New trailz motor

[mr.pibb]

Ok I have a curry trailz bicycle and I want a new motor. I want to upgrade to 48v. I want a replacement 48v motor ideally in the 1000 watt range because, I would like to see top speeds of aprox. 30-35 mph on flat ground.

Initally I gravitated to the 48v 1000w my1020 (11 tooth).
http://tncscooters.com/index.php?route=product/product&path=52_57&product_id=328

I did a lot of research and was about to purchase one today for $90 until I realized I would need like a 80T sprocket on the tire to get a decent enough ratio to maintain within 80% of the motors loaded rated 3000rpm. :?

Since theres no way that would possily fit and I am not going to make any more gearboxs or anything like that I am back to the drawing board. Unless there is a easy fix Im not seeing...
------------------------------------------
---------------------
I was able to find 600W GEARED Motor - 36 Volts Style: MY1020Z3
http://tncscooters.com/index.php?route=product/product&path=52_56&product_id=337

This motor is essentially bolt on to the old trailz which I do really like. The transmission is the same overall dimensions ect. I just dont think it is powerful enough for 30+ mph. Please let me know what you think.
-----------------------
The stock oem trailz motor propells me at about 15.3 mph; geared at 9:20
This means I am actually doing about 440 rpm and the motor is rated at 470.(everything stock)

Building on those numbers...
If I get the 600w motor geared at 10:20 (stock wheel sprocket) not much will really change as far as top speed...
The rpm will essentially stay the same. The only gain is the 1T on the new motor.
440rpm @ 10:20 gearing only gets me to about 17 mph
Thats only a 1.7 mph gain...
(I imagine I will gain considerable acceleration though because of the higher amp draw)

Im looking to get 30-35 mph.
So I would have to change the gearing yet again. It appears that I cant enlarge the motor gear more than 1T. Or atleast I dont know where to find one. I would have to drop the wheel sprocket down to 16T.
440rpm with 10:16 gearing gets me a top speed of about 21.3 mph... getting closer

I have read that other people have put 36v to the oem 24v motor and seen 23+ mph and the motor doesnt fry.
If I put 48v to the new 36v motor I image I would end up with around 600 rpm(450*1.33). That would bump top speed to about 29

Not quite 30-35, but 29 isnt bad and I could probably live with it considering I would have to spend probably a lot more time and money for a better result. I could go to a hub motor and thats a good thought, but this upgrade would realistically only cost me around $150 for the motor, controller, and new 16T sprocket.

My questions are:
Can I get away with 48v to this motor? I would think yes because it is only 1/3 more voltage and people are doing 50% more going to 36 from 24.
Do you guys think that I will see in real life what Im thinking I will get?
Is this a good plan?
Should I go with another more powerful motor- and if I do how can I easily and cost effectively gear it to 30-35 mph?

Thanks!
(((I based all my calculations off of this calculator: http://www.arachnoid.com/bike/bike.cgi )))

 

[mr.pibb]

Ok Ive been doing more thinking (never a good thing) :lol:

I put a little more thought into the my1020 1000 48v motor.
After realizing I would need a gear box or someway to drastically reduce the gearing I was going to give up entirely on that motor. But I think I may have come up with a simple solution. A standard bicycle freewheel sprocket with that large Tooth doesnt exist. However tnc sells sprockets for 8mm chain that goes up to 72T. They also sell a Freewheel Assembly (LEFT HAND) that I can use to attach the sprocket. It says it has a 1 3/8 threads on the freewheel to attach to the wheel. Im hoping that is the correct size to mount to my wheel? Can anyone confirm this???

The motor is actually set-up for 8mm chain too. Im confindent that the chain will be strong enough because I have a goped gsr40 with 25# chain and I can hit right around 40mph no problem. 8)

With the 3000 rpm motor 11T pinion and 72T sprocket the geared mph is 35.5 mph loaded
That seems right about perfect...

The only problem I have now is the HUGE sprocket. I would have to make a new mounting plate or modify it to extend further back. If I can make it happen I think this is better than using the lower 600 watt my1020z3. I wont have to worry about cooling and burning up the motor. What is your guys thoughts on going this route?

 

[neptronix]

scrap the bike and start anew.

you'll need to upgrade the controller and the battery and motor.. you'd be better off selling the bike whole and using the $ to convert a bike the right way

 

[mr.pibb]

There's no "wrong" way to do anything really; just better ways. I practically got the bike for free. What can I get for a bike missing the stock motor and a dead battery? Not much... If I can get a motor, controller, batteries and everything for under $300-400 its well worth it. You want to buy the bike as-is? Id take $200 :wink:

I have 4 e-bikes. 2 trailz and 2 a2b.
This is just one project that I am interested in. I wanted to see if its possible to easily convert a trailz to 48v. If it happens that it costs more than its worth I will probably scrap the idea. However to sell it as-is isnt practical. I would have to put another $250 just to buy the stock motor and stock battery. Why not spend a little more and get 48v speed?

I am fairly committed to making this happen!

 

[buzzfirst]

I would go the 48 volt route. With the larger motor you may, again may, have a little unused power for the speeds you want to accomplish. The 600 watt motor doesn't seem to be enough to go 30 mph for any length of time and if it did it would be dependent on rider profile and weight. I seem to remember seeing a chart here somewhere that showed the power required for different speed and almost all of your 600watts would be used up just fighting the wind at 35mph. Drag increases at the square of the airspeed for planes and you have to add rolling resistance to that. I'm currently working on a moped conversion and I am hoping to get 30 mph out of 1500 watts of power. Not sure I will get there though. Good luck with it, hope all goes easily.

 

[mr.pibb]

Yes I believe I have found the chart you were referring to. (reposted) Its numbers are pretty good for me. I will end up with about 240 lbs total with rider weight. I live in FL so there is no hills to speak of besides the dump. The chart refers to 35mph at 960W. So yeah I think this will work. Thanks for yorur input. Good luck on the moped as well!

 

[mr.pibb]

OK guys for anyone interested: I just bit the bullet.

Just ordered:
my1020 1000W 48V
reverse thread freewheel
2 sprockets 63T & 72T
4 feet of chain
(4)*20ah sla batteries
Cheapy 50A contoller
56T chainring (up from the 44T)
11-30T rear cog (14T-34T stock)
Misc: master links, connectors, grease, ect.
-----------
Total Cost: priceless 8)
~~ under $400

I am hoping for a delivery by saturday so I can start building this weekend.
Dont Worry LOTS of pictures will be taken. I need some pics of my sweet ride anyway. :wink:

This is only the start: I have much more plans for this Beast of a bicycle.
Some may laugh, but I am currently working on a more serious mph build on a a2b too.
I dont want to ruin the surprise so you guys will have to wait for the rest.
However I will say that I would like to repaint atleast the trunk possibly frame.
Its needs it bad, but actually right now it kind of adds to the mystique.
I believe I have also come up with a name: Sunburn

I hoping that this build works out nicely and I can help out anyone else looking to doing something similar.
This is one of the first forums that I would actually like to add to instead of just taking.
Keep up the good work fellow EV'ers!
I will keep you posted!