Motor for 130 mm rear drop outs
- Thread starter Babsbike
- Start date
It's nice that options for everyone's needs are available at reasonable cost these days!
It'd be great if mid-drives could use motorbike chains. On my bike at least, weight doesn't matter. Cassettes and chains for my bike are pretty cheap, so there's no reason for me to try any of the following - bear in mind I don't know motorbike chain dimensions: I'm wondering if removing 4 of 8 gear cogs from my cassette, doubling up the four which remain, then doubling the 52T chainwheel (bolting or riveting two chainwheels together for double width, or getting a custom thicker chainwheel and rear cassettes made [or file away metal from the rear cog sprockets?]), allowing me to use a motorcycle or some other wide chunky chain which fits... would result in 20,000+ miles between chain replacements on my legal 648W (-20%) 250W rated mid-drive conversion. The doubled/thicker cassette might last longer too? The indexed gear shifter would have to go. Would need a custom/double cogged adapted beefed up derailleur. Or if I installed a more powerful mid-drive motor and only needed one gear, for flatish terrain, I could simply use two bicycle chains? Of course, bicycle chains would wear faster, a single motorbike chain would last much longer. Someone must have tried something like the preceding already? Might be terrible ideas. Perhaps use of such contraptions ended in disaster and fatalities.
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I remember my first Green raleigh bike inthe early 70's 'as a young nearly teen, it had 3 spd sturmey and had a frame not unlike a pashly or swizzbee type design.
I was privileged. My dad bought me my first bike in 1963 for passing my 11+. It was a used BSA with 4-speed Sturmey Archer gears. Nobody else had 4- speed. It was definitely better than 3-speed. At the time, it seemed like a reward, but actually was the necessary transport to get to the grammar school 4 miles away. As well as to school every day, I went everywhere on that bike mainly for fishing. I was gutted that he sold it without my knowledge when we moved to Germany. He figured that I could ride my sister's bike but she couldn't ride mine, so all bikes were sold except the one. Thereafter, I never saw any of my sisters nor my mum ever ride a bike, but I still needed a bike to go fishing and generally get around, so had to suffer the ignominy of riding a girls bike until I finished University and was able to buy a Vespa 90 for £30.
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Of my 8 gears, for all my ebike needs, there's so much power on my 20" wheeled conversion I usually only ever use gears 1,5 and 8, even heavy trailer hauling uphill (gear 1 of course lol). I zip up and down between those gears, with the gear sensor pausing motor power perfectly in all the but one set of circumstances. Wearing out gear 5 necessitates purchase of a new cassette, or did - since increasing the controller amp limit from 15A to 18A, I now use gear 6 more often than gear 5.
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On my gravelbike I use 10 speed with shengyi dgw12 (2,2kg) motor with integrated cassette-torquesensor but with a different ratio setup as on my MTB´s, Trekking or citybike.
My latest build-MTB will get a 12-speed "sram-eagle" with cassette integrated Torque-sensor 10/50teeth sprocket. I know I will never use higher as maybe 30-teeth of my 50teeth cassette but as most things we don´t really need, it is nice to have in case the motor does not work anymore or other stupid reason that I need to find to justify my desired investment into my bikes
At the moment my hobby is to convert different motors with cassette integrated torquesensors because the ridefeeling is more natural
If you need to widen the drop-out to build in a motor, as long you don´t need much muscle to make it work I would do it. If I need really strong effort of my muscle to make it work, I wouldn't do it.
My latest build-MTB will get a 12-speed "sram-eagle" with cassette integrated Torque-sensor 10/50teeth sprocket. I know I will never use higher as maybe 30-teeth of my 50teeth cassette but as most things we don´t really need, it is nice to have in case the motor does not work anymore or other stupid reason that I need to find to justify my desired investment into my bikes
At the moment my hobby is to convert different motors with cassette integrated torquesensors because the ridefeeling is more natural
If you need to widen the drop-out to build in a motor, as long you don´t need much muscle to make it work I would do it. If I need really strong effort of my muscle to make it work, I wouldn't do it.
If it would be up to me, you could already buy those motors.... but it isn´t up to me.
I was thinking about converting those motors myself as a business but it is not efficient so I gave up on that thought.
I assume you know sales manager Daniel from Shengyi, maybe you give him a call whether he already can tell more. The more customer ask, shengyi is forced to react on market demands
My into Kclamber converted "shengyi-x2" is so far the best hubmotor possible for pedelec, if shengyi would decide for production, it could become a new standard for Hubmotor-performance with a very reasonable price
Of course I have a few minor points how to make this good motor even better the easy way but also here, their boss need to be convinced....
Ahhh...
I forgot, 130mm is not possible at the motors I mentioned it is rather 135-137mm. A normal drop-out for 135mm can usually used up to 138mm in tolerance
I was thinking about converting those motors myself as a business but it is not efficient so I gave up on that thought.
I assume you know sales manager Daniel from Shengyi, maybe you give him a call whether he already can tell more. The more customer ask, shengyi is forced to react on market demands
My into Kclamber converted "shengyi-x2" is so far the best hubmotor possible for pedelec, if shengyi would decide for production, it could become a new standard for Hubmotor-performance with a very reasonable price
Of course I have a few minor points how to make this good motor even better the easy way but also here, their boss need to be convinced....
Ahhh...
I forgot, 130mm is not possible at the motors I mentioned it is rather 135-137mm. A normal drop-out for 135mm can usually used up to 138mm in tolerance
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I think your torque sensor is a very good idea. Can the electronics be entirely built into the motor lid? If that can be done, sell it to the aftermarket.
If filing of the titanium dropouts is needed: I've read titanium clogs up files, so filing chalk first should help prevent clogging a bit, as it does when filing aluminium? Keep a very fine short wired file brush handy, in case the filed titanium clogg doesn't easily fall out with a light tap or two.
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- The number of gears is relevant to those who like to maintain a fairly even cadence irrespective of terrain, ie up/down hills, level ground etc.
- Some ebike riders especially those new to ebikes or relatively inexperienced in the unassisted world, use increasing motor power to go up hills whilst others like me stick to the 'unasssited' cycling habit of dropping a gear or two rather than upping the power.
- The number of gears is not as important as the highest and lowest ones from any given cassette.
- One of our aged club riders of many years cycling experience has an 11-speed ebike and he does at various times/riding condition, use all of them because like me, old cycling (and gear changing) habits still persist.
As I would prefer to use a rear hub motor this is a problem - they don't seem to exist ! I have done a limited amount of research and it seems that respacing a titanium frame is likely to be very difficult and I cannot find any reference to anyone who claims to have done it. So this is an appeal to the experts on this forum - is the 'magic motor' out there, or could one be tailored by deleting some spacers? I would want to retain an 8 speed cassette.
What is the problem you have? Why can't you fit any of the normal available motors? I think your research is completely flawed. Try talking to people' who have actually done it.
Hub motors do indeed exist. I have one in my bike and I am presently building a new one into a wheel for somebody else.
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Sign up to the cycling uk forum (no need to be a cycling uk member) and ask about 'springing' the rear forks there.
I'd be amazed if nobody there hasn't tried it.
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The problem is in the title: Motor for 130 mm rear drop outs
All O.P. can find is 135 mm motors and is concerned about springing his titanium frame.
Blimey, every day's a school day as I'd have thought the same as the OP that a hub motor advertised as having an OLN of 135mm would be great with a frame with the same OLN but potentially problematic with a frame of OLN 130MM.
Read post #7.
I can't get over how many guys on this forum want to make things more difficult than they are, doing hours of BS research and taking opinions from people, who don't have a clue, when if they were to actually do it, they'd have the answer in seconds.
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The terminology is certainly confusing if 135mm motor IS for 130mm drop-outs.
Post 7 (https://www.pedelecs.co.uk/forum/threads/motor-for-130-mm-rear-drop-outs.46586/#post-700689)
suggests O.P. can get away with 135 on his 131 titanium hub; that is great, and makes most of the thread after post 7 irrelevant to the original question.
However, that post makes it look as if a smaller difference (140/137) would not work easily on his alu Canondale. Would you say '140mm motor IS for 135mm drop-outs'? Would an 135 wheel fit easily into an 130 stiff alu frame?
O.P. was in the lucky position of having an appropriate wheel around and being able actually to do it (or at least, actually test it) as you suggest. Posting his result on the thread may have taken him longer than the experiment itself. Most people wouldn't have relevant bits hanging around to allow them to try such tests.
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