Bosch CX vs. Yamaha PW range questions

[Telkwa]

Good morning!

A few days ago I was elated. Bought my wife, who's quite short at 4'11", a 14.5" Trek Women's Powerfly 5. Bosch CX drivetrain, 500Wh battery.

I'd been looking for a better bike ever since I bought her a Liv Amiti. The Amiti is not the right bike for our local rails-to-trails, but at the time of purchase it was the only small frame ebike that we could find parked in a bike shop. I knew about bikes like the Trek Powerfly or Liv Vall-E, but nobody had one on the floor and I wasn't gonna take the risk of ordering to find she didn't have sufficient standover.

Next day we rode our usual 20 miles RT on a local rail-to-trail. She played with the boost settings, spending most of the time in the higher modes. Her battery went from almost full to almost empty.

WTH

She can ride the same route with her 400Wh Liv, half in Standard boost and the other half in High, and get back to the car with about 40 - 50% remaining.

I was so depressed I hardly slept the next coupla nights. I thought the Trek was the answer to my prayers.

Does anyone have any experience with the Yamaha PW vs. Bosch CX drivetrains? AFAIK the Bosch is considered top-of-the-line, but it looks to me like the Yamaha is way more efficient?

I replaced the Amiti's narrow 700c tires with some 2.1" wide knobbies, which is as wide as the frame will allow. The Trek comes with 2.3". So it's not like there's a huge diff in rolling resistance.

 

[MarkF]

The Bosch CX is there strongest motor so it's going to use more energy. It's also winter, is the battery on the cold side? It sounds like your wife is using to much assist so she doesn't have to work as hard. Can you adjust the assist levels down some?

 

[Telkwa]

Hi, Mark -
Thanks for the quick reply. My message was already getting too wordy so at some point I had to stop. We've been riding every day that we can since spring of this year. Probably rode the same 20 mile stretch of trail at least 100X now. We've got a pretty good feel for how the cold affects my Haibike and her Amiti, how much boost we can get away with, effects of tire psi, etc.
It was about 45 F when we took the new bike out, so yeah a bit cold but not arctic.
Setting boost back would be the obvious thing to do. But she can fly at full boost on the Amiti and return with power to spare. If she rode the Amiti in Eco the whole time it'd probably go 50 miles!
I'm sure you see what I'm trying to say here. If the 500Wh Trek in Eco goes as far as the 400Wh Liv in Standard/High, that just doesn't seem like money well spent.

I have a question for you while we're on the subject of power. The Bosch CX is rated at 250 W and 75Nm torque. The Liv's SyncDrive is rated at 80Nm and I think it's 500W. From the numbers it seems like the PW is actually more powerful?

 

[Alaskan]

I have both a Bosch CX bike as well as a Bosch performance speed. In eco mode I can get over 60 miles in warm weather at 15mph, 45 miles in tour, 25 in sport and 18 in Turbo. I weigh in at 210.

I think on flat ground there is very little difference in motor efficiency one brand vs the other. Some climb hills better. Some do better at lower cadence.

Variables that will effect range are:

Weight (bike + rider + gear)
Speed
Rider effort
Tire profile
Temperature
Assist level (rider watt input versus motor)

Pedal harder, lower speed, go further.

It doesn't matter what the manufacturer calls an assist level. It's purely about actual wattage output to the rear wheel.

 

[LimboJim]

In my experience, the PW is at least 20% more efficient than the CX using similar assist levels actoss the same terrain.

My CX-equipped Haibike Allmtn churns through its 500Wh battery about the same time/distance/elevation gain as my old PW-oufitted Allmtn did its 400Wh battery.

I'm curious about the difference between the PW-X and the CX.

 

[Alaskan]

In my experience, the PW is at least 20% more efficient than the CX using similar assist levels actoss the same terrain.

My CX-equipped Haibike Allmtn churns through its 500Wh battery about the same time/distance/elevation gain as my old PW-oufitted Allmtn did its 400Wh battery.

I'm curious about the difference between the PW-X and the CX.

That is astounding. Not having ridden the Yamaha, I am not qualified to comment other than to wonder why. The team at blue monkey came up with such a different conclusion. I am not saying they are right or you are wrong. It's just that the conclusions are at such variance. Did it feel like, regardless of assist level you were putting out the same effort with both bikes? Did the CX manage to get up the same hills a bit faster or with somewhat less effort. That alone could account for the difference. It's a puzzlement.

 

[LimboJim]

That is astounding. Not having ridden the Yamaha, I am not qualified to comment other than to wonder why. The team at blue monkey came up with such a different conclusion. I am not saying they are right or you are wrong. It's just that the conclusions are at such variance. Did it feel like, regardless of assist level you were putting out the same effort with both bikes? Did the CX manage to get up the same hills a bit faster or with somewhat less effort. That alone could account for the difference. It's a puzzlement.

I think that the CX's EMTB mode skewed my anecdotal "results." It's far more powerful (and faster) than the PW's STD mode, and for the trail hills I climb regularly - as much as 25% grade - that's where I spend a lot of time. With proper gearing, but modes help(ed) get me up most climbs, but I definitely worked harder in STD than I do in EMTB. I seldom use(d) Turbo/High on either Allmtn model.

Also, Mikey's comparison was between the Bosch Gen2 motor, not the CX, and the Yamaha PW. Gen2 peaks at 63Nm (after an update - it was just 60Nm before) vs CX's 75 and PW's 80, but there's been some skepticism over the measurement of torque in the industry. And watt consumption isn't necessarily correlated to torque, IMO, so I don't think numbers "on paper" tell the whole story.

 

[Telkwa]

Since there are a few folks looking in on this, does anyone know what these drive motor numbers mean? Does a 250W motor consume 250W at full crank, or does it output 250W? Due to thermal and mechanical losses, what goes in is not the same as what goes out.

Any more links to motors and such would be awesome.

LimboJim's thoughts on efficiency are exactly the sort of feedback I was looking for. I wish I'd looked into this more thoroughly before we bought the Bosch bikes. To me it was just "Bosch is better" and I never went beyond that.

Alaskan, I agree about wattage to the wheel. Unfortunately, I have no way to quantify my wattage, nor the motor's.

 

[Alaskan]

I think that the CX's EMTB mode skewed my anecdotal "results." It's far more powerful (and faster) than the PW's STD mode, and for the trail hills I climb regularly - as much as 25% grade - that's where I spend a lot of time. With proper gearing, but modes help(ed) get me up most climbs, but I definitely worked harder in STD than I do in EMTB. I seldom use(d) Turbo/High on either Allmtn model.

Also, Mikey's comparison was between the Bosch Gen2 motor, not the CX, and the Yamaha PW. Gen2 peaks at 63Nm (after an update - it was just 60Nm before) vs CX's 75 and PW's 80, but there's been some skepticism over the measurement of torque in the industry. And watt consumption isn't necessarily correlated to torque, IMO, so I don't think numbers "on paper" tell the whole story.

Interesting! The bike I ride most has the 28mph Bosch which still has the old Sport mode, not EMTB. The EMTB I have on the CX powered bike. I really prefer the manual control of assist levels help to get maximize range. I suspect that EMTB is mostly Sport on flats, if you are pushing speeds close to 19 and closer to Tour at 15mph and lower. It feels like EMTB moves up to Turbo level assist levels when climbing hills. That will eat up electrons real quick. If I want to go fast and far, then I pack a spare battery in a trunk bag, put it in sport and easily average around 18mph, getting close to 28 or 30 miles per battery, depending on topography. I try to resist the temptation to use Turbo when I have range concerns.

 

[Alaskan]

@Telkwa I wouldn't despair you decision to go Bosch. I did a 53 miles ride last week in just under 3 hours (17.9mph average) with the assist set at sport the whole time. There was only a rise and fall of 1135 feet so mostly flat or easy inclines. It was 38 degrees out and the paved trail was littered with debris from a big wind storm I had 15% remaining on one battery and 40% on the other so I used around 800 watts of battery power. My average output was 104 watts. This was on a full suspension bike that probably weighs close to 80 lbs, with spare battery, Folding lock, spare tube, tools, water, snacks etc. plus my 210 lbs.

 

[Alaskan]

An article well worth reading with in depth comparison (written in July 2017)

 

[PDoz]

An article well worth reading with in depth comparison (written in July 2017)

I don't think that artcle takes into consideration the way riders respond to the various motors.

As an example, they describe the yamaha as a diesel - torque at low revs - which is why I bought my giant ( I used to prefer to pedal slowly when mtb riding) . Ironically, many people end up spinning at higher cadence on the yamaha after a while - usually 80 or above . I think it's because we tend to ride over the top of the torque curve and fall back into the torque as we hit resostance ( hills etc) - this just feels right on the yamaha, and ends up being incredibly efficient. If you spin at lower cadence on the yamaha it throws out enormous amounts of assistance and chews through power - great to wander up a hill , but not very efficient or rewarding.

With the bosch, especially one in trail mode, the temptation is to ride at lower cadence then rely on the automatic increase in boost as human torque input increases. It just feels different.

The take home message is that after a few rides, we tend to adapt our riding style to suit the bike and work out a balance between efficiency / enjoyment etc.

 

[vincent]

I have a 2017 haibike hardtail 3 inch tires with the Yamaha
it is the px I think, not px-w
210 lb rider, with 15-20 lbs in the my backpack and probably 3-4 lbs in tools on the bike bag
between 60-70 on cadence
I believe the bike weighs about 48-50 lbs stock but not sure on that

I have a lot of 20-30 mile rides on this bike and have yet to hit halfway point on the battery
believe it has 10 notches on the battery and I usually come back with 4 notches used

this is in flats or climbing off road stuff
it has been incredibly efficient for me

have a friend with some 2016/2017 haibikes, one Bosch and one Yamaha , he has commented on the better efficiency of the yamaha
my guess is he has a higher cadence than I do, he is a much more advanced rider

these are not the same motors so not sure how much this will help

 

[LimboJim]

Interesting! The bike I ride most has the 28mph Bosch which still has the old Sport mode, not EMTB. The EMTB I have on the CX powered bike. I really prefer the manual control of assist levels help to get maximize range. I suspect that EMTB is mostly Sport on flats, if you are pushing speeds close to 19 and closer to Tour at 15mph and lower. It feels like EMTB moves up to Turbo level assist levels when climbing hills. That will eat up electrons real quick. If I want to go fast and far, then I pack a spare battery in a trunk bag, put it in sport and easily average around 18mph, getting close to 28 or 30 miles per battery, depending on topography. I try to resist the temptation to use Turbo when I have range concerns.

I'm seriously considering bringing back Sport mode on my CX bike at its next update. I think I'll get better range.

 

[Trail Cruiser]

Good morning!

A few days ago I was elated. Bought my wife, who's quite short at 4'11", a 14.5" Trek Women's Powerfly 5. Bosch CX drivetrain, 500Wh battery.

I'd been looking for a better bike ever since I bought her a Liv Amiti. The Amiti is not the right bike for our local rails-to-trails, but at the time of purchase it was the only small frame ebike that we could find parked in a bike shop. I knew about bikes like the Trek Powerfly or Liv Vall-E, but nobody had one on the floor and I wasn't gonna take the risk of ordering to find she didn't have sufficient standover.

Next day we rode our usual 20 miles RT on a local rail-to-trail. She played with the boost settings, spending most of the time in the higher modes. Her battery went from almost full to almost empty.

WTH

She can ride the same route with her 400Wh Liv, half in Standard boost and the other half in High, and get back to the car with about 40 - 50% remaining.

I was so depressed I hardly slept the next coupla nights. I thought the Trek was the answer to my prayers.

Does anyone have any experience with the Yamaha PW vs. Bosch CX drivetrains? AFAIK the Bosch is considered top-of-the-line, but it looks to me like the Yamaha is way more efficient?

I replaced the Amiti's narrow 700c tires with some 2.1" wide knobbies, which is as wide as the frame will allow. The Trek comes with 2.3". So it's not like there's a huge diff in rolling resistance.

Both motors are equally efficient in terms of how much energy consumed per actual mechanical power (in watts) produced. It's more a factor of the design of the controller algorithm on how much juice is released into the motor.

Assuming that the overall weight are equal, the one that consumes more battery is also the one that felt more powerful, and easier to attain higher speed. Unfortunately, there is no exact button for both to have equal power output.

 

[Telkwa]

Thanks for the links to previous threads.

I'm 62 now, and I seem to be developing a bad habit of wanting everything to work itself out with as little effort on my part as possible.

One thing I've picked up from you guys in the last few days is I need to bring the batteries inside.

JayVee, the frustratingly non-specific Liv manual shows a fancy "EVO" display and a simpler "Charge Display". Her Amiti has the Charge Display. The manual indicates that the EVO display has cadence, but no mention of cadence for the Charge Display. I monitor her cadence. A bit slower than I'd like to see but not bad.

I weigh twice as much as she does. That's part of the reason why I freaked when she almost drained the battery on the first ride.

The shop has a 30-day return policy. I haven't ridden my new Trek at all. I need to talk with them. On the one hand, I want to do our standard ride on my bike. On the other hand, I don't want to get the bike dirty if I'm gonna return it.

vincent, you're getting very impressive battery life. You must be doing something right!

 

[MarkF]

Depending on how cold it is outside, a cold batteries run time can be reduced 10 to 40%.

 

[Telkwa]

Thanks, Mark -
I brought all the batteries inside this morning.

 

[Telkwa]

Good morning!

I'm feeling much better about the whole thing this morning. Yesterday at about 8:30 AM or thereabouts I brought the two 500W Bosch batteries in from the cold. Night time temps probably in the 30's F. We went for a ride on our standard 20 mile route at about 1:30 PM. The batteries still felt cold to the touch. Both batteries were fully charged, but they'd been charged in the cold garage.

I wanted to be somewhat scientific about it, so I went 10 miles out in ECO. At our turnaround the LCD showed battery at two clicks down. I went to TOUR on the way back. I wanted to stay in TOUR the whole way, but Patti was getting away from me so I went to eMTB at roughly mile 15 or so. The LCD indicated about half charge when we got back to the car, mile 20.

My wife, well, she had other ideas. She went the 10 miles out in TOUR, then 10 miles back in TURBO. Her LCD indicated the same amount of charge, roughly half.

When we got home I brought the batteries inside and plugged them in. Both of them started the charge cycle with 3 of the 5 LED's illuminating solid, then after a few seconds the 3rd LED started blinking. I took that as further confirmation that the batteries were at about half charge. Understood that the charge indicators are based on voltage so not entirely accurate, but these are the indicators we have to work with.

We compared our perceptions of the Bosch boost levels vs. the two bikes that we've ridden a hundred times on the same route (Haibike with standard Yamaha PW drivetrain, and Liv with their SyncDrive version of the same Yamaha motor).

The Bosch ECO felt a little stronger than the Yamaha ECO.
Bosch TOUR felt like it was between the Yamaha STANDARD and HIGH.
Bosch TURBO felt like it provided more boost than the Yamaha HIGH.

I realize these are very subjective comparisons, and based on a small dataset. For example, if the Bosch is just a little bit more responsive when you accelerate that alone might lead a person to believe it's more powerful.