Hi. I moved from a KTM e Cross P to a KTM Bosch-driven bike and missed my torque sensor and experience of the hub drive despite the pitfalls of design. I find up steep hills I have to keep my cadence high to get up. These are very steep hills mind does anyone know of any bikes with a combination of cadence and torque ie pressure sensors? After my less happy experience with the Bosch would be happy to go back to hub drive as well. Thanks.
Experience with hub-drives with BOTH torque- and cadence-sensing assist?
- Thread starter Jeremy McCreary
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The motor: Powerful drive for eBikes
The mid-motor supports the pedelec from gently to powerfully. The Bosch eBike drive is optimally tuned thanks to a precise sensor concept, allowing a natural riding sensation and riding fun.
www.bosch-ebike.com
[Seamless or powerful – most importantly natural. Drive units from Bosch eBike Systems give you a unique riding sensation. Three sensors measure the rider's pedal power, cadence and speed over 1,000 times per second. This facilitates an organic interplay between you and your eBike. ]
Bosch BDU's have like other mid-drive DU's a mix of cadence and torque sensors. With the internal motor controller and the firmware on these systems regulate the behavior of the DU. What you discribe would be a logic for many mid-drive bikes, because they perform better at a cadense around 70 to 90 RPM in general. For simpler systems where the controller moslly works with speed and torque applied to a torque sensor this works a bit different indeed.
Jeremy McCreary
Bought it anyway
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- USA
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- Carlsbad, CA
At the very least, the Specialized Turbo PAS for their mid-drive ebikes uses rider power, cadence, and wheel speed sensors to determine motor power. Once you have rider power and cadence, you can calculate rider torque.
The result is very impressive, but you need to keep cadence above 70 rpm to reap the full benefit. My 250W, 35 Nm Vado SL mid-drive handles our steep hills (10-20%) quite well at the 80-90 rpm cadence my knees demand.
Detailed explanation and interactive graphical model of the basics of the Specialized PAS here:
Visualizing and exploring the power-sensing PAS in Specialized mid-drives — an interactive graphical model
For our more math-minded Specialized mid-drive riders, here's an interactive graphical model of your bike's tunable power-sensing pedal assist system -- hereafter, just "PAS". The model doesn't cover complex PAS responses to transient events like starting out or approaching PAS cut-off speed...
forums.electricbikereview.com
In normal riding, rider power is the main determinant of motor power. The user can program the 3 assist levels to modify the relationship through the Specialized app.
The OP was after something different: A hub-drive that can be switched between torque-sensing and cadence-sensing assist on the fly.
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Chazmo
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Jeremy, I thought I’d note for you here that my Juiced bike lets you turn off torque and go strictly with cadence, but the normal mode is a combination. There is no setting on the Juiced controller to go “only” torque sensor. Aventon and Lectric may do the same thing. BTW, good choices. If I were buying today those two would be at the top of my list.
Caveat: I still haven’t tried riding the bike with pure cadence. Gotta try it sometime, but I’m having too much fun riding the bike as designed.
Caveat: I still haven’t tried riding the bike with pure cadence. Gotta try it sometime, but I’m having too much fun riding the bike as designed.
I thought I would throw this out there, it's sort of related to your question. Many of the newer Velotric ebikes, including the Breeze 1, have 15 PAS levels. What I have found on my Nomad 2 is that I don't use all 15 PAS levels. What I DO do is use different levels depending on if I'm in cadence or torque mode. For example, if I'm in cadence sensor mode, I'm usually in Eco, PAS 3. If I'm in torque sensor mode, I prefer Trail, PAS 3 or 4 the majority of the time. So, the 15 PAS levels allows you to find your "sweet spot" PAS level(s) depending on your riding mode. If the ebike didn't have both cadence and torque mode, then 15 PAS levels would probably be overkill.
Jeremy McCreary
Bought it anyway
- Region
- USA
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- Carlsbad, CA
Agree, any way you cut it, ability to dial in just the right amount of assist for the occasion is a very valuable feature — especially if you like to pedal in a fairly narrow cadence band (82-92 rpm in my case).
Per the official product page, the Breeze's 15 assist levels come in 3 blocks of 5, with each "mode" like Eco or Trail having its own block of 5 tunings. That's one way to get assist flexibility.
My torque-sensing hub-drive does it another way — namely, by offering 9 assist levels in a single block. The levels aren't tunable, but still plenty of flexibility to stay in my preferred cadence band on our local mix of flats and hills.
In contrast, my friend's torque-sensing Aventon Level.2 has only 5 non-tunable levels in a single block — just not flexible enough for my taste. And the lowest level is way too powerful.
My newer power-sensing mid-drive takes both approaches to assist flexibity. On start-up, you have 3 tunable assist levels (ECO, SPORT, TURBO "modes") available in 4 different tuning "presets" (Universal, Battery Saving, Racing, and custom). This vaguely resembles the Breeze approach with different terminolgy.
I ride in the default Universal preset 90% of the time, as it generally gives me all the cadence control I need. But I can also enter Micro Tune at any time from the handlebar. Then I get 10 non-tunable assist levels in a single block — especially handy for matching pace with other riders.
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Chazmo
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@Jeremy McCreary , that Breeze 1 looks like a nice ride. Unfortunately it doesn’t come with fenders or rack. I like the relatively light weight. That’s sweet. That’s really impressive given the big, heavy hub motor.
Does she have any interest in fatties? If she doesn’t mind a few pounds more (including fenders and rack) maybe she’d like the Nomad fat-bike. The Nomad 1 is pretty inexpensive, although I don’t know how many or if the right size is available. Of course, the Nomad 2 is out there and it’s more expensive.
edit: Oh, I don’t know if the Nomad 1 has all the cool tunability… The web site says it was updated last year, so maybe???
Does she have any interest in fatties? If she doesn’t mind a few pounds more (including fenders and rack) maybe she’d like the Nomad fat-bike. The Nomad 1 is pretty inexpensive, although I don’t know how many or if the right size is available. Of course, the Nomad 2 is out there and it’s more expensive.
edit: Oh, I don’t know if the Nomad 1 has all the cool tunability… The web site says it was updated last year, so maybe???
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Jeremy McCreary
Bought it anyway
- Region
- USA
- City
- Carlsbad, CA
No real use case for a fatty, but yes, the Breeze's low weight is a big attraction in her case.
My theory — soon to be tested, I hope — is that the lighter, more responsive, and easier to handle her ebike, the less it'll just sit in the garage. The Breeze is one of the lightest e-cruisers around, and we'd try it with first without fenders to keep it that way.
The geometry and PAS design are also promising, and I'll soon be able to buy and service one 5 miles from home. Lots of boxes checked here. Fingers crossed that it tests as hoped.
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