Bluesfrog

What are the problems involved with two motors? I have had a mid drive mess up and not be rideable. I had to walk the bike back to the house at 0400 and then drive the truck to work. I was thinking about having a front and rear hub motor with dual battery for long lasting use. Micah Toll did a you tube review of one just a few weeks back possibly for Electrek. I have to go back and find it to see if the rear was a hub drive or mid drive? What do you guys think about this use of hub motors? Be Well, Bluesfrog

Bluesfrog

The Super Monarch?

2old

I constructed a dual-motor bike with separate 350w, 36V, PAS front and 1000w, 52V, throttle rear and it worked perfectly for me except (and I'm ashamed to say this) it was too fast. Plus there was no need for the extra weight of two systems. I did it as an exercise since I've maintained that challenged individuals could have two separate systems and never worry about getting stranded. It's more challenging with one battery and a split throttle, but two separate, dedicated systems, piece of cake.

Novalite

I thought if a motor failed one could always ride further on own power alone?
Can a mid drive not be disengaged or so?

2old

Of course you can. My statement was about physically challenged individuals having two dedicated systems. There are times when I ride my e-bikes without power for "fun".

chas58

I've seen this done with two small hub motors. Seemed a little too complex for the value for me personally.

Novalite

I was referring the topic story, this part:
"I have had a mid drive mess up and not be rideable. I had to walk the bike..."
As I interprete it, the bikes drivetrain was unusable due to that mid drive failure. And I wondered how/why.

2old

You're correct, and sorry I misinterpreted; should have been usable since a clutch disengages the motor from the pedaling system. However, can't say definitively whether it could happen, but hope not since sometimes I'm pretty far out in the woods.

Bluesfrog

At 0400 it was dark and I couldn't see there were two chain guards. Only the larger outer one. I thought I re-aligned the chain and gave a hard push by standing on the pedal. All I did was twist the chain. The inner chain guard made it tough to see what was going on. After thoroughly jamming the chain I walked the bike home. It was in warranty and Trek provided a different chain ring to keep the chain from jumping. On the dual drive unit and with a front hub motor I could have driven the bike home and the rear would have free wheeled to allow a powered ride to the house. AS it was I could only walk the bike home, the chain was jammed. Something I suspect here. The factory KNEW there was a problem and the inner chain guard was used to keep the chain from jumping when changing gears! I haven't had it happen after getting the new chainring. Be Well, Bluesfrog.

Bluesfrog

How about 2 350 W 48 V overvolted to 52 volts with a separate battery for each? I'm guessing a controller for each? A brake mounted switch front and rear for Regenerative braking. That is to help slow the bike down more than to generate a recharge. Be
well, Bluesfrog.

2old

Just remember you (almost) always need a Direct Drive motor for regenerative braking. The only place that I'm aware of with a geared motor with this feature is ebikesca. That's what I did with the dual system: two motors, two batteries, two controllers, two throttles.

jetpilotVE

Does not seem to make sense having the added complexity, cost and weight. A single motor that is of good quality will give you a better overall experience (unless you need more traction or torque)

2old

I agree, and did it just to see what it felt like and to prove the concept (as if it needed to be proven) that two dedicated systems would insure that a physically challenged individual could go e-biking and not worry about a motor failure since there was a "backup".

Bluesfrog

Maybe we could try this again for VE. Rear drive goes out. Front drive gets you home. SAVVY? Be Well, Bluesfrog.

Bluesfrog

An update of sorts here. The Trek shop put on a new chain and adjusted it free of charge as they have always done for me. I have used these guys for 12 years now. They are the best I have seen or dealt with, ever. They then said there was a new chain ring coming from Trek and subsequently installed it. Later yet they called and said there was an inside spacer or chain guard if you will. When it came in they installed it free of charge, again. In between the last two factory "fixes" the chain came off one more time. After the last fix the chain has stayed on about 200 miles. Since I have had no recent problems I think it is fixed. This started as a way to get around a failure of electrics, partly by having redundancy built in. If could have limped in at the first problem I wouldn't have been upset. They kind of expect me to show up on time at my prison job and if I'm walking the bike I might not make it. It means someone has to stay late. Be Well, BluesFrog.

chas58

Interesting.

If this is 1x and there is only one chain ring (i.e. no front derailleur), the chain ring should be specific to 1x. That means you can't really shift with it as the teeth hold the chain much better. Even better: a narrow-wide chaingring ( https://www.worldwidecyclery.com/blo...ainrings-guide ). Even better - a chain retention doohickey. I don't know if you get chain slap, but a rear derailleur with a clutch helps too (although this sounds like overkill for you).

Or follow the KISS method.

A bike with a rear hub drive is more reliable, less maintenance, and inherently redundant:
- I've had my chain break so I can't pedal. Just rode home with my motor.
- I've had motor issues. Just ride home pedaling without the motor.
There is inherently less wear and tear on the system with a single hub motor (assuming your not doing something where you need full power at low speeds for extended periods of time).

glad things are working out for ya.

chas58

Oh, and worst case scenario - carry a lock so you can lock and abandon your bike and get an uber to work.

ARider2

Can you provide a little more information about the problem and the e-bike in question? The reason I ask is I have had the chain come off on my Cannondale Mavaro that has a mid-drive Bosch Active Line Plus system. The chain came off the front chain ring and I had to remove the chain guard to put it back on. What is the model bike and what is the drive unit? Can you provide more information about the replacement chainring that was put on? Thank you!

Bluesfrog

Bosch Active Line. No plus. I would say Trek ordered many of them and Trek installed them so Bosch has no control over how they are installed. I have a few more miles on the bike now and since the inside chainring bushing/ device/ guide whatever was installed has stopped the chain from jumping off. And guys, there IS no Uber anything in this town, not even friends on the road at 0400. I do have a heavy chain and a Trek 520 from 2008. It is studded and ready to go. Be Well, Bluesfrog.

Leisesturm

andychrist

Am in the midst of installing dual hub drives in my RANS Stratus XP XXL recumbent cargo bike.

Here’s the “Before” shot:



Admit that the front drive doesn’t make a whole lot of sense given how [relatively] lightly loaded it is (though the hub motor adds like a ton), but a single 500W hub obviously can’t provide the same torque as a 750W mid drive so am doubling up as a precaution. Each wheel will run on a separate system, thus two 52V 21Ah battery packs and two controllers. Left half twist throttle and brake lever, 500C display for the front; right half twist, brake lever and P950C for the rear. Won’t be installing any PAS sensor — for one thing, AFAIK my bike’s press-fit cartridge BB does not support any models Bafang has to offer; for another, am only planning on using assist when climbing (up to 12mph) so any mode that stays on over that would just be a waste for me. Seems only reason for PAS or torque sensors is to comply with local ordinances that prohibit throttles, which is not really applicable in the rural area where I live, riding along the highway shoulders. Plus having cargo biked here so long, local law enforcement unlikely to notice I’d converted one of my rigs, have always had so many extra appurtenances on board. Battery packs will be hidden in blue 6-gallon tubs (with lids!) that kinda match the color of my bike, and the motor controllers mimic the finish, size and shape of one of my frame bags. Only real tell-tell feature will be the hubs, but the front disc rotor disguises them traffic side and the rear blue Igloo panniers drape down far enough to obscure that little detail.

Am still waiting for the Easy Reacher under seat rack for the tubs and a few more parts/tools to come in needed to customize the build exactly to my Stratus so might be a while before it’s up and running, will post pics upon completion.

Bluesfrog

Well good luck with your project. It will give you what you want in boost. I currently use the lowest assist on my Factory Trek Verve + 2 for most things. But to melt into traffic and to bring lots of groceries home I use the maximum assist called Turbo. I look forward to seeing your success. Be Well, Bluesfrog.

Leisesturm

I know that there are press fit adapters for the Tongshen mid-drive. I bet if you check you might find that there is a way to get press fit adapters for the Bafang mid-drives as well. The Tongshen allows throttle use btw. Clearly a lot of people don't know that from comments I see. I just put my Tongshen motor in the frame today. Am on my own with the battery because it is a DF cargo bike and I am not using a downtube battery. A mid-drive will do with ease what it looks like you are planning to spend a lot of money and time trying to accomplish with hub motors.
Edit: I wondered about that press fit BB so I did some checking. I'd be very surprised if the Stratus BB is really press fit. Specs charts say Truvativ 2pc. I am going out on a limb and guessing it is an ISIS spline BB with external bearings. Neither the Bafang or Tongshen will care because the BB shell itself is standard English threaded 68mm.

andychrist

My Stratus was built up by a previous owner, it did not come factory standard. Bottom bracket is indeed press fit, takes an FSA Vero crankset 52-39-30. Bafang does not offer any compatible PAS sensors; have read that there are adapters available but my searches for such have been fruitless. Kind of a moot point though because further research confirmed my original impression that BB sensors/PAS systems are superfluous where throttles are allowed — the rider is in effect the torque sensor.

And hub motors have significant advantages over mid-drives. They reduce wear on the drive train whereas mid drives increase it, and make shifting easier by adding slack to the chain while the bike is propelled under battery power (so no need for gear sensors either). Also allow all the original gears to be retained, unlike mid-drives which are limited to a single chainring.

My dual 500W hub system will offer redundancy and should provide at least as much torque in total as Bafang’s 750W mid-drive. Probably easier to install than a mid drive while more forgiving, plus will offer redundancy. System cost about the same, got a terrific deal from Bluenergia on AE, came in around $750 with the extra half twist throttles. They have a US warehouse and ship incredibly fast and free, their four packages got to me less than a week from ordering. Oh and should mention, bought the host bike without wheels so saved like $400 off the seller’s original asking price/shipping, which applied to the dual hub system reduced the outlay closer to $350 thus definitely less expensive after all than any comparable mid-drive.

The T-Cycle Easy Reacher rack came in yesterday evening, so this morning will install that and a pair of DIY underseat panniers for Luna’s DireWolf battery packs which should be delivered later today. Hoping to be able to cruise to the polls by evening!

Bluesfrog

I hope the new system is working and the bugs are easy to work out. PHOTOS or it didn't happen. Be Well, Bluesfrog.