mountain bike-first build...man i am confused

[mountain biker]

first time ever to look up this electronic bicycle thing. it has caught my attention. I used to ride bicycles all the time in japan for transportation. was first experienced with a shimano gear shift system. believed it had 4 four gears.internal hub.... any way... I have looked at a bunch of sites, physics site and the seemingly limited suppliers in the us. seems like everyone just imports Chinese technology...which I am cool with.....I have called about 10 bike shops and most will not deal with any buy a Chinese motor and put it on....seems like price for bike motor etc...is around 1500 with battery for most of these places..i have even offered to pay their 65 dollar hour labor charge for hub motors but they just wanted to sell their bikes they had, however im sure they are better engineered than a typical bike because of e bike. but surely with the help of walmart I can find one that can handle an ebike motor....gut it seems like yo can get twice your value or 4 times your value if you get from the large bike suppliers like (bms...don't me to plug this but they seem to have a great selection but their shipping adds about 100 bucks or so would love to find an American supplier with technical support that adds a stocking fee for working motors etc)..noticed Walmart sells e bikes for 1000 or something but very little technical info on it and seem like we are in the 250 watt max range gearless hub terrirtory.....

I would like to start posting some interesting physic stuff I found out on the interet to help the people who have invested less than 200 hours or so on this ebike thing.


my build....haven't got a bike...but looking at bikes at Walmart to add a hub..want a mountain bike. noticed some have shocks and can be gotten around 200 bucks assemlbled. I have very little bike knowledge.

my fears----fork size so I can put a bike on...if I get an internal hub peddling or cassette type gear mechanism for peddling....does this effect second motor..
so bike selection is crucial...does it have disc brakes does it have v brakes....

looking to add a front hub motor...then later on add a rear wheel drive hub....or add a direct drive type system maybe with hub(the auto double speed drive would make interesting gear ratio)

so front hub is first...looked at q75 q85 q100 q100h magic pie2 smart pie 3 etc.... so confusing...just got an email from xiojang I believe about their 350 watt double speed automatic motor...and juding from threads in here its an 8 to1 and then a 4 to 1 gear ratio....confused about torque. though ......

want to get to 15 just on motor maybe up to 20 with peddling. ideal use motor for 4 to five miles per hour and then I add antother 4 to 5 miles per hour to make a nice easy cruise for me and not draw as many amps from battery.

want to be able to peddle. looking for a long range of 30 miles which seems unheard on...most builds seem to relate to top speed and not as a mode of transportation.
looking at mountain bike as an alternative. because I like the idea of using this thing as a bug out vehicle. first objective must be street legal. I must follow moped rules in my state for ebike(HOWEVER THERE IS SOMETHING THAT SAYS MUST KEEP 20 MPH OR BELOW I THINK ITS TREATED LIKE A 49CC ENGINE I DON'T NEED INSURANCE JUST A VALID DRIVERS LISCENSE..OBVIOUSLLY THE WHOLE EBIKE THING HASN'T KICKED OFF...THE CLOSET BIKESHOP THAT WOULD TALKE TO ME WAS 100 MILES AWAY. so I assume brake light front light etc....confused about turn signal though...however the legalities may not be practiced I just want to be in compliance I will have no problem keeping it under 20 mph. un assisted. and juding from the bicycle physics post I seen it would be pretty hard to exceed that speed if I keep my motor range around the 200 to 500 watt range.

NEED 300 pounds...bike 70 me 180 and then 50 pounds of carrying stuff.
I have played around on the bike simulator and it seems torque doesn't effect it...where am I missing something on the bike simiuluator.

will need bike racks.

batteries would love to desing something that could have folding out bike racks for solar panels...they are proected may get some charge time then fold out and get more power however exposed to envinronment.
tire selection bike model...fat tires seem cool don't know how they will help traction

so confused.....please help you electric bike guru's

looking for a bug out bike....

so lets keep it simple...if that's possible..front hub motor. can pull 300 pounds at 10 mph
h or 250 pounds at 15.
looking at q100h something with torque or those xionag motors with an 8 to 1 to a 4 to 1 gear ratio change seem pretty clever at 350 watts price was about 111 was quote I believe with another 70 bucks worth of electronics controllers... and 70 bucks shipping.

 

[mountain biker]

this was a pretty cool site. I found that gives me some ideas about tire friction and air flow...it seems 15 miles per hour and beyond really require that hp
http://www.endless-sphere.com/forums/posting.php?mode=reply&f=3&t=63691
Bicycle efficiency and power -- or, why bikes have gears.



When you try to determine how fast a bike can go, what you do is you match the power available against the power required, at a given speed. This energy budget indicates whether you can go faster, or whether you can even hold your current speed.


Power available:

A human engine has a torque curve similar to that of a steam engine, more or less, which is to say that it is flat until a certain critical rpm, at which point it begins to drop off, because the energy used in accelerating and decelerating massy components (legs) begins to take up all the energy produced.

Power produced is the product of torque times rpm. (a quick digression: your torque is a product of your leg length, your crankarm length, your wheel size, your gear ratio -- what we're talking about here, though, is torque measured at the crank itself. So the only things that are of issue are leg geometry, crankarm length, the rider's weight, and, most of all -- the rider's leg strength.)

So if we revisit the previous graph to show POWER produced, it will look like this:



This is just the torque curve above, with each point multiplied by the matching rpm. One thing to notice here in comparing this to the previous graph is that your power is still rising even after you've passed the torque peak. You can actually feel this when you're pedalling really fast up a hill -- you feel like you almost can't push on the pedals because you don't have time to, but you're still going like anything.

So we can make a graph showing three different riders and their power curves, like so:

This shows three cyclists: the lowermost curve is the power curve for a beginning cyclist; the middle one for a fairly serious recreational cyclist, and the top one for a track racer. Notice that there isn't much difference in the force they can exert (I'm making some assumptions here -- a beginning cyclist can push 120 lb-feet and peaks at 90 rpm, whereas a serious track racer like Marty Northstein can generate 160 lb-feet at over 175 rpm.)

The point here is that strength is less important than smooth, fast pedalling.


Power Required:

Now, the next subject is: where does the power go?

There are two places: friction and air resistance.


Friction:

Friction losses are from bearings, from the viscosity of grease, from the chain, from the tire squishing against the pavement. Knobby tires are rougher; soft tires smoosh more; heavy grease or badly-maintained and corroded bearings take more force to move.

Estimates of friction losses are between 15% of total power, for a Huffy moutainbike that has had little maintenance, to maybe 0.5% for an Olympic track bike. (The friction losses in powertrains for bicycles are the lowest of any machine, because the speeds are low and the power is low.)

The power required to overcome friction rises linearly with speed.



On this graph, the upper line is an old mountain bike; lower is a nice track bike.


Then there is the huge one, that serious cyclists spend most of their time fighting:


Air resistance.
Drag from the air isn't a big problem at low speeds. However, it has one unsavory characteristic: the force required to overcome air drag rises as the square of the speed. As we saw before, power is force times speed, so the power rises as the CUBE of the speed.



The top/leftmost line is a mountain-bike with wide tires and a rider sitting upright. The middle line is a road bike with a somewhat crouched rider. The bottom/rightmost line is a time trial bike with disc wheels, the rider almost flat and wearing slick clothing to minimize clothing flutter.


The power a human can generate is highly dependent on the duration of the effort. In a four-second burst, a weightlifter might generate 3 horsepower. A world-class cyclist will generate 0.65 hp for a 1-hour time trial -- all-out effort. Most recreational cyclists generate about 0.35 hp for a sustained (2 hour) ride. Consider 1 hp to be the absolute maximum you can generate, and this chart will give you a rough idea of how fast you'll go, depending on your bike. As resistance increases by the cube of speed, the contribution to drag of different things on the bike is variable -- because not everything is going the same speed. At zero speed, the bike might contribute 15% of the total air drag of the system, more if it's a mountain bike. But, the bottom of the bike wheel is always still, right, because it is touching the ground. So the TOP of the wheel must be going twice as fast as the bike itself, and because the power required rises nonlinearly with speed, the bike takes up increasingly more of the drag as the speed rises, which is why reducing spoke count and trying to cover the wheel becomes a big issue at high speeds.

So now we can generate a sum total of power required, by adding the friction losses to the air resistance losses.

The upper line is a Department Store mountainbike -- with lots of friction and an upright riding position. The lower one is a well-maintained racing bike with lots of aerodynamic modifications to try and make it more slippery. As a general truism, on a bike you're mostly fighting rolling friction from the tires below 12 mph.

Above that speed, your power starts going primarily into fighting air resistance. If your bike is particularly friction-prone, with low-pressure tires, the crossover point will be at a higher speed

 

[mountain biker]

http://www.thetoolhut.com/Torque-Conversion-Metric-English.html


torque conversion from inch pounds to NM.....looking at q100h it says 40 NM.so that means. 86 foot pounds....if you look at the foot pounds on chart it says we produce around 140 or 150 foot pounds at start up.... they say power is rpm times torque...so then 25 rpm at 140 foot pounds must produce a 1/4 horsepower.... so then 201 rpm at 86 foot pounds must produce 1/4 horsepower too....

 

[mountain biker]

http://www.thetoolhut.com/Torque-Conversion-Metric-English.html

Torque Conversion Chart Metric to English
This printable torque conversion chart of newton meters to foot pounds is provided by TheToolHut.com

Newton Meters (N-m) Foot Pounds (ft. lbs.) Newton Meters (N-m) Foot Pounds (ft. lbs.) Newton Meters (N-m) Foot Pounds (ft. lbs.) Newton Meters (N-m) Foot Pounds (ft. lbs.) Newton Meters (N-m) Foot Pounds (ft. lbs.)
1 = 0.7 32 = 23.6 63 = 46.5 94 = 69.3 125 = 92.2
2 = 1.5 33 = 24.3 64 = 47.2 95 = 70.1 126 = 92.9
3 = 2.2 34 = 25.1 65 = 47.9 96 = 70.8 127 = 93.7
4 = 3.0 35 = 25.8 66 = 48.7 97 = 71.5 128 = 94.4
5 = 3.7 36 = 26.6 67 = 49.4 98 = 72.3 129 = 95.1
6 = 4.4 37 = 27.3 68 = 50.2 99 = 73.0 130 = 95.9
7 = 5.2 38 = 28.0 69 = 50.9 100 = 73.8 131 = 96.6
8 = 5.9 39 = 28.8 70 = 51.6 101 = 74.5 132 = 97.4
9 = 6.6 40 = 29.5 71 = 52.4 102 = 75.2 133 = 98.1
10 = 7.4 41 = 30.2 72 = 53.1 103 = 76.0 134 = 98.8
11 = 8.1 42 = 31.0 73 = 53.8 104 = 76.7 135 = 99.6
12 = 8.9 43 = 31.7 74 = 54.6 105 = 77.4 136 = 100.3
13 = 9.6 44 = 32.5 75 = 55.3 106 = 78.2 137 = 101.0
14 = 10.3 45 = 33.2 76 = 56.1 107 = 78.9 138 = 101.8
15 = 11.1 46 = 33.9 77 = 56.8 108 = 79.7 139 = 102.5
16 = 11.8 47 = 34.7 78 = 57.5 109 = 80.4 140 = 103.3
17 = 12.5 48 = 35.4 79 = 58.3 110 = 81.1 141 = 104.0
18 = 13.3 49 = 36.1 80 = 59.0 111 = 81.9 142 = 104.7
19 = 14.0 50 = 36.9 81 = 59.7 112 = 82.6 143 = 105.5
20 = 14.8 51 = 37.6 82 = 60.5 113 = 83.3 144 = 106.2
21 = 15.5 52 = 38.4 83 = 61.2 114 = 84.1 145 = 106.9
22 = 16.2 53 = 39.1 84 = 62.0 115 = 84.8 146 = 107.7
23 = 17.0 54 = 39.8 85 = 62.7 116 = 85.6 147 = 108.4
24 = 17.7 55 = 40.6 86 = 63.4 117 = 86.3 148 = 109.2
25 = 18.4 56 = 41.3 87 = 64.2 118 = 87.0 149 = 109.9
26 = 19.2 57 = 42.0 88 = 64.9 119 = 87.8 150 = 110.6
27 = 19.9 58 = 42.8 89 = 65.6 120 = 88.5 151 = 111.4
28 = 20.7 59 = 43.5 90 = 66.4 121 = 89.2 152 = 112.1
29 = 21.4 60 = 44.3 91 = 67.1 122 = 90.0 153 = 112.8
30 = 22.1 61 = 45.0 92 = 67.9 123 = 90.7 154 = 113.6
31 = 22.9 62 = 45.7 93 = 68.6 124 = 91.5 155 = 114.3
Conversion Formula: Newton Meters x .73756 = Foot Pounds.
print chart button

 

[mountain biker]

Falco’s classic line retails from $1295 (250W) to $2195 (750W). Falco is offering an introductory price of $695 to the early adopters of the Falco Fusion Sports Drive at their Kickstarter campaign.

left a voicemale on phone number. looks like a nice websit....torque 40nm for 500 watt 750 was 60 nm ....but man they look awesome. a lot of smart features.... like their look and webpage but wondering about the price tag...

 

[chisixer6]

mountain biker;

look here..... http://www.electric-bike-kit.com/hill-topper.aspx

all you need is a good bike plus this kit, look at the video, it took me 30 minutes to assemble because I had to get the little fatter axle to the fork. tis was my intro to ebiking and loved it since, got 6 ebikes now, of various kinds of config. talk to you a little later.

 

[MadRhino]

my build....haven't got a bike...but looking at bikes at Walmart to add a hub..want a mountain bike. noticed some have shocks and can be gotten around 200 bucks assemlbled. I have very little bike knowledge.

A good MTB shock alone cost much more than 200$. If you plan to be a mountain biker, you need to start looking elsewhere than Wallmart for bikes. They sell whole bikes cheaper than a good front brake, but they are not real MTB, only BSO (bike shaped objects) that can kill you at first jump.

 

[mountain biker]

hey I appreciate that....yeah, I do get the romantic notion that I can drive twenty miles per hour down some dirty road hit a sharp incline of like 10 degrees and think I can magically fly for afew feet....however the reality that may be my last ebike ride.lol....okay...I was looking at the double shock system on the above mentioned Walmart bike....so I see the relity is I am basically just looking at mountain bike styles than actually mountan bikes.... can you give me some ideas of brands that Walmart or kmart might cary that are cheap and I could apply a xiogdang 2 speed electric front hub motor on.

you mentioned die on first jump what do I need tolook out for...how do I judge forks etc...I am assuming you mean the bike is unable to be landable or maybe something elese..please feel me in..and I appreciate everything you got. totally new here and

its not easy looking at all these motor options, first getting used to sticker shock on prices of batteries...confused about batteries...(man even looking at mppt type charge systems for lifepo4....for solar. basically laptop size giving out 15 watts at noon. give me 20 or 30 hours to charge...like two or three days...fo 36 volt 10 amp...

or more approiately a motor with a lot of torque..noticed the q75 had a low ratio of like 13 to 1 and the q 100 had 12 to 1 ratios I think the q75 was 200 wats...the q100 was like 300 watts....any low gear ratio motors that could get me up a hill?

 

[dogman dan]

BSO is fine for a bike that will only ride street, or moderate dirt roads. Look for the ones with a rocker attached to the shock. they make the cheap shock work much better. But be aware that the frames on these bikes are weak, and 2000 miles can wear the frame out. Typical riders never wear out the original tires, that last only 500 miles.

DONT go with a cheap lower power front hub kit. Get a decent rear hub. Mac, BMC, or equivalent. Or a direct drive will work.

You need 1000w at least for what you want to do, so it's 48v, and at least a 22 amps controller you need.

Graphs are great, but I got what I'm recommending from doing the ride for 10,000 miles. 1000w will get your 300 pounds down the road, and with pedaling, up hills that are 5-8% ok.

You won't climb 10 degrees with cargo, but a short 10 degree hill can be done with hard pedaling.

Hub motors under heavy loads up hills can't go 5 mph. You have to pedal up to 12-15 mph at least up the hills or they overheat. This will be easy with 1000w. On the flat, using only 200w or so, you can go slow as you want.

There are lower rpm hubmotors, so look for one of those if you really want to ride only 10-15 mph. Google trike kit.

 

[d8veh]

hey I appreciate that....yeah, I do get the romantic notion that I can drive twenty miles per hour down some dirty road hit a sharp incline of like 10 degrees and think I can magically fly for afew feet....however the reality that may be my last ebike ride.lol....okay...I was looking at the double shock system on the above mentioned Walmart bike....so I see the relity is I am basically just looking at mountain bike styles than actually mountan bikes.... can you give me some ideas of brands that Walmart or kmart might cary that are cheap and I could apply a xiogdang 2 speed electric front hub motor on.

you mentioned die on first jump what do I need tolook out for...how do I judge forks etc...I am assuming you mean the bike is unable to be landable or maybe something elese..please feel me in..and I appreciate everything you got. totally new here and

its not easy looking at all these motor options, first getting used to sticker shock on prices of batteries...confused about batteries...(man even looking at mppt type charge systems for lifepo4....for solar. basically laptop size giving out 15 watts at noon. give me 20 or 30 hours to charge...like two or three days...fo 36 volt 10 amp...

or more approiately a motor with a lot of torque..noticed the q75 had a low ratio of like 13 to 1 and the q 100 had 12 to 1 ratios I think the q75 was 200 wats...the q100 was like 300 watts....any low gear ratio motors that could get me up a hill?

The Xiongda is the only smallish motor that can climb steep hills because of its low winding speed and low internal gearing. It's wider than most motors, so it would be best if your donor bike has a steel rear subframe because steel is much easier to stretch than aluminium. Also, it saves a lot of messing about with torque arms. Use a magnet to check whether the frame is steel. The ideal is a aluminium main frame with a steel sub-frame. It's almost impossible to put a front Xiongda motor in suspension forks.

Here's my Xiongda bike, which was very cheap. I changed the bottom bracket for a cartridge one and the brakes to Avid Elixir hydraulic ones. Both of those changes are necessary on cheap bikes rather than desirable. Make sure that your donor bike has at least the mounting points for disc brakes.

 

[dogman dan]

More data on that Xiongda would be nice, I haven't seen that one before. (can't read every thing here)

Links to where you buy it, links to threads on it.

What are you running it on? What voltage and amps controller?

Can this motor handle 300 pounds up a steep hill? I still think regardless of winding, another 50 pounds of cargo is going to take 1000w minimum.

Not mentioned so far, the bafang mid drive. There's your real solution for grinding up a hill slow. I just haven't been able to destruct test one yet myself. I can't afford to buy motors just to smoke em.

 

[mountain biker]

hey thanks for the heads up on front suspension frame mounting. really impossible.....but you said almost....how would you do it? also a lot of bikes I have seen at Walmart have the same look as yours but a bunch of them have vbrake or rim brake type set up....if I take out the disc brake and put vbrake or rim brake up front would that work? thank you for all your help.

there is a thread called double speed motor. in general bike discussion and there is also a thread in technical... and man there is a lot of info on the motor. I think you would be happy with all the info the posters have put up.

im new to forum so I don't know how to post the url or things but man you would be happy.

also looking at sailboat winches...seem they are 20 pounds..or so...but like 600 dollars...for about 300 pounds of winch and also small deep sea boat fishing type winches... the atv winches have 1500 pound...pulling nice but that would snap my bike probably... but weight is 33 pounds or something....looking online..

but picking up a lot of info on forum here....putting in auxiliary cigarette jacks for such devices. running step down convertors dc to dc from battery...maybe even running off leads from the new Chinese controller for the double speed motor.....thank you forum and posters

 

[mountain biker]

I was dreaming front wheel because of easiness.....but man you are going to challenge me now....it makes more sense on back wheel...wow...would that change the number of my gears...cassette?

 

[dogman dan]

Not on a cheap bike, they will be 7 speed, and most bike motors come stock with a 7 speed. 9 speed screw on freewheels do exist though.

Build your first bike with the cheap MTB, but just don't expect top performance from it. A fork upgrade to one of these, will result in a bike that can handle very rough trails, but that can come later. The stock fork will just bottom out all day on a really rough road or trail. You can still trail ride it, it just will jar your elbows a lot.



http://www.walmart.com/ip/Mongoose-Status-2.4-Mountain-Bike/23891018

This one is "adequate" It will have a slightly better crank and front chainring, and the front shock might be slightly better than in the under $200 class bikes. The main feature you want is the rocker on the rear shock. This will feel a lot better with a cheap shock than one without the rocker. It's possible to upgrade the rear shock too, but better bang for the buck to shop for a better bike, used later on.

 

[mountain biker]

I appreciate that....I was just on the double speed web site..they said the new double speed is coming soon????what do they mean? and man they have a silly video on you tube promoting this double speed motor...some dude is biking up a hill peddling a little and I presume his budy is struggling behind..he waves at him like come on you can do it...next scene his buddy looks like he is having a heart attack..wobbling around on the bike and the double speed motor guys just laughs and smiles and hits his throttle and starts peddling up a steeper hill....kind of a v pattern attack on the road...45 degrees one meter left then 45 degrees one meter right.... that was cool...but isn't that a human rights violation, leaving someone who might need medical help behind???also those hills seemed ridcuaouslly steep...I don't have an ebike but they looked pretty intense..noticed they never showed the dudes gear ratio in the video...so this could of been a specially made bike....either way I am sold on the double speed....it sounds cool and a lot of people like it...the first gear rushing to use less amps is a pretty cool concept....

thank you guys for everything....

 

[d8veh]

More data on that Xiongda would be nice, I haven't seen that one before. (can't read every thing here)

Links to where you buy it, links to threads on it.

The Xiongda is a two speed motor that changes its internal gear by reversing. It can haul 130kg up a 14% hill without pedalling even though its very small. All the info is here if you have time to read it:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=58490
http://endless-sphere.com/forums/viewtopic.php?f=2&t=59369&hilit=xiongda

 

[dogman dan]

Thanks for the links. Sounds cool, an actual second gear inside, not just a two winding like the old clytes.

Will be reading it, but at 200w, does it really work well with 300 pounds? That's what this guy is talking about. I've no doubt it can haul 200-250 pounds up a hill with the lower gear.

Two of them would make a bad ass hill bike!

 

[MadRhino]

Climbing steep with a small 200w motor, you can only do it very slowly or a very short time.
Climbing requires power, climbing steep and fast requires a lot of power
Riding back down steep and fast requires a very good bike.

Don't dream, there is no wallbike with a 200w motor that is gonna make a good mountain ride.

 

[mountain biker]

hey I appreciate that...yeah I was looking at a bike someone suggested,,it looks pretty cool...it seems the high end of Walmart side..anything over 129.99 seems highedn on the bike section there...yeah I guesse I am looking for something that can do 10 miles or so max on offroad....I guesse my ground cleareance from sprockets derauler is only about 7 inches on most of these things...
http://www.walmart.com/ip/Mongoose-Status-2.4-Mountain-Bike/23891018

http://www.walmart.com/ip/35206176
http://www.walmart.com/ip/35206176

but reading those reviews on the 2.5 they seem like the bike is dodgy...man so much second hand info all word of mouth...

or something from the mongoose line...I don't know..they were cool as a kid and they seem to be a standardized company and if I needed parts I could probably get one.

 

[mountain biker]

yeah I am not looking to go over 20 or so or rough road...is that even possible on the above mentioned wally world bike? I don't think according to the posters who have the double speed motor believe that is even doable on a 36 volt system unless you put a lot of pedal power to it...I think around 15 seems top unassisted. with mtb tires.
I like the idea of going to wally world simply because they will ship it to my house or I pick it up and if I got issues I can return it. this is just my first build... so just learning the ropes so to speak right now on it...

what kind of speeds would you recommend and what is capable of a bike like this done safely... probably 20 miles per hour on flat land or maybe 25 is okay on it right?

 

[dogman dan]

That's about right, even up to 30 mph can be fine for the cheap disc brakes on those.

The real issue with these bikes is the poor front shock will bottom out when riding fast off road, and the weak frames develop a tendency to go into high speed wobble. This " high speed" wobble can happen at 15 mph on a weak enough frame.

Put power into perspective, a medium strong rider ( who can pedal 200w for 30 min or more) on a very low geared mtb can grind up very steep hills in 1st gear. At 3 mph. this is too slow for hubmotors, and your lowest gear on a wallbike will be about 8 mph. They are in fact, built for street or very mild off road.

So 250w on the xionga, plus your 200 or so, can be enough to grind up some very steep hills. It's just not nearly as fun as blasting up the same hill with 2000w, perhaps not even bothering to pedal. Once you power up to this level, you really do need a better, stiffer frame, and much better shocks.

I still advise this. Get a 1000w motor, preferably one of the larger planetary gear motors. Get a Mac 10t, similar BMC, or I sell one too. Up to you to hunt down which US based company I work for.

Run it at 48v. This will do great on the street, very efficient in stop and go urban riding, and it will get up steeper hills good enough to ride trails that cheap bike can still tolerate.

Screw the 250w. That's for Europe or other places not allowed more power. Or those that only want 250w for whatever reasons.

 

[teslanv]

I'm a Bafang BBS02 fan. I love the balance & weight distribution of the mid drive and its mule-like ability on steep hills.
Read my signature thread for more info.

 

[d8veh]

Just to make it clear, the Xiongda can still make good power at 3mph because of its low internal gearing. It's like a winch winching you slowly up the steep hills. Mine took me (total 130kg) up a 31.5% hill with steady pedalling in bottom gear. My friend riding next to me melted the phase wires on his bike.

 

[markz]

Hey bro, there is a community bike shop in my area here in Canada. They have people giving away bicycles to this shop because they are doing a good deed to our community. The city alone is a million, but its a very rich city. People throw away expensive strollers because of a bit of rust or flat tire. The average crappy bike at the bicycle community store is $50, decent is $100 and above. I personally have gotten very nice bikes from that store, that needed a bit of work for around $100, if not free sometimes. On the other hand I have found nice bicycles laying around train stations and in back alleys, with minor (to me) problems, such as broken or missing rear derailleurs, chains, flat tires. I can do any repair on a bike with a bit of google search and youtube video watching. On that note I did replace my digitizer (screen) on my cell phone for $20, where the cell phone repair shop wanted $80. I guess I could have done the same for unlocking it. On that same note for vehicles (cars, trucks) if you repair them yourself, invest in tools and repair manuals, you save thousands if not millions of dog-hairs (dollars, pesos, euros, rubles). That goes to show you that if you spend time researching and digging around, you will get a way better bike then some crapola from CrappyMart!

Will those Bafang be good for like 300 pound rider with mtb? Whats the weight difference between that crank style setup and the dd hub?

 

[mountain biker]

this is from the mongoose official sight...but it doesn't tell me how many diameters the drop outs are right...it does tell me rear is steel and front is an allumnim alloy....I sent an email from the website but they have unanswered questions posted on there from over 3 years or so....very werid.
Bottom Bracket: 5 piece bottom bracket
Shifters: SRAM MRX twist shifters
Cog Set: 7 spd 14-28
Chain: KMC Z-51
Front Derailleur: MTB
Rear Derailleur: Shimano TZ-30
Wheel Size: 26"
Rims: Alloy
Front Hub: Alloy Disc hub
Rear Hub: Steel
Tires: 26 x 2.1 MTB
Pedals: Resin body
Handlebar: MTB riser bar
Stem: MTB stem
Headset: Threadless
Brake Levers: Alloy/resin lever
Crankset Chainwheel: 3-piece alloy crank
Spokes: Steel
Grips: Kraton
Saddle: MTB Saddle
Seat Post: Steel
Seat Clamp: Quick Release
Extras: Kickstand