Range differences between types (road vs. MTB vs. City)

[The duke]

I bought an electric mountain bike. I use it primarily for errands and pleasure riding. I thought it offered the most comfort for a novice rider as well as the most versatility, allowing me to trail ride, gravel ride or stick to city streets. Now I'm wondering if I made a mistake by buying a type of e-bike that gets poor range?

I first noticed how I was at a significant disadvantage with rolling resistance when I passed a pack of analog roadies while going uphill, but then, they passed me coasting down that hill.

I'm wondering if electric road bikes, with all other things being equal, get a significantly greater range over mountain ebikes or city/urban ebikes?

With the highest level of assist on my BH ATOM X with a Brose S and 700w battery, I get a disappointing 25-30 mile range. How much better would I do with a road bike with the same battery/motor? If I switched to slicks instead of knobbies, would that eliminate the difference?

 

[bob armani]

I bought an electric mountain bike. I use it primarily for errands and pleasure riding. I thought it offered the most comfort for a novice rider as well as the most versatility, allowing me to trail ride, gravel ride or stick to city streets. Now I'm wondering if I made a mistake by buying a type of e-bike that gets poor range?

I first noticed how I was at a significant disadvantage with rolling resistance when I passed a pack of analog roadies while going uphill, but then, they passed me coasting down that hill.

I'm wondering if electric road bikes, with all other things being equal, get a significantly greater range over mountain ebikes or city/urban ebikes?

With the highest level of assist on my BH ATOM X with a Brose S and 700w battery, I get a disappointing 25-30 mile range. How much better would I do with a road bike with the same battery/motor? If I switched to slicks instead of knobbies, would that eliminate the difference?

Hey Duke-I also use my eMTB for the same purpose riding as you have mentioned. I kept the knobbies on mine and I have a 500wh battery with no complaints. I generally ride in Eco-STD modes and I have plenty of power with very little range anxiety. In Eco, I can get approx 70 miles of range on a single charge. In STD mode a bit less. As you have indicated, the range you are getting on a 700wh battery does not seem right. Compared to my battery, the only thing I could see different is steeper inclines and wind resistance causing your decrease in range. I have the Yamaha PW-X series motor rated at 250w/500w peak. In addition, I have a BH commuter with a 36V 11.6amp battery, and am getting just about 23-25 miles of range on a single charge in the highest level of assist avg 20-23mph. It has a Dapu 350w hub motor. That said, I find it a bit odd you are getting such a low range number on your Atom X.
Perhaps someone else could chime in?

 

[PDXzap]

Here's a calculator from Grin. Maybe it might shed some light?

 

[Over50]

...With the highest level of assist on my BH ATOM X with a Brose S and 700w battery, I get a disappointing 25-30 mile range. How much better would I do with a road bike with the same battery/motor? If I switched to slicks instead of knobbies, would that eliminate the difference?

On first reading, I found the range figures you cited surprising. But now that I think about it a bit, maybe it seems in line with my experience on my Bosch commuters. I ride on the lowest levels of assist (no hills, 170 lb rider) and I see about 45-60 miles of range on a fully charged 500 WH battery. The high-end would be on tailwind days and the low end on headwind days. I've never ridden in Turbo mode for more than a short sprint (Bosch's highest setting) but I imagine if I attempted my entire commute in Turbo, particularly with some headwind, my range would be around 25-35 miles. So if you have some hills and wind then perhaps your range observations are not so abnormal.

I'm noticing a difference in range between my Rohloff bike (R&M) and my traditional drivetrain commuter (Haibike). The latter seems to average to 5-10 miles more on a fully charged 500 WH battery. There are small weight differences and geometry difference (Haibike a bit lighter, has a shorter wheelbase ...) between to the two bikes but I'm suspecting the drivetrain is the main reason for the difference. I could be totally wrong and perhaps it just comes down to weight, but I'm suspecting the traditional setup is slightly more efficient vs an IGH.

 

[The duke]

Here's a calculator from Grin. Maybe it might shed some light?

I'm waaaaay too stupid to understand that

 

[The duke]

On first reading, I found the range figures you cited surprising. But now that I think about it a bit, maybe it seems in line with my experience on my Bosch commuters. I ride on the lowest levels of assist (no hills, 170 lb rider) and I see about 45-60 miles of range on a fully charged 500 WH battery. The high-end would be on tailwind days and the low end on headwind days. I've never ridden in Turbo mode for more than a short sprint (Bosch's highest setting) but I imagine if I attempted my entire commute in Turbo, particularly with some headwind, my range would be around 25-35 miles. So if you have some hills and wind then perhaps your range observations are not so abnormal.

I'm noticing a difference in range between my Rohloff bike (R&M) and my traditional drivetrain commuter (Haibike). The latter seems to average to 5-10 miles more on a fully charged 500 WH battery. There are small weight differences and geometry difference (Haibike a bit lighter, has a shorter wheelbase ...) between to the two bikes but I'm suspecting the drivetrain is the main reason for the difference. I could be totally wrong and perhaps it just comes down to weight, but I'm suspecting the traditional setup is slightly more efficient vs an IGH.

Yeah, I'm a 200+lb. Rider with about 10lbs of gear on my 51lb bike. I've got really fat 2.8" plus sized tires that I keep at a low 19lbs of pressure to give a cushy ride, and my rides are very hilly. Add that all up and I'd bet we'd have similar results.

You didnt mention tires or riding position (hence increased wind resistance) in your comparison. Are the tires about the same on both bikes? Does one keep you way more upright than the other?

So weird that you'd attribute an almost 20% range difference to drivetrain. Wonder if that's right?

 

[GregGritton]

The electricbikereport.com web site has bike reviews with a standardized range test. I looked at a number of these, and almost always, the higher average speed a bike delivers the more power it uses. While I was mostly interested in city/commuter bikes, I did check out one mountain bike, the "iZip E3 Peak" at https://electricbikereport.com/izip-e3-peak-electric-bike-review-part-2-ride-range-test-video/. It used more power than the other bikes I looked at with a similar average speed (16mph), but the difference wasn't huge: 16.6WHr/mile instead of ~14WHr/mile.

If this is indicative, you will lose some range on a mountain bike, but commuting one should be doable.

Do see if you like the ride position. My favorite feature of "city" bikes is the upright position that makes it easy to look around; the opposite of road bikes.

 

[Feliz]

I get more range from my Yamaha powered MTB than I do from most of my other bikes ( on the same roads ), mountain bike doesn't always equate to poor range.

 

[Over50]

...You didnt mention tires or riding position (hence increased wind resistance) in your comparison. Are the tires about the same on both bikes? Does one keep you way more upright than the other?
...So weird that you'd attribute an almost 20% range difference to drivetrain. Wonder if that's right?

I ride on the Super Moto-X tires (27.5 x 2.4). Wide tires but street treads and I think they are very efficient for their width. I run them at about 42 psi which is pretty stiff. My ride position is medium-upright on both bikes but a bit more stretched out on the R&M (longer wheel base and top tube). Reading your description, it sounds like we're getting similar range results.

I don't have anything scientific on the drivetrain difference as it relates to range. And in fairness, I haven't switched batteries between bikes (ie put the 500 WH Haibike-branded Powerpack on the R&M). Its just with almost every commute I compare the mile mark where my batteries drop a "bar" on the Bosch 20% indicators. The Haibike always beats the R&M. I can almost always complete a 35 commute on the Haibike with a little over 20% remaining but the R&M is usually under 20%. If I commute on the R&M and any amount of headwind is forecasted, I always go dual-battery.

 

[PDXzap]

The Haibike always beats the R&M

Are the weights similar?

 

[Over50]

I believe the Haibike to be a bit lighter. Haven't weighed them but this is solely based on the "carry down the stairs to the basement" test.

 

[AHicks]

What I'm wondering is with your concern over range, why would you be riding with the highest level of assist? Your speed can/will make a very noticeable in your range. If you want to go further, step one and 2 is pedal harder and slow down.

You may find that on some rides you don't need full assist, and you could gain some efficiency by dialing back a bit in some areas of your ride? Basically, a lot of us have noticed a learning curve when first starting out on our e-bikes. Myself, with several hundred miles under my belt, I was a MUCH more efficient rider, having learned how to use my gears and assist levels in a manner that was battery friendly. This alone made quite a difference in range.

You could also boost your tire pressure, or possibly go to narrower (slick) tires. I recently changed the stock 2.3" width knobby tires that came on my bike to 2" "slicks". That small difference alone has me running a full gear higher on average, making a very noticeable difference in my available range. Bonus is the fact the new tires are QUIET!

Bottom line is, it's all about compromises. Lots of them! -Al

 

[The duke]

I get more range from my Yamaha powered MTB than I do from most of my other bikes ( on the same roads ), mountain bike doesn't always equate to poor range.

So I take it that you believe the Yamaha motor is more efficient than others? Interesting! Would be interested in seeing data comparing ranges of different motors...that's not usually discussed.

 

[MikeDD]

I have a full suspension e-mtb with 2.8 tires. My owners manual recommends 27 psi for the tires. I have found this psi does not affect the ride that much. You could change tires to 2.4 to 2.6 with a center rib if you still need the off road tires. You do not have to go with a pure street tire. I have been looking at something like the Maxxis High Roller II, although the price scares me.

 

[bob armani]

I get more range from my Yamaha powered MTB than I do from most of my other bikes ( on the same roads ), mountain bike doesn't always equate to poor range.

I concur with your range statement on Yamaha powered E-bikes. I get a considerable amount of range with my Haibike F/S eMTB. I am 135lb rider and I max out tire pressure to 38lbs recommended on the knobbies. I also have learned to get the max efficiency out of each ride with using gears and assist levels as indicated above. I usually do not max out my battery recharges to 100%, and limit them to 80% capacity to maximize battery life. At 80% recharges, I am getting 70miles plus using Eco. I also have Eco+ mode that just helps move the bike forward a bit. In Eco, I can see a considerable difference in my assist level, with little need to move up the scale to higher levels on straights. I am also riding at an average speed of 16-18mph while monitoring the battery usage meter on my interface which indicates very low battery output during each ride. This way, I can maximize battery output usage. From the get go, I was riding in the 2nd to highest PAS level (High), reaching over 20mph in a snap. I later realized that this was not necessary on daily rides and I in turn, lowered PAS levels to find them suitable.

 

[Slowpoke]

I have a heavy(76 lbs)all hard tail fat knoby tire 26x4 bike.Its a slug,upright riding with stuff hanging everywhere.However with 48v14amp, rear hub, tires at 20 psi I can get 100 miles in one charge.3rd gear pas1 heavy peddeling 80 rpm.I avg 11 mph.Pas 2 my distance drops to 65 miles,pas 3 about 45,pas 4 about 35 miles.I can monitor amp draw with my Grin Cycle Analist v3 and I use 1 amp/10 miles.It also displays watts,volts etc.I can't imagine how far I could go with a efficiant streamlined dual batt bike.Here is the stats from the 100 mile ride.6/27/19 start 54.6 v 14 amps.Finish:100.09 miles,9hrs 2 min,45.2v, used 10.4 amps, 517.11 watts, 5.1 wh/mi,avg 11.1 mph.I still had power and estimate maybe 10 more miles but I was tired and didn't run it down.

 

[Rexlion]

Resurrecting this old thread, I just want to ask whether some of the OP's slower coasting has to do with motor drag from the Brose? Some motors apparently have more drag when unpowered than others. I think his low tire pressure (19 psi) had to be a factor also.

 

[Grueso]

And resurrecting again (because I think it's a good thread title that comes up in searches), to add that the energy spent on fighting air resistance for a given distance increases with the square of the speed (power needed goes with the cube of speed, distance obviously linear).
So reducing the speed from 20 mph to 14 mph, or from 24 mph to 17 mph, will almost double the range on flat ground.
Race bike position vs upright reduces the frontal cross section to about 2/3, so that's also an easy factor 1.5 range extension at higher speeds.
Rolling resistance (see https://silca.cc/blogs/silca/part-4b-rolling-resistance-and-impedance and https://silca.cc/pages/pro-tire-pressure-calculator) and air drag are equal at around 11 mph, give or take; at 16 mph rolling resistance is then still about a third of the total.


In summary, the huge air drag variation with speed is more significant than 10 or even 20% efficiency differences between motors or drivetrains.

https://www.gribble.org/cycling/power_v_speed.html has a simulator that might be a bit easier to use than the Grin simulator linked earlier in post #3.