Anybody else running an electric front hub?

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Blaze

Guest
Does anybody here have the electric hub kit installed? I bought an electric hub kit from Spookytooth. It's the same type of hub I have seen from companies like Crystalite and Wilderness Energy.

Mine is the 48v 600w brushless motor. The performance specs as advertised are 24mph with a 20 mile range when using 20Ah Sealed Lead-Acid batteries. The range is right where it should be, with the batteries taking me 21 miles without pedaling, even when starting and stopping a lot. The speed, however is only about 17 miles per hour. I was wondering if anybody else had built one of these and gotten it to go any faster. I weigh about 185 pounds, so we can factor that in. I saw one place selling motors saying that they were advertising top speed based on a 140 pound rider.

One thing I am going to try is soldering the main power wires. Just the heavy wires carrying all the amps. That might help, 'cuz the connectors look pretty cheap and they look like they could be a source of high resistance. It seems odd to use such heavy gauge wire and cheap crappy connectors. It could be a voltage bottleneck.

That said, the bike is still pretty fun to ride. This kit makes almost no noise at all and it climbs medium sized hills pretty good.

***** A note on the battery Amp/hour ratings *****

Many makers of quality SLAs (sealed lead acid batteries) will build a good battery, then rate it 15% lower than what it is actually capable of, just so the customers still get the full rated power even after the battery starts to age a bit. This means a good brand like Panasonic or Yuasa will build a battery and label it as a 17Ah battery, even though it really runs at 19-20Ah. Since the good 17Ah batteries really hold nearly 20Ah, the Chinese battery companies have taken to labeling all of their 17Ah batteries as 20Ah, when the real rating might be lower. The basic idea here is that a cheap 20Ah battery has the same or even less power than a good quality 17Ah battery. Don't pass up a good deal on a quality 17Ah battery because you are holding out for a 20Ah battery. The 17Ah battery will be better if it is a reputable brand.
 


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Butch

Guest
I also have the exact same front electric hub that you mentioned and was wondering why I wasn't getting close to the 24 MPH that spookytooth claimed. I too get a max speed of 17 MPH. I have 4 12V 10aH batteries.
It's a lot of fun to ride but I'd like to get a little more top speed out of it if possible.
 
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gone_fishin

Guest
e-bikes...finally!!! :D

it's now official guys, we have it all at MBc 8)

we (the bike shop) will be building an e-trike up this way in the spring for the owner (an elderly gal), & i get to put one on a stretch cruiser, maybe i'll actually know something about them by then :)

btw-i'd completely settle for a silent 17mph 8)
 
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Blaze

Guest
Butch said:
I also have the exact same front electric hub that you mentioned and was wondering why I wasn't getting close to the 24 MPH that spookytooth claimed. I too get a max speed of 17 MPH. I have 4 12V 10aH batteries.
It's a lot of fun to ride but I'd like to get a little more top speed out of it if possible.
Is yours the version with the chrome and red circles on it, kind of like a bullseye? That's the one I have.
 
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Blaze

Guest
augidog said:
e-bikes...finally!!! :D

it's now official guys, we have it all at MBc 8)

we (the bike shop) will be building an e-trike up this way in the spring for the owner (an elderly gal), & i get to put one on a stretch cruiser, maybe i'll actually know something about them by then :)

btw-i'd completely settle for a silent 17mph 8)
Yeah, it still is pretty cool, even if it doesn't break 20mph.

One VERY important thing you need to know when putting that hub on: you MUST fabricate a torque arm to get the torque away from the axle! When you hit the brakes on a coaster brake, the axle would just spin around and mess stuff up if it wasn't for the little torque arm that's attached to the back hub. Same thing for a front hub motor. Mine has a lot of torque and has spun completely off a couple of times. Luckily, I was going slow (the most torque is when you start from a dead stop), and caught it, so it didn't break the wires. I stuck a 10mm wrench over the flattened part of the axle and used a hose clamp to secure the other end of the wrench to the fork. I did this on the side with no wiring, since that side of the axle is solid. The wrench worked so well, I decided to cut the box end off with a grinding wheel, paint it black, and now it is my permanent torque arm. I have very sturdy steel dropouts on my front forks, and the motor still had enough torque to bend the dropouts wide enough to let the axle spin off. I have no idea why these things would ever ship without a torque arm included in the kit. It is absolutety necessary! Do not deliver any bike to a customer without a torque arm to secure the axle from spinning out of the forks.

Hey Butch- did you have any problems with axle torque?
 
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Butch

Guest
Blaze, thanks for that suggestion. I haven't had any problems yet with axle torque but to be on the safe side I'm going to get started on installing a torque arm right away. Yes it is the chrome and red one that looks like a bullseye.
 
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Blaze

Guest
I have a tendancy to test the limits of an installation. I would repeatedly go from a dead stop to full throttle, and that's how it failed. I knew it would stress the forks, but I wanted to make sure that if I loaned the bike to somebody who didn't accelerate carefully, it would still work fine. I think the installation should be able to handle the full operating range of the equipment. In this case, that means going to full throttle from a complete stop. If the motor is capable of generating that kind of torque, then the forks should be capable of handling that kind of load.

The wrench idea is working great. I wouldn't use too cheap of a wrench, but then I wouldn't use a Snap-On wrench either. I used an Ace Hardware 10mm wrench. Grind the box end off (you dont need to, but it keeps it from looking like you forgot your wrench on the bike) and paint it to match you forks. The order I bolted it together goes from the hub out on the side without the wiring: washer, wrench, washer, fork, nut. The first washer keeps the wrench off the area where the bolt changes from round to flat. Then the wrench. The next next washer keeps the wrench off the fork. Then the fork. I didn't have room for the last washer, so I put the nut on without it. I didn't really want to, but the nut was slightly bigger than the washer anyway, so I went ahead and did it. Before you tighten everything down, hose clamp the wrench to the fork next to where you ground the box end off, then tighten the side with the wiring. This will force the axle to rest against the edges that will be handling all of the load. Lastly, tighten the side with the wrench install on it, and you should be ready to go.

I have another idea on how to grind the wrench down a little to eliminate the need for one of the washers and hold the wrench in better, but I haven't tested it yet. I will draw it real fast and put it in this post...

 
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Blaze

Guest
Well, my wheel popped off again today. When I got it back home, I ground down the wrench and axle to keep the wrench locked to the axle. After putting it back together to test it, the system no longer works. That was the 4th time the wheel fell off, and this time it finally broke something. The wheel turns, but it only turns at about 7mph now, with the wheel lifted off the ground and not being ridden. I'm not sure what's going to happen next. I sent an email to the guys I bought it from. They still never responded when I told them their 24mph motor only goes about 18mph.
 
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