Calcoaster
Well-Known Member
- Region
- USA
Here’s another test report I came across showing the efficiency o the HPR50.
Another new TQ motor: hpr40
- Thread starter Calcoaster
- Start date
Yako
Active Member
- Region
- Europe
Again, just from press blurb, but TQ claim a system efficiency of 80% on the HPR50, and we know that the ‘40 has a few differences in the motor (like the lack of a second freewheel/clutch) so I guess that’s where the claimed additional 10% efficiency comes from. I’d love to know the real figures!
Not really surprising Spesh press rate their main future rival for road bike motors very low…
Not really surprising Spesh press rate their main future rival for road bike motors very low…
Calcoaster
Well-Known Member
- Region
- USA
Yes, it’s logical that the hpr40 will prove to be at least as efficient as the HPR50, likely better. Besides evolving motors, there are still gains to be made in battery technology which will increase range per battery size/weight = more miles per same physical size battery.
Yako
Active Member
- Region
- Europe
Wow that is great stuff! I had a long phone call with the ‘40 Product Manager at TQ last week, trying to sort out those crazy claims of their customer services person, and one of the things I also wanted to check was whether they had addressed the derating that the HPR50 was known for. She said not only had the case design changed, to allow for greater cooling, but that also the 40 produced considerably less heat as it is rated at 200w and they had seen no derating in their testing. That would up the efficiency considerably. I’ll be looking out for Testmybike’s review of that one!
Calcoaster
Well-Known Member
- Region
- USA
It’s nice to get your input and analysis, both here and on your YouTube channel! And you’re so right about the heat/efficiency connection: basic physics says less heat = better electrical/mechanical conversion. Thanks for your reviews!
mschwett
Well-Known Member
- Region
- USA
some interesting data !
90% would be pretty incredible - and quite at odds with what’s shown in the report @Calcoaster posted, which indicates much lower efficiency than a typical mid-drive!
90% would be pretty incredible - and quite at odds with what’s shown in the report @Calcoaster posted, which indicates much lower efficiency than a typical mid-drive!
Calcoaster
Well-Known Member
- Region
- USA
The testmybike site has a few other interesting articles.
www.testmybike.com
Artículos - Test My Bike
Artículos que potencian tu conocimiento. TestMyBike Analiza la Eficiencia de los Motores TQ HPR50 y Fazua Ride 60: Un Estudio de Estándares y Potencia Como ya hemos explorado en artículos anteriores, en el mundo de las bicicletas eléctricas, la eficiencia de un motor no es solo un detalle...
www.testmybike.com
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
IS TQ HPR 40 delivering only 200 W peak power?!
Calcoaster
Well-Known Member
- Region
- USA
That’s what they advertise- 200 watts peak or continuous. Meant for lightweight road bikes and riders who want some assist but still expect to work for it.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
While @stompandgo is a fine and nice guy, we have known @mschwett from his best side for several years now. Mark in an accomplished road cyclist who has owned many analog bikes and e-bikes, and was always approaching cycling from the engineering and scientific side; he was not interested in how a human would provide their watts but how many watts were required to accomplish the goal.
Mark has helped me a lot with planning for my hilly gravel races. It was him to make me aware the rider and the e-bike must provide enough combined power to allow climbing up a certain grade at a certain speed. The gearing ratio -- he correctly reasoned -- was only to provide the necessary cadence so the e-bike motor could run at the max efficiency. Additionally, a rider who could muster a high cadence, was expected to deliver more leg power to the cranks than a slow "grinder".
I respect @stompandgo as an experienced road cyclist and a coach as well as his expertise in the bicycle mechanics.
You two should shake your hands and become friends instead of going to war and Ignore.
Signed:
The one who is the most quarrelsome person on these Fora (except his sworn enemies)
Mark has helped me a lot with planning for my hilly gravel races. It was him to make me aware the rider and the e-bike must provide enough combined power to allow climbing up a certain grade at a certain speed. The gearing ratio -- he correctly reasoned -- was only to provide the necessary cadence so the e-bike motor could run at the max efficiency. Additionally, a rider who could muster a high cadence, was expected to deliver more leg power to the cranks than a slow "grinder".
I respect @stompandgo as an experienced road cyclist and a coach as well as his expertise in the bicycle mechanics.
You two should shake your hands and become friends instead of going to war and Ignore.
Signed:
The one who is the most quarrelsome person on these Fora (except his sworn enemies)
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
Calcoaster, something is either strange or... it is a marketing hype. The older Specialized SL 1.1 motor is providing 240 W peak mechanical power, which is 35 Nm at the reference angular speed of 6.28 rad/s (60 rpm). TQ HPR 40 is therefore weaker than the SL 1.1, and it has the torque of 31.8 Nm at 6.28 rad/s, certainly not 40 Nm. Interesting.
Calcoaster
Well-Known Member
- Region
- USA
They claim 40nm and 200 watts peak and nominal for the hpr40. The hpr50 claims 50nm and 300w peak, 250w nominal. It’s upgrade now being used by trek and BMC, the hpr60 claims 60nm, 350 w peak and depending on the source, 250 or 300w nominal.
I read the reason for the two different nominal values for the hpr60 is related to the European rules limiting continuous power to 250w. Maybe their marketing uses different specs depending on where they are advertising.
I don’t know why the basic formula of torque = force X distance doesn’t always seem to work out when dissecting motor power ratings. Must be some magic involved.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
The basic formula for torque in rotating systems is T = P / omega
where,
T = torque [Nm]
P = power [W]
omega = angular speed [radian/s]
Forget the 250 W. We are only talking the motor mechanical peak power. The only thing that matters is the max motor power. Torque is a marketing gimmick to hide the actual peak power from the legislators. Torque without the angular speed is of no meaning. Therefore:
- TQ HPR 40 with 200 W of power is the weakest motor. Torque @60 rpm or 1 Hz or 1/s (6.28 rad/s) is 31.8 Nm
- Specialized SL 1.1, 240 W goes next; torque 38.2 Nm
- TQ HPR 50, 300 W; torque 47.8 Nm
- Specialized SL 1.2, 320 W; torque 51 Nm
- TQ HPR 60, 350 W; torque 55.7 Nm.
Last edited:
Calcoaster
Well-Known Member
- Region
- USA
Yes, there has always been marketing hype involved in ratings of all kinds. That’s probably why we rarely see the actual test parameters and data. I’ve never seen TQ state the angular velocity (stated as rpm or otherwise) their torque or power specs come from.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
The issue with the hub-drive motor is we don't know the reference angular speed. As @mschwett was explaining, the X20 motor has a good torque when it spins fast, that is, on the flat. The steeper the climb is and the slower you ride, the slower the hub-drive motor spins, losing its torque. That's why geared hub-drive motors are poor climbers.
