fooferdoggie 

Ok I just got a new display on my Ebike that lets me see what wattage I am imputing compared to what the bike is providing. I only had a short ride and I was only feeling so so and just got my bike back from the dealer from the upgrade. tomorrow morning will be better as a test. as I get healthier I use less and less assistance. I am stuck between the next to lowest level going too fast with it but the lowest is a bit too low to maintain my speed. I think it is 100% verses 25% I want to keep track of how much power I am putting out and my heart rate. my bike is heavy 53 pounds and 1.5" tires so at the lowest level of assist hard for me right now to maintain 22mph. I am wondering how much wattage does it take to keep a road bike at 20 mph if someone weighs 250. that would be pretty close to me and my bike weight . at least now I will have a better idea of how many calories I am using. here is my first ride. I will hook up my HRM tomorrow and really get a better idea.

Bigbus

You went 6.68 miles averaging 15.6 MPH and burned up 189 cals. The cals seems low for the speed/distance/weight. It seems it should be closer to 48 cals/mile. Just my $2 worth.

caloso

I’m not sure what the question is. Are you asking how much power it takes to do 20mph on a standard road bike? I’m assuming no wind and flat ground, right?

Looking at some Strava segments where I averaged 20mph, I would say 225 +/- 10w. This is on a Tarmac with 25mm training wheels and tires. Note that weight of the rider doesn’t make much difference on a steady interval on a flat road, so yours might be a little higher but not by much.

caloso

Seems close enough to me: 135w for 25min is 3375 wmin = 202.5kj

ZHVelo

But OP said it is an E-Bike so some of that speed came from the bike, not OP. Does that change your view?

DrIsotope

Am I wrong in reading that the activity states "avg. user power" at 135W, and "power output" at 277W? So the OP was doing about half the work.

fooferdoggie 

according to the bike I did 30% of the work. I will ride better today and get a better idea. this is my commuter bike so its s all city riding so lots f starts and stops. I have one way I can go to work where I can get a lot more even riding in the 9.5 miles of my commute. This s a e bike with a mid drive. the harder you push the more the motor helps to some extent. I am working to use as little assist as I can and still manage the 30+ miles I ride a day every day. my usual average through town is about 17.5 mph and on the bike path 18 to 19 mph if I push it. Now I can really knowhow much I work compared to the bike.
I may be riding bit much I get 20 to 240 miles a week and a minimum of 30 miles a day. the bike as flat bars and I am at about 60 degrees so a fair amount f wind resistance when you cruise at 22+mph.

fooferdoggie 

right a good idea if I could power a analog bike well.

Riveting

Power meter pedals, or a crank arm power meter, will empirically answer the OP's question.

This calculator estimates 230 watts is the answer to the question Bike Calculator

fooferdoggie 

my e bike has a built in torque sensor. but how would I know what a regular bike needs verses a 52 pound bike?

Riveting

Any difference in bike weight makes very little difference in maintaining a specific speed on flat ground (assuming all other things are equal, like rider position, tire tread/width/psi). Uphill is a different story. That calculator shows that it's only a 6 watt difference for a bike that weighs 25 lbs. vs. 55 lbs.

For comparison, the calculator shows that simply changing position from the hoods to the drops gains you 37 watts, or 1.5 mph. Aero is everything, once you're above 17 mph.

Bigbus

My bad. I missed that completely. Thanks for clearing that up.

burnthesheep

I designed the product inspection test skid for Fallbrook's e-bike IGH combo electronic cadence control unit years back. When we went to commission it in Austin, they had us ride e-bikes to lunch with their stuff on it.

The % assist you could ask for to me seemed to work really really well. Like, it wasn't like a 4-position selector switch. It really felt like it had a good working range of assist.

I would investigate why your bike is having trouble with the granularity of the assist level it is providing. That could really improve your user experience and data you're looking for.

But, for road bike, I'd say that wattage of over 200w on flat for 20mph would be probably on a pretty non-aero setup on standard tires. I ride a pretty aggressive setup road bike and I do rides that average 20mph with 60 feet per mile elevation on only about 205w or so AP. Then again, my Stages power meter is probably junk.

Iride01 

A regular bike that weighs 40 pounds or a regular bike that weighs 17 pounds?

Maybe what you should look at is what other riders do on similar routes with non electric bikes. That will be the wattage that is needed to move them over that route at their combined weight of bike, equipment and their own weight.

It already sounds as if you can figure out what wattage you are putting into a particular route separate from what the bike gave you. So if you are wanting to compare your effort to another cyclist without an E-bike, then you have the number you need.............. I'd think!

rubiksoval

In similar terrain I'm about the same at 170 lbs. Two of my last shorter rides on different routes were 204w AP for 20 mph and 211w AP for 20.1, so sounds like a good estimate.

caloso

That looks like it's within the ballpark of the data that rubiksoval, burnthesheep, and I all gave.

I don't know how ebikes work but it seems to me that if it has a torque sensor built into the crankset so it can figure out how much boost to give, then it can certainly figure out how much power the rider is putting into the system. 135w sounds reasonable.

caloso

"analog" = human powered?

hubcyclist

I have less aero gear (base model Allez with stock wheels) and on recent rides I did outdoors in a flat area near my parents' home, some segments of 20mph had me putting out 225-241w (I weigh about 160ish), and it seems like around 200w keeps me around 19mph, but that's just a really quick glance at a few segments that average %0 gradient over the course of a few days. Maybe I should get a hold of some more aero wheels and see what I could do with those lol

fooferdoggie 

I goofed up and erased my ride this morning I guess or it only syncs once a day don't know for sure. . but I was doing about 190 or so watts and it was not too hard to do I could maintain it. 225 was not bad but I could not go the whole ride like that.
ok here is my morning ride a little slower then usual but not too bad. Now I can see how much power i can put out. I just realized it does nto include my average heart rate. How does heart rate effect calories. looks like my garmin is only 50 calories off but it does not get the wattage output.

fooferdoggie 

bosch does not allow any changes in the assist levels. I am pretty close to the lowest level but its a big jump 100% down to 25% it might be that I have been kinda of tired too. with 1.5" tires and a little motor drag the 25% is a small difference between no assist and the 25% it is a subtle difference. Bosch has such a great system that the bike just makes you feel stronger it does not push you along. but now with the wattage meter I can see how much is me and how much its the bike.

fooferdoggie 

yes mine works with a torque sensor so the more power you put in the more the motor kicks in till you start going faster my wattage starts to increase a fair amount above 22mph. now my speed on the same assist level on flats has creeped up to around 24. usual;y the nI hit 22 and could hold it with not much effort I would drop down a assist level. but thats too big of a drop now for me to maintain . but I will get there. now the nI have a good bike path and need to get to work I may crank up the assist a notch and cruise at 26mph. now I will be able to see the wattage on that.
I got the e bike so I could ride at all and slowly I am working harder and harder. I watch way too many people on their fat tire e bikes hardly peddling at all. I want to get exercise and I am proud I can ride 30+ miles a day.

rubiksoval

Using pedal assist to go 26 mph is ridiculous, ESPECIALLY on a bike path.

If you want to work hard, get a bike without pedal assist. At those speeds, you're a danger to everyone, yourself included.

This is the problem with e-bikes for some people. They write checks that the riders' don't have the skills to cash and the common sense to use appropriately.

fooferdoggie 

I only do it when the path is clear. at 6:30 in the morning it usually is. I have had roadies follow me. and sometimes pass me.its wide paved path. I don't take chances. but I I don't usually need to go that fast. and riding without power does not give you more of a workout unless you can put more power into the ride then you normally can. I put as much effort in as I can so riding without power would not be be a better workout it would just be slower. if I ride without power I cant do 20 maybe I can do 15. I commute 25 miles a day going faster saves a lot of time. Yes I keep it safe I don't don't do crazy things.
I work as hard as my body will let me. since nov I ride 20+ miles a day and since the last three months its been 30+ miles a day. 220 to 240 miles a week. since nov I have put 5200 miles on my commute bike and 1600 on the tandem in 3 months. I think that's pretty dam good.

rubiksoval

You have a bizarre idea of what constitutes a workout. If you're capable of pedaling a bike on your own, but you add assistance purely so you go faster, then you've lost the whole "workout" concept and have simply turned it into a moto ride. I can understand the commute aspect and needing to get to work, but your claims of riding 220-240 miles a week simply aren't true, and your apparent need to rip around at 24-26 mph is, again, ridiculous.

Obviously you can think that's good if you want. I think it's a farce and a danger.

caloso

I'm sorry, but this doesn't make any sense. The only thing that matters for training is Time x Effort. Think of it this way: If you rode up a hill, you'd go less far in the same time than on flat land, but if you put in the same wattage, it's the same effort. Similarly if you rode into a headwind compared to a tailwind. Or if you rode on a stationary trainer where you literally go zero distance. This is exactly why people use powermeters for training, because they use them to measure effort and it eliminates all the other variables.

And I totally agree with RS about riding an electric bike on a shared path.