honcho

As the years pile on, each new hill I slowly pedal up brings to mind that someday I will want/need some sort of mechanical assistance.
I'd like to prepare for the future in something of an unusual way by fitting a a conventional bottom bracket to a bicycle frame built to accept a Shimano STEPS motor. Perhaps even taking it one step further by fitting a Pinion gearbox to a STEPS mount until the electric motor becomes a necessity.

Why am I interested in pursuing this approach? First, I'm lazy and if I get on an E-Bike I'll use the assist rather than pushing myself to do what, for now, I can still do. Second, we occasionally fly with our bike to cycling destinations and if the terrain is amenable to riding without assistance, we can avoid the hassle of trying to transport a lithium battery . Third, my riding partner and I would like to get a new custom tandem and by equipping it this way, we will be ready for the future when the spirit is willing but the legs are weaker.

It's likely the economics may not make much sense but it still appeals to me.

Any thoughts or ideas?

2old

ebikes are improving all the time; IMO, you'll have an outdated one by the time you're prepared to "reconvert". Plus, it's probably a fairly big job to convert an OEM ebike to non-status.

unterhausen

I don't think it's that easy to replace the motor with a bb. Just take the battery off

I was looking at building a steps frame, and would definitely need to make something to hold the motor case onto the bb post on my frame fixture. What I came up with was a fairly large piece of aluminum. I actually started working on the 3d model of it, but all I had was a drawing in the wrong format to use easily, and I got tired of the job. I should try again.

The way Shimano does things, I would almost guarantee you will need a different mount in 10 years. They could have used the same mount for their e-mountain bike system, but they didn't. Next generation road is not going to be the same either.

You can see what the mounts for the 6000 and 8000 systems look like at this link:
https://framebuildersupply.com/colle...c-motor-mounts

CliffordK

If you are getting a custom frame built, then it should be pretty trivial to have your framebuilder build up a false motor for the frame (although it depends on how much customization your frame builder wishes to do as it may not be a usual request).

However, I'd encourage you to look at hub motors.

You would be able to drop the motor and battery in a matter of minutes. The swap of the crank based motor would likely be a major hassle.

Or, another option would be to get the custom bike built with the brackets for the mid drive motor, but don't actually install it. Install the hub motor kit, then you can upgrade later.

@2old & @unterhausen mentioned the big risk that E-Bike technology is rapidly evolving. New motors will come out. Different brands than Shimano which may or may not use the same mounts.

Batteries are also evolving, and don't have an infinite shelf life if you wish to buy it now and use it later.

MORE POWER? LESS POWER? You may find your tandem needs are not the same as the typical stand alone bike needs, and you may look more at some of the cargo bike configurations (and thus, the flexibility of a hub drive might be nice too).

The last thing is that if you have 2 people pedaling plus the motor, you could put a lot of stress on the chain. Are you using a IGH, or a standard derailleur system?

Doc_Wui

The economics make no senseto me because first I would have to buy an ebike to get the Steps motor, as they don't sell them alone. Next I have a custom tandem frame built to accept it. Finally someone fashions a BB module that fits in place of the motor. If money didn't matter, it could be a custom bike thing to display at shows.

Otherwise, you can buy a kit mid motor and install it in your tandem when you run out of energy. Or you can install a strong cr-moly front fork and put in a bigger front motor.. THese two projects, any shade tree mechanic can pull off.

nfmisso

Here is a concept for a roll your own tandem mid drive ebike.

Take one standard tandem, create a brake to hold a standard rear wheel hub motor between the riders, with a single freewheel on the hub motor, with the chain line matched to one of the cogs on these cranks:
https://www.sjscycles.co.uk/cranks/s...558d65&geoc=US

Use standard tandem cranks on the left for the timing chain if synchronized pedaling is desired, or add a third chain ring to the above cranks, with one set of the cranks above in each position for independent pedaling.

When electrified, this will be a 1X drive train, prior to that a 2X is practical.

The largest 104BCD chain ring that I have been able to find is 52T. DECKAS offers narrow-wide chain rings - great for 1X, not so much for 2X.
https://www.ebay.com/itm/DECKAS-Bike...sid=m570.l1313

Hub motors typically spin around 250 to 400 rpm, choose the freewheel size and chain ring size used for the motor to approximately match your max cadence, or a bit higher. There also needs to be a chain tensioner in the system. With normal human compatible gearing, even a 250W hub motor mount mid drive system is a lot of boost.

Only cadence based PAS will work, unless you can engineer your own torque based system. On my bikes, I am not using PAS, I just use the throttle.

EDIT: just found this: Cranks 170mm - Freewheel Crank Set - Sick Bike Parts which allows other options, basically roll you own.

honcho

I originated this thread a few years back and lo and behold, a bike appears on the market that incorporates my concept. The latest non e-bike version Hase Pino tandem has a regular bottom bracket and crank in a holder that fits the space where the Shimano STEPS motor is on the e-bike version.

I believe all of Shimano's current STEPS motors are using the newer, 8000 series mounting pattern. I do not know for certain for this to be fact.

As one respondent to the original thread pointed out, Shimano doesn't sell STEPS motors to non-builders, but the motors and other components are readily available in various markets.

Another respondent suggested a hub motor and that is certainly a reasonable direction to choose. However, the best supported e-bike systems are those from the big brands (Shimano, Bosch, Brose, Yamaha) with most aftermarket hub motors having inconsistently available dealer support. We've been burned once by the bankruptcy of an e-bike motor manufacturer (bionx) so this weighs into our thoughts going forward.

Choice is good, right?

Leisesturm

There is no guarantee that even though the high profile, big name, manufacturer (Shimano, Trek, Giant) or the motor companies (Bosch, Bafang) are still in business some time in the future, a particular motor system could easily become obsolete and no longer supported some time coming. But this ignores the bigger point that the o.p. mistakenly thinks of an e-drive as something someone is forced to. Like someone couldn't actually want e-assist while in the prime of life, health and/or fitness. Why are e-assists provided on 17lb. full carbon uber racebikes? Do you imagine the rider of an Allant 9s is a doddering 80y.o. with incipient Parkinsons? Of course not.

But, surely, IF one really thinks they don't need an e-bike ... gah, the Super Saver tip o' the Week has got to be to simply not buy one? Wouldn't it suck to pay $$$ for some kind of Shimano STEPS ready chassis that you then ride as some kind of freak non-assist hybrid. A rather heavy one because of the 2.4" clinchers, the hydraulic disc brakes and the overall much more robust construction done in anticipation of MAJOR horsepower throughput. Wouldn't it suck (rocks) to have that investment made only to have world governments greenlight rebates to buyers of new eassist systems in the face of advanced Climate Change? Of course.

honcho

As I wrote, choice is good. My personal desire to have a bike that can easily accomodate a mid-drive motor is a preference. Your snarky response was uncalled for. E-bikes are here to stay but each of us can approach them as we see fit. We have a stable full of conventional bikes and I believe there is merit to a bike that has a path into the future.

Leisesturm

There are plenty of mid-drives that will bolt into a standard bottom bracket. There are zero standard bottom brackets that can bolt into a specialist mid-drive mount by Bosch, Brose, or Bafang. You knew that and posted anyway. My snarky response should have been expected.