Spindle size for Pedal assist?

I am wanting to put a motor on my Rambler, but I cannot seem to find info on the spindle size so I buy the proper pedal assist. Since it is still January in Illinois, the trike is in storage at the moment. Help?


  • rambler fits a 68x113mm, JIS square-taper bottom bracket although going down to 110 might fit better. the grin-tech modified patterson crankset should be a perfect fit.

    suggest terratrike customer support for bb spindle length range.
  • Spindle size isn't an issue at all if you use a mid-drive motor. Since you wouldn't be replacing the rear wheel at all...

    The biggest advantage of a mid-drive motor would be the ability to use the gearing in the rear with the motor. (Which can't be done with a hub motor.)

    I put a mid-drive on my Rover. Easy to do, it just replaced the front crank set. The motor I have is the Bafang BBS02. Since the motor replaces the cranks, you lose the gearing on the front. The motor's input more than compensates for this. I still use the 46T stock chain ring and get better results than I had anticipated. I can climb pretty steep hills I'm sure I couldn't do with a hub motor.

    Check out Luna Cycles for pricing systems. I would link to the Luna Cycles site for the motor I have, but links to that site never seem to work from this forum. Call them and specify things like the measurements from the crank to the left handle bar (for the display and the throttle controls.) And to the rear wheel mid-spoke. (Speedometer magnet.) Also, you want to mount the battery somewhere low, so look into the Low Rider Rack from TT to mount the battery. You will also need to measure this distance to the crank.

    Last word of advice if you go with Luna Cycles is to get both the Gear Shift sensor that works for the type of gearing you have on the rear wheel, and to ensure the motor you get has the 3rd brake connector or you will need to purchase a "Y" to put this sensor into the system.

    (BTW, I did just make a post in the last few days with a lot of this info already in that post.)
  • Since I have the IGH rambler, I decided on this kit:
    I will look at Luna for the battery, but I am going with the TCDM IGH not a mid mount motor.
    My topic with most of my plans ands questions is here:

  • edited January 29
    It is interesting to note that the thread you linked to has a picture of a BBS02 "inspired" by Elrique64. I am the same Elrique64 that inspired that particular build.. The person there and I had been in contact quite a bit during his testing/development. Even though he has a recumbent bike and not a trike, he opted to use the same method for motorizing his ride as I did.

    I have no experience with that particular hub, so can't speak to how it works. I'm going to guess though, that the IGH in it is an independent system: It looks like a typical hub motor system... The motor spins the wheel or the chain spins the wheel. While you CAN use both methods together, the motor doesn't move the chain. The motor spins the wheel regardless of the level of pedal applied. (The amount of chain that gets moved by the pedals.) So the motor is going to move the wheel regardless of how much pedaling you are doing.... The fact that it uses an IGH instead of a derailleur just means you have a clean chain line.

    Please let us know how this works for you. While I have invested a lot of time on this and other forums concerning the BBS02 (or BBSHD) on trikes, I'm genuinely interested in other options. (I'm still waiting to see some RL results on the EVO for example...)
  • doesnt quite work that way, elrique - on a hub motor, chain only moves when the pedals are turned.

    advantages over a mid-drive motor: no increased wear on the driveline, no strain on the boom, and should the driveline crap out you still have a get-me-home.


    would have chimed in if i had seen your endless sphere thread.

    thumb throttle is happy with a right-side handlebar mount on a rambler.

    several potential problems:

    a sturmey hub requires a pause when shifting gears. should be ok if shifting under power as long as the pedals stay still.

    if grin used an xrf-5w hub you will have miserable top-end pedal only, but pretty good doing hill climbs. this can be overcome depending on wallet.

    more serious concern is grin caveat that this is a wheel designed for a horizontal dropout. you will want a pair of grin torque arms for wheel securement - whether you have sufficient axle length to mount them is another matter.

    i wouldnt invest in a battery or mount any of the control parts until you have secure wheel mounting accomplished. this package would be ideal for a rover with a patterson crankset. if it fits the rambler, would think you will be a happy camper.
  • JamesR wrote: »
    doesnt quite work that way, elrique - on a hub motor, chain only moves when the pedals are turned.

    Knew that already, which was exactly the point I was trying to make. Thanks for the confirmation, though.
  • Add torque arms to the cart..check.
    Once I get to the point of buying this stuff, I WILL make it work. I am trying to do this with a minimum of false starts and wasted effort though. OTOH If I end up needing to cut the drop outs clean off and weld up a new set, so be it...
  • There are two major different motor systems when it comes to ebikes and etrikes.

    The first is the hub motor system. The motor is basically the wheel so it doesn't matter one whit what type of gearing you have on it, because the motor is completely separate of the hub/gearing the wheel has. The gearing is for the rider/pedals and not for the motor itself.

    The second is a mid-drive motor that replaces the crank set of the bike/trike and uses the existing rear gearing, since the mid-drive moves the chain just the same way the pedals move the chain. That means you are adding your own power to the equation and using the motor to boost your power output. Think of it as bionics, if you will... Because that's kind of how it works.

    You haven't bought anything yet... This is good, because you can still make some educated decisions and you aren't out anything more than the time it takes to research the options.

    Take a look at the Bafang BBS02 or BBSHD or the Tongsheng TSDZ2 motors. You can get either of the first two from Luna Cycles, or the third from Amazon or other sources. There are many more options available for the first two than the last one, so I'm partial to them....

    Don't be the guy that spends a couple thousand dollars on a motor system to be disappointed with what he has... At least check them out before you get tied to something...
  • edited January 30
    "The motor is basically the wheel so it doesn't matter one whit what type of gearing you have on it, because the motor is completely separate of the hub/gearing the wheel has. The gearing is for the rider/pedals and not for the motor itself"

    totally wrong. probably easiest to find a bionx equipped trike to discover the error of above statements. in reality, there is little difference in pedal-assist results between crank-turner, chain-puller, and wheel-turner beyond complexity - motorized wheel being the simplest configuration.

    there is also a 'real' mid-drive configuration in the form of the currie ezip. in contrast to the usual crank-turners and boom-mounts, this setup spares driveline components from an early demise. there is, contrary to expressed opinion, a fifth mode of electric assist in the form of the rubbee and variants.

    my opinion on driven wheels is based on both rover and rambler with 3 different types of golden motor wheels, with internal and external controllers on direct drives and a geared wheel with external controller.

    what would probably work well on a rambler (havent tried that yet) is the new golden motor edge, 5-phase sinewave drive, 8-speed cassette.
  • JamesR wrote: »
    totally wrong. probably easiest to find a bionx equipped trike to discover the error of above statements. in reality, there is little difference in pedal-assist results between crank-turner, chain-puller, and wheel-turner beyond complexity - motorized wheel being the simplest configuration.

    You are right. I have no experience with hub motors at all. They don't fit the way I want to ride.

    WOT or WOPAS in my case has 8 potential speeds. I KNOW I can climb a hill with PAS mode 9 and 1st gear and still make it to the top of the hills that I've seen other ebikes have to stop and walk up... So while I have no PERSONAL experience riding a hub motor, I DO have experience riding with others that do... Add in the extra weight of a trike and walking up that hill just got harder.

    I know I can use the gearing on the hub and control the speed I'm going even at max RPM from the motor. I know I can use the gearing and the motor to climb every hill I've encountered so far.

    Can you do either with a hub motor?

    What I KNOW will work well with a Rambler is a BBS02 or BBSHD and the existing rear gearing. No "probably" involved at all..... And with the controller built into the motor, still probably the easiest to install by a garage mechanic or LBS with a little bit of pre-planning.
  • There is a,excellent discussion regarding e trikes at the Recumbent Trike F.B. page minus the bickering.
  • industry opinion from the proprietor of endless sphere:

  • @TCEd without the bickering? Where's the fun in that?
  • Jrobiso2 wrote: »
    @TCEd without the bickering? Where's the fun in that?

    E trike or E bike is an expensive purchase new or doing a conversion. Although I'm not considering it now I'm still trying to learn the technology and options without bias/bickering etc.. It's obvious someone likes mid drive and someone else likes hub drive.

  • Like most things in life, each technology has its positives and negatives. I hope the aim of most of us on the Forum, is to help one another make informed decisions. While I considered a hub motor before deciding on and installing a BBSHD on my Rover, I am confident I made the right choice for that trike at that time. I can't say that mid-drive motors are better than hub motors, but I can tell you I know 3 people who installed hub motors first, then replaced them with BBSxx and all 3 are now satisfied. But a hub motor might be just the thing for you.
  • I know that in my case, my biggest worry with the BBS mid-drives is how much stress will I put on my Sturmey-Archer 8 spd IGH and its sprocket? If I had an external gear set in the rear, I'd be much less worried.
  • Here's a link on various recommendations for mid-driven IGH's: https://www.electricbike.com/mid-drive-kit-igh/

    The SA-8 isn't listed here. I've read from other sources that this hub can be broken if you try shifting it under pedal only load If you go with a mid-drive you NEED the gear sensor to prevent breaking the hub under motor power. This is a cheap <$50 investment to prevent tearing the hub up.
  • So is the Nuvinci hub best for adding EVO?
  • Any hub can work fine if you get the gear sensor which senses when the hub shifts, and momentarily pauses the motor so everything works without a hitch. The NuVinci hub would eliminate the necessity of purchasing a gear sensor as their is essentially just one continuous gear.
  • So is the Nuvinci hub best for adding EVO?

    The EVO that TT have said they will be selling as an addon to your trike is a hub motor. That means the NuVinci hub would be replaced completely by the motor hub and an external shifting system.

    @TrikeBirder is right about not needing the gear sensor with the NuVinci hub, since that hub is designed to be adjusted as needed, to keep your cadence where you want it. It's the only gearing system that you wouldn't need it for, at all. (Keep in mind, there is a sensor for IGH's and another for external gearing. For all other gearing systems, you need to get the right sensor for your gearing.)
  • edited February 12
    Ok, I am willing to listen and have no ego invested in either choice. There are several reasons I was thinking hub motor over the other options.

    First off, Since I have gotten this trike, I have discovered that it is easily possible for me to Ride well past what should normally be the limit of my endurance. Since about the last mile (to get home) of any route I choose to ride is up some steep seeming hills, I have found myself on more than one occasion needing to stop and regain some stamina. I have also found myself at the bottom of my driveway, without either the ability to pedal up it, OR the ability to stand up to walk up it. My main intention for electrifying this trike is a sort of insurance policy, and probably to make some of the hill climbs a bit easier to manage.

    I have the Rambler with only the IGH, no derailleurs or external gears. Replacing one IGH with another seemed simplest. Yes, I know I can add derailleurs, but that is more stuff to buy and sort out.

    Perusing the site I am probably going to buy my stuff from, it seems I have my choice of 3 different TCDM PAS in stock, a 114, 120, and 128. Instructions above indicate that I need 113 or smaller. The Patterson cranksets are out of stock. And the recommended 68x113 does not seem to match up with anything. I know this seems stupid, but since I have never touched any of this, I have no idea where the tolerance(s) is/are. Does the 113 mean I have to be at least 113 to fit or at most 113? I wish I had a LBS that was even ebike friendly, but they range from Meh to hostile...
  • 1 mm is approximately 1/25 of an inch. as the ebikes.ca site states: "It is usually no problem if the spindle is a few mm longer or shorter than the one being replaced."
  • I would be more confident if they had not included the term "usually" since with the inevitability of time it's ALWAYS me that finds the exceptions...
  • IF you go electric, you wouldn't be replacing one IGH for another - you'd be replacing an IGH with an electric hub AND external gears. This now means adding a rear derailleur, etc and more chain, and possibly changing out your shifter as well.
  • Nope, I am going with the TDCM IGH which has 5 speed Sturmey Archer internal gears. That is one reason why this project has been over a year in the making...
  • I hope your project works out the way you want and expect. I always believe in undertaking any new adventure with "eyes wide open", so to speak. To that end, and before anyone currently with, or contemplating getting, Sturmey Archer equipment, I encourage a good reading of: https://www.sheldonbrown.com/sturmey-archer.html
  • on the other hand, ebikes.ca is an engineering solution site unlike the usual retail vendors. email grintech with your concerns.

    by the way - silly millimeter spindle length is going to be less of a concern diy than length of cables. measure needs carefully, ask for length required when ordering kit.
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