The e-bike thread.
04-11-2013, 11:14 AM
#541
Boost Pope
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Where there are some systems which drive the chainj or the front crankset, the majority drive the rear wheel directly, including all of the systems we're discussing here.
Many of us still like being able to use the pedal system, however. That is where freewheel discussion comes into play. With very high-geared freewheels it's possible to achieve higher speeds through a combination of pedal and motor power.
Many of us still like being able to use the pedal system, however. That is where freewheel discussion comes into play. With very high-geared freewheels it's possible to achieve higher speeds through a combination of pedal and motor power.
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04-11-2013, 02:30 PM
#544
The motors we're interested in (mechanically enlightened people that we are
) are the ones embedded in the rear wheel rather than the front for obvious reasons. The motor is the hub. There are other setups which drive the front sprocket, or act on the braking rim, or push on the tire directly.
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04-11-2013, 02:35 PM
#545
Yes I know what a freewheel is, I have a shimano fw tool and know how to use it. Putting real derailers and shifters and a good freewheel was the best thing I did to my $30 mountain bike.
Speaking of cheap bikes, did anyone notice that there's an electric mb up on woot for a surprisingly good price.
Speaking of cheap bikes, did anyone notice that there's an electric mb up on woot for a surprisingly good price.
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04-14-2013, 01:49 PM
#551
In a weird way, I got to test drive my bike tonight from out here in sunny Kandahar province.
I had to run from A to B to A again and one of the civilians offered to let me use his bike. It was dusk so I threw on my reflective belt (safety first) and sped off. Was weird covering so much ground so quickly since I usually walk everywhere I need to go around here.
I knew his was a 29er, but I didn't realize until I got to point B (where there was light) that his bike is a Diamondback Overdrive V, almost identical to the Overdrive Expert I ordered from Amazon for my e-bike base. Just add cable disc brakes to the bike I was riding and you'd have my new bike. Cool.
I had to run from A to B to A again and one of the civilians offered to let me use his bike. It was dusk so I threw on my reflective belt (safety first) and sped off. Was weird covering so much ground so quickly since I usually walk everywhere I need to go around here.
I knew his was a 29er, but I didn't realize until I got to point B (where there was light) that his bike is a Diamondback Overdrive V, almost identical to the Overdrive Expert I ordered from Amazon for my e-bike base. Just add cable disc brakes to the bike I was riding and you'd have my new bike. Cool.
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04-14-2013, 04:41 PM
#552
Boost Pope
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So, back in town, got everything re-assembled and running.
To re-cap, here is what the axle looks like installed into the frame after I shaved down the torque plate and removed the un-needed second shim from the inside (having shaved the brake caliper mount). I have highlighted in green the area which the old nut used to engage, prior to having made these modifications:
It's pretty obvious from this why I was having troubles.
I don't have any in-progress shots, but with the new threaded insert installed on the axle, and then the new 20mm nut installed over top of that, it feels *much* better. I was able to apply considerable torque using a big open-end wrench, and it didn't feel like the fastener wanted to yield at all- nice and solid.
Here's what it looks like all together:
Beefcake!
So, back to where this all started with two flats in two days. Turns out that the rim strips which come on these wheels are just utter garbage. For those not familiar, the rim strip is a band of materials (usually plastic or plastic-impregnated fabric) which wraps around the "inside" of the rim (from the point of view of the tire and tube) and protects the tube from the many holes drilled into the rim to accommodate the spokes. Here's a picture of the stock rim strip (in white) that came on the front wheel of my bike:
This one's not horrible. It's a somewhat sturdy-ish plastic material, but it isn't wide enough, wasn't centered properly, and doesn't provide excellent coverage in all areas:
The one that came with my rear wheel was just utter garbage, however. An ultra-flimsy little strip of rubber that was barely wide enough to cover a spoke hole, and almost as thin as the lies the Hustler tells himself about his life:
In that image, the old one is on the right. On the left is a new one I picked up from Nashbar, which is a world apart in terms of size and quality. Very thick, fairly stiff, and wide enough to cover nearly the whole rim from edge to edge, leaving only the bead area exposed. Here's what it looks like installed:
My guess is that the old weaksauce rimstrips just weren't doing the job at 80 PSI, allowing the tube to sort of herniate out into the spoke wells and become punctured. Pretty sure that won't be happening any more.
These things are so cheap I can't understand why a bike/wheel manufacturer wouldn't use decent ones. I paid $2.99 for a retail pack of two:
To re-cap, here is what the axle looks like installed into the frame after I shaved down the torque plate and removed the un-needed second shim from the inside (having shaved the brake caliper mount). I have highlighted in green the area which the old nut used to engage, prior to having made these modifications:
It's pretty obvious from this why I was having troubles.
I don't have any in-progress shots, but with the new threaded insert installed on the axle, and then the new 20mm nut installed over top of that, it feels *much* better. I was able to apply considerable torque using a big open-end wrench, and it didn't feel like the fastener wanted to yield at all- nice and solid.
Here's what it looks like all together:
Beefcake!
So, back to where this all started with two flats in two days. Turns out that the rim strips which come on these wheels are just utter garbage. For those not familiar, the rim strip is a band of materials (usually plastic or plastic-impregnated fabric) which wraps around the "inside" of the rim (from the point of view of the tire and tube) and protects the tube from the many holes drilled into the rim to accommodate the spokes. Here's a picture of the stock rim strip (in white) that came on the front wheel of my bike:
This one's not horrible. It's a somewhat sturdy-ish plastic material, but it isn't wide enough, wasn't centered properly, and doesn't provide excellent coverage in all areas:
The one that came with my rear wheel was just utter garbage, however. An ultra-flimsy little strip of rubber that was barely wide enough to cover a spoke hole, and almost as thin as the lies the Hustler tells himself about his life:
In that image, the old one is on the right. On the left is a new one I picked up from Nashbar, which is a world apart in terms of size and quality. Very thick, fairly stiff, and wide enough to cover nearly the whole rim from edge to edge, leaving only the bead area exposed. Here's what it looks like installed:
My guess is that the old weaksauce rimstrips just weren't doing the job at 80 PSI, allowing the tube to sort of herniate out into the spoke wells and become punctured. Pretty sure that won't be happening any more.
These things are so cheap I can't understand why a bike/wheel manufacturer wouldn't use decent ones. I paid $2.99 for a retail pack of two:
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04-14-2013, 07:45 PM
#554
2 Props,3 Dildos,& 1 Cat
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totally china. sell a few hundred thousand wheels for 50 cents more each and that's some CEO's Ferrari!
Also I don't know why I didn't think of this before... tapered pipe thread nut!
Also I don't know why I didn't think of this before... tapered pipe thread nut!
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07-03-2013, 10:06 PM
#560
Boost Pope
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I am massively unimpressed.
Details:
"250-watt direct-drive electric motor"
Direct-drive motors are heavy, inefficient, and have shitty low-end torque as compared to planetary-gear motors. (This was the primary failing with my first e-bike build.) There's a reason that all electric cars, even those with no gas engine at all, still use conventional gear-reduced differentials, and e-motorcycles use belt or chain reduction at approximately the same ratio as their gas-burning cousins. And 250 watts is utter weaksauce. You can't even buy sauce this weak at the grocery store. You have to start with the weakest weaksauce that they sell in the baby-food aisle, and then mix it with distilled water to get sauce this weak. I'm running my geared motor at 1,300 watts (25A @ 52v), and the folks at endless-sphere would consider this to be "adequate, but unremarkable."
This is not hyperbole. I've done some checking around, and it is literally impossible to buy a motor-controller combo rated for less than 250 watts at ANY of the vendors I looked at.
"342 watt-hour battery"
A 342 watt-hour battery is kind of ho-hum. Better than most lead-acid packs, but hardly mind-blowing. My battery is 598 watt-hours (52v, 11.5ah), and it's not even top-of-the-line. The current gen version of my battery is 925 watt-hours (50v, 18.25ah) and it only costs $725. All in all, the tech specs on this bike, at least the e-portion of it, are entry-level casual at best. For $6,000 you are getting about $800 worth of electronics (half that at wholesale) stuck into a very pretty frame with some high-end accessory parts on it and some clever marketing.
"Earlier this week we took these bikes on a loop around Central Park in NY. Oh man. I fully expected to hate this thing, but it's just so incredibly fun."
Yeah, Central Park is totally flat, so I'm sure it's fine there. Try repeating that same road test in SoCal. Or anyplace that has some elevation changes, for that matter. You'll hate it. Also, ironic sidebar: e-bikes are illegal to operate on public roads or sidewalks in the entire state of New York. Source: NYS DMV - Recreational Transportation
(Not that they actually enforce this law, at least in Manhattan. I see 'em everywhere.)
It's also not ideal for city life because it accelerates so quickly, and because it's so heavy it's not as maneuverable"
Are you kidding me? My bike is slightly heavier and a LOT more powerful, and it's an absolute joy in the city. That quote alone tells me that the reviewer was paid (or blackmailed) for the article. There's just no way that a 250 watt e-bike with a direct-drive motor accelerates so quickly as to be un-enjoyable. The laws of physics preclude it. It saddens me that the e-bikes which get the most press are the ones that are the very worst examples of the breed, both in terms of absolute performance AND price : performance ratio. I honestly wouldn't accept this bike as a gift, much less spend money for it.
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