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This hub puts out 48 N-m though it’s for rear drive but almost enough to crack the aluminum dropouts in the earlier graph with no torque arm...

“Torque: 48 N.M; Max speed: 34mph”




 

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Another big fan of the mid motor TSDZ2, put one on a very cheap Muddy Fox 26 mountain bike with upgraded wheels . Now done 2500 very tough miles without a problem, much of it through mud. The TSDZ2 feels controllable and natural. My recommendation would be a minimum of 48v 500w, 750w would be better. PSWPOWER website is a good cheap source of motors and batteries. Ensure your bike wheels are strong enough and there is space around the bottom bracket to slide the motor in.
 

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Putting a 1500W motor into a bicycle conversion is like dropping a V8 into a Nisan Micra, this is six times the legal maximum power. If you hurt someone else on this expect to go to court, and possibly prison and if you get hurt yourself don't expect your life insurance to pay out.
 

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Putting a 1500W motor into a bicycle conversion is like dropping a V8 into a Nisan Micra, this is six times the legal maximum power. If you hurt soemeone else on this expect to go to court, and possibly prison and if you get hurt yourself don't expect your life insurance to pay out.
Accelerating through ~4mph with ~48Nm on a 26in tire is ~250w. So accelerating with 250w battery limit from 0-4mph could conceivably snap aluminum dropouts.
 

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Discussion Starter · #25 ·
The first question that needs answering is what bike are you thinking of converting?

The second is probably whether you intend to stay within the rules/law for your conversion, as motor power and thumb ‘throttles’ are areas you need to think about.

Do you still intend to pedal, or are you wanting something to power you up the hill without any input from you?

I’ve converted 4 bikes to e bikes now, but all with TSDZ2 mid drive motors.

Check out endless sphere;

So, if I were to get this Kit from PSWpower, am I right in thinking all I'd need would be a battery and charger, and then I'd have everything I need?
 

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Discussion Starter · #26 ·
If you’ve worked on bikes before, it’s not difficult. You need a bike with a standard bottom bracket shell width, 68-73mm, and the tools to remove the old bottom bracket.

Crank arms are square taper, no special tools to install them, but you’ll need pullers for the old cranks.

The mid drive motors come with their own spanner for tightening the motor shell mounts.

You’ll need space somewhere to mount a battery, the bottle mounts usually, and then it’a just a case of running wires neatly, fitting the controller on the handlebars, speed sensor on the chain stay and a magnet on the spokes to pass it.

This is one of my conversions, the batteries are in the black triangle bag, no room for a traditional bottle battery on this frame. I’ve also fitted a smaller front chainring, the kits are easily adaptable to take standard 5 x 104 BCD chainrings.

If you’re converting a standard hard tail, it’s even easier.

View attachment 138751
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That looks great.

I'm just hoping to use an old bike and see how much use it would get before spending too much.

That mid drive does look much tidier than a hub motor, and sounds like it'd be more reliable.
 

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Accelerating through ~4mph with ~48Nm on a 26in tire is ~250w. So accelerating with 250w battery limit from 0-4mph could conceivably snap aluminum dropouts.
I am not sure I follow your maths, arguing that 1500W = 250W doesn't really make sense given that the torque curves are largely independent of revs. This wasn't really the subject of my post, bicycles structures, the places they are used, the riders protection equipment and local laws are designed around a persons power which is about 300W. Putting a 1500W motor on a bike is going to lead to problems. As much as anythinhg its perception of other road or off road users that is the issue. Our American cousins have made use of their freedom to put powerful motors on bicycles with the result that all bikes, powered or not, are starting to be banned in many state parks.
 

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I am not sure I follow your maths, arguing that 1500W = 250W doesn't really make sense given that the torque curves are largely independent of revs. This wasn't really the subject of my post, bicycles structures, the places they are used, the riders protection equipment and local laws are designed around a persons power which is about 300W. Putting a 1500W motor on a bike is going to lead to problems. As much as anythinhg its perception of other road or off road users that is the issue. Our American cousins have made use of their freedom to put powerful motors on bicycles with the result that all bikes, powered or not, are starting to be banned in many state parks.

At the rpm the hub will be turning close to 4mph on a 26in wheel, 48Nm * 5.2 rad/sec angular speed = 250w

At higher speeds, the torque will be lower for constant 250w power limit.

Not sure if you clicked the link, it says “Restricted to 250W and 16mph (25km/h) speed by default as a road-legal pedal bike conversion kit.”
 

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So, if I were to get this Kit from PSWpower, am I right in thinking all I'd need would be a battery and charger, and then I'd have everything I need?
Yep, that kit along with the controller of your choice (I use the VLCD6 on my conversions as it’s small and neat, but the VLCD5 is nice and you can programme them too) and then a 48v battery and charger and you’re good to go.
 

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At the rpm the hub will be turning close to 4mph on a 26in wheel, 48Nm * 5.2 rad/sec angular speed = 250w

At higher speeds, the torque will be lower for constant 250w power limit.

Not sure if you clicked the link, it says “Restricted to 250W and 16mph (25km/h) speed by default as a road-legal pedal bike conversion kit.”

I like the maths but you need to state your assumptions. The equivalent 250 W Voilamart unit, which is what I happen to have, is here https://www.voilamart.co.uk/sports-...onversion-kit-speed-hub-motor-cycling.htmland is quoted as a torque of 15Nm. Restricted by default means there are two wires which if left unconnected limit to something less than full power. On the 250W kit the default is supposed to be 15mph but is actually 5mph and also seems to reduce the torque, delimiting it results in it running out of puff usefully at around 15mph.
 

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Yep, that kit along with the controller of your choice (I use the VLCD6 on my conversions as it’s small and neat, but the VLCD5 is nice and you can programme them too) and then a 48v battery and charger and you’re good to go.
Fitting the TSDZ2 to the very latest mountain bikes can be problematic due to wider wheels requiring a wider chainstay. Check also for any welds around the cables under the bottom bracket, the clearance around motor is limited. Modern hybrid or older hardtail mountain bikes are more straightforward. The hardest thing is getting the old bottom bracket off. Something like a Trek 4500 off Gumtree is perfect. I bought the Trek and a Specialized hybrid dirt cheap from Gumtree with the intention of converting, but they were so good I ended up keeping them as they were. Once the bottom bracket is off it takes about two hours to fit the motor and battery. With a 48v 13ah battery using full pedal assist on hilly roads I get 30 miles in winter and 40 in summer.
 

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I like the maths but you need to state your assumptions. The equivalent 250 W Voilamart unit, which is what I happen to have, is here https://www.voilamart.co.uk/sports-...onversion-kit-speed-hub-motor-cycling.htmland is quoted as a torque of 15Nm. Restricted by default means there are two wires which if left unconnected limit to something less than full power. On the 250W kit the default is supposed to be 15mph but is actually 5mph and also seems to reduce the torque, delimiting it results in it running out of puff usefully at around 15mph.

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At the rpm the hub will be turning close to 4mph on a 26in wheel, 48Nm * 5.2 rad/sec angular speed = 250w

At higher speeds, the torque will be lower for constant 250w power limit.

Not sure if you clicked the link, it says “Restricted to 250W and 16mph (25km/h) speed by default as a road-legal pedal bike conversion kit.”
 

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I have done a lot a research, and much procrastination on conversion kits. My opinion is higher voltages are better eg 48v or otherwise 36v (starting at £360). The mid mount kits are expensive, but better than hub motors.

Rear hub is ok, definitely not front hub. I've seen 48v rear hub motors+tyre on internet for circa £200. The hub motors don't have the sophisticated interface that are seen on the mid mount kits. Any type of motor will attract unwanted attention, so buy a very expensive lock for the bike and consider it's highly likely to be nicked if left unattended.
 
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