My Outrunner-Upgraded Small Light Viza Volt Scooter

[kfong]

Go to allelectronics.com. They have currie scooter parts and chains. I placed an order from them recently for cheap brushed motors and picked up all kinds of surplus scooter parts. Can't beat the price.

Kin

[swbluto]

Oh, well, the new update seems to be that my belt will just wear out faster than normal industrial levels(Which, they being on the orders of years of operational time I imagine, 100 hours would work for at least a year.) when exceeding the ratings. So I'll continue with the belt and see how it goes.

On another note, this scooter feels dreamy. I'm not sure how to describe it, but if you can imagine how removed you are from "standard life" during a dream with a hint of euphoria, that's how I feel just riding this thing. It's a really weird sensation. I guess that be because of my childhood dream(originated at 9 years old, I believe) was to develop an "anti gravity" board like Back to the Future's mattel version, and it seems like this approximates that goal quite closely. I don't think I can ride this well in a desert or other non-paved surfaces, unlike I theoretically could with a real anti-gravity board, but it comes close to the result of an anti-gravity board in urban settings.

[rs-racer]

How fast wil i go with that motor on 24V?

[fechter]

I use a 5m-15 HTD belt on my souped up Zappy. It's lasted over 400 mi so far (made by Goodyear).

On the motor sprocket, you might try putting Loctite on the bore of the sprocket as well as the screw threads. This will eliminate any play between the sprocket and the motor shaft which will reduce the likelyhood of the screws loosening. I used the blue stuff. It comes off OK with a bit of force.

[swbluto]

How fast wil i go with that motor on 24V?

That depends quite a bit on the type of batteries you have and the sprocket ratio. But, assuming you have at least 4Ah of a123s or >15C lipo and you gear it for the highest speed on flat-land, my simulator suggests 32 mph. With my current stock gear ratio, it'd be about 30 mph. I just got my dewalt battery packs in so I just need to take them apart and start the soldering process(OMG, only 60 contacts to solder now. ), but I suspect I won't get that done for some time since it's a lot of work and I don't have much available free time (I also need to get a special torx t-10 screwdriver... garsh, mother, grrr....). Anyways, it'd be running at about 33 volts which would give me 37 cruising speed but, seriously, I don't want to find out what happens if my tires blow(Which it seems tires occasionally do, and small scooter tires seem more vulnerable due to holding a bit less air. I'm wondering if I should add the Slime just to simply slow down the "blow out" process so I won't get seriously injured.), so I'll definitely be limiting it to 25 mph or so on the occasional roadway or generously wide and open multi-use path.

Also, I changed out the tiny two servo connectors(a pain to connect) to a serial cable connector. It seems like it might come off easily(And, no, I'm not going to use the screw terminals), so I'm not sure how appropriate that'll be (I really need to find a suitable connectors... I'm seriously thinking that cat5 network connectors are my best bet), however, I've also switched the side of the scooter where the power and data connectors connect so now I can push freely with my oh-so-comfortable right foot. So, hopefully, cable disconnects won't be a problem and riding this thing won't be as awkward.

Anyways, fechter, what kind of power are you running at? It's reassuring to know that your timing belt has lasted so long. I don't think I'll be going 400 miles per year, so hopefully the belt will last over 6 months.

[rs-racer]

I have two 12V 12A battery's. I would be happy with 20/25 MPH, what would be the runtime?

[swbluto]

Ahhhhh, it sounds like you're talking about SLA batteries. They are quite a different beast(And quite deficient)! I found my 24V 12Ah SLAs were good for about 20 amps and they lasted for 6-7 ahs and their output voltage was something like 10V each at 20 amps. If you limit it to 20 amps, using my simulator, it appears you could expect 5-6 miles at 18 mph. Going up hills are just out of the picture with those, as you need amps and SLAs generally don't put out much without significantly dropping the voltage. Also, I'd think you'd need to limit the amperage as you'll kill the batteries rather quickly if you don't actively limit it. It appears the motor likes to draw 50 amps with ordinary gear ratios which would hit a 12Ah SLA rather hard.

[fechter]

Anyways, fechter, what kind of power are you running at? It's reassuring to know that your timing belt has lasted so long. I don't think I'll be going 400 miles per year, so hopefully the belt will last over 6 months.

It's hard to say exactly since I never had it fully instrumented. I'd estimte around 1.5kw. It climbs a 10% grade at about 17mph. Runs around 20mph on flat ground.

[rs-racer]

Yes i'm talking about SLA battery's. I want to use them for a while and then switch to lipo's. I'm goining to order HXT 63-74 motor with the 100A super simple controller, motor mount and servo tester.

[swbluto]

Ok. Make sure to check out the ebike's non-hub section before making any significant investments you might regret. That's where the "RC crowd" hangs out, so they have tons of experience with various products. In particular, I haven't heard too many good things about Hobby-City's controllers but I haven't really messed with them, so I wouldn't personally know.

[swbluto]

Just added a one-liner piece of code that made my throttle-controller a "current controlled" version instead of a regular "crystalyte version". So, basically, this means that no longer does the top 80% of the throttle range feel like the same. An increase in throttle corresponds to a direct increase in the allowed current, everywhere in the throttle range.

Also, I had a simple accident. Well, no accident really, but I was taking a left onto the side-walk and this car just turned on their blinker at the last second to enter the parking lot, so I jumped onto the curb a little bit earlier than the sidewalk's ramp and the back of the scooter hit the curb and swung around. Didn't really think much of it.

I then was starting to go home about 1.5 miles away and the scooter has this weird handling, it's like the handle-bar column wants to go this way and then that way, as if it's trying to jerk around. I looked for any obvious obstructions and there were none. So, I'm starting to think some internal might be damaged which would be SOL for me as they don't make this scooter anymore. I'm hoping it's as simple as a bearing but I don't know how to replace bearings and I'm not sure if there are repair shops for scooters in my area.

Oh well, it was a good learning lesson. Nahhhhh.... I'm building an a123 pack to release the power of the beast within! Now I need to find some kind of "balance connectors" or some jizz like that so I can connect to my LVC and some kind of array of single-cell chargers. I bought these "Thunder power" 6s balance connectors from the store (I asked if they had connectors so I could connect to it, but they said it's supposed to come on the charger.), but a couple of google searches suggests it only works with particular chargers suggesting, OMG, finding a connector for my own charging solution with this balancer seems like it's not going to be satisfying. So, I'm still looking out for some kind of suitable general-purpose charging connectors that I could expect to have hundreds of connect-disconnect mating cycles and I was hoping there'd be something available locally as I want to get done with my pack NOW!

(Although it appears my drill press isn't going to be up and running for at least another week so constructing an appropriate pcb circuit for my LVC doesn't seem like it's going to happen for a while.The bread-board just isn't very satisfying. By the way, I ended up getting some special smd boards for making the voltage dividers as the same thing on a bread board with through-hole components would've been a mess. I definitely couldn't protect against shorting with that many resistors. )

[swbluto]

I've officially determined my Ping lifepo4 battery is inoperable(The amount of sufficient capacity cells has passed below an acceptable threshold (12s)), so a vague notion of getting a replacement "capacity pack" is somewhere on the "to get" list. The current battery pack I have in the works is an a123 pack that I'm building(I just need to attach an LVC board and wire up a charging single-cell charger-array solution) but that's more for performance than long-range - the a123 pack is supposed to last 3 miles in ordinary usage, lol, 5 if I'm budgeting my current. Unfortunately, I've become quite skeptical of cycle-life claims in the process of my Ping battery essentially dying, so I'm quite hesitant at just jumping at the most appealing lifepo4 opportunity (Even when it includes a ping 3.0 pack) and I *must* have cycle life tests performed before considering any cells that I'm considering of investing greater than $400 in. So, that puts my automated battery tester nearer to the front of the project priority list and I'm sure the results of that knowledge will benefit others. Unfortunately, cycle life tests require time as you can only get maybe 8-10 discharge-charge cycles in a day so an indicative 300-600 cycles would take something like 1 to 2 months, and a "full life test" would be more on the order of 3 to 4 months so that's going to put off my battery purchase for at least another 3 months (effectively, at the end of summer - HAH. ha. Which might actually be relatively good timing because I'm considering building an R/C bike by that time.).

Anyways, my scooter's handling was just fine - I just found I reversed this part that's near the steering column when I was trying to find a replacement nut that came loose and flew off during my scooting travels, so it partially interfered with the steering. Now it's good and everything is alright. Can't wait to get my female headers and get my drill-press working so I can construct the LVC board and stuff.

Today, I went to Fry's in Renton, Bellevue's Downtown area at the Bellevue Park and Ride and downtown Seattle near Jackson and 4th. Two notable things during my travels - 1) I almost flew into a wall. Really, I was just uncomfortably close passing by it as I came up a sidewalk ramp that kind of "directed me" in the direction of the wall. I thought the idea of me slamming into a wall at 15 mph would be funny and I'm curious as to what my medical situation would've been if that actually happened. 2) I was going around 23 mph on this particularly special brick-like surface in Bellevue and I applied the rear-brake and, ohhhh wow, the rear wheel started to swerve out from underneath me to the left as it started sliding. Luckily, I let off the brakes before I actually fell but that was a scary feeling.

And, oh yeah, there are NO more problems with disconnecting connectors while pushing to scoot (used for going up steeper hills)! So, this thing has evolved to a state of unadulterated AWESOMENESS! Another thing I noticed today, since I was scooting everywhere when walking would've been fine, I noticed I didn't feel tired when coming back home. I'm starting to think this thing is going to deprive me of exercise that I've been getting used to during the last 9 months and I'm going to get pudgier.

[swbluto]

viewtopic.php?f=14&t=10493 -

Here's the in detail report of my battery pack and current charging system. I charged it yesterday and took it out and, wow, these batteries are awesome! The scooter was like a whole 'nother beast! The drive system started to noticeably oscillate during the acceleration part and it had no trouble climbing decent hills.

In regards to the Ping battery, I'm thinking it might be more economic to simply replace the dead groups with easy-to-work-with cells instead of buying an entirely new battery pack. I'm thinking about headways, but it doesn't seem like there's an economic source for relatively small quantities. However, that plan might be foolish as I have a very vague idea of what kind of continuous power levels I'll eventually converge to on my capacity-pack running vehicles. At the moment, I'm hovering at 800 or so watts but when I get my RC e-bike project running after this Summer, I can easily imagine that jumping to 2000 to 3000 watts to sustain 40 mph. Anyways, my pings "at the right voltage" are good upto 800-900 watts (Well, 20 amps) and they're meant more as "capacity pack" creatures for longer distances, so they might be soon antiquated when I get my higher-power capacity-needing e-bike running. My scooter is meant for shorter distances (Say, upto 2 miles though 1 mile is the average), so it doesn't hurt to not have the pings available.

[fechter]

You might consider some RC Li-po batteries. They can really crank out the amps for a small size.

[swbluto]

You might consider some RC Li-po batteries. They can really crank out the amps for a small size.

I would if I weren't strapping the batteries to my back. Also, with LiPo, if people saw any wires, they could probably accurately describe that I was carrying a bomb.

But, I've been thinking it might be possible to use the original battery tray to get some excellent LiPo. But that would make the scooter heavier and more cumbersome on the bus("Your space" is very limited aboard Seattle's buses). So, I'm going against the idea for now. If I were able to take a car for some reason (say, a shared commute), then it'd definitely be an extremely attractive idea.

When I get my RC e-bike running, I'll consider having a LiPo booster pack since I'm projecting I'll need 3000-4000 watts to maintain 30 mph up steeper hills. Anyways, I was doing a real world test and here are the short-hand results:

I plugged in at 1:33ish
ended at 1:56ish.

So 23 minutes = 2/3 ah @ 32 volts = 21 wh.

I went about 1/2 a mile, so I was using approximately 42 wh/mi gunning at full throttle.

At 40 Wh, I could expect about 3.5 miles on a 140 wh pack, as I originally calculated and predicted. If I use the throttle less generously, I could expect about 4-5 miles.

Also, I'm at school and just recharged the battery in the library! So far, my system is rocking.

[swbluto]

More user experiences at higher current levels:

The brakes started getting weak and really squealy after a stop-go commute home. Also, the back tire was at 130 degrees fahrenheit even though the ambient temperature was 72 fahrenheit. Something in the drive system is becoming more noisy as I'm hearing a "clack clack" while slowly walking it. With that, I have a feeling I'm going to be needing to take apart the motor sooner than I wished. The 14 gauge wire also apparently gets hot(I would describe it as 150 degrees fahrenheit) while pushing 40 amps and so do the 45 amp connectors(Although, that may of just been the wire's heating bleeding onto the andersons).

Anyways, all and all, it doesn't seem like my scooter is meant for constant 25-30 mph speeds in a stop and go environment. Bummer. So, I guess I'll just go 20-25 on a consistent path-way (10 to 15 on campus) and go WOT on the occasional smooth roadway.

Edit: I measured a typical 30 mph with intermittent 10-20 mph periods ride which meant the average motor current was probably something like 60 to 70 amps right before coming home, and I put my hand on the motor's can. Oh jeez, it was hott! By my estimation, it was probably around 140-150 degrees. That's the part of the outrunner that holds the magnets, so it seems I'm starting to pushing the motor's heat tolerances. It seems that heat tests for continuous hills would be necessary, and I probably won't ride another large hill until June 20th. In the other news, I haven't measured my controller to be above 140 degrees so far. I'm guessing the fact that the controller is no longer doing current limiting with relatively high currents means that the average switching losses has significantly decreased. Ironically enough, though, if I slow down, my current limit goes down which practically ensures current-limiting which means greater controller heat. So, in essence, for my situation...

more speed = less controller heat, greater motor heat
less speed = more controller heat, less motor heat.

It's a fine balance, I suppose.

On a hill, more throttle would generally mean greater controller heat AND motor heat since the "top speed" nearly always corresponds to a motor current level in excess of my programmed current limit, so there's no trade off there.

[swbluto]

Well, anyways, I was wanting to do some hill climbing testing and I attest there aren't any huge hills in the area immediately around here (I.e., walking distance), so I made due with a short drive-way. I measured the angle of the road to be 18 degrees which corresponds to something like 30%, and my scooter was able to climb up it at around 5ish mph. My ebike calculator seems to suggest that, suggesting my simulator is probably accurate for grade-related speed information. So, I could probably trust its assessment of 15-20 mph on an 8% incline.

As a comparison, my hub motor on the bike that consumed nearly as much power would come to a complete stop at 8% and its top speed was only 30ish mph. So, in essence, geared drives rock! (Or something's rocking that I'm not quite spotting. My batteries are putting out something like 1200 watts(30v*40 amps) and my ping battery put out like 900-1000 watts, so there's not too much of a difference in terms of input power. Aha! It must have to do with the much lower internal resistance of a higher-RPM motor that results in generally higher efficiency at lower speeds.)

[recumpence]

I have found high RPM geared down gives HUGE power with reletively good efficiency.

Your experience is the same as mine in that way.

Matt

[swbluto]

Indeed. Anyways, I went away from the "different battery" comparisons since I thought that might be unfair, and compared a 48v battery limited to 20 amps on my original c'lyte 407 bike and my scooter(Basically, same battery, different drive systems). The original c'lyte would've gone 10 mph whereas the scooter would've gone 16 mph up a moderate hill. I think that's significant.

In the news, I got a flat back tire. I looked at the tire and there are no visible puncture marks, so I'm guessing that the Mr.tuffy liner isn't appropriate for an 8" tire or I was simply bad at installing it. But, I can't confirm that as I don't have the tools to take apart the hub and replace the tire. So, I'm stuck until I find the right tools and, in the worst case scenario, that appears to be 1 month from now. I'm going to visit the local e-scooter shops in the area just in case I might luck out with whatever resources they have. Two companies that I'm thinking of is http://soundspeedscooters.com/ and http://www.levseattle.com/, but I don't get the impression they have anything related to my scooter. (Although, I think I saw that LEV seattle's store had a few scooters with 8" kind of wheels, so maybe.)

[swbluto]

I went to Soundspeed scooters and the guy there had this nifty tool that was used to pull off the brake hub. He went onto say something like "All you have to do is cut up these metal bars, drill a few holes, put a few screws here and there..." and I replied "But I don't have a metal fabrication shop.". And, $20 later, I was in business. I can remove the brake hub that's necessary to taking apart the wheel to replacing the tire so now I'm replacing it.

I just took it apart and found out that it doesn't seem like Mr.Tuffy does so well in 8-inch tires. Upon taking it apart, there was a ton of this black dust that I assumed to be rubber that came out immediately. Taking out the tire, I found Mr.tuffy bent backwards and wrangled up and the inner tube had a lot of rubber shaved off near the edges where the Mr.tuffy touched it. I blew the tire up and discovered the hole was, surprisingly enough, near the center of one of these "Mr.Tuffy" craters/ditches. So, I've ditched the Mr.tuffy and opted for the Green Goo in getting me threw the next set of inner tubes. In the mean time, I need to order more inner tubes and I think I should think about doing something to the front inner-tube that I don't believe I've done anything to.

[swbluto]

Ok, I replaced the back tire and it seems to work well, so far. I noticed that my back tire started skidding a bit when braking from 25-30 mph on some nice sidewalk-like pathway.

I noticed that my connector's pins on the serial back connector would be pushed back when connecting it. This was noticeable because my scooter wouldn't work when twisting the throttle. So I'm trying to use CA glue to secure the pins to the connector and I'll try to remind myself to not push too hard.

Other than that, I tested out my scooter on this 5% type of hill on campus to see how it would do and, man, it's awesome how this thing just eats hills - I was easily doing something above 20 mph! This is so much better than my electric hub bike, by like an infinity. I was also doing some simulations, and it turns out that the scooter's thrust in the lower area of the speed range is about twice as much as my bike which means... twice the acceleration(I've fallen backwards off it a few times!)! Twice the fun! And more hill climbing speed! I can only imagine was 60 amps would do.

But I'd have to upgrade my cables as they get pretty toasty right now (About 130 to 140 degrees).

[swbluto]

Ok, I was just doing some aerodynamic measurements. I found out that my "frontal surface area" was about .7 sq. meters standing up. I used google to do the conversion for me - average width is in inches and the height is in feet. Basic formula -

(average width*height*12) sq. in. in sq. meters

So I googled...

http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=Zvp&q=%286*15*12%29+sq.+in.+in+sq.+meters&btnG=Search&aq=f&oq=&aqi=

for example. I then bent down to see what my frontal surface area was in the "aerodynamic scooting position" and it came out to .4 sq. meters! Doing the simulation on that and I was achieving 35 mph! So I've been probably getting 32 mph on my scooter, in the bent down position, haha (I don't know if I'm accurately taking into account the bad bearings on my motor, though, so maybe it's more like 30). I don't usually hold it in that position for long periods, though, since it's not too good for the back, but I will for the occasional .3-.5 mile straight stretch of road. The thing I realized is that I'm taking up less cross-sectional area than I am on a bike. The bike requires the legs to go the side of the bike whereas the legs can go directly behind the handle-bar stem on the scooter in the right position. Also, I'm kind of forced into a slightly upright position on the bike and I'm not aerodynamic at all.

But, compared to standing up, the scooter does worse as I found my surface area .7 m^2 as opposed to the usual .55 m^2 during biking. But considering I'm standing up when my typical speed is more like 10-20, aerodynamics doesn't matter as much.

[swbluto]

Just a quick list of updates.

I've upgraded the bearings and added some extra epoxy to the magnets to help secure them. When I damaged the motor in the process of upgrading it, I noticed that it had difficulty installing everything on the scooter's mount and frame, but I tried to work around it and it's been successful so far. It seems that the clicking I tried to get rid of didn't disappear, but it does seem quieter and the motor seems to turn more smoothly. At a distance (say 100 ft.), the only thing I could hear was the whine of the electric motor, so it seems there should be no worries about reducing whatever reducible sounds that I think may bother others in the vicinity (I can't really get rid of the whine).

Also, the home-made Oak wooden motor mount split along the grain so I decided to revert to the aluminum and acquired some 1/2" 6"x48" aluminum stock from Earthworks Recycling and acquired the necessary machinery to work with metal (hack saw, special hole saw, metal-working radial arm saw blade) and then fabricated the necessary bits. One thing I can easily say is that working aluminum is much louder and slower than working with wood. I'm kind of glad that I now have aluminum stock hanging around because I have a feeling I'll be creating another motor mount for the other HXT motor I have.

Also, it really seems I have bad luck with the data-wire connector. The DB9 connector (standard serial port type, I think) seems great, but it doesn't seem like I'm hooking up the wires correctly or crimping it right or something because the wires have ripped out of the connector due to stresses and such. So, I'm looking into getting "the right crimper" (I thought my servo crimper would've worked) and trying again with official 9-wire ribbon cable instead of individual strands. Any suggestions for a 6-15 wire connector that has a pretty high connect-disconnect cycle life and is pretty easy and quick to connect while remaining relatively secure under moderate forces?

[swbluto]

Ok, so I got to experience my new and improved temperature sensor now that I've got it installed "correctly". I've programmed it so that it temporarily reduces the maximum current depending on how much over the limiting temperature is (and cuts out completely at the cut-off temperature) and I started to notice a significant decrease in power (i.e., my "top speed" wasn't nearly as fast). I at first worried I might've over-discharged my a123s but their resting voltages was at 3.24 volts per cell average, so I checked the ESC and it felt like it was about 190 degrees Fahrenheit. I let it cool for 10 minutes, and revved off again and it was as powerful as I had known it, with its 30+ mph top speed and all. So, yay, it works! It doesn't cut-out, it just becomes a noticeably poorer performer.

I also felt the motor's "can"/"bell"/case and it was pretty hot, like probably 170 degrees fahrenheit. It seems these HXT motors get pretty hot at what I'm calculating a ratio of 40 continuous amps for 700 grams or .7kg, so about 60 continuous amps per kilogram. Improving thermal transfer on these motors like livingforphysics has done would probably substantially alleviate this. It looks like the 1.5kg motor I have can put out 90 continuous amps, which corresponds to about 42-45 mph on a standard bike. With increased cooling effectiveness, maybe I can eke out 50-55. Although I'm only really looking for 40ish mph with power to spare on hills (And that seems to correspond to a gear ratio of 15 to 1, eeks.).

Also, the ground wire ripped out of the crimp-style DB9 connectors I've been using suggesting I'm not making these connectors correctly or something, so I decided to splurge on official connectors that already had wire attached and I just hacked that apart (The lack of ground wire effectively disabled my throttle and produced strange seemingly random behavior in the motor). I secured the dable at two points on the scooter's frame so that virtually no stress is placed on the individual wires that I twisted together and soldered to the brake and throttle lines. And I have 5 wires to spare, yes! I just wonder what kind of current carrying capacity 26 gauge is, however, cause I need to power the back-light to the LCD module.

Hmmm... it seems this place thinks it's about .4 amps. Shucks. Oh well, I guess I could power the backlight at 40% (It seems 100% corresponds to 1 amp).

[swbluto]

So I took the scooter through about .3 miles of grass fields since the alternative was dirt roads. It was bumpy, but it made it through! About 2 miles down the sidewalk, I felt noticeable clunkiness in the back wheel and upon further inspection, it seems the bearing had popped out and it was spilling its balls! So, uhhhh, I have to correct whatever to prevent that in the future. For now, though, it seems my electric vehicles are on hold. I could possibly get the bike up and running, but it doesn't really go that fast at lower voltages and I don't know of an easy combination with my existing batteries to produce a desirable top speed and capacity. (I have the following batteries - 10s2p a123 30v 4.4 Ah; "48v 10ah" more like 30 volt 8 ah ping 1.0; 24v 20Ah ping 2.0)

My 48V 10ah battery is problematic and is now more like 30 volts 8ah and it doesn't have any sort of protection on it, although I was building an LVC prototype for it originally. I guess I could combine that with the 24v ping to get 54V 8Ah. That would produce a desirable voltage and a range comparable to what I originally had (Like 10-14 miles). There's a significant weight and space penalty, though, for the unusable capacity.

The area around the bearing is pretty complicated to describe, but the wheel is tilted at a slight angle relative to the line of motion since the timing pulley on the wheel is about 1/2" to the right of the timing pulley on the motor. I wonder if this might've have encouraged it to pop out when the belt was spinning the wheel? Also, I noticed this small metal tube had penetrated the inner race into the bearing - I wonder if that arrangement was bad for it? I don't know how it was originally set up, but it seemed this arrangement has worked up until right now and it kind of seemed logical, but I'll admit I'm clueless about wheel-bearing mechanics.

For now, I'm guessing I'll want a longer shaft to put into the motor and I suspect that's going to take me time to source as it'll probably have to be custom made (But I don't have a lathe, I believe.), and that'll allow me to reverse the timing pulley to bring the timing pulley more in line with the wheel's pulley - that's the way it was originally set up on the original motor. And I'm thinking that I might have to do something about how the metal tube part was pressing on the inner race - I'm not sure if that was a bad thing to do. It seems like the inner race and shield doesn't move while the outer race does move as the wheel rotates, and I think I KNOW you're not supposed to press on the shield, so I guess it might have been O.K.