Author Topic: Pendix Central Electric Motor, suits many Thorn bicycles  (Read 527 times)

Andre Jute

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Pendix Central Electric Motor, suits many Thorn bicycles
« on: March 09, 2020, 12:56:39 PM »
SJS is offering an electric Thorn bike at
https://www.sjscycles.co.uk/bikes/thorn-nomad-565l-with-pendix-motor-ex-test/?geoc=US
Dan has a thread on it at
http://thorncyclesforum.co.uk/index.php?topic=13733.msg102096#msg102096

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Here are some considerations about the very attractively presented Pendix retrofit motor SJS will be stocking.

All those different Pendix numbered types from 150 to 500 to be seen at SJS at https://www.sjscycles.co.uk/ebike-motors-accessories/ and more at Pendix's own site at https://pendix.com are the same motor of 250W, presumptively legal in Germany and therefore throughout the EU and presumably still in Britain. The numbers indicate only that you get a bigger battery or a bigger charger or two batteries and both chargers with the kit, not what they're trying to imply to innocents, that you get a more powerful motor. Torque is a so-so 50Nm for the top models (300 and 500), and an even less impressive 32Nm for the 150 models, left for dead by the cheaper (but not as beautiful) Bafang central motors. However, if the wattage can be upped, the additional torque locked in the motor by the hard 25kph limit (which is the electronic cause of the more notional 250W limit) can be freed.

Bear with me for a brief interjection: For anyone to whom an electrified bicycle is actually necessary, 25kph/15mph is in my opinion more than enough for the simple reason that as one grows older ever smaller accidents become life-changing or even -ending. A broken hip will very likely end one's cycling days, and could cause complications ending in a casket. The severity of incidents and damage increases with speed. But torque is an entirely different matter: the older/weaker you grow, the hillier your riding pastures, the more torque you need. And the truth is that the pedelec paradigm is hostile to bicycling logic in that it is proportional to your own input at the pedals. You don't have to be Einstein to grasp that such a bureaucratic stupidity reduces electric input just when electric input should be increased to a greater proportion of the total power, say when you're pedaling up a hill, or accelerating from a standstill. So the pedelec laws give you more assistance when you least need it, on the flat, and less when you really need it, on the hills. Duh. End of diversion.

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I know y'all are law-abiding citizens so this information is provided only to allow you to identify and report to the police any scofflaws you may find on the road.

Surprise, surprise, the aftermarket has already stepped in to fill the hole. The Badass Box 4 Pendix is a contactless device for faking out the software of the Pendix electric motor so that it can go faster than 25kph/c15mph. It does it by clamping over the Pendix sensor and forcing it -- contactlessly (I'll explain why this is important in a minute) -- to report a lower speed than the bike is actually travelling, which also causes the readout of the Pendix to report the wrong speed, trip and cumulative distance and so on. However, almost everyone who actually needs an electric motor on his bike has a heart rate monitor/GPS/map facility on his bike's handlebars, for which plenty of free software to report speed and distance is available, or otherwise a small, inexpensive dedicated bike computer can do the job. The Badass Box 4 Pendix is a tiny, light device:



The reason any enhancement must be contactless is newly proposed French legislation, which will slap a fine of Euro 30,000 (you're reading that right, thirty thousand) on anybody altering the electronics of an electric bike, likely to become EU regulation, and may be applied in Britain too if the bureaucrats are too lazy to make their own regulations. One presumes that the usual exceptions for offroad riding will be included, but you never know with the French -- if they propose to punish a cyclist to the extent of several magnitudes of the punishment for a motorist for the same class of offence, what aren't they capable of? This whole affair isn't legislation, it's persecution.

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It is for consideration above -- unlocking all the torque in a very torquey motor -- that I earlier advised those buying the Bafang BBS central motor (descended from the torque-optimized BPM hillclimbing motors) to buy their motors and control software only from dealers who didn't cripple the software, so that the individual bicyclist could tailor the response curve to his own cycling environment. I bet there's a run on uncrippled  motors held by those good dealers...

Note that the Bafang cannot be made to fit Thorns with the eccentric bottom bracket unless you're willing to fit an ugly, dirty chain tensioner. The Bafang is used here only as a contrast to the newer Pendix.

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If you're an old roadie who believes as an article of faith in a narrow tread (Q factor), or if you've instinctively disliked even the slightly wider tread that a Rohloff's wide chainline forced on you, you'd better try any bike electrified with a centre motor before you buy it. The Bafangs sit centrally in front of the bottom bracket, the Pendix, which from the photos seems narrower, sits between the bottom bracket and the chainring with, if I read the literature right, a symmetrical extension on the non-drive side. Personally, being a social cyclist of no perceptible elegance or aerodynamicism, I like a wide tread, so I don't care, but the drop-bar-brigade might.

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As I say, this information is provided only to permit you to be a good citizen.
« Last Edit: March 10, 2020, 02:09:30 AM by Andre Jute »

PH

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Re: Pendix Central Electric Motor, suits many Thorn bicycles
« Reply #1 on: March 09, 2020, 11:06:24 PM »
All those different Pendix numbered types from 150 to 500 to be seen at SJS at https://www.sjscycles.co.uk/ebike-motors-accessories/ and more at Pendix's own site at https://pendix.com are the same motor of 250W, presumptively legal in Germany and therefore throughout the EU and presumably still in Britain. The numbers indicate only that you get a bigger battery or a bigger charger or two batteries and both chargers with the kit, not what they're trying to imply to innocents, that you get a more powerful motor. Torque is a so-so 50Nm,
Interesting summary and insight, but are you sure about the above?  The Pendix website list the 150 as having 32Nm max torque and also without the same power settings.
I've had a test ride on an Airnimal with one, it's certainly a neat and well made looking unit, but I wasn't impressed. Compared to several purpose made E-bikes with mid motors I've tried, Bosch and Shimano, it wasn't as smooth or as powerful, despite costing almost as much as some complete bikes. Although putting all the controls in with the battery cuts down on the wiring, it also means that you're paying for this stuff twice if you double up on batteries.  And having the control on the battery is far less convenient than on the handlebars. 
I'm still toying with the idea of getting an E-bike or maybe an electric motorbike for work, but this was quickly crossed off the shortlist.  I'm quite surprised Thorn have gone with it, I see the appeal of converting a bike you know and like, but starting from scratch with a pocketful of cash I think you could do a lot better. 

Andre Jute

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Re: Pendix Central Electric Motor, suits many Thorn bicycles
« Reply #2 on: March 10, 2020, 02:03:26 AM »
Thanks for the heads-up, Paul. I've altered my post to reflect the fact that the lower models have 32Nm and the top models 50Nm.

It's a good-looking kit, but for me that's not enough to overcome crippled and inconvenient controls -- and the torque is very important for a tourer on public roads, none of which come without hills. Even on the flat, breaking away a bike from a standing start when it is carrying luggage is a torque problem.

One really good thing about the Pendix is the 48V battery: i think that will soon replace the current standard of 36V batteries which, outside the United States, has been running a long, long time.
« Last Edit: March 10, 2020, 02:12:25 AM by Andre Jute »