Article: How Far is Too Far to Bike to Work

[Harry Meatmotor]

@SolarBikeCar 156589 wrote:

…and a person of average power output (say 100 watts) will not be able to move your commuter bike at an average speed of 20 mph. As you admit it takes more than 250watts on a road bike to achieve that speed.

This topic is about commute lengths and the point I’m making is that math and physics predicts a sweet spot somewhere short of 10 miles and that it can be stretched with electric assist to about 15.

You were asking how to get an average speed of 20mph for 45 minutes, no?

That estimated 260-280 watts @ 20mph is on a 27lb commuter bike. That’s also only about 10% more effort than your target of “human input of less than 250 watts”.

My proposal: Lose weight, ride more, get stronger. Cost = $0.

Your proposal: Spend upwards of $7,000 on a car-shaped pseudo-bike with motors.

One of these proposals might be physically healthier and provoke less spite from your fellow trail users.

[cvcalhoun]

@SolarBikeCar 156597 wrote:

Implicit in the conversation is that we are talking about human as the sole energy input since your objection was to e-assist. Methinks you knew that.

On the contrary. It was you who said the advantage of the ELF was that it allowed you to get to work in less time than an ordinary bicycle, using less than 250 watts of human input. If you count the motor, your vehicle requires more than 250 watts. So implicit in your statement is that we are not talking about vehicles that have human as the sole energy input, and that in measuring the watts, we’re counting only those provided by the human. By that measure, a car fulfills the requirements–the human provides less than 250 watts.

[SolarBikeCar]

here is a model of power requirements for the given scenarios. Focus on the black line and the right scale which has the power requirements at speed for a 2% grade.
That’s 500 watts to go 20mph with a 220 lb gross vehicle weight. To get average speed of 20 I need to go about 25 on the straight-aways which increases the power requirements to 800 watts.

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[Harry Meatmotor]

@SolarBikeCar 156604 wrote:

here is a model of power requirements for the given scenarios. Focus on the black line and the right scale which has the power requirements at speed for a 2% grade.
That’s 500 watts to go 20mph with a 220 lb gross vehicle weight. To get average speed of 20 I need to go about 25 on the straight-aways which increases the power requirements to 800 watts.

[ATTACH=CONFIG]14186[/ATTACH]

Not modeled; real: Lose weight + get stronger = average speed of 20mph. Simple!

[SolarBikeCar]

@Harry Meatmotor 156612 wrote:

Not modeled; real: Lose weight + get stronger = average speed of 20mph. Simple!

this model (which matches my real world experiences) proves that you underestimated the power or overestimate the speed and thus are not giving a true picture of what is required to commute 15 miles in 45 minutes over a 2% grade. One has to pay to lift the weight over the grade and you have to fight wind drag and saying a magical incantation doesn’t allow one to defy physics.

[Harry Meatmotor]

@SolarBikeCar 156613 wrote:

this model (which matches my real world experiences) proves that you underestimated the power or overestimate the speed and thus are not giving a true picture of what is required to commute 15 miles in 45 minutes over a 2% grade. One has to pay to lift the weight over the grade and you have to fight wind drag and saying a magical incantation doesn’t allow one to defy physics.

Do you have a power meter on a bike, other than your car-shaped pseudo bike? How much do you weigh?

[dkel]

@Harry Meatmotor 156614 wrote:

Do you have a power meter on a bike, other than your car-shaped pseudo bike? How much do you weigh?

Dude, you’re feeding the troll. Every post from this turkey turns into an argument. Just do what I’ve done; this is what I see when he posts:

This message is hidden because SolarBikeCar is on your ignore list.

[Brett L.]

Let him be a troll, and ignore him. He’s picking arguments to fight, ignoring the ones that he can’t. It’s not advancing the thread, and serves no point other than to get people mad.

[Crickey7]

I guess the issue is why is one required to accept as predetermined a set of variables, namely 15 miles in 45 minutes over a 2% grade (which would apply in only one direction in any event). Why is it that none of those can vary? Some people drive part of the way. Some people take longer than 45 minutes. People often say things are not possible because they’ve claimed certain variables are not variable, that they are fixed. Only one of those is fixed, the 2% grade.

[lordofthemark]

@Brett L. 156616 wrote:

Let him be a troll, and ignore him. He’s picking arguments to fight, ignoring the ones that he can’t. It’s not advancing the thread, and serves no point other than to get people mad.

Nah, for a minute it had me contemplating how to get onto the Memorial bridge in Va without using a trail OR a limited access road. Or riding through ANC.

There is not a way, is there? If someone wants to get from NoVa to central DC without using a trail or sidepath, and without using a limited access road, you need to take the Key Bridge? (I mean assuming that Chain Bridge is just too far out of the way).

[AFHokie]

@SolarBikeCar 156597 wrote:

Implicit in the conversation is that we are talking about human as the sole energy input

Dude, you invalidated your own argument. Your bicycle wheeled hybrid-power vehicle is not solely human powered either.

Sent from my SAMSUNG-SM-G930AZ using Tapatalk

[SolarBikeCar]

@AFHokie 156619 wrote:

Dude, you invalidated your own argument. Your bicycle wheeled hybrid-power vehicle is not solely human powered either.

Sent from my SAMSUNG-SM-G930AZ using Tapatalk

I’d would rather have a human powered only vehicle and would if my commute was less than 10 miles.
Since my commute is 15 miles I have e-assist.

[DismalScientist]

Where was this intolerance when I was trying to get e-bikes banned from Freezing Saddles?:rolleyes:

[vvill]

@SolarBikeCar 156630 wrote:

I’d would rather have a human powered only vehicle and would if my commute was less than 10 miles.
Since my commute is 15 miles I have e-assist.

I don’t think the issue is using an e-assist to make 15 miles easier. It’s the “I must do it in 45min and average 20mph, on the trails” (and on a vehicle that takes up much more of the trail than a bicycle). Some options for dealing with a bike commute that’s too much are) cut down the number of days or, b) go multi-modal or c) yes, potentially have an e-assist for some days so you can rest more. But not so you can average 20mph and endanger others.

Do you drive a car through a neighborhood signposted 25mph at 45mph to save time – because it takes too long to drive at a reasonable speed otherwise? Of course, you’d rather drive at 25mph but since it’s too far, y’know…

[consularrider]

@Steve O 156567 wrote:

In theory.
In reality, averaging 20 mph on a 15-mile commute is only possible if virtually all of it is on a grade-separated trail. If even 3-4 miles of the commute is on streets or any kind of urban infrastructure, there is no way. Look at dcv’s commutes. He is a truly badass, very fast rider and he averages, over 19 miles, 17ish on his fastest days.
Exactly once I averaged 20mph+ on my 8-mile commute from near 7 corners to 13th & L NW DC, which I rode hundreds of times. There was a truly miraculous, once-every-thousand-years confluence of green lights the entire ride (AND I exhibited utter disregard for other trail users, behavior of which I am now ashamed). Averaging 20 mph day in and day out is just not possible except in the rarest of circumstances.

Well, Strava just told me that the day in 2014 when I averaged over 17 mph on my commute there must have been something wrong with my GPS.

[Author]

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