub that is coming with the complete bike. Older frames are almost always 150 mm, very old prior 2000 were 135, and very recent ones are back to 135 mm. They had been near standard 150mn tru-axle for 15 years at least. Don’t count that a hub motor axle will fit the bike dropouts, you need to make custom dropout plates for a proper build with any powerful hub motor anyway.

Large triangle space is about sure to be on frames that have poor suspension design for a big hub motor. They are more suitable for lighter hubs, or BB drives. Best frames for heavy hubs have a high pivot (or virtual pivot linkage) swing arm with low shock/travel ratio. Old DH bikes are compact design, you need a Large frame ideally. Old DH bikes in good condition can be found for about 1000$, bikes that were 5 to 8 k$ when new.

I'm starting to think maybe I should get a MXUS hub with longer axle and mount it on a fat bike. The MXUS usually comes with a wider rim for 2.5-3.0 tyres anyway and I guess bigger tyres is kinda like suspension in a less mechanical sense. Never rode a fatbike though.

So far the best frame I've found which is full suspension and has dropouts large enough and a frame triangle large enough is a 2011-2012 Voodoo Canzo. Which appear to be quite rare.

Depends how fast you want to ride. Fatbikes are not made for speed. Batteries in the triangle are a common obsession, hence the box frames that are popular. I find the frame triangle is not the ideal place for batteries. I fit the controller there. I prefer batteries to be quick-release cases or bags.

You better rent a fat bike for a few days and do a lot of riding before you pull the trigger and buy a fat bike.
Full suspension fat bikes are out there but they are expensive.
Its more common to find front suspension rigid frame fat bikes.
4" tires has a bit of cushioning because of all the air in the tire, depending on the psi of the tire.

MartyMcfly1 said:

I'm starting to think maybe I should get a MXUS hub with longer axle and mount it on a fat bike. The MXUS usually comes with a wider rim for 2.5-3.0 tyres anyway and I guess bigger tyres is kinda like suspension in a less mechanical sense. Never rode a fatbike though.

So far the best frame I've found which is full suspension and has dropouts large enough and a frame triangle large enough is a 2011-2012 Voodoo Canzo. Which appear to be quite rare.

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MartyMcfly1 said:

I'm starting to think maybe I should get a MXUS hub with longer axle and mount it on a fat bike...
So far the best frame I've found which is full suspension and has dropouts large enough and a frame triangle large enough is a 2011-2012 Voodoo Canzo. Which appear to be quite rare.

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You don't need exotic dropouts for multi-kW power. XOFO DD45 w/ 45mm stator fits standard 135mm dropouts with a single freewheel.

MartyMcfly1 said:

The MXUS usually comes with a wider rim for 2.5-3.0 tyres anyway and I guess bigger tyres is kinda like suspension in a less mechanical sense.

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While true, the problem is that ebike tires aren't available in fat sizes. I've only seen up to 27.5 x 2.60 or 27.5 x 2.80

You may have more options if you just put a single gear on the rear and get rid of the cassette as you only going to pedal when it breaks down in any way.
as I don't know what gear combo you would need to pedal at 40 to 45 miles an hour. 64t/11t ?

Does anybody besides MXUS make an ebike motor that has a stator wider than 35mm and that will fit in a bike with 135-142mm dropouts?

A single speed freewheel is OK.

Thanks

QSmotors makes the QS205-50H (much better than the MXUS in build quality). The axle is not welded in, so even if you find they cant' supply you with a version of the motor with the right sshoulder width, then you can have the one it comes with modified to fit (or just have a whole new one made). It may also require modifying the side covers (or having new ones made), if QS can't supply it in the width you need.

The casing is wide enough you might indeed be stuck with a singlespeed freewheel, though.

This is the 150mm version
https://www.amazon.com/QSMOTOR-Bicycle-Dropout-Brushelss-Permanent/dp/B085NGCYCL
http://www.cnqsmotor.com/en/article_read/QS%20Motor%203000W%20205%2050H%20V3I%20E-Bike%20Spoke%20Hub%20Motor%2072V1120RPM/1213.html
https://ae01.alicdn.com/kf/H3e09ba191d874cf38032b4d9f52a8f12a.jpg



They also make the QS273 40H motor that's not as wide a stator as the 50H (but more than 35):but it says it's still 152mm dropout width.
http://www.cnqsmotor.com/en/article_read/Quanshun%20Motor%203000W%20-%204000%20Watt%20273%2040H%20V3%20DC%20Brushless%20Hub%20Motor%20For%20Bike/833.html

amberwolf said:

QSmotors makes the QS205-50H (much better than the MXUS in build quality). The axle is not welded in, so even if you find they cant' supply you with a version of the motor with the right sshoulder width, then you can have the one it comes with modified to fit (or just have a whole new one made). It may also require modifying the side covers (or having new ones made), if QS can't supply it in the width you need.

The casing is wide enough you might indeed be stuck with a singlespeed freewheel, though.

This is the 150mm version
https://www.amazon.com/QSMOTOR-Bicycle-Dropout-Brushelss-Permanent/dp/B085NGCYCL
http://www.cnqsmotor.com/en/article_read/QS%20Motor%203000W%20205%2050H%20V3I%20E-Bike%20Spoke%20Hub%20Motor%2072V1120RPM/1213.html
https://ae01.alicdn.com/kf/H3e09ba191d874cf38032b4d9f52a8f12a.jpg
H3e09ba191d874cf38032b4d9f52a8f12a[1].jpg


They also make the QS273 40H motor that's not as wide a stator as the 50H (but more than 35):but it says it's still 152mm dropout width.
http://www.cnqsmotor.com/en/article_read/Quanshun%20Motor%203000W%20-%204000%20Watt%20273%2040H%20V3%20DC%20Brushless%20Hub%20Motor%20For%20Bike/833.html
HTB1lH8AomBYBeNjy0Feq6znmFXap.jpg_.png

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Thank You Very Much for the info and the links .

MartyMcfly1 said:

I'm starting to think maybe I should get a MXUS hub with longer axle and mount it on a fat bike. The MXUS usually comes with a wider rim for 2.5-3.0 tyres anyway and I guess bigger tyres is kinda like suspension in a less mechanical sense. Never rode a fatbike though.

So far the best frame I've found which is full suspension and has dropouts large enough and a frame triangle large enough is a 2011-2012 Voodoo Canzo. Which appear to be quite rare.

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Schwalbe lists a 26" fat tire as ebike certified for 25 kph...but that is only about 16 mph. The Schwalbe Pick-Up, Super Moto-X, and the Maxxis Hookworm are the three best ebike tires IMO so I'd work backwards to get the correct size rim to use one of those three tires IF you run a bicycle rim. You can go with a moped rim and use it on a bicycle with moped tires...a better choice than a bicycle tire if you plan on running over 30 mph. The best ebike tires are rated for 50 Kph/32 Mph.

Regarding the allowable power for different rim diameters...the tire diameter determines the final gearing so a large diameter is geared higher than a small diameter. The higher you gear your bike, the harder the motor has to work to accelerate you and the bike so a large diameter rim is more likely to overheat your motor than a small diameter rim. Just a tidbit...for a given motor, ALL windings (Kv ratings) are capable of the same torque output per battery amp. There is no such thing as a torque winding or a speed winding...they all have the same torque capability for a given motor design if fed the same battery amperage...that always stirs up some discussion :lol: .

Different kv (9kv and 13kv for example) motors will have different torque from stand and in low speeds. Never forget that besides theory there is practice. No matter what people say.. if you want better torque and efficiency in low speeds than low kv, and chasing dynamics in higher speeds high kv - 13kv for example.

mxus only if you are going to use light ebike, if near or over 50kg than qs205v3 hands down unless yourself very light weight.

Then why do the two DD45 motors with the only difference being the Kv have the torque output lines on top of each other in this simulation?

https://ebikes.ca/tools/simulator.html?motor=XF_DD45_4T&batt=B5220_GA&cont=C40&hp=0&cont_b=C40&motor_b=XF_DD45_3.5T&batt_b=B5220_GA&hp_b=0&bopen=true

They don't, one looks more torquey and the other more speedy. :wink:

They have the same torque output from about 5 to 40 kph.

The differences below 5 kph and above 40 kph are due to:

A. On the low rpm range, the controller limits the phase amperage for the higher Kv.

B. On the higher rpm, the differences are because the slower Kv is approaching its top speed.

Between they are the same...except for the tiny differences due to losses.

If I increase the controller allowable phase amperage, they are the same from 0-40 kph:

https://ebikes.ca/tools/simulator.html?motor=XF_DD45_4T&batt=B5220_GA&cont=cust_35_200_0.03_V&hp=0&cont_b=cust_35_200_0.03_V&motor_b=XF_DD45_3.5T&batt_b=B5220_GA&hp_b=0&bopen=true