Jump to content

Recommended Posts

I know a few others have done a 3-speed upgrade to their Sondors. I am in the process of doing the same with mine. So I thought I'd share my journey here and hopefully get some good feedback and inspire others to do the same. This upgrade is inspired by @biknut and his amazing upgrades to his Sondors eBike.

I'm still waiting on parts, but here are the items I am using:

3-Speed threaded freewheel cog with gearing that is similar to the stock rear cog:

I believe a full standard rear 6-7 speed geared cog assembly works if you spread the frame, or remove some of the cogs and cut the shaft down. I am going to try this as a side project.

The stock freewheel on my bike has I believe 16 teeth, and the above freewheel has 16/19/22 which, with the stock chainwheel, gives you a hill gear, a medium gear and then a "stock" higher speed gear. To change this, you will just need to replace the front chainwheel with something with the number of teeth to give you the ratio you want. I plan on changing mine so the middle gear is "stock" speed and there's a low end hill gear and then a higher speed gear eventually.


I'll be using just one of these two for my conversion.


Note this derailleur is designed to mount directly to the rear wheel axel instead of the frame. The frame mounted kind would work but would complicate the install process.


I went with a 5-speed chain to make sure I had plenty of length considering the cogs are pretty small in the rear. I am hoping it is long enough. If not I will get a 6-7 speed chain and then just remove some links to shorten it as needed. I am hoping whatever slack is there can be easily taken up by the derailleur.

Shifter Cables:

There are lots of these out there. You need to just make sure that they have the correct cable and housing size and that these match, and the end using the correct terminator. (the round piece on the end that connects to your shifter, I am not sure what this is called.)


Zipties - I have a ton of these and they can be found at any hardware store or Amazon, etc.

Freewheel removal tool - An awl or small screwdriver can also work, but the tool helps with the process. This of course depends on your freewheel and how tight it is based on how much you've ridden and how much pressure you've put on it. The stock freewheel has 2 dimples on the main body to be used as loosening leverage, I am not sure if it has the standard 2 lug slots, I need to check mine and take a photo and link to the right tool. But a good solid flathead screwdriver and a hammer should be able to loosen this up.

I am expecting the first parts by next weekend and my first task will be to put the freewheel on and ride with just it. Then I can add the derailleur, shifter and cabling and adjust the derailleur to shift nice and smoothly.

  • Like 2
Link to comment
Share on other sites

Great project. I look forward to seeing your results. I haven"t had enough time or good weather to ride my new bike much, so I don't have enough input to know what mods I need to do to maximize my riding pleasure. I will keep an eye on this post to see how good your results are. I appreciate the fact that you are sharing your upgrade journey with the community and look forward to more. So far I have I have just installed turn signals, lights and a motor cycle style switch, on the left grip, to control it all. I also turned my throttle up side down so when I go forward I push the throttle forward instead of down. Seemed more natural. I have a set of fenders on order along with the computer. I will install them when they arrive.

Looking forward to more of your project. I have a feeling I have some new gears in my future.

Link to comment
Share on other sites

It's going to be a fun project. I've been spending a lot of time learning about gear ratios, tuning derailleurs, and so forth. The only thing I am concerned about is the derailleur at this point. I am not the best at tuning them to hit the gears right, but I'm learning and worst case, I take it to the bike shop and they tune it for me if I give up.

I was hoping to get started this weekend but my 3-Speed freewheel just went from due this weekend to due early next month. So that will delay things unless I can find another that can ship faster. I may check with the local shop to see if they have any thread based cog cartridges that fit on the Sondors threading that I can take apart and cut the main part down and reassemble to make my 3 speeds work without frame spreading.

I've measured my existing 2 bikes with 6-7 gear cog freewheels in back and I'd need to spread the frame around 1", which I am not comfortable with, to fit an existing 6-7 speed cog freewheel on there.

I like your idea of flipping the throttle up so forward is "forward". I ride a motorcycle, so a twist grip is kind of where I am headed but I'm worried about accidentally hitting the throttle as I ride and grip it. I had that issue with one of my bikes which had a twist shift system and I kept changing gears when riding. It's why I've decided to use a shift lever instead for my 3-Speed conversion. I don't want to risk a shift in the wrong time, especially if I get out into some tough riding spots. Nothing kills the buzz like shifting up or down and losing your momentum. :D

Link to comment
Share on other sites

I don't have a problem with altering the spread on the rear frame because the frame material appears to be fairly substantial. My fear would be possibly marring the finish on my yellow frames. I recently purchased a power coating system with some yellow powder so I could make brackets and any other little items I might need for my bikes. What I don't have is a large enough curing oven to hold a bike frame, (yet, lol). I do have a set of porta-power hydraulic rams for doing auto body work that would make a "spread" pretty much a piece of cake, especially if it's only 1 inch. I am a bit uncertain of the line-up geometry of the chain from front to back. If you spread the back do you just spread the right side, leaving the left with it's present geometry or can you equidistantly spread both sides.

I am totally new to the world of modern bicycles. The last time I owned a bike was about 50 years ago. I'm a retired IT guy with an education in mechanical engineering and I have a fairly extensive shop with a milling machine, metal lathe 5 welders of various types including a plasma cutter and just about every other tool that you can think of (ok, I confess, I'm a total tool junky). I am able to do any modifications that I want to the frame. What I really want is to keep it simple. Partly to reduce the need for constant fiddling and to reduce the need to go riding with a bag of wrenches and such. The name of this game is "Fun", something I don't get enough of. So I really like your concept of using a 3-Speed freewheel  instead of the larger 6-7 gear. Also, while the added weight isn't that much, every additional oz. adds up. If need be, a second gear could be added to the peddle gear to create a 6 speed drive although that does add extra complexity, not to mention another lever.

I like that you are going to use a shift lever instead of a grip shift. I agree that a grip shift could cause a miss-shift at an inopportune time and might be awkward to use with a thumb throttle. I did some digging on Amazon myself and I agree with your your parts selection with one exception. I think I would go with the Shimano EF-51 Shifter/Brake Lever Combo (3 x 7 Speed). I would mount the brake/shifter on the left side, using the 3 shift lever. Right now I have a motorcycle turn signal/horn/light switch on the left side and with a separate shift lever I think it will get pretty crowded. By using a combo shift and break lever I should get a more compact, less cluttered, control cluster. I want to keep the e-throttle lever on the right and as uncluttered as possible.

I just received my light kit from eBay and for $12 it was a real bargain. The light is easy to mount on the handle bar or, preferably on the left front fork, and has it's own lithium battery pack that is compact enough to fit inside the battery compartment. The light is black anodized aluminium and well made with long cables made of heavy gage coated wires that look like the factory throttle wires. There is also a standard 5x2.1mm jack that plugs into the battery pack. I could run the lights off the bike battery but the battery pack is so nice that I think I'll just use it as is and maybe put a regulator attached to the bike charger port to charge the light pack. You can never have enough battery power. If I have to peddle home on empty at least I'll still have lights. Since the light is easily removed it's also a great trouble light. Also, I think I can run my turn signals, stop light and horn off the light battery. The pack has (4) 18650 lithium ion batteries in it. all in all a great deal for the money. I just went to eBay to check out the light to send a link and found out that they accidently sent me the $21 package for $12. The deluxe kit includes the battery & charger. The $12 one is just the light. Here's a link for the deluxe kit on AliExpress for $14.36. Still a great deal for the money.




Here are the turn signals I'm using s-l500.jpg nice motorcycle grade led signals. $9.50 for a set of 4


I also got some nifty little led light plugs that go in the end of the handlebars. They are gold colored and look great with the grips. You just press on the bulb/switch to turn them on. Makes evening riding a lot safer when they can see you coming. Last but not least, I got the controller computer from my room mate for Christmas, along with a set of black fenders. I can't wait for them to arrive, (you know how slow Sondors can be). They should arrive at the end of February.


Link to comment
Share on other sites

It sounds like you are the right guy to have in on this thread then. Your experience will most likely come into play as I do my conversion, and we can learn and create this mod with more then one brain. :D


I did look at the brake/shift units but decided against it until I had figured out how the current brake lever is working in regards to cutting off the motor. I am not sure if it's completing a circuit, breaking a circuit, feeding power or grounding, creating a level of resistance or varying the resistance in order to create the shut off. So I figured, the shift levers were cheap and I could change to a break level combo anytime later and figure out how to work the engine stop into it. I hoped to have that resolved already but I've had a series of bad luck in regards to tubes/tires going flat. And some of my 3-Speed parts have been delayed so I'm trying to keep my mind busy and learn/grow while I wait.

I started a thread on lighting, would love to see your lighting kit discussed in more detail there with pics etc. I know I hope to add a working brake light to mine and possibly turn signals as well. For now I just use the lights I have installed and am happy. Once I get it upgraded where I can go further, I do want to get my lighting (and fenders) more road friendly for sure.

Frame spread, that is something I have been pondering. A long enough chain should have enough bend to accommodate a decent amount of sideways shift for any gearing situation I'd think. I need to look at my 21 speed and see what the extreme bends it goes to are from furthest chainwheel to opposite cog.

I'd say for solidity and frame strength, the spread should be even, otherwise you'd have to offset your wheel with spacers to keep it centered. And then there's the question of do you do so on both sides to keep the frame consistent. So if you do say 1.5" of spread, split it between the left and right side, add spacers on the one side and the rear cog on the other, vs just bringing the right side out some to fit the wider cog assembly and then deal with any issues that may arise from that.

I think @biknut or someone mentioned that chain rub on the frame would be an issue if using a full 6-7 speed cog in the rear without modification. I don't know if it would be as simple as flattening some of the frame itself where the chain rubbed and then compensating somehow inside to keep the frame tube's strength intact (like a small hole drilled and then that area filled with some JB weld to keep the bend spot from becoming a weak spot).

When I get my other bike back tonight, which has a 3/7 gearing system, I will do some chain tests and measure and shoot some photos to help us visualize the concept and chain bend etc.

Still hoping my 3-Speed freewheel will come magically before it's due date so I can get started!

Link to comment
Share on other sites

Ok, so I've recieved almost everything for my upgrade except the freewheel with 3 cogs. In the meantime, I've started doing some measurements of freewheel's that are 5-7 speed to see how much spreading would be required if I were to go that route.

The 3-Speed freewheel I have on order is the same size as our single speed, so nothing special is required. But the others all take up a lot more space. I've been measuring them on bikes I come across and it seems to be a matter of 1.5"-2" from inner to outer edge on most screw type freewheels of 6-7 speed variety.

This means that a spread of 1" is the minimum one would need to fit the larger freewheels onto the Sondors. There is some frame flattening happening as the frame goes into the back wheel plate, but it's not nearly enough to avoid chain rub on the frame.

So, to use a 5-7 speed freewheel, one would need approximately 1" spread on each side to keep the wheel centered. Not sure if this frame will handle that without some extra attention.

I've got a 5 speed on order that is supposedly able to be taken apart and reassembled, spacers and cogs. If this is true (it was cheap so if I hack it and it breaks, so what), I may be able to cut just enough of the outer end off to keep the whole threaded part and a little of the fluting for removal, and put back on the choice of gears I want. But, this is all up in the air and I'm pretty much relying on the 3-Speed unit that is same sized as ours for my project to go forward.

Link to comment
Share on other sites

I haven't seen a rear end taken apart so I am not familiar with the mechanical make-up. If you put on a larger sprocket assembly, that requires spreading the frame, do you need a longer axle to hold the new assembly? I think I'll google up some bike sites and find some exploded views of bike rear ends. I'm sure there is tons of info about bikes on the web or in bike blogs.

The three cog freewheel that you have ordered, is it on backorder or coming from China? I am waiting for you to get yours and then I will order one. Too bad we are so far from each other, I would love having you over and using my machine shop, collaborate on this project. It would be easy to cut down a 5-7 on my lathe. Depending on which of the cogs you wanted to keep, you could cut off the top or bottom gears and pick which ones you wanted to keep.

I assume that the three cogs that you ordered are a good middle of the road selection of gear ratios. How does the diameter compare with the stock gear? Is the stock gear the size of the second cog of the three? The nice thing is, I have 2 bikes to modify so I can work on one and have the second one to compare to. The second bike is for my lady, who is just a little thing and could use some gear help that would be different than mine. I'm 6'1" and 175 lbs so I have more leverage than her 5'6" 145lbs. She might benefit from a slightly different 3 gears than me. We both agree that we would like to keep the gear selection as simple as practical so 3 gears is our preference. If I wanted to add a little more selection I would probably add a second cog to the pedal gear instead of more gears at the drive. Adding a smaller drive gear at the pedal for her and a larger one there for me and keeping the 3 stock gears in the back might be just the right combination.

Looking forward to your further adventures. Spring is coming and I am looking forward to working on the bike as well as riding it.


My Sondors eBike.JPG

  • Like 2
Link to comment
Share on other sites

Totally off topic but have you ever seen an electric tractor? While I was redoing the front walk on my house, I blew up the motor on my DigIt bucket/back hoe tractor and it was stuck in my front yard blocking my front steps. So I could move it into my driveway I installed a 5 hp electric motor that I had just purchased for my shop air compressor. It's not battery powered and requires a long extension cord but it was fun to drive and really quiet. I'm in the process of installing a v twin 500cc honda,  water cooled shaft drive engine in the tractor right now. $100 off of craigslist. Definitely cheaper than $1200 for a replacement B&S engine and a lot cooler.


I'll share a picture of the new engine when it's done.


  • Like 1
Link to comment
Share on other sites

Yeah, the 3 speed I have on order is coming from China I believe. I can't find anyone who has one in stock to ship quickly. And I ordered another with the same gearing from another place to have a backup.

For the one I got... They all tend to be around the same gearing, 16/19/22 or similar. With our current front gearing (39T for me), that makes one the top end normal stock speed and the other two hill gears. I want to upgrade the front so its hill, stock, then top end, so I have more speed pedaling gear. One project at a time though. :D TO change, all I have to do is go up or down in front on the chainwheel by a few teeth and I've moved the whole range around.

Taking apart a 5-7 speed freewheel supposedly is not difficult, for the ones that can be taken apart. I was told they should have a fluted shaft with cog/spacer/cog/spacer repeating to the end, then usually some kind of screw on or clip on end piece to stop them from coming off. And I was told that since the threading 'we Sondors users" need is only .5 of the very inside part that we should be able to cut as much off as we want making room for our choice of 3 cogs with spacers. The problem then is you are cutting off the part that your cap/end nut attaches to. So you then have to weld something so it stays, or drill out holes and run a screw or simialr through create the end stop piece. I have not yet received my test piece, but am told a lot of tolder 10-speed bikes and older rear cogs have this. And that some from SunPack or something use a threaded nut on the outside that goes all the way down the flutes, and cutting off the end just means fixing the threads and using that same nut to hold it together. Not sure how accurate this info is as it came to me via a friend online who has not done this in a while.

I figure best case, I pay $15 for a rear 5-7 speed cog, cut the end off, put on the gears I really want and have it tack welded. Worst case, this doesnt work and Im out $15. No biggie. I'm learning as I go.

Today, I get the derailleur out and temporarily attach and start learning how to adjust it.

Im also not a huge fan of the shifters I got so I'm thinking Im going to order one like the one on my Giant. I'm also going to look at the brake lever and see how its stopping the motor, be it a broken circuit or what. Photos of the parts will come soon as well.

Link to comment
Share on other sites

I am so close to getting to start I can feel it. I have everything but the most important part, the rear cog freewheel!

I am considering putting the rest of the parts on and tuning the derailleur as if the 3-Speed is there so I can learn. As long as I don't shift while riding, the chain won't come off. And it will let me test fitment and learn how to adjust it all.

Also attaching some photos of my Giant's 7 speed cog unit (cassette style just for width and reference) and the Sondors stock freewheel and a measurement.

Sometime today or tomorrow I start assembling to learn the derailleur adjustment. Go go go!





Link to comment
Share on other sites

I started fitting components on my bike today and ran into my first snag. The chain I got is not the right length and the links are longer then the ones on the bike.

Even when it fully seated on both the chainwheel and the cog on the freewheel, run through the derailleur, I needed another 4 or so inches of chain, the derailleur was hyper extended otherwise.

The one I got is 1/2" x 3/32" with 7.3mm links. I believe I need same size but with 7.1mm links. Can anyone confirm this? Im going to have to order several chains to get the right size.

Best part, the bike fell over (was on seat/bars with bars on a towel and the steering twisted) and it bent the connector link on the chain so I can't return it. Ugh. It was only $10, but still, that's the kind of stuff that happens to me.

Now i have to find a longer chain with the right length links. I wish this was better documented so I didn't have to learn it all by trial.

Link to comment
Share on other sites

7 minutes ago, alienmeatsack said:

The one I got is 1/2" x 3/32" with 7.3mm links. I believe I need same size but with 7.1mm links. Can anyone confirm this? Im going to have to order several chains to get the right size.

Best part, the bike fell over (was on seat/bars with bars on a towel and the steering twisted) and it bent the connector link on the chain so I can't return it. Ugh. It was only $10, but still, that's the kind of stuff that happens to me.

The one I got is 1/2" x 3/32" with 7.3mm links. If I hold it up next to the stock chain, it very slowly gets "off" alignment link to link as I go further down the chain, so I am guessing the links are a tiny bit too long on it. When it sat on the chainwheel, it only connected to some then was off the rest on either side. This is confusing to me, I don't really know chains and the specs and what I need.

Best part, the bike fell over (was on seat/bars with bars on a towel and the steering twisted) and it bent the connector link on the chain (so I can't return it) - it was bend it or not catch the expensive bike. I caught the bike and bent the chain. Ugh. It was only $10, but still, that's the kind of stuff that happens to me.

It wouldn't let me edit my post to correct it after I hit send too fast before reading it.

Off to amazon to order several chains to try in different sizes I guess. This project sounded easy and I was only worried about the derailleur, now that is the least of my worries.

Would love some feedback from anyone who's done this before.

Link to comment
Share on other sites

Sorry about your problems. I have done some investigating about the replacement 3 speed sprocket and now I am somewhat confused myself. The sprocket that you ordered from amazon is a 34mm inside diameter freewheel sprocket with a 10mm pitch with 16-19-22 teeth. 

  • Product Name : Speed Freewheel;Speed : 3
  • Screw Inner Diameter : 34mm/ 1.3";Outside Diameter Max. : 92mm/ 3.6"
  • Pitch (tooth to tooth) : 10mm/ 0.39";Tooth Width : 3mm/ 0.12"
  • Overall Depth : 17mm/ 0.68";Material : Metal
  • Weight : 228g;Package : 1 x Speed Freewheel

I looked at another conversion on this blog and he is using a similar cog but on close examination it turns out that the cog he is using is slightly different (although it looks the same). Here are the specs off of eBay.





Product Name Speed Wheel for Bicycle
Screw Inner Diameter 34mm/ 1.3"
Outside Diameter Max. 92mm/ 3.6"
Pitch (tooth to tooth) 8mm/ 0.31"
Tooth Width 4mm/ 0.16"
Overall Depth 16mm/ 0.63"
Tooth Quantity 16, 18, 21
Material Metal
Weight 224g
Package 1 x Speed Sprocket Freewheel

You will notice that the pitch on this freewheel is 8.mm and is a 16-18-21 tooth cog. They both have the same 92mm diameter. Which one is correct?

Here is another one.  The pitch is 9mm. This one ships from the US so is my prefered one.



Product Name Bike Drive Sprocket
Center Thread Diameter 34mm / 1.3"
Outside Diameter

Small: 67.5mm / 2.7"

Medium: 76mm / 3.0"

Large: 89mm / 3.5"

Tooth Quantity

Small: 16

Medium: 19

Large: 22

Total Height 17mm / 0.7"
Pitch (tooth to tooth) 9mm / 0.4"
Material Metal
Weight 222g
Package 1 x Bike Drive Sprocket

That's three different pitches on essentially the same hub. Very confusing.


Also from what I have been reading, the 7.3mm that you are referring to isn't the distance pin to pin, it's the chain width, I think 7.3mm is the most common. The 7.1mm chains are used on 8 speed cassettes.  Be careful before you sink more money into chain. Here is a great source for information about chains.


Hope this helps some. As for me, I now realize how much I don't know. Time to do my homework.

Link to comment
Share on other sites

Thanks for the feedback! I too have run into the pitch issue here on my end. I've spend a good part of the day trying to figure out what pitch is what and where and how to tell what chain fits what pitch. There is so much to know about these things. Even the diameter of the chain's little round bits as well as the width of it plays into things.

But I came to the same conclusion you did, that the pitch is the issue. One of the two I have on order is 10mm pitch, the other is 9 (and looks like the image above). So what is the pitch of our stock chainwheel and cog? What is the best pitch to shoot for? These are things churning in my mind!

I believe that I can resolve this by replacing the front crankset and get a spider style assembly so I can replace chainwheels easily. or buy an all in one single speed chainwheel style crank set. Then I just have to find the right number of teeth and pitch. Since the rear cog is changing, I'd assume that changing the front would also be a good idea to get the chain sizing to match.

I am going to the bike shop to have them recommend what I need so I get the right parts. After the 3speed freewheel comes. One of the two. I have two on order just to be safe.

I intended on putting a slightly larger T chainwheel on anyway, just hoped to use what I had for a while. This project, like so many of mine, has turned into a pain, an education, and a ordeal.

But when done, I'll have lots of knowledge.

I wish @biknut would toss in some of his experience on this since he's done it successfully. He could probably answer all of our questions in one felled swoop. (please and thanks good sir?)


Link to comment
Share on other sites

21 minutes ago, MisterFixIt1952 said:

Hope this helps some. As for me, I now realize how much I don't know. Time to do my homework

I found this on another site that helps break down the sizes into a little more "organized" manner. And it's an interesting lesson across the whole page.


Taken from the page:


Chainrings fit six chain-tooth sizes, measured by length (pitch) and width:
1/2" x 1/8" "sinlge" for track, BMX, cruiser bikes, one-speed, three-speeds, and the rare derailleur bike.
1/2" x 3/32" "shifting" for road, hybrid, mtb bikes, single-speed and 5-, 6-, 7-speed freewheels
1/2" x 5/64" "narrow" for any bike with 9- or 10-speed cassettes
1" x 3/16" "skip tooth" for old-time bikes with inch-pitch sprockets
1/2" x 3/16" "heavy duty" for BMX, Worksman and exercise bikes
10mm X 3mm "micro" for Shimano Dura Ace 10mm chainset

I purchased a 1/2 x 3/32nd chain or did, since I bent it, it got put into the "maybe I can use it later" pile.

It didn't work because I'm betting our bike uses the 1/2 x 1/8 or something else.

So much to learn. Now I see why others who've done this changed out their entire drive train from front to back. BEcause of this pitch and size thing.

I can't do anything else at this point except wait for one of the freewheels to come. Then take it and the bike to find a chain at the bike shop.

In the meantime I can get a chain tool, a crankset puller and freewheel remover because a biker can never have too many tools. :D Man I am glad I'm not married, my wife would kill me at this point.

Link to comment
Share on other sites

5 minutes ago, alienmeatsack said:

In the meantime I can get a chain tool, a crankset puller and freewheel remover because a biker can never have too many tools. :D Man I am glad I'm not married, my wife would kill me at this point.

I just knew you and I were cut from the same cloth. I've been married 3 times and never met a woman yet that appreciated the need for "More Tools!". I love american made and buy them when I can (Porter Cable, Dewalt, Snap-On etc.) but I must confess my addiction to crappy Chinese tools from Harbor Freight. I own some tools that I don't use that often that I couldn't afford to own if I had to buy American. I often have to rebuild them or modify them to work properly but they usually get the job done (and break frequently).

Back to the project at hand, My room mate just bought a high end cargo eBike called a Juiced Rider. It cost like, $2500 and has a range of 50 miles or more. Sturdy little sucker with a reinforced alloy frame, 20" wheels and a cargo rack. I will check out his gears and chain and see what the setup is. Definitely cargo class.

Link to comment
Share on other sites

@MisterFixIt1952 - I have a rule, if you goto Lowes or HomeDepot and you don't leave with a tool, you are doing it wrong. When it comes to bike tools, I used to have all the cool stuff when I was a teen, now I have nothing. I need crank pullers, chain tools, you name it. I figure what the heck, lifes short, why not blow my money on something I use once. I mean, I could eat, boooring. I want tools instead. :D

@InfosecGuy - I can't speak for everyone but I have OCD and a deep seeded need to learn, grow and share. And I am a little crazy. I can't leave anything "stock". Many a gadget has died at my hands while trying to make it better.

I will conquer this 3-speed conversion, share the results and others will too. And if I fall, someone here will jump in and pick me up and steal my tools. It's the law of the land. :D

I hope to chat with the bike shop guys about the chains and cogs this week. And maybe order the crankset and tool so I can be ready. Depends on how funds go. I'm tapped out due to all the stuff I've bought for this upgrade, and bills. I used to be good at this stuff in the 80s when BMX freestyle was the rage. I did all my own work, did gear mods, you name it. I got old and forgot it all. But I'm getting the knowledge back thanks to the internet! woot!

  • Like 1
Link to comment
Share on other sites

Super excited, two parts came today, one of which I was not expecting for a week or more.

1. My first of two 3-Cog freewheels. This is the 10mm pitch one (!??). I have something I can actually take to the bike shop to find a chain and chainwheel now! Part that has me concerned, it looks identical to the two others above in @MisterFixIt1952's post... and that I've seen online that claim to be 8mm or 9mm pitch. But it's supposed to be 10. So, worst case, the bike shop measures and fits a chain to it and gives me a true sizing. Looks like the chain will need to be semi narrow as well. The gears on this seem to line with the cog but I can't do more then what connects if I set it on the chain. I'll loosen up the backwheel and wrap the chain around it to see if it fits just for giggles later. This freewheel came all the way from our lovely friends auf Deutschland. (Wie geht's du es Fruenden!)

2. My new better 3-speed shifter. I -love- the shifter on my Giant, it's a Shimano SRAM thumb shifter. And I did not like the one I got for this project at all. I put it on my extra bike and hated using it. So I got one like is on my Giant. I now officially have 10 shifter cables and one casing. Not sure how that happened.

I am so excited! I have all but the chain and chainwheel now!

I know the chain is too short, so I have to extend or find a longer one when I get a new one. The one I got before was 116L, and the derailleur was hyper extended. So I figure I need another 10 links or so at least. Hoping to just find the right chain that's extra long and I can cut it down and add a master link to get it just right.

Tomorrow, the bike shop and I shall meet to find out what chain works and then get me a matching chainwheel and crank set. I think I'm going to try and get one that I can remove the chainwheel and bolt a new one on the "spider" if possible. And I'll be keeping the 170mm arms, I like the leverage.



  • Like 1
Link to comment
Share on other sites

I was about to ask a question about chain length but I thought I would read the Wiki again before asking. After carefully re-reading it I had a sudden revelation. The chain in use on modern bicycles has a 1/2" (=12.7 mm) pitch, which is ANSI standard #40, where the 4 in "#40" indicates the pitch of the chain in eighths of an inch (4x1/8= 1/2). All this talk about 3/32, 1/8 etc. refers to the roller width only and has nothing to do with the chain length. Twenty half-links in a new chain measure 10". Therefore any cog should fit any #40 chain. The only difference between cogs might be the thickness of the teeth, therefore the width of the rollers. Now we all realize that Chinese products are often mis manufactured so that needs to be taken into account if something doesn't fit right but for the most part any cog set with the correct inside diameter and threads should, in theory, work. The difference between a 16-18-21 or a 16-19-22 is not a problem. They are just slightly different diameters (regardless what the chinese specs say. They should all still fit a standard #40 chain. The only variable then becomes the roller width and overall length.

From Wiki


Chains come in either 3/32", 1/8", 5/32", or 3/16" roller widths, the internal width between the inner plates. 1/8" chains are used on bikes with a single rear sprocket: those with coaster brakes, hub gears, fixed gears such as track bicycles, or BMX bikes. Chains with 3/32" wide rollers are used on bikes with derailleurs such as racing, touring, and mountain bikes. Fixed sprockets and freewheels are also available in 3/32" widths so fixed-gear and single-speed bikes can be set up to use narrow and lighter 3/32" chains. Finally, chains with 5/32" wide rollers are used on freight bicycles and tricycles.


New chains usually come in a stock length, long enough for most upright bike applications. The appropriate number of links must be removed before installation in order for the drive train to function properly. The pin connecting links can be pushed out with a chain tool to shorten, and additional links may be added to lengthen.

In the case of derailleur gears the chain is usually long enough so that it can be shifted onto the largest front chain ring and the largest rear sprocket without jamming, and not so long that, when shifted onto the smallest front chain ring and the smallest rear sprocket, the rear derailleur cannot take up all the slack. Meeting both these requirements is only possible if the rear derailleur is compatible with the gear range being used on the bike.

In the case of single-speed bicycles and hub gears, the chain length must match the distance between crank and rear hub and the sizes of the front chain ring and rear sprocket. These bikes usually have some mechanism for small adjustments such as horizontal dropouts, track ends, or an eccentric mechanism in the rear hub or the bottom bracket. In extreme cases, a chain half-link may be necessary.


Anyway, hope this helps a bit. I'm going to order my 3 speed hub tonight and I will wait to see how your project goes.


  • Like 2
Link to comment
Share on other sites

Nice info @MisterFixIt1952! I've copied it to my Evernote sheet with all my data to take to the bike shop. I'm not quite awake yet so it's a lot of data to process, but I'm learning here which is good. I don't think I ever really knew much about chains even back when I rode BMX. 48 years old and learning something new, ftw!

Lengthwise, I know that 116L I got was too short by about 6-10 links, as the derailleur was hyper extended. And that was not even on the largest size cog it would be on. PLus to get the gearing ratio right I'm going to have to go up to around a front chainwheel with 46T if I did my math right to maintain that 2.44 ratio on the main gear like our 39/16's have now. which is more links.

I'm going to do some measuring for my trek to the bike shop today, take the cog and hope they can get me the right chain and answer a few questions etc. With luck I'll come home with the right chain (in size and length) and a crankset with a nice perfect chainwheel. Worst case, I get a few bits there and order the rest.

My other 9mm pitch chainwheel shipped today so there's that other insanity on the way now too. :D

Now that my proper shifter is here I can start with the install of the shifter and cabling and get photos to post so it's not just us scratching our heads. It's really nice to have another brain involved here, more minds = better thought out project. Thanks for being part of this @MisterFixIt1952!

With any luck we will be shifting like pros in no time!

Link to comment
Share on other sites

Update... I dropped into the bike shop this morning. Their lack of knowledge in this area puzzles me. I pretty much stumped them. We did find a chain that fit the 3 speed freewheel and will hopefully shift well, and I got the tools to remove the old freewheel and the stock cranks. But they had no idea how to calculate gear ratios or what they were, which I found odd.

I measured 2 of the bikes in the shop from crankshaft center to rear axle center and they were both 2-3" shorter then our Sondors which probably accounts for some of the chain length issue I had. I still think I'm going to have to buy 2 chains and combine 2 and then remove the excess to get the right length.

Now I get to get online and buy the crank parts and hope my ratio calculations are correct.

My Sondors has 16T in back and 40T in front - which is a ratio of about 2.5 revolutions of the 16T to 1 of the 40T. The closest I can get to that on the middle 19T gear is 46T which gives me a 2.42 ratio, or 48T which is a 2.52 ratio, the latter being closer. I am trying to make sure the middle gear is as close to the stock gearing as possible for the cadence sensor to work correctly with PAS. This will give me a hill gear and a speed gear.

Our stock cranks are 170mm, so I'm going to get the same length there. I just need to find the parts online and then figure out how long the chain really needs to be. I still think another 6-10 links will bring the derailleur to a much better spot.

Hopefully once I've completed this project a mod will give me the power to move the actual mod work to the top and all the conversation below so folks don't have to wade through our chatter as we figure this out.

Link to comment
Share on other sites

1 hour ago, alienmeatsack said:

Update... #2

A new crankset is ordered and due later this week. I've been reading a lot about the chainline and alignment. Hoping that I don't need to replace the crankshaft/bearings to get the correct alignment.

My plan for tonight is to loosen the chain so I can see if it will work with the new freewheel as a temporary step. I know there's enough space in the chain for me to try running it and the 16 and 19T gear without shifting etc on the stock chain. So I want to try that to make sure it works. And once I start freewheel removal, it's the point of no return, especially when I pull the chain since I don't have a master link in the correct size to repair it.

If all goes as planned I should be doing the actually full modification this weekend. But I'd be happy just to get the new freewheel in place, test the new chain, and start figuring out the shift cable location and all that.

My goal is to have an eBike that does not need the battery power to ride. Not because I plan on riding without it, but because I want to be prepared. And because it was supposed to be a fun modification project. It's becoming less fun and more work, but I'm learning. And sharing what I learn helps others. So, it's a win. I think.

Link to comment
Share on other sites

Steve, I don't have Facebook access, so anything you can share here to help us with the 3-Speed mod would be greatly appreciated. I'm learning as I fumble my way through in hopes that my pain is someone elses gain. Any help I can get to save me trouble = good.

Look forward to seeing your results and your thoughts hopefully here too :D

Link to comment
Share on other sites

  • Andi featured this topic
  • Andi pinned this topic

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By Roy Temper
      Motor Wires and Derailleur Protection Protect your motor wires going through the rear axel and if you have a derailleur with a derailleur guard. One of the best I have found is available at REI and is highly effective and provides a great deal more protection than the cheep thin guards sold online. Certainly worth the $20 i paid and if you have an REI near you it's available in most stores or at: REI.com

    • By Brandnew
      Just Ordered Fold X, LCD Screen question? I am Gary from Lagrange Ga. I just ordered a Fold X for myself and one for my wife, both with the 7 speed option. The info on the site shows the LCD screen and states 5 gears and 5 levels of assist.  Referring to the LCD screen it states "this option supplies Fold “X” with five gears and five levels of electric pedal assist plus added torque for increased hill-climbing power, even greater range, and improved towing capacity."  I understand the levels of assist but what would the 5 gears be that would be controlled from the LCD display? Does the LCD screen show miles or speed on the original bikes?
    • By 3D-vice
      Know your Gear - Freewheel vs Cassette Hey all,
      on my quest to gain more knowledge about bike parts, I stumbled over this nice video:
      Freewheel vs Cassette - What Are They? Can I Convert?
      As a noob, I found this especially helpful, since I'm about to exchange my original rear wheel with a new one. If those with professional knowledge out there have things to add, please feel free to do so.
    • By CrazySondorsRider
      Hello everyone. I've been a lurker here for a while and learned a lot from this forum. Well here's the situation, I got into a small accident last week and ended up bending one of the crank arms. It ran fine just up until tonight when I was riding home from the beach. My bike will no longer freewheel.  For a while if I pedaled enough the bike wouldn't freewheel but after about 2 minutes it would start to freewheel again. I'm at a loss at what I should do, my roommate fixes bikes for a living on the weekends at a local flea market and he says he doesn't have the tools to remove the cog that is on the bike. I have the fat tire Sondors bike from indigogo.
    • By MisterFixIt1952
      I have been working on a  3-Speed Conversion with alienmeatsack, biknut and steve-condie . I have 2 yellow bikes purchased on the third day of the first indigogo campaign, one for myself and one for my lady. I have purchased most of the needed parts. Three speed freewheel cog set, the derailleur and a new 52t sprocket crankset. The only part missing, besides a chain and some misc. hardware, is a shifter. Due to the odd pitch (pitch is the measurement between cogs) of the 3 speed cogset (6.2mm vrs. 5mm-5.5mm found on most 6-10 speed bike cassettes) I am unable to find a suitable index shifter that will work with a shimano derailleur. Apparently, no one makes an index shifter for a 3 speed, only a friction shifter or a twist grip shifter. I would really like to use an index shifter with a gear indicator. Not so much for myself, but to simplify shifting for my ladies bike. She likes things obvious and simple. Myself, I would use whatever I could cludge together, if I had too. With only three speeds it just strikes me that you should just be able to thumb the shift lever and shift up or down with the indicator showing 1, 2 or 3. Yeah, right!! We all know what should be and what is are often miles apart. No one makes a 3 speed rear derailleur shifter, they only make 3 speed front derailleur shifters and the two are entirely different animals with different pull lengths (the length of cable pull required to move the chain to the next cog).
      To solve my problem I have decided to investigate building an electronic derailleur controlled by an up-down shift switch. Now this might seem like a complicated solution to the shifter problem but being a mechanical engineer (in a former life) I decided to investigate the possibility. Shimano and Sram both make electronic shifters but at a cost of close to $2,000 for the set, I decided to see what good old DIY ingenuity could accomplish. Never dismiss the capabilities of a broke man with an expensive dream. Necessity truely is the mother of invention. Besides, it sounded like a fun project and being retired, I'm supposed to have time for fun projects, right?
      So, I did what any modern inventor would do, I went to Google for information regarding electronic derailleurs. To my delight, I found quite a bit of information on the subject. It seems that when shimano came out with their $2000 electronic shifter/derailleur setup, for road bikes, it set off a storm of shifter envy among the poor but inventive DIY community. The best website, devoted to the subject of servo shifted derailleurs, was DIYshift.com by Preston Fall (a fellow Oregonian). This site is referred to in almost all of the web articles that I came across. Unfortunately, the site is no longer available having been replaced by what ap[pears to be an Asian porno site. What makes this so unfortunate is the fact that most of the newer articles used DIYshift.com as a model for their designs and they refer to that site for pictures and details leaving little, useful, detailed information, just vague descriptions of the actual mechanism. Also, there are half a dozen uTube videos about DIY shifter projects. As is usual with uTube videos, there is a noticeable lack of hard information about how to build one with builders showing very little detail and few closeups, preferring to tease you with their cleverness and leaving you to fend for yourself figuring out the details.
      The good news is I found the contents of DIyshift.com on Github https://github.com/Diyshift (thank you Google)
      Here is a list of all of the uTube videos devoted to electronic shifters. https://www.youtube.com/results?search_query=DIY+electronic+derailleur This is worth checking out so you can see what the possabilities are.
      I also found an instructable detailing how to build an electronic derailleur. http://www.instructables.com/id/DIY-Electronic-Derailleur/
      This project is totally awesome. Not only does it solve the shifter problem but it can easily be upgraded to a larger cassette by changing the programming. Also, I have some ideas to turn this into an auto shift by putting a strain gauge on the crank chain that will automatically upshift or down shift depending on how much force I am putting into peddling. Much better than the cadence system built into the controller. It would be easy to also put together a shifter that would also shift a front derailleur by using a 2 channel servo controller. Do to the cheap cost of servo controller boards, DC-DC converters and arduino processor boards, this project could be put together for about $50 plus the cost of the derailleur. The whole system could be powered by the bike battery or a separate 7.4v Li-On battery, like the kind used in RC models. According to what I've read, a 7.4v battery is good for about 40,000 shifts (a conservative estimate).
       I plan on putting some real effort into this project, including designing a circuit board, shift switch with an led readout showing the gear selected and the servo mount. The software has already been written but I will check it out and make sure that it works with my version and is easy to use. I have an idea that will allow me to program the controller wirelessly using my tablet or a smart phone making it easy to tune the system. I think I will see about putting together a complete shift kit with everything but the servo and the derailleur. I have quite a bit of work to do on this but I will post more information as it comes. I am shopping up parts right now and still waiting for my shimano 105 derailleur to arrive. I'll know more when it gets here.
      Let me know if anyone out there that has any experience with one of these electronic shifters or if there is anyone else interested in this project.
  • Popular Now

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use and Privacy Policy.