Cargo bike, BB issues and drive choice

[misterjones]

Hi, I’ve been lurking a while for research purposes but decided I should ask some questions.

I have a plan to build up a (relatively) lightweight cargo bike - an Omnium Cargo if anyone is interested - with some kind of assist. The bike would be around 25lbs, I’m 160lbs, and I would carry up to 50-60lbs, totaling around 235-250lbs. I live in LA and try to avoid the really steep parts keeping most of my riding to grades less than 8%. I cannot imagine riding faster than 25mph unless i’m going down hill. I am most certainly not a hot rodder.

I’ve read a lot of pro and con arguments regarding mid drive vs geared hub. The technical proof for either systems worth seems well covered but I am very interested in opinions based on rider preference/experience. I was particularly curious about some riders who don’t use pas and seem to regard the assist much like an on-call blessed tail wind. I like to pedal but, when carrying extra weight and going a little extra distance, I would like to create my own wind-at-my-back.

I am interested in, but resisting, a mid drive, specifically the BBS02, because I’m concerned that installing it is a permanent deal. The way it mounts inside the BB (presumably touching the threaded interior, damaging it) and then a toothed washer gets torqued down against the BB face denting it and potential destroying the threading nearest the edges. Which would mean I couldn’t return the bike to non-assist in the future (I might, it is a great bike for touring apparently, and I would need to fly it to where I would tour). If mid drive is what I use, I'm still not sure if I should go 3, 5 or 8 speed igh, or stick with an 7-8 speed cassette. I can always carry a spare chain...

If I chose a rear hub motor and it dies while out on it I could still pedal - and have a double chainring up front. However, as simple as hub motors seem to be in the mounting and de-mounting, I worry they mightn’t give me enough of a hand.

So, maybe I’m over worrying the mid drive mounting issue. Or maybe I’m under estimating the capacity of a geared hub motor given my parameters. I'm new to electric assist so I have no experience with which to judge how much stress my parameters may put on either system. I’d love to read a few more anecdotes about other riders experiences.

 

[Bicyclista]

Why not just order the Omnium Cargo Electric with the Shimano STEPS 8000 mid-drive motor? Yes, they're only taking pre-orders now, but if you're willing to wait, it might be the best option.

I agree that damaging the bottom bracket of a quality bike by mounting an aftermarket mid-drive motor is not a good idea.

 

[misterjones]

Why not just order the Omnium Cargo Electric with the Shimano STEPS 8000 mid-drive motor? Yes, they're only taking pre-orders now, but if you're willing to wait, it might be the best option.

I agree that damaging the bottom bracket of a quality bike by mounting an aftermarket mid-drive motor is not a good idea.

I had considered that option, desired it even!, but they'll be around $5300 plus shipping which is a little over my budget. I already own many of the bike parts I need for this project, and was planning on buying just a frame set and front wheel. I can build the bike up - including whichever electric system I choose - for a little less than $3000. Perhaps I should be asking this -have people noticed any permanent damage on their frames, particularly on 68mm English threaded bottom brackets, after installing a BBS02?

 

[Bruce Arnold]

I think you'd find that the rear hub drive would meet your needs and be a lot easier to install. Go to YouTube and check out E-bike Commuter. I particularly recommend this video on what a hub motor can do, and this one where he does 45 km with 180 kilos of bike, gear, rider and passenger. BTW he is running a front hub motor but I don't think that's relevant to your basic question.

 

[tomjasz]

I had considered that option, desired it even!, but they'll be around $5300 plus shipping which is a little over my budget. I already own many of the bike parts I need for this project, and was planning on buying just a frame set and front wheel. I can build the bike up - including whichever electric system I choose - for a little less than $3000. Perhaps I should be asking this -have people noticed any permanent damage on their frames, particularly on 68mm English threaded bottom brackets, after installing a BBS02?

There seems to be a big rush towards mid drives, but many of us don't need the complexity and gear drive hubs are amazingly adept at handling grades. With far less problems, often lower prices, and much easier access to repairs and parts. The right GD hub can run on 36,48, 52, and some even on 60V batteries. Offering an entire ranges of power and speed. I don't sell hub drives but feel free to message for more information. As far as BBS02B for a cargo, I'd blow that idea off in favor of a BBSHD, if you MUST have a mid drive.

 

[tomjasz]

have people noticed any permanent damage on their frames, particularly on 68mm English threaded bottom brackets, after installing a BBS02?

No, I've run 1000W BBSHD on several aluminum frames, 68mm, 73MM, and 100MM bottom brackets. Chain line can be an issue, a real pain in the arse, (always google the frame and the motor used to find other builds)but not frame damage.

 

[misterjones]

I think you'd find that the rear hub drive would meet your needs and be a lot easier to install. Go to YouTube and check out E-bike Commuter. I particularly recommend this video on what a hub motor can do, and this one where he does 45 km with 180 kilos of bike, gear, rider and passenger. BTW he is running a front hub motor but I don't think that's relevant to your basic question.

I have seen the video of him hauling his daughter and camping equipment. The other I've not seen before, so thank you. It's a useful companion piece. It was after seeing him use a front hub motor (with a heavy load), and someone else posting on this forum doing the same but for their road bike, that had me wonder if a hub motor might just do what I want. I enjoy building wheels and have a nice never-laced rim sitting around that would look good around a hub motor (or an IGH...).

 

[misterjones]

No, I've run 1000W BBSHD on several aluminum frames, 68mm, 73MM, and 100MM bottom brackets. Chain line can be an issue, a real pain in the arse, (always google the frame and the motor used to find other builds)but not frame damage.

This is very helpful. I'm familiar with resolving chainline issues so that's not so bad, but good to know in advance. The Omniums have 68mm BBs and 135mm rear ends so nothing out of the ordinary there. But I appreciate the "real world" experience regarding what a mid drive unit will do to a bike frame when installing. Sadly I've only found one other person posting on the internet about mounting a similar mid drive on an Omnium and there are no pictures or follow ups. A BBS02 or a BBSHD will fit in the BB, but now I'm looking closely at the frame geo and seeing that (what constitutes) the down tube on the Cargo is at a very low angle meaning there may be a clash between it and the very necessary big kick stand. I enjoy a challenging project but I can also see why some people prefer to buy off-the-shelf bikes.

 

[JRA]

The bb threads can be chased if there is any damage to them as well as the shell can be re-faced. Specialty tools but a good shop should have them.

As far as a power plant goes either would do the job if set up properly. A combination of PAS and throttle gives the best of both worlds and can be achieved using either system.

 

[tomjasz]

This is very helpful. I'm familiar with resolving chainline issues so that's not so bad, but good to know in advance. The Omniums have 68mm BBs and 135mm rear ends .

This frame? If yes I'd be more inclined to think about a hub drive, geared from eZee or MAC. A BBS02 would be a serious mistake for a cargo bike, in my experience. I just sold a eZee gear drive that will do 15 miles of 7.5% grade without overheating. If insisting on a mid drive conversion only the BBSHD makes any sense. Just program it for lower amps, dumb it down a bit for longevity. Personally I ride MAC now that I've sold my BBSHD's. There were unnecessarily fast for my use.

 

[misterjones]

The bb threads can be chased if there is any damage to them as well as the shell can be re-faced. Specialty tools but a good shop should have them.

As far as a power plant goes either would do the job if set up properly. A combination of PAS and throttle gives the best of both worlds and can be achieved using either system.

I like your particular setup - throttle only(?) on a front hub - the idea of “cycling over the motor” is kind of what I had in mind. Would you share with me any tips for your riding style? I’m assuming throttles are spring loaded and so would have to be held open. I also have some uncertainty regarding how ok it is to run hub motors at loads that would, eventually, lead to over heating but are in practice only used for short bursts - a steep grade may only be a 5 minute climb. I reply to Thomas below about it a bit.

FWIW, I think your silver bike is also probably the most attractive ebike I’ve ever seen.

 

[misterjones]

This frame? If yes I'd be more inclined to think about a hub drive, geared from eZee or MAC. A BBS02 would be a serious mistake for a cargo bike, in my experience. I just sold a eZee gear drive that will do 15 miles of 7.5% grade without overheating. If insisting on a mid drive conversion only the BBSHD makes any sense. Just program it for lower amps, dumb it down a bit for longevity. Personally I ride MAC now that I've sold my BBSHD's. There were unnecessarily fast for my use.

After using the extremely fun simulator over at ebikes.ca I discovered the 20” front wheel of the bike I have in mind performs better with the mac motors. I did up the weight parameters of the bike (forgot to add the battery and motor, duh) and ended up doing simulations with the loaded bike weight nearer the upper end of the bikes carrying limit - 385lbs, but IRL I’d stay below 330lbs. And at 0%, 4%, 8%, and 12% grades to see how they performed. I wouldn’t want to be on a >8% for very long. It’s a shame there’s no way to simulate a (dumbed down, which I’d do) BBSH as a comparison. I’m not sure it would give me any more speed on a flat (20mph), and if they have good torque but are slow on a climb then I may not gain much there either.

 

[JRA]

mj, yes I only have a throttle on my road bike(s). A key factor is ease of access to the throttle itself as it should fall easily to hand (thumb actually for my preferred throttle type). Another key factor is to be able to program the throttle so that it doesn't come on too strong and ramps up evenly. But the most useful feature that is programable is the cruise control feature. This allows you to hold the throttle, I have mine set up for one second, and the motor output will vary to your input/terrain to keep you going at around the speed it was engaged at. A quick blip of the throttle disengages the cc btw, I also have a regen button that stops it. The bottom line for me for road riding is being able to separate my input/cadence from the motor as I find PAS limiting in that regard. I use a Cycle Analyst to access these feature btw and also it does an excellent job of keeping me informed of my battery charge among other useful bits of info. They can be plumbed in to most e systems.

Climbing steep stuff I still try to keep on top of the motor as much as possible allowing the motor to retain a higher PRM seems to keep it cooler. I don't go for speed uphill other than faster than I normally would be able to and to preserve battery as I am generally in no hurry but have a distance I want to achieve in mind. So in general basically what I try to do is use the motor to aid in momentum to maintain a higher average speed than I would on an analog bike and also to aid in starting off.

Thanks for the compliment on the bike. It is a lot of fun to ride and although it isn't technically legal ridden responsibly it is about the only way that I see e drop bar road bikes becoming popular. The mid drive ones the manufacturers are starting to put out based on EU standards just don't seem like they will draw much of a crowd as many road cyclists can maintain the average speeds they are capable of on their own. People routinely win 100+ mile races, on gravel, with an average of 20mph or so. Road bikers average higher.

 

[Felt Hauler]

Legal, fun to ride, great range

 

[tomjasz]

Legal, fun to ride, great range

Nice, very nice. I’ve seen a few quite nicely designed frames from Felt. I didn’t realize they did a cargo frame.