Currie Kick Scooter conversion

Lightweight / Folding / Portable EVs - seats optional

Re: Currie Kick Scooter conversion

Postby ElectricGod » Tue Apr 11, 2017 11:30 am

LAst night I took the scooter out for a ride to test the new controller settings. The lights started to blink and then went out completely. I have a bike light so I turned that on and continued on. I got up to 30mph going full out on 48 volts. I'll definitely upgrade to 65 volts. Later the scooter stopped working completely so I walked it home. I can definitely kick myself along, but with no frewheel, coasting is limited. I got home, opened the battery box and found my mosfet switch and the DC-DC converters were fried. I don't know what else is damaged yet. Grrr! I don't know why they failed either.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Sun Apr 16, 2017 8:04 am

I figured out my problem. The mosfet switch which is made out of IRF4110's weren't getting enough voltage on their gates to fully enable the mosfets. As a result, the DC-DC converters were turning on and off since the mosfets were not turned on all the way. This on/off cycling under load caused them to burn out. As it turns out, I don't need a mosfet switch. I don't know why I didn't do this to begin with, but whatever. On the down tube, there is a 30 amp rocker switch that applies battery voltage to the enable wire in the controller. It was originally used to disconnect battery power from the original motor controller. Anyway, I am using the switch to apply power to the DC-DC converters. It still enables the controller, but now it also applies power to the peripheral items too. I still had to replace the DC-DC converters, but no biggie...I was using ones that were good up to about 55 volts and now it's good up to 90 volts. This takes care of an issue I was concerned about when I upgrade to 60 volts. Also, the original DC-DC converter maxed at 6 amps and now I have 20 amps.

I'll take it for a ride later today now that it's all back in working order.
Last edited by ElectricGod on Sun Apr 16, 2017 8:07 am, edited 1 time in total. View post history.
E-Bike XB-502 (Moped) conversion project
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Sun Apr 16, 2017 8:29 am

Oh yeah...added a kick stand...everybody needs to prop up their ride.

Image

Some final pics of the scooter.

Image
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Last edited by ElectricGod on Mon Aug 28, 2017 6:33 pm, edited 1 time in total. View post history.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Sun Apr 16, 2017 7:39 pm

I took the scooter out for it's first real maiden ride that's longer than 1/2 mile. I got 10 miles and the back tire blew. I was riding along and everything was great. All of a sudden I was swerving all over the trail. I pulled over and my back tire had come off the rim. Without pressure, these tires will pop back in place with no tools so getting the tire back on was easy, but then the valve stem was ripped off the tube. That was a good long walk home...10 miles! Battery capacity is at about 50-60% so that part was good.
Last edited by ElectricGod on Sun Apr 16, 2017 7:41 pm, edited 1 time in total. View post history.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Mon Apr 17, 2017 2:30 am

I was curious how much of a pain pulling the back wheel off would be. I have to loosen the motor so it will slide down and create slack in the chain. Then pull the chain off the driver sprocket. The kick stand is in the way of removing the tire so loosen the axle nut and a 6mm bolt to get that off. Loosen the other axle nut and it comes right off. It was much easier than getting the back wheel off the blue scooter. Swapping out the tube was easy too. The tire comes off easily and then replacing the tube is quick. I think it all took maybe 30 minutes.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Wed Apr 19, 2017 7:37 pm

I finally got to do a longevity test tonight...18 miles! I'm pretty damned happy with that distance.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Wed May 03, 2017 8:20 pm

The tires I put on this scooter are horrible. I was hot dogging around yesterday just testing things out and there's a curve I like taking at 28-35mph. 35 is really pushing it! I don't recommend anyone doing that curve at 35 without working up to it...a LOT!!! The tires were fully aired up. I went around that curve doing 25 or so and the back tire rolled over. The tire didn't come out of the rim, but the side wall totally collapsed going around that curve. I nearly wrecked! These tires worked fine in a straight line, but on curves where side to side stability really matters, they are total crap. The side walls are just too flimsy. I've bought another set of tires that will hopefully have stiffer side walls. This is the very thing I replaced the factory tires for. I want high performance, grippy tires that can handle taking a corner at 30+. GRRR! These tires are grippy, but shit on turns. They say 35psi max on the side wall. I was already at 35psi. Today I added another 5 psi. No roll over on the same curve. Still...going with another tire!

I didn't build this scooter to be limited by crappy tires.
Last edited by ElectricGod on Wed May 03, 2017 8:23 pm, edited 1 time in total. View post history.
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Re: Currie Kick Scooter conversion

Postby Ianhill » Thu May 04, 2017 10:32 am

Sounds like fun I've seen a big boy fold his complete rim over like that funny as hell :), I'm in the same position for decent tyres on a 20 inch rim it's either moped tyres or 19 inch trails tyres so I'm still on the look out for something light but decent, I've sorted a shock for the rear I got an suntour epicon 165mm eye to eye 38mm stroke brand new for £60. Stock one is 150mm eye to eye 31mm stroke both have 1500 lbs max but I'll have a lockout now on the rear.
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Re: Currie Kick Scooter conversion

Postby aethyr » Thu May 04, 2017 3:34 pm

ElectricGod wrote:I was using ones that were good up to about 55 volts and now it's good up to 90 volts. This takes care of an issue I was concerned about when I upgrade to 60 volts. Also, the original DC-DC converter maxed at 6 amps and now I have 20 amps.


What step down converter are you using that can take 90v in?
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Re: Currie Kick Scooter conversion

Postby Ianhill » Thu May 04, 2017 4:13 pm

China does a 120vdc to 12vdc 20 amp max dc-dc step down convertor, 3 wire shared common and phases.

At 90v or 24s some 110/240vac to 12vdc 2amp etc mains transformer plugs will work im not sure on how the circuit manages to oscillate the primary to secondary but its handy none the less for powering a few leds etc.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Fri May 05, 2017 1:41 pm

Ianhill wrote:China does a 120vdc to 12vdc 20 amp max dc-dc step down convertor, 3 wire shared common and phases.

At 90v or 24s some 110/240vac to 12vdc 2amp etc mains transformer plugs will work im not sure on how the circuit manages to oscillate the primary to secondary but its handy none the less for powering a few leds etc.


I've been using purpose build DC-DC converters for a while, but a switching power supply that will take a variable input voltage will work just as well. This is the DC-DC converter I used in the Currie.

http://www.ebay.com/itm/24v-48v-72v-96v ... 4d4e177fa1

or for a bit more voltage and physically larger, I have one of these too, but the voltage range isn't high enough for my moped. I need 130 volts at least.

http://www.ebay.com/itm/electric-36v-48 ... 21126930d8

I also knew that AC switching power supplies will also run on DC. I looked around until I found a 12 volt, 10 amp power supply that had a decent input voltage range and bought one on ebay.
http://www.ebay.com/itm/191981131504?_t ... EBIDX%3AIT

I've had this power supply 2 days now. I plugged it in long enough to see it worked and then took the case apart and started modifying the power supply. There were two tabs on the circuit board on either end that I cut off. They were only extending the AC and 12 volt lines out a little. I soldered wires directly to the solder traces and saved about 5/8" length. The red/black wires on the right end are the AC input side and the left yellow/brown is 12 volts out. To be sure no pins on the bottom side of the board ever wore through the insulation, I laid down 4 layers of electrical tape before running the input wires across the PCB. The power supply was rated for 100-240 volts AC. I've tested it as low as 69 volts DC (18S) and it still outputs 12 volts. I tried 48 volts (12S) and that didn't work. At $15, that's much cheaper than a true DC-DC converter. On the input side there is no right or wrong way to connect DC to it. It was designed to run on AC after all. This power supply will go in my Moped build. It is physically the same size as the second DC-DC converter I listed, but at much less $$ and much more input voltage range. I'll wrap the whole thing in 2" kapton tape to make it water tight. The output is 100% isolated from the input...perfect for EV uses.
Last edited by ElectricGod on Mon Aug 28, 2017 6:36 pm, edited 2 times in total. View post history.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Mon May 08, 2017 1:27 pm

I pulled the controller from the scooter last night. There's a few wire positions that I wanted to access. I added cruise control, reverse and low voltage operation. Since I was inside the controller, I swapped out the shunts for higher amperage ones. I've been limited to 40 amps with the old shunts and yet the AOT290 mosfets are capable of so much more. There are 5 LED positions that do something. I added an LED to each position. So far one blinks a steady pattern, one lights up solid and one blinks momentarily when I enable the controller. The other two...who knows.

Image
Last edited by ElectricGod on Mon Aug 28, 2017 6:39 pm, edited 2 times in total. View post history.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Mon May 08, 2017 1:55 pm

The new tires also arrived so I pulled the wheels and swapped the tires out. The other back tire was already showing wear at the center of the tread. It has maybe 50 miles on it. How is it wearing out already? Crap tires! Anyway, both front and back tires are now replaced and these side walls are a good bit stiffer. Also, the old tires max pressure was 40 PSI. The new tires are 60 PSI. That extra pressure will reduce rolling resistance and make the tires side walls stiffer. Still, the walls on these tires are stiffer than the other ones anyway.

Image
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Last edited by ElectricGod on Mon Aug 28, 2017 6:40 pm, edited 1 time in total. View post history.
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Re: Currie Kick Scooter conversion

Postby zootr4 » Tue May 09, 2017 8:01 pm

ElectricGod wrote:Chain noise on this thing was quite significant. There's a delrin block that the chain rides against to maintain tension. I removed the block and replaced it with a bearing. Now the chain has something to roll on rather than slide on. It made a huge difference. Noise from the chain dropped by 70% at least.

Hi, I am new to e-scooter and new to this site. Have a currie-ezip750 that makes a lot of noise. i am wondering where this delrin block is and what bearing to replace it with (and where to get supplies like that). The noise is a little dangerous as it can mask approaching traffic noise. Great to be able to reduce it.
Thanks in advance.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Wed May 10, 2017 6:08 pm

zootr4 wrote:
ElectricGod wrote:Chain noise on this thing was quite significant. There's a delrin block that the chain rides against to maintain tension. I removed the block and replaced it with a bearing. Now the chain has something to roll on rather than slide on. It made a huge difference. Noise from the chain dropped by 70% at least.

Hi, I am new to e-scooter and new to this site. Have a currie-ezip750 that makes a lot of noise. i am wondering where this delrin block is and what bearing to replace it with (and where to get supplies like that). The noise is a little dangerous as it can mask approaching traffic noise. Great to be able to reduce it.
Thanks in advance.


A bearing was an improvement, but still noisy IMHO. The chain had a rolling surface to run on, but it was still metal on metal. I eventually abandoned the tensioner altogether when I upgraded to a new motor and 100% rebuilt the rear end. However, if you get on ebay and look for rubber chain rollers, you can buy them in various sizes and they include bearings. There are a variety of cheap bike chain tensioners that you can buy on ebay for a few dollars. You just need the tensioner wheel. As an alternative, on my blue scooter, I have a wood tensioner wheel. Because of a chain alignment issue, the chain ate the original rubber roller. As a temporary stop gap until the replacement rubber roller arrived, I mounted a block of teak (any hard wood would work...oak, ash, teak, hard maple, etc) on my drill press and used some files to shape the block into a roller. I expected it to last a week or two at most, but here I am almost a year later and the wood roller is still going strong. I've never bothered to put the rubber one on. If you make it yourself, any two sealed bearings of the same size will do the job. The hole in the center of the wood for the bearings is slightly over sized. I shimmed the hole with paper all the way around the bearings to take up the gap. My bearings were 12mm OD, but the closest drill I had to that was 9/16" which is about 2mm too large. I cut a long strip of paper and coiled it inside the hole for the bearings and then shoved the bearings in. The paper can't go anywhere and if it gets wet, the water can't deteriorate the paper since it's jammed between the bearing and the wood. Anyway, the paper has done the trick and not failed after almost a year of use. If you don't have bearings look around on ebay. You can find pretty much any size you want.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Thu Jun 01, 2017 4:04 am

I have new batteries for the Currie. I bought 8 graphene 10000mah packs to make into a much better pack. The used lipo pack and the 3 lipo packs were not cutting it for me. I couldn't deliver enough power to the motor. Now I can!

This is the packs. They just arrived today. I'm short a couple of 750mah graphene packs I bought for my qaud copter. Don't know what happened to them or why they weren't in the box. Hobbyking never said anything either.

Image

A seller on ebay (yimia) makes some decent BMS. I've purchased probably 6 of their 20S BMS. They are built with the AOT290 mosfet which is my favorite 100 volt fet so that makes me happy. I just recently purchased 2 of their 16S BMS for about $52 each and they were kind enough to keep on using the AOT290. The first few pics are stock shots from their ebay auction, but I can tell you they use AOT290's on the actual BMS. I have one complaint and that is there is no heatsink on the mosfets. I added one. This BMS is quite small at 2" x 3" x 3/4". It's about 7/8" thick with the added heatsink, but still quite small. These BMS use the Mitsumi mm3474 LION battery monitor control chip. It has 5 channels on the chip, but you can select to use 3, 4 or 5 cells per chip. The 16S BMS is set to use 4 cells per chip. The 20S version uses all 5 cells per chip and can be upgraded with a few minor parts to 24S. Each channel on the BMS has an LED that lights when a channel is over voltage and then flashes as it gets that cell back down to safe again. Otherwise the LEDs stay off.

Image
Image

The BMS on the left is how they came to me and the one on the right is with the added heatsink. The aluminum part in the far right is the new spacer that the mosfets screw to. It's a little thicker and longer than the brass screw plate that the BMS originally used. Since it's aluminum, it ought to conduct heat much better too. I'll probably redo the spacer to make it span the circuit board width for better heat spreading and then screw the heatsink fins to it. Right now just the edge of the heatsink is in contact with the spacer so heat transfer isn't as efficient as I would like. I added some double sided foam tape to the board to keep the heat sink off the power traces underneath them. It's only stuck to the board, but not to the heatsink. Once I have the power wires soldered in place and the balance cables made up for 4S sets, I'll put clear heatshrink over the BMS. There will be two of these BMS in the Currie. That will give me about 100 amps continuous. At 65 volts, that's about 6500 watts which is more than I could ever need on this scooter. I really doubt I'll ever pull more than 60-70 amps.

Image
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Re: Currie Kick Scooter conversion

Postby Ianhill » Thu Jun 01, 2017 9:49 am

Yum yum mmmmm.
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Re: Currie Kick Scooter conversion

Postby OhmDaddy » Thu Jun 01, 2017 11:33 am

Did you happen to use thermal paste when installing your heatsinks, or just bolt directly on?
That looks like a prime idea, especially when there are situations where you are going to be pulling that large current.
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Re: Currie Kick Scooter conversion

Postby Ianhill » Thu Jun 01, 2017 4:08 pm

It looks like a thermal strip is sandwich between correct me if I'm wrong Mr god.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Fri Jun 02, 2017 12:49 pm

Ianhill wrote:It looks like a thermal strip is sandwich between correct me if I'm wrong Mr god.



LOL! Mr god...BTW...I came up with electricgod as a joke...I thought it was funny and clever. Several gigawatters have complained about my ES name saying it's pretentious and that I don't deserve to have a name like that. I think they are generally jealous that they didn't think of it. It fits my general sense of sarcasm and lack of propriety for things considered sacred...including gigawatters.

I have thermal tape, but I used paste. You want the best possible conduction of heat you can get. Either one would have worked equally. Tape tends to be "use once and then discard" if you ever take things apart again. Since I was kind of prototyping as I went, I used paste since it is "reusable". I'm not 100% happy with this added heat sink idea so it will get pulled apart again. I'll probably make a larger single piece heat spreader under the fins that extends to the boards edges. It will add another 1/8" to the thickness, but these BMS are so tiny anyway...I'm not worried about it. The screws and stand-offs between the two boards are all brass. I have loads of nylon screws and standoffs. I don't want the heat sink accidentally creating a short between the two boards via the stand offs. They will get replaced. For a cheap BMS, I'm pretty happy with the MM3474 chip used and the general design of these boards. The manufacturer has made several mods that I have asked for...like AOT290's instead of the 30N10. The way these BMS detect overload current is nice too. They don't need large shunts to do it so the mosfets are running power directly with no extra resistance to waste power on. There are no large resistors or shunts in the power path that are used for measuring voltage drop. It's done with a tiny SMT 10 Megohm resistor and a special pin on the chip. It works...I've over loaded the BMS in my blue scooter before and the BMS shut off.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Sun Jun 04, 2017 2:08 pm

A bit more work done...

I received these 4S 10,000mah packs a few days ago and for now they are going through a few cycles to be sure they are 10,000mah or better.

Image

This is the completed BMS. I attempted to make a better heat spreader, but my cross vice is so sloppy, that it won't hold steady enough to machine a chunk of aluminum with the correct profile. I'll be looking for a small milling table. They are much more accurate and stable than a cross vice. Everything I have found in a cross vice is the same horribly bad Chinese machining. Anyway, I'll see about making a better heat spreader later. This will do for now. The short black wire connects to batt- and the red wire is load-. I can't finish setting them up until more 4S balance connectors arrive.

Image
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Re: Currie Kick Scooter conversion

Postby fromanoc » Wed Jun 07, 2017 6:20 pm

nice man. I got a curie ezip 750 scooter. I replaced the controller for a cheap chinese ebay controller (20 bucks shipped) 48v 30 amps (DC brushed). Replaced the lead acid batteries for lipo. It fits 8 packs of 6s 5ah turnigy lipo, at 12s 20ah. replaced the throttle too with one with display for battery voltage.

I'm having a blast commuting with it around Boston. It goes 33 mph on a 80 tooth rear sprocket, now I'm running 65 tooth but haven't clocked it. Also tried a 50 tooth and was too fast on flats with poor acceleration. It has a free wheel.

It goes about 25 miles on a charge, and I bought a bulk charger from china's BMS battery. Just plug and charge (only charge up to 4.08v per cell) and cells don't unbalance more than 0.03v or so after one month of daily use.

The motor gets warm but definetely under 100 C after a 2-3 mile ride. It gets above 100 C after a 6 mile or londer ride. I read ceramic magnets demagnetize at 300 C or higher, so I'm not worring too much. I don't notice any power loss yet.

Maybe I'll try brushless next, but is good and cheap as it is, just a bit noisy.

here is a pic, one charging (outside) and with my dog who loves going on runs tied to the scooter =). lately I removed the seat and ride it standing up.
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Re: Currie Kick Scooter conversion

Postby ElectricGod » Fri Jun 09, 2017 11:29 pm

I'm about to be running at 73 volts. I'm finishing up the BMS's for the two LIPO packs. Once that's done, it's ride-able again.
E-Bike XB-502 (Moped) conversion project
viewtopic.php?f=10&t=83302&p=1222730#p1222730

Currie kick scooter conversion project
viewtopic.php?f=35&t=83830&p=1227407#p1227407

My kick scooter project
viewtopic.php?f=35&t=75177
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ElectricGod
100 kW
100 kW
 
Posts: 1234
Joined: Sun Nov 01, 2015 5:24 pm

Re: Currie Kick Scooter conversion

Postby ElectricGod » Mon Jun 12, 2017 2:11 pm

The battery packs are done. I used one set of the Graphene packs I bought and a set of the cheaper style that was already in the scooter, but now made into a 16S pack. Graphenes are a bit larger for the same capacity so both sets of them won't fit in the battery bay right now. I need to rearrange the wiring and various other items that sit in the front of the battery box to make a bit more room. I want to mod the battery box anyway. I'm going to add an access hole in the bottom of the box that gets me an opening under the front down tubes. There's plenty of space in there for all the wiring and whatnot, but I can't see inside the space to get things arranged in there very well so I'm essentially just cramming them into the space. I've wanted to take the box off again since I made a couple of early design choices that are not optimal and I can't get at the main power wires on the contactor without removing the battery box. The access panel will seal up to the bottom of the box and will be held in place by several 6-32 screws that thread into brass inserts in the plywood bottom. If I do it right, the access panel will be no thicker than the aluminum trim already protecting the box.

Each battery pack has it's own 16S, 50 amp BMS. These BMS use the AOT290 mosfet which is pretty awesome. Anyway, If I need more than 100 amps, I'm doing something significantly wrong. 20,000mah of capacity ought to get me pretty far down the road. With the cheaper pack and a reused set of old 8000mah LIPOs, I got 18 miles at 48 volts. I should now see something like 24 miles and my top speed will be about 40mph...which is much closer to what my expectations were when I started building this scooter. At the time, I didn't have the $$ for more packs and 16S BMS to get more voltage and amperage. The packs will sit inside the box so that the two BMS are side by side and sort of "nestled" together. The wires will simply lay on top of the packs to get back to the distribution buss in the very front area of the battery bay. If I need to, raising the deck a little won't be a problem. It slopes towards the back by about 1/8" anyway, so adding a spacer to level the deck will be easy and will get me a little room above the battery packs if needed.

Image
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Last edited by ElectricGod on Mon Aug 28, 2017 6:48 pm, edited 2 times in total. View post history.
E-Bike XB-502 (Moped) conversion project
viewtopic.php?f=10&t=83302&p=1222730#p1222730

Currie kick scooter conversion project
viewtopic.php?f=35&t=83830&p=1227407#p1227407

My kick scooter project
viewtopic.php?f=35&t=75177
User avatar
ElectricGod
100 kW
100 kW
 
Posts: 1234
Joined: Sun Nov 01, 2015 5:24 pm

Re: Currie Kick Scooter conversion

Postby ElectricGod » Fri Jun 16, 2017 2:54 pm

Still spending on this scooter...LOL! I found some really nice looking wheels for it on ebay. I've looked and looked everywhere and never saw these before. There is pretty much 3 or 4 crappy options of which I have the best of them on it now and they use cup bearings which let dirt and water into the axles. These new wheels use 10mm axles and sealed bearings. They are cast aluminum and then machined. Hopefully the machining isn't crap. The original wheels on my blue scooter were made the same way, but the machining for the bearing seats was off center so the wheels wobbled. Hopefully these are NOT that way.

I found them on ebay for $40 each.
http://www.ebay.com/itm/262079466840?_t ... EBIDX%3AIT
http://www.ebay.com/itm/Bike-Bicycle-Fr ... SwJblXAj4S

Image
Last edited by ElectricGod on Mon Aug 28, 2017 6:48 pm, edited 1 time in total. View post history.
E-Bike XB-502 (Moped) conversion project
viewtopic.php?f=10&t=83302&p=1222730#p1222730

Currie kick scooter conversion project
viewtopic.php?f=35&t=83830&p=1227407#p1227407

My kick scooter project
viewtopic.php?f=35&t=75177
User avatar
ElectricGod
100 kW
100 kW
 
Posts: 1234
Joined: Sun Nov 01, 2015 5:24 pm

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