Geared Hub vs Mid-Drive?

[dogman dan]

RE the 900 watts. There is no reason to try to get up hills with less watts. Particularly with a hub motor, the most efficient thing is to charge the hill at 15 mph at least, or whatever the motors max is.

Its most efficient, and easier on the motor. Trying to lower the watts just makes the motor run low rpm, and lose efficiency. At whatever speed, the most efficient way up that hill is to keep the motor working at 15 mph rpm. Or more! if it can do it.

With a mid drive, its different. In your lowest gear, you can grind up it at 5 mph with the motor spinning efficiently.

But bear in mind,,, the work to put x amount of weight up y grade of hill never changes. Up that hill will take x watt hours, or more if the motor runs inefficient. The thing to watch is your average watt hours per mile.

 

[dogman dan]

If you haven't made purchases yet, Pete,, you do live just a few miles from one of the biggest electric trike vendors in the USA. https://www.electrictrike.com/

The usual stocking issues however. That goes for cars, tvs, whatever, because of covid.

These are geared motor trikes btw. Call them up, ask if you can demo one when the stock arrives. Tell them dogman dan sent you. I used to work for them.

 

[MadRhino]

Mid drives don’t like long chain line. So, unless you have the fabrication skills to build a custom mid drive closer to the wheel, a low KV geared hub is your best choice to make a slow climber trike.

 

[PeteCress]

Mid drives don’t like long chain line. So, unless you have the fabrication skills to build a custom mid drive closer to the wheel, a low KV geared hub is your best choice to make a slow climber trike.

Actually, I was moving ahead on a Mac 10 geared hub until I hit a chain line issue - something about dished vs centered rear wheels and ICE being out of step with the world...

So I made a somewhat impulsive decision to keep it simple and ordered something called "TSDZ2", which is torque-sensing and has the advantage of allowing me to leverage the Rohloff from my diamond-frame bike that I cannot ride anymore.

Noise level on the TSDZ2 is reputed tb something of a crap shoot - depending on some production variable, I guess. But if I can live with the racket that my rental Outrider makes, I figure I can live with anything - and I just might luck out and get a quiet one to the benefit of other trail users.

The Shimano-mid-drive-assisted ICE Adventure that I rode last week seemed OK chain-wise, as did the AZUB Ti-Fly. My nipples get hard just looking at the TiFly, but the supply chain being what it is....

I pick up my slightly-used ICE Adventure HD this Saturday, and am hoping to see the TSDZ2 within a week.

Then we will find out if I have shot myself in the foot.... -)

 

[Grantmac]

Does your tadpole have a jackshaft nearer the rear wheel?

 

[PeteCress]

Does your tadpole have a jackshaft nearer the rear wheel?

Looks like there is one right at the rear triangle's pivot point.

 

[Grantmac]

If it uses a standard bottom bracket you could see about mounting the mid-drive there fairly easily.

 

[MadRhino]

If it uses a standard bottom bracket you could see about mounting the mid-drive there fairly easily.

:thumb:
Even if there isn’t, a common BB could be fitted there pretty easily.

 

[PeteCress]

A big mid-drive con for me is that it gives you less flexibility in designing the system (controller, motor, bottom bracket, cranks are all a fixed system).

After hearing something about wheel dishing and ICE being out of step with the rest of the world, I made an impulse-driven decision to "Keep it simple" and went with a mid-drive - without further investigation of the dishing issue.

Bad Idea.

Turns out that "Simple" is actually a hub drive because of gearing.

To wit:

• With a hub drive, you get to keep your existing 3 front chain rings and still have at least seven on the rear cog - maybe more.
  
• With a mid-drive, you are reduced to a single front chain ring, maybe two if an adapter is available.
  
• A single front chain ring is totally insufficient for non-assisted pedaling because a trike does not allow you to use your body weight to rotate the cranks - making the wide range of a triple necessary for climbing even the slightest hills.
  
• All that said, now you are looking at a rear hub gearing system to make the mid-drive trike operable without assist. So much for "Simple".... Works for me because I have a well-broken-in Rohloff already available from one of my no-longer-used bikes, but "Simple" is really a hub drive.
  

 

[AHicks]

Is the "dishing" issue even relevant on a trike build?

 

[MoneyPit]

A typical DIY mid drive shouldn't need body weight on the crankarms to get itself going. On a Bafang, you upshift and the settings you input into the controller gently/slowly initiates assist as you rotate the crankarms. If you want the motor to just kick in, dab in 50-100w via the throttle. The fact that you upshifted prior to stopping should mean throttle starts are safe for the drivetrain.

What did you do buy one (Cyc? Tongsheng?) that uses torque sensing?

I've personally never dished a wheel build and dealt with alignment via approaches to the front chainring. Luna = tons of offset. Lekkie = a bunch. 130 bcd adapter = minimal. This one is an 11 spd and most likely to run into being on a hill dead and needing a difficult startup. No issues.

 

[PeteCress]

What did you do buy one (Cyc? Tongsheng?) that uses torque sensing?

Tongsheng flashed with OSF.

Will be a week or two before it's installed & in use.

Fingers crossed...

 

[MoneyPit]

Tongsheng flashed with OSF.

Will be a week or two before it's installed & in use.

Fingers crossed...

Bummer. But I would think you can get into that drive's config and tailor its values to at least minimize the physical force needed at startup. And in any event, you should be able to dab in the throttle after a downshift. You will want to ask around and find out if the Tongsheng on throttle from a dead stop has issues (controller, internal gears). The BBSHD doesn't but the BBS02 is not quite as robust.

Tons of people here know the Tongsheng inside and out. I've always stayed away from them as the HD meets my needs and I like having one drive across the fleet to simplify spare parts.

Also... with the right amount of elbow grease and aftermarket support you can accomplish the impossible. I came across this today when I was in the process of adding another one of these motors into my shopping cart.

 

[PeteCress]

Pete, keep us posted on what you do and how it works.

OK, the fix is in and the winner is:

• A slightly-used ICE Adventure HD - more because it was available than anything else.
• The Rohloff hub from my never-again-tb-ridden bike.
• A TSDZ2 mid-drive.
• A luggage rack and various bags.

I seem to have lucked out with the TSDZ2's noise level. Either I am a bit more deaf than I thought or this thing is reasonably quiet - on a par with the noise from the Rohloff hub ... and I have a history of being somewhat neurotic when it comes to noise.

The TSDZ2 has transformed the 1.25-mile 9° grade at the end of most of my rides from an ordeal to "no beeeg ting".

I am not particularly in love with the ICE product:

• The cabling to those drum brakes hangs way down, just begging a sapling stump or something to give new meaning to the model name "Adventure".
• The elastomer rear sus looks half-ass to me. OTOH it's simple/light and maybe Greater Minds Than Mine have determined that it is 100% sufficient for a trike.
• I call BS in ICE's "no brake steering" claim. Certainly it is not as heinous as that on the Outrider I rented for POC, but it is clearly present.
• After-market add-ons are ungodly over-priced - making me wonder about the trike itself. OTOH, ICE products are made in the UK and I guess somebody has to pay for those 6-8-week vacations...
• My nipples get hard just thinking about AZUB's Ti-Fly X.

On Day-1, if riding a bike is a "10" in the pleasure scale, this thing was a "2" or a "3" - but the TSDZ2 already has it up to a "5" or a "6" and I can see "7" or maybe even "8" sometime in the future.

I am discovering some trike-specific things:

• Go-Cart Stuff: like the increased sensation of speed, zig-zagging as one coasts across an off-camber parking lot, and so- forth.
• The ability to stop and just sit there.
  
• Pleasant Interactions with Strangers: I guess a funny-looking old guy at knee height is about as non-theatening as it gets.

https://photos.app.goo.gl/yxMC6YTpmSSzpVdz6

 

[raylo32]

One caution, Pete... Did you get your TSDZ2 from a vendor that sells them with OSF and hardware cooling mods? If you don't have cooling mods that long last climb is going to overheat your motor which may shorten its life. I have a TSDZ2 on an old but fairly light hardtail MTB, all up weight with me on is about 230 pounds... which is surely lighter than your setup... and like you have a 2 mile climb at most of my ride finishes. My climb is more like 5 or 6% and before I did cooling mods the motor would quickly reach critical temperatures there. I was afraid to really ride the bike since we also have lots of other hills here. I did some DIY mods and it's all good now. But take care if you haven't dealt with this issue yet.

I got my OEM TSDZ2 from Eco Cycles a couple years ago back when all they has was OEM setups But I have since installed cooling mods and OSF which pretty much eliminates the overheating issue. Now they sell kits pre-flashed to OSF and have an option to also include cooling mods. I am probably going to get one of those kits soon for my GF's bike and save myself some work.

https://www.eco-ebike.com/collections/tongsheng-tsdz2/products/tsdz2-w-850c-torque-sensing-pedal-assist-with-throttle-and-e-brakes-36v-48v-52v-10-18a-250-750w


OK, the fix is in and the winner is:

• A slightly-used ICE Adventure HD - more because it was available than anything else.
• The Rohloff hub from my never-again-tb-ridden bike.
• A TSDZ2 mid-drive.
• A luggage rack and various bags.

I seem to have lucked out with the TSDZ2's noise level. Either I am a bit more deaf than I thought or this thing is reasonably quiet - and I have a history of being somewhat neurotic when it comes to noise.

The TSDZ2 has transformed the 1.25-mile 9° grade at the end of most of my rides from an ordeal to "no beeeg ting".

[/quote]

 

[PeteCress]

One caution, Pete... ... that long last climb is going to overheat your motor which may shorten its life.

I have been looking for a reliable soutce of LM35 temp sensors... Sounds like Texas Instruments is the real deal, and I should be installing same within a week.

Got a text in to my motor supplier about the heat-mitigation mods and if they are not there already, I guess heat sensor installation time would be the logical time to do them too.

Meanwhile, bco my own ignornance and ineptitude, my motor has been limited to 240 watts since Day-1... and I think I'll leave it that way at least until the temp sensor and heat mitigation are installed.

 

[donn]

Meanwhile, bco my own ignornance and ineptitude, my motor has been limited to 240 watts since Day-1... and I think I'll leave it that way at least until the temp sensor and heat mitigation are installed.

That will be easier on your drive train, too.

 

[raylo32]

Yup, definitely do both at once. One trick I did when installing the sensor was to not cut the wires... I spliced into them just opening the insulation and soldering 2 wires for the sensor in. I then soldered 2 wires to the sensor and hooked all of these up to a 2-wire mini connector so I can easily unplug the sensor but leave it in place and go back to having a throttle with a simple setting on the display if I want to at some point. In my experience once you have the cooling mods done and proven that they work for how and where you ride you can disconnect it and forget about it. So far I have just kept my sensor online since I really don't want or need a throttle on this bike, but why not keep the option open.

Not sure I would overthink the sensor source. I got some branded SEPP from Amazon (not currently available) and they work perfectly. This isn't rocket science. If you are really concerned get some and test them. Again, they don't have to be 100% accurate. Close is really good enough.

One caution, Pete... ... that long last climb is going to overheat your motor which may shorten its life.

I have been looking for a reliable soutce of LM35 temp sensors... Sounds like Texas Instruments is the real deal, and I should be installing same within a week.

Got a text in to my motor supplier about the heat-mitigation mods and if they are not there already, I guess heat sensor installation time would be the logical time to do them too.

Meanwhile, bco my own ignornance and ineptitude, my motor has been limited to 240 watts since Day-1... and I think I'll leave it that way at least until the temp sensor and heat mitigation are installed.

 

[Triketech]

I am not particularly in love with the ICE product:

• The cabling to those drum brakes hangs way down, just begging a sapling stump or something to give new meaning to the model name "Adventure".
• The elastomer rear sus looks half-ass to me. OTOH it's simple/light and maybe Greater Minds Than Mine have determined that it is 100% sufficient for a trike.
• I call BS in ICE's "no brake steering" claim. Certainly it is not as heinous as that on the Outrider I rented for POC, but it is clearly present.
• After-market add-ons are ungodly over-priced - making me wonder about the trike itself. OTOH, ICE products are made in the UK and I guess somebody has to pay for those 6-8-week vacations...
• My nipples get hard just thinking about AZUB's Ti-Fly X.

On Day-1, if riding a bike is a "10" in the pleasure scale, this thing was a "2" or a "3" - but the TSDZ2 already has it up to a "5" or a "6" and I can see "7" or maybe even "8" sometime in the future.

Cabling can be rerouted but you may need to add some Brake Noodles at the exit of one of the drums.

Elastomer can work pretty well its just set up rather hoaky on ICE trikes. Has the rural British design all over, but it works within the limits of reasonable expectations. HPV uses a combo steel coil & foam polyurethane spring with an anti-rollbar and it works really well on the hardpack. Not bad on the softpack, for that you'll want a Steintrike Wild One. That is likely to be my next trike for some desert riding.

The Adventure has a bit higher center of mass than I like. It's more of a comfort trike at the expense of handling.

Braking takes a bit more trigger balance than an upright. Most have a bit of feel of braking; to totally eliminate that would take a 4th wheel.