Joseph Magee, the product developer of the VECTr, is looking for feedback on his design as he conducts market research. The name is short for the Variably Expanding Chain Transmission, and is a new way to change your front drive ratio. They have built a working prototype along their journey towards production.

The system is said to be better than typical current designs by reducing the wear and friction of a front derailleur, reducing wear on the chain from drastic chain angles (cross-chaining), can change gears quickly, and can be adjusted anywhere in between a 22t and 44t equivelant.

Watch the video, and take their survey. Tell us what you think of VECTr


  1. SamSkjord on

    This may be the first time someone’s actually asked for critical comments on bikerumour! Normally they just arrive, non-stop, about everything.

    I like it because I want VTEC to kick in on my bike, y0.

  2. onion on

    Could the video be any more terrible? Goodness.

    It’s a clever idea and fun mechanism, but the prototype still looks pretty rough in its operation. Even with much more development, it’s hard to imagine this ever becoming a viable alternative to any of the options already out there.

  3. SamSkjord on

    In all cereal; looks like a pretty cool system, presumably you could put this front and rear then have a narrow totally enclosed drivetrain with decent range?

    A lot of it will come down to how smooth it feels but if it’s smooth enough you could have the osymetics/qrings effect just by changing the rate at which different parts expand/contract.

  4. Mars on

    2 problems:

    -The ratio will essentially change 4 times throughout the rotation as the cranks go round, being hardest at the top but then easiest 45 degrees after that.

    -The chain will be vey likely to fall off. Think about the tolerances effort on narrow-wide chainrings. on any normal chainring it’s already likely to be dropped, imagine when you only have four small contact points.

    I’d love to be constructive but can’t see a way around these. (Maybe a small upper chain guard?)

  5. InWyo on

    I’ll echo the concerns about jerkiness, but will also give them the benefit of the doubt. This may just be a proof of concept and is going to be refined considerably.

    BUT…could this type of set-up be expanded as a CVT? With the bio-feedback interfaces with DI2 and other electronic drive-trains, if you have an infant amount of ratios to fill the gaps of the discrete steps in the rear, it would be very valuable in time-trials and triathlons.

  6. Pete on

    LOL I tested this back in the early 80s, what a great idea and so terribly flawed execution.
    So will not judge this particular unit, but IMO this entire concept requires a more complex design & more exotic materials = too high a cost of manufacture.

  7. Pete on

    Specifically the old design had twice the contact points for the chain, but was made of hard plastic that would break. The patent on that one has run out.

  8. Francisco on

    This is the first ‘CVT-esque’ transmission I have seen that doesn’t have inherently high frictional losses, so a tip of the hat for that. Sadly it has other problems.

  9. Johann on

    @Mars: Agree about the 2 points but there could be some way around, at least for the second one. Not by adding an upper guide, but simply have your 4 bit of chainring circulating between 2 plates that would be close enough to each other to avoid that the chain get stuck somewhere in between.
    As for the feel, yes it’s going to be a lot like pedalling square. But having those arches of chainring not only translating but also a little bit pivoting in opposite direction by group of 2 would get to some sort of oval ring which could be acceptable and limit the ratio range.

  10. Ventruck on

    I have the same concerns already mentioned. If you hate the feel of oval rings, I’d imagine these being worse. Anything short rear cogs in perfect alignment sounds like a recipe for the chain skip/falling in the expanded gear position, especially under load.

    And that video didn’t really help the appeal at all. Supposedly 10+ years in development and this guy could not find another pair of hands for a couple minutes to demonstrate smooth operation in the video?

  11. chasejj on

    Just stop already!!
    Front derailleurs are not that awful. The issue with the options in front is the brain damage riders go through trying to decide on a single front shift or multiple shifts in rear and the never ending doubt that ensues with that decision. I contend that 1X is cool but is really only popular because it removes the option. Period.

    The answer is the integrated gearbox ideas, but they need to drop some weight and gain some more efficiency before they are fully accepted. But I sure get excited about an enclosed set of gears driving a belt that requires no lube and thus no metal lapping operation with my drivetrain.

    I really challenge someone to ride a recent Shimano/Sram product that is adjusted properly and tell me that they don’t shift well in front or rear?

  12. Kark on

    I’d imagine a system based on an iris valve rather than straight radial expansion could approximate a “round” profile more effectively and an iris valve on a helical plate cam would be more effective at resisting the chain load working to contract the effective pitch.

    but, complexity of either solution is likely to outweigh advantages over convention mature solutions already available so.. fun experiment but uh,!

  13. Tony Baloney on

    True genius, well except for the part of not putting a pedal on the non-drive side for the purpose of this demonstration, so what is most likely a herky jerky feel when actually pedaling the bike with this “contraption” on, it looks as it it hard to pedal. Oh and the true genius comment is sarcasm!

  14. Frippolini on

    Looks very “squarish”, that is not smooth round crank arm spinning. I could be wrong, but looks like a nightmare for anyone favoring smooth round crank arm spins?
    Second concern is durability and how well the system performs once subjected to dirt, dust, sand, oil, etc. I can easily imagine the system clogging up / becoming very difficult to change gears. What is the advantage to regular shifting systems (interior and exterior)?
    Third, what niche market are you aiming for? Those who don’t have gears on single gear bikes that lacks derailleur hangers and the rear width to post-install an integrated gear hub? How big is that market, are they prepared to buy this, and how will you distribute the product? I can easily imagine the product being too complicated to install for an average normal person, which leads to the necessity of engaging bike mechanics and bike shops. Any plans?
    Fourth… In general I applaud the going from an idea to a conceptual model; but I would recommend that you let it rest at this stage unless you truly believe this product will add some significant value compared to the other established systems.
    Good luck, and good work going from idea to workable model.b:)

  15. Graeme Smith on

    Another thing: how do you run the shifting cables to actuate this? Some sort of a gyro like BMX bikes use that could carry the force through rotation?

  16. Joe Magee on

    Thank you for the exposure, and all for valuable feedback.

    The main advantage of the system is to prevent chain drop by maintaining a consistent chainline, and giving at least 5 gearing options on the crank, while weighing as much as or less than 3 chain rings, being simple and so inexpensive to produce.

    I have to do more road testing, but the square-ness of the chain path when VECTr is in expanded position (lumpiness) will not be as noticeable since larger gears are used on downhill or level roads when the pedal momentum is at play, and crank loads are not heavy.

    In more contracted settings, the squareness would be less pronounces, and in the smallest position, non-existent.

    I see it replacing the rear cassette, too, so that would address some of these concerns y’all mention.

    Anyway, thanks again.

  17. nick_outdoors on

    1. Reshoot this video with a pedal attached so the crank rotation does not look so choppy.
    2. I would not buy simply because of the place by the chain on such small of an area.
    3. I don’t want to pedal a square.
    4. Good idea in concept, but needs better execution

  18. Charles Versaggi on

    Ditch the disco music. It’s distracting. I want to hear the chain drive moving to better judge friction and smoothness. Put a narrative to the video that explains what you’re seeing. The quality of image could be better as well.

    As for the concept, like others I’m concerned about the angularity I’m seeing. Why can’t this be a perfect circle? Seems to me the angularity will stress the chain, maybe even the rider.

    Interesting concept, but I’m not understanding why this is major leap from the status quo.

  19. Pmurf on

    Frankly I’m surprised neither BR nor any commenters have mentioned the slightly similar (in function) and eerily similar (in name) VYRO system posted 2 years ago:
    I think the VECTr design is cool, and simpler than other solutions, but I would echo the smoothness concerns of others. I think the chain would have to be supported at more points than 4 to avoid the hi-low effect at larger gears. I applaud the solicitation of feedback from the designer though! Definitely taking the survey.

  20. Dude on

    This is another case of an enthusiastic designer building a product without doing the requisite market research or business planning first. Clearly they haven’t identified drivetrain product attributes, relative importances, table stakes features, and resulting product-market fit requirements. Being innovative for innovation’s sake isn’t enough. It has to meet all the key attributes of competing systems while delivering order-of-magnitude improvements on at least one critical attribute. This doesn’t even have an identified target market – so it’s a solution in search of a problem. Sorry, A for effort, F for product.

    Here’s 3 key ways this fails already: 1) non-round chainring (or equivalent) makes it appealing to what is already a niche market at best, 2) 22-44T equivalent limits it to relatively lower geared applications such as commuting, cx or mtb, 3) the aesthetics are appalling. Here’s a bonus: this is unlikey to be cheaper than a FD.

    You’ve got an unproven device with potential performance issues going up against an established solution that does a very good job already. Front shifting is essentially a solved problem.

  21. Ol' Shel' on

    Unless you are applying for a patent on some small part of the expanding chainring system, you’re not likely to get a patent. Similar systems have been shown publicly, ruling out a broad, easily-defended patent.

    I’ve been playing with drivetrain ideas for years, and the expanding ring was my first million-dollar idea… I do wish you all the best!

  22. Chris on

    This would suffer horribly from a phenomena called ‘cogging’, whereby the transmission of a constant torque is impossible due to the stepped changing of the effective diameter of the chainring at four locations.

    Even round chainrings cog a little, for every tooth. Involute gears were designed to overcome this problem in part (the other part being the elimination of sliding contact between gear teeth, but that’s not important here).

    Please don’t try to start a Kickstarter campaign.

  23. Joe Magee on

    All of these comments are actually helpful. _Especially_ the sarcastic ones! Some people seem not to understand that this is the first working model, a proof of concept, so no, not the slickest product available. Yes, expanding chainrings have been tried for over a century (I can show you at least twenty patents going back to the 1870’s). But what does that tell you? That the idea hasn’t worked, so it can’t work? Maybe. Or, that it should be able to work, but so far no one has made a commercially successful version. Mine might be because (a) it is much simpler than those 20+ prior attempts, and so (b) it is much lighter, and (c) easier and cheeper to produce and (d) it would be compatible with current (or future) components (as opposed needing a special frame). I think I may address squareness in future versions with 5 or 6 gear segments. Also, the target market probably is not “performance” bikes, but commuters and city bikes and their bike builders (then after-market components). Or not. I’ve been working on this because I like bikes and heard the expanding chainring was so far an intractable problem, and I thought surely not. It is a lot harder than I first thought, but obviously many have solved it, but none (comercially) well. Maybe this will. Thanks again. Take the survey!

  24. Dude on


    You still need to do some meaningful market and business analysis. Having faith that your solution is the best isn’t the same as proving that you have a viable product for the market. There are attributes beyond pure function that you need to consider.

    Don’t fall into the designer’s trap of building a great solution to no-body’s problem.

  25. Dude on

    Also, you need to find some advisers in the space who know both the bike market and product development, and you need to be coachable. Be open the the possibility that every single one of your assumptions may be wrong, and that your product may be a dog (not saying that they are / it is, but you need to be willing to listen to the market and get both validation and rejection without suffering cognitive dissonance). Only then can you figure out what the market actually needs and fit product to market. Until then, you’re building solutions looking for problems.

  26. Joe Magee on

    @ Dude.
    Duly noted. I thought my use of “maybe”‘s and “might”s indicated I did not have exaggerated and unfound faith in the success of this design. This present exercise is me listening to market needs. So far, some negatives, some positives. I solved the problem that I set for myself in producing the working model, now I am seeing if maybe someone else would find it valuable for their problems (or with delighter features) and be willing to compensate me for my effort. No guarantees. I am consulting with business school professors and engineers, and will certainly take their evaluation to heart. Thanks for the cautions.

  27. Joe Magee on

    FWIW, here are the poll results. Thanks to all who participated. The design has generated enough interest, and is still under development. Look for more refined versions!

    “1. Have you ever seen a device like VECTr before? (If so, tell us where in ‘other’?)” 103 Votes
    Answer Votes Percent
    No 79 77%
    Other: 16 16%
    Yes 8 8%

    Other Answers
    Seen some similar concepts and protos
    Inside my own head.
    “never actually seen, but basic idea has been floating around”
    “A book while researching bike drivetrains in college, 1997.”
    Browning Transmission
    The 80s.
    In my mind
    Deal Drive (never seen one … just read)
    old rear gearing system video on park tool website
    “Bicycle Magazine, 1980s”
    I think I saw a system similar to this developed by a car manufacturer
    Truvativ hammerschmidt; not popular though
    “radial gear, google it.”

    2. Would you be interested in purchasing VECTr? 101 Votes
    Answer Votes Percent
    Yes 27 27%
    Yes (conditional) 8 8%
    Not Sure/Maybe 10 10%
    No 56 55%

    “3. How much would you pay for a reliable, easily installed component based on the VECTr design?” 87 votes
    Answer Votes Percent
    $0 (would not buy) 9 10%
    No more than $50 14 16%
    $50 – $100 13 15%
    $100 – $200 34 39%
    $300 – $500 9 10%
    $500 or more 3 3%
    Depends on Quality 5 6%

    “4. Do you know of any bicycle component manufacturers who make innovative or unconventional gearing systems? (If so, tell us who in ‘other’?)” 88 votes
    Answer Votes Percent
    Yes 18 20%
    No 47 53%
    Other: 23 26%

    Other Answer/Votes
    FSA Patterson/3
    Re Above/1
    Sturmey Archer/2
    Truvativ Hammerschmidt/6


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