effect of bikes on mi/Kwhr.... post yours!

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dtbaker61

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Next time I have the rack full I'll try to take some "average power at 60mph cruising speed" measurements to compare with normal driving, that should give us a good idea of the aerodynamic impact.
our highways are posted 75mph, and 'normal' flow is closer to 80-85.... so that makes a lot more difference when considering aero drag.
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I don't have a lot of data taken with bikes on, and part of the problem with the data I have is that it has a lot of confounding variables - lots of elevation gained or lost on those days, so hard to tell what the baseline should have been.

However it didn't seem like the loss in efficiency was bad - I was still out performing the ABRP estimates (when set to the default 3.1 mi/kWh), and after the fact I found that if I had tweaked ABRP to 3.4 it would have predicted very closely.

Next time I have the rack full I'll try to take some "average power at 60mph cruising speed" measurements to compare with normal driving, that should give us a good idea of the aerodynamic impact.
I also didn't pay close attention to mi/kWh with bikes on but agree that it didn't seem like the loss in efficiency was that bad. Next time I have two bikes on for a longer drive, I'll pay more attention and collect some data (although climate use may confound my numbers).

Just had the ebikes (one 38 lb and one 50 lb) on the rack today for a 10 mile drive each way on 40 - 50 mph secondary roads. On the way out, no climate use, got 3.0 mi/kWh. On the way back, with climate use, got 2.5 mi/kWh.
Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0664

Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0663
 

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our highways are posted 75mph, and 'normal' flow is closer to 80-85.... so that makes a lot more difference when considering aero drag.
I routinely do 80 plus on the highways with the bikes on (just staying with traffic for the most part). I'll get some data at those speeds.
 
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I also didn't pay close attention to mi/kWh with bikes on but agree that it didn't seem like the loss in efficiency was that bad. Next time I have two bikes on for a longer drive, I'll pay more attention and collect some data (although climate use may confound my numbers).

Just had the ebikes (one 38 lb and one 50 lb) on the rack today for a 10 mile drive each way on 40 - 50 mph secondary roads. On the way out, no climate use, got 3.0 mi/kWh. On the way back, with climate use, got 2.5 mi/kWh.
Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0663

Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0663
wow, that specialized is a monster LOOOOONG bike! I bet you have to be pretty careful on narrow roads!
 
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wow, that specialized is a monster LOOOOONG bike! I bet you have to be pretty careful on narrow roads!
Yeah, 46.7 inch wheel base and my wife wouldn't let me take the fenders off (it's hers), which made getting it on the 1up rack even more trouble. But, I figured it out and it's very secure. Bike's a real cruiser, once you get it on the trail.
 


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I captured data from the same hour-long drive, same direction, one with and one without the bike rack. There is a lot of noise in the dataset, of course, and the temps were slightly different, but my initial results show that between 50 and 70mph, there is about a 5% increase in cruising power due to the bike rack. That would be higher at higher speeds, and lower at lower speeds, but those are my initial results.

I'll post the detailed results in the next few days in a thread and link here.
 

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Here's my experience on a trip on the Wednesday before Thanksgiving with one bike on the car and outside temperatures of about 43º F both ways. I did not use climate control (except for the heated steering wheel).

This is not a controlled scientific experiment published in a peer reviewed journal. I do not know the real effect of the bike on range because I did not do the trip without a bike. Even if I did, I would not be able to control for all the variables that go into efficiency. So, all I can do is relate my experience and subjective impressions for what they're worth. I guess that's "real world" data.

Outbound:
  • 32.2 miles in 47.92 min for average speed of 47.21 mph.
  • First part of the trip was on state road with stop lights but the last ~ 18 miles of the trip were on highway at speeds of 75 - 85 mph.
  • I believe the relatively low Acceleration (47%) and Speed (36%) scores in "How is my driving?" reflect the high speeds on the highway.
  • Average 2.8 mi/kWh.
Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0680


Homebound:
  • 45.9 miles in 57.42 min for an average speed of 47.96 mph (essentially the same as Outbound).
  • Started home from a different location but the trip was a very similar mix of the same state road and highway at the same average speed. One difference is that it was rush hour and my maximum speeds on the highway portion of the trip were 55 - 65 mph. Also, it was dark (still need to see how that effects range).
  • The better Acceleration (60%) and Speed (79%) scores in "How is my driving?" probably reflect the lower speeds on the highway for the return trip.
  • Average 3.5 mi/kWh!
Ford Mustang Mach-E effect of bikes on mi/Kwhr.... post yours! IMG_0696 2


What do I think I learned?
  • High speeds kill range fast (nothing we didn't already know).
  • Also, maybe the hitch, rack, and bike don't have that big of an effect on range, even at high speeds on the highway. I'd be getting 2.8 - 3.0 mi/kWh at those speeds over the summer before I had the hitch and with no energy going to "Ext. Temp.".
I hope to collect some more real word data with bikes on and off, if winter cooperates.

EDIT: Oh, and I should mention elevation change. There wasn't much. It's pretty flat around here relative to some parts of the country and downright mountainous relative to other parts.
 
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geez. i spent all summer carting around varying quantities of bikes on a kuat rack (not that that matters but it's a nice rack) and really didn't notice a mileage change. road bike on the back on a 400 mile round trip...3.5mi/kwh. in the summer. mountain bikes 600 miles round trip, 3.3? doesn't seem super different from my normal performance.

i have been avoiding a roof rack for ski season because winter range is already lower and i really don't want to need to be towed out of the mountains
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