LockH
1 PW
^^ Hehe... But again, yer exchanging the size of the manufacturers gas tank for a tiny cup. :wink: ... and aero drag becomes FAR more relevant/important. :wink:
Cheapest e-components for 55mph?
- Thread starter Tony01
- Start date
So are you claiming that tandems do not have this problem, and all the drag brakes installed on tandems are due to people's ignorance? I doubt that.Chalo said:
On the plus side, disk brakes have eliminated the need for drag brakes. We have 180mm disks on our tandem and while they get hot during descents, it's not a problem. (Unless you accidentally touch one, which I did once - had a pretty good burn in the shape of the cooling holes on the disk.)
I'm a skydiver, and one thing that I have learned during my skydiving career is that getting away with dangerous decisions does not make that decision safer. Using an unsafe main parachute 100 times in a row without problems does not reduce the risk on the 101st use, and making 100 toggle-whipped hook turns does not make the 101st safer. But it does make people THINK they are safer, which is one of the reasons there are so many landing injuries.Buk___ said:
Chalo
100 TW
billvon said:
I can say that I've never faced the problem you're hypothesizing about, even when I weighed 400 pounds, lived in a city with >20% grades, and routinely reached 55mph on my bicycle commute to work. Maybe it's because I wasn't fascinated with lightweight rims? I think it's because it's mostly an imaginary problem. My rims were never too hot to touch when I checked them.
I think most of the appeal of a tandem drag brake is in the captain not having to squeeze the lever constantly on a long descent. More of a hand saver than a tire saver.
When a German cycling magazine tested an assortment of brakes to failure, all but a few of the discs failed earlier than normal rim brakes at the same power level. And they weren't using the kind of heavy, wide rims we tend to favor in this community.
Some quotes from various bike forums, mostly bikeforums.net:Chalo said:
"I blew out my rear once on a long downhill. I got off and started to pull off the wheel to change the tire and singed my hand on the rim it was so hot."
"A riding partner of mine took his 650c bike out West and had his valve stem area melt to the rim because of the braking."
"The details of what actually happens is unknown, but it surely does happen. The pressure in the tire goes up, the hot rim expands, the hot rim gets softer, the bead may also be affected by the heat."
"This is more an issue with tandems - with around twice the weight for the one set of brakes. A drum drag-brake was an option on some bikes in the past."
"On our first tandem, the cantis worked extremely well but just braking to a stop on the downhill to my house from 35mph to 0 over ~200yds resulted in a rear rim uncomfortable to touch for more than a few seconds."
From personal experience, my rims got too hot to touch when we were touring fully loaded in the north of Luxembourg, where we would see ~1000 foot descents. (Not on a tandem.)
So you might be right and tandem manufacturers, tandem riders and everyone else might be wrong. It doesn't matter much to me, since our tandem now has disks.
skyungjae
10 kW
I'm looking forward to seeing a build thread. I would've loved having an e-bike back when I lived in San Jose back in the day. Amtrak supposedly doesn't allow e-bikes due to the battery, but I don't know if it's really enforced. Down in So Cal, Metrolink is e-bike friendly. They don't allow gassers though. Anything that produces noxious fumes are a no-go.
markz
100 TW
If you build it correctly, Amtrak would have no clue its an ebike.
This obviously experienced rider of gas machines may have had a run of good experiences with unsafe machines, and thus trust them more than is warranted.Buk___ said:
That's why I used the skydiver example. I know several people who have gotten away with patently unsafe practices for years, and used that evidence to "prove" that they are being safe. And since both skydiving and riding powered bikes is _relatively_ safe, you can do it dozens, even hundreds, of times without seeing the results of that unsafe practice. Over time, however, the odds do catch up with people.
In the end, of course, it's up to you. I assume you posted here because you wanted to talk about it, even when the opinions don't match yours.
billvon said:
I have no interest in this thread beyond voyeurism for well-built machinery:
I'm just niggled by people jumping on the "unsafe" theme erroneously started by someone who read the title & username, and nothing else; when the OP's information and pictures give strong indications that this is a experienced builder producing well-constructed machines; and an experienced rider of those machines.
One man makes bad assumptions and many others jump on the bandwagon. Its not just unfounded, its unfair on the OP.
He may be a "beginner" with e-bikes, but you don't construct the machine above without some knowledge and experience.
I for one would like to see what he could do with it.
wturber
1 MW
billvon said:
As a curious outside observer, I found this ...
http://www.rodbikes.com/articles/disco-fever/disco-fever.html#disc-comparison
Things don't seem so clear cut to these tandem bike specialists.
??? They like rim brakes; so do I. Both my current electric bikes have rim brakes on the rear (just because it's easier to deal with a hub motor without having to deal with the disk too.) They're just sometimes insufficient at high weights/speeds, as in tandems and some ebikes; on such bikes disks (or in the olden timey days drum) brakes are often used. And as the article mentioned, those tandem bike specialists used disk brakes for that purpose as well.wturber said:
wturber
1 MW
Buk___ said:
Billvon makes a good point about what appears to be safe vs. what is actually safe. Surviving so far is not proof of safe practice.
OTOH, I do agree that many of us may be premature at evaluating how risky this guy's behavior really is. If I back up a bit and re-evaluate, the reality is that I don't really know one way or the other. I'm suspicious of using MTB wheels and tires (is he running speed rated tires?) at 50+ mph, but I don't have the data to know that is unwise. It just seems to me that regular use at those speeds is likely to be near the design limits of many of those kinds of tires and wheels. But that impression could be wrong ... or maybe right.
wturber said:
I agree. But the OP has the experience of riding his 60mph gas-powered bicycle. How many other can say the same? Who's judgement is likely to be better, his experience or others assumptions?
Many believe that any e-bike is dangerous -- look at NY -- but mostly those will be people will be those who've never ridden one.
wturber
1 MW
Buk___ said:
Without further info, I'd call it a coin flip.
Tony01
100 W
I have a lot to say on the safety of bike frames, brakes, and wheel components. The short version is, respect the power 
Stock steel quality bicycle frames will work fine up to around 4hp with little to no modifications. When my bike was a schwinn, I braced the heck out of it: 212cc Schwinn build thread, motorbicycling forum, post 7.
Brakes: Rim brakes work great. I prefer hub brakes however. If you think mechanical disc brakes are good, try a 4-piston hydraulic.. you'll never go back!
Rims: Modern double-wall alloy rims are extremely strong, and the friction coefficient of the rim keeps the tire on twice as good as a steelie. But I run cheap $14 50mm wide steelies. Good enough. All rims needed to be prepped by deburring, degreasing, cleaning, and careful airing of the tire to seat the bead properly.
Tires: The preferred tire by many is a maxxis hookworm or CST cyclops. Maxxis is owned by CST (cheng shin tire), which also makes motorcycle tires. The reason these tires are cheap relative to MC tires is BECAUSE they do not need to be speed rated. Just because they are not rated, does not mean they aren't good for high speeds.
My current build is built for a lot more power than it has. I started with a 1969 yamaha CT1 dirtbike that I hardtailed with 10ft of .100" wall 7/8" tubing and modified the fork to fit a bike hub. Easier said than done.
Although it will take a few months for me to get all the parts needed for an e-build, I will start a build thread here. Mostly, when I get the motor, the build will start.
Stock steel quality bicycle frames will work fine up to around 4hp with little to no modifications. When my bike was a schwinn, I braced the heck out of it: 212cc Schwinn build thread, motorbicycling forum, post 7.
Brakes: Rim brakes work great. I prefer hub brakes however. If you think mechanical disc brakes are good, try a 4-piston hydraulic.. you'll never go back!
Rims: Modern double-wall alloy rims are extremely strong, and the friction coefficient of the rim keeps the tire on twice as good as a steelie. But I run cheap $14 50mm wide steelies. Good enough. All rims needed to be prepped by deburring, degreasing, cleaning, and careful airing of the tire to seat the bead properly.
Tires: The preferred tire by many is a maxxis hookworm or CST cyclops. Maxxis is owned by CST (cheng shin tire), which also makes motorcycle tires. The reason these tires are cheap relative to MC tires is BECAUSE they do not need to be speed rated. Just because they are not rated, does not mean they aren't good for high speeds.
My current build is built for a lot more power than it has. I started with a 1969 yamaha CT1 dirtbike that I hardtailed with 10ft of .100" wall 7/8" tubing and modified the fork to fit a bike hub. Easier said than done.
Although it will take a few months for me to get all the parts needed for an e-build, I will start a build thread here. Mostly, when I get the motor, the build will start.
MadRhino
100 GW
Alu double wall rims are thin as foil, but they are stiff for their weight. I prefer thick single wall Alu, I use 57 mm wide for the street.
Light bicycle tires are not dangerous to speed, they are dangerous to torque and brake heavy. I like the Hookworm, the 2 X 60TPI ply. I ride one set every middle summer. They last 4 or 6 weeks, because I ease on them. They are a good ride on nice warm pavement. I ride the Duro Berm Master the rest of the summer, and the Wildlife on bad conditions that’s half the year here.
I have no doubt about your frame strength, only weight bothers me.
Big brakes can be found used and better than new: Hope M6 or Magura Gustav last a lifetime, the latter requiring more frequent yet cheaper maintenance. New brakes are not as big, but some have 4 pads per caliper. Heavier, faster bikes need big calipers and large pad surface. Larger rotors also help shedding heat. I like the Hope 225mm with any big caliper.
They are using bicycle DH forks on motorcycles now, I don’t see why we’d use a heavy motorcycle fork on any ebike but a monster Chopper.
Light bicycle tires are not dangerous to speed, they are dangerous to torque and brake heavy. I like the Hookworm, the 2 X 60TPI ply. I ride one set every middle summer. They last 4 or 6 weeks, because I ease on them. They are a good ride on nice warm pavement. I ride the Duro Berm Master the rest of the summer, and the Wildlife on bad conditions that’s half the year here.
I have no doubt about your frame strength, only weight bothers me.
Big brakes can be found used and better than new: Hope M6 or Magura Gustav last a lifetime, the latter requiring more frequent yet cheaper maintenance. New brakes are not as big, but some have 4 pads per caliper. Heavier, faster bikes need big calipers and large pad surface. Larger rotors also help shedding heat. I like the Hope 225mm with any big caliper.
They are using bicycle DH forks on motorcycles now, I don’t see why we’d use a heavy motorcycle fork on any ebike but a monster Chopper.
Tony01
100 W
I looked up everything in your post. Dammit Rhino, why'd you have to show me those monster brakes. Now I have to upgrade 
I'm only using the motorcycle frame and fork because it was cheap ($80 for a rusty motorcycle) and was easier than building a whole new frame. With this one I only built the rear section. Yeah, it's heavy. Really heavy. So heavy I want to build a new, lighter bike. Bet I could build a lighter ebike.
57mm single wall- how thick is the wall? I've only had the double wall 80mm in my hand. You mean something like this?
https://www.ebay.com/i/121953203036
Or this https://www.3gbikes.com/parts/wheels/26x57rims/ I dunno they look slightly different.
Yeah definitely going to upgrade to the 225mm rotor when I run out of replacements. Been searching for a bigger rotor.
I'm only using the motorcycle frame and fork because it was cheap ($80 for a rusty motorcycle) and was easier than building a whole new frame. With this one I only built the rear section. Yeah, it's heavy. Really heavy. So heavy I want to build a new, lighter bike. Bet I could build a lighter ebike.
57mm single wall- how thick is the wall? I've only had the double wall 80mm in my hand. You mean something like this?
https://www.ebay.com/i/121953203036
Or this https://www.3gbikes.com/parts/wheels/26x57rims/ I dunno they look slightly different.
Yeah definitely going to upgrade to the 225mm rotor when I run out of replacements. Been searching for a bigger rotor.
markz
100 TW
Fat tire or motorcycle rims.
Also look for 2T motors, dunno how common they are, or another option you could rewire the windings. I dunno much about 2T but they can be trouble or pesky to dial in, perhaps due to inductance or something else that is beyond me, so a controller able to handle 2T. Search it, or maybe someone will chime in.
Also look for 2T motors, dunno how common they are, or another option you could rewire the windings. I dunno much about 2T but they can be trouble or pesky to dial in, perhaps due to inductance or something else that is beyond me, so a controller able to handle 2T. Search it, or maybe someone will chime in.
Chalo
100 TW
markz said:
Seems to me that such a fast wind motor is only suited for turning really fast, because it's apt to run super inefficiently at more ordinary speeds. I want my motor to be running out of steam when I'm running out of gears to pedal along with. For me, that means using a slow wind and choosing a voltage to get the speed range I want. If I used a fast wind, that would mean an expensive high current controller and big fat cables. No, thanks.
MadRhino
100 GW
2t motors in very small wheels are OK. In a normal wheel, they are controller killers. A big, 50H 4t motor in a 24’’ rim is making a reliable bike, easy to build 60 Mph yet efficient at lower speed.
My actual 57mm rims are similar to those linked, only 24’’. Motorcycle wheels are too heavy for me, but those single wall alu rims are just in between double wall DH rims and motorcycle type. They are perfect to ride a 3.0 tire on pavement. There is a motorcycle type Alu rim that is made 24’’ bicycle size, sold by Eastgem in China. I haven’t tried them yet, but looks good.
My actual 57mm rims are similar to those linked, only 24’’. Motorcycle wheels are too heavy for me, but those single wall alu rims are just in between double wall DH rims and motorcycle type. They are perfect to ride a 3.0 tire on pavement. There is a motorcycle type Alu rim that is made 24’’ bicycle size, sold by Eastgem in China. I haven’t tried them yet, but looks good.
dogman dan
1 PW
I guess I was not so clear about the reason to ride your e bike less than 55 a lot of the time. And I only mean 40 mph for less, in terms of safe braking, not skidding a tire in an emergency stop till it flats, etc. In any case, I get it that you are personally able to ride safe at motorcycle speeds. Bet you can corner it in a counter steer just fine. Others would just splat into that car.
Its' likely to be safer if you upgrade to moped tires and rims. But there are good bike rims, and better than average bike tires out there. Looks like you have good wheels and tires now.
The real reason I was saying to ride closer to 30 mph is,,, again,,,, trying to be cheap. If you only need 10 miles range, then it can be cheap at 55 mph. 1500 wh will do it, and can still be well under a thou for the battery. But if you want to ride 50+ mph for 40 miles on one charge, now you need 6000 watt hours of battery, and a way to carry it on a bike. Bear in mind, this is about 80 pounds of battery!!!!
So how long a ride are we talking about here?
If you just took cheap out of the title, you'd get few people arguing you can do a 55 mph e bike. It's just not really possible to make it safe for anyone to ride cheap, or make it go far at that speed cheap. So far you defined cheap as about $2000, which is not really all that cheap anyway. It's plenty for a 40 mph ride, that goes 20 miles per ride. And again,, I don't object to it being able to hit 55 when you want to, briefly. It's not safe to ride 40 mph, among cars that are going 55-70 mph.
Personally, to play with cars at 55, I'll take a gas motorcycle every time. I've nicked out of a bad spot plenty of times on that scoot, or other motorcyles, by having nearly instant double the speed I'm going there when I need it. My first instinct when cars f--k with me is gas, not brakes. Avoid and leave that texting driver behind me, not brake and deal with him again in a mile.
Its' likely to be safer if you upgrade to moped tires and rims. But there are good bike rims, and better than average bike tires out there. Looks like you have good wheels and tires now.
The real reason I was saying to ride closer to 30 mph is,,, again,,,, trying to be cheap. If you only need 10 miles range, then it can be cheap at 55 mph. 1500 wh will do it, and can still be well under a thou for the battery. But if you want to ride 50+ mph for 40 miles on one charge, now you need 6000 watt hours of battery, and a way to carry it on a bike. Bear in mind, this is about 80 pounds of battery!!!!
So how long a ride are we talking about here?
If you just took cheap out of the title, you'd get few people arguing you can do a 55 mph e bike. It's just not really possible to make it safe for anyone to ride cheap, or make it go far at that speed cheap. So far you defined cheap as about $2000, which is not really all that cheap anyway. It's plenty for a 40 mph ride, that goes 20 miles per ride. And again,, I don't object to it being able to hit 55 when you want to, briefly. It's not safe to ride 40 mph, among cars that are going 55-70 mph.
Personally, to play with cars at 55, I'll take a gas motorcycle every time. I've nicked out of a bad spot plenty of times on that scoot, or other motorcyles, by having nearly instant double the speed I'm going there when I need it. My first instinct when cars f--k with me is gas, not brakes. Avoid and leave that texting driver behind me, not brake and deal with him again in a mile.
wturber
1 MW
dogman dan said:
Yep. Years ago (1977-1978) when I had a Honda CB-125 I concluded the same thing. That thing could probably do 60mph with a tail wind, but it was barely adequate for city 45mph streets because there was almost no acceleration "headroom" and 45mph streets have traffic that averages about 50-55mph. I rode it for about a year before I retired it due to safety concerns (not the bike per se, but other drivers.) And that was before we had zombie drivers with their noses in their phones. BTW, it had dual drum brakes - cable operated if I recall correctly... ;^)
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