Your life, single speed vs jackshaft?

Discussion in 'General Questions' started by Frankenstein, Jul 27, 2016.

  1. Frankenstein

    Frankenstein Active Member

    How does being a single speed rider compare to a jackshaft, and therefore multi-speed, rider?

    I'm trying to understand a friend's point of view on the way a single speed bike behaves, vs my jackshaft behaves, more specifically the nature of a running engine while moving the bike, with and without a shift kit or jackshaft.

    I'm using a jack shaft along side a nuvinci 360 hub, no derailleur, no odd 4 stroking issues, since bike while under load can be geared higher to run at peak engine performance. You know Yada Yada...

    Then I used to have gears gears, like with a derailleur before that, and before that a single speed bicycle,where the engine connects directly to the back wheel via a single chain.

    For example, I've almost popped a wheelie several times, by accident, with a single speed, and never had that problem with a jackshaft.

    Get it? How's your experience with a jackshaft vs none.
     

  2. butre

    butre Well-Known Member

    single speeds are more efficient at transmitting power, but need a wider power band to be worth a damn, multi-speeds are inefficient, but since you can keep it within a thousand or so RPM you can build the motor for peak power. just 2 different ways of doing the same thing, each one comes with it's own advantages and disadvantages.
     
  3. gary55

    gary55 Active Member

    I have a shimano nexus 4 speed hud that was on the bike when I bought it used. Since motorizing it it's seen about 1000 miles, and has held up well. Just from feel I would say 3rd gear is about where my 44 tooth single speed compares to it on flat ground. I notice the power loss of the multi speed bike on uphill cause it won't climb as well as the single speed without dropping to 2nd gear. The up side is flat ground cruising 30 mph at half throttle in 4th. I am building a kustom kruiser using a nuvinci 360 hub, and would be real interested in your experience with this hub. I read where they have been rated for 9.5 H.P in industrial CVT uses with a 15 % power loss that's more than made up for in variable ratios. Any way how's yours treatin ya.
     
  4. Frankenstein

    Frankenstein Active Member

    I would say that the nuvinci is one of the best parts of my bike, it's got the advantage of a cassette minus the issues I face with a cassette and derailleur. One of the biggest things is when I have to slow down suddenly, in a high gear ratio, I can easily twist the shifter and gear down halfway through the gearing at a full stop, so unlike a derailleur where if you stop in 4th gear you have to move forward until you can shift and drop a gear, and then do it again and again to 1st,on the nuvinci I can go from the highest, down to halfway, without moving an inch, then a quarter of a turn of the pedals let's me gear the rest of the way down to its "first" gear or ratio.

    When it comes to higher speeds you don't get that derailleur wobble, like the spring that tensions the chain doesn't get tight and untight as you accelerate. The lack of a clunk in the gears is nice, since you don't need to wait for the chain to get seated fully on the next gear before hitting the gas. And at lower speeds, such as under the halfway mark on the ratios, you don't even have to shift before clutching or braking, just clutch, stop, and lock the clutch and twist it down to lowest gear before starting again. I can do this without letting my clutch go, I roll the shifter with my thumb, it's that easy.

    It's litteraly every advantage a derailleur has, without the problems, including taking the back wheel off, you loosen the cables a bit, and it clicks off, and is free from the shift cables, you then slip the wheel off without fighting a derailleur and it's auto-tension.

    Only disadvantage is that a cassette can be customized to be the gears you want on each spot, so you can change it to be an increase of 2 or 6 or 30 teeth per gear change. On the nuvinci your gear ratio is all one set, and predetermined by the sprocket you attached, so if you put a smaller one on, then you get a higher top speed but lose some low end torque as a result.

    It's held up remarkably well, never had a single problem, and I can also use a heavy duty half link chain instead of a weaker multi speed chain, so now I have 2 chains that are nearly indestructible, don't deal with breaks or stretch or anything stupid like my chain flying off into my spokes with a derailleur attached at 35mph.

    Definitely do it, it will hold up to the force a stock engine puts out, my engine is at least twice as powerful as stock and I'm worried about my sprockets being torn apart more than anything.
     
    FurryOnTheInside likes this.
  5. gary55

    gary55 Active Member

    I had a feeling this would be the case, but it is great to here these results from first hand experience of someone knowledgeable in motorized bikes . Now I'm even more anxious about getting started on this project. I build and repair these machines up here in Prescott Az.. It seems like all I ever work on is someone else's bikes. That's probably a good thing though.
     
  6. Frankenstein

    Frankenstein Active Member

    During the almost 2 and a half months my bike sat being "fixed," I ended up spending more time fixing other people's bikes than my own. It's hard to resist fixing a problem I know all too well how to fix, especially when I see them becoming frustrated with the issue. It also kept my mind off my bike which caused me so much headaches I eventually curbstomped it and was ready to light the spilling fuel on fire. Let the garbage man pick it up come Wednesday...

    I was looking at attempting at a shifting chainring, the nuvinci doesn't have room for 2 sprockets, but I think perhaps the shift kit chainring freewheel dothingybob could be made to shift between at least 2 sprockets, like how a 21 speed as 7 in the back and 3 on the front. A chain tensioner would be required, but doing that will let my drivetrain cover a much larger gear ratio.

    I would be careful about the 360 in only one single aspect, the company who manufacturered it seems to of discontinued it entirely, the Web page and all related info and media were apparently deleted or removed. I tried contacting them on this issue but never got a reply. I know they come with some kinda warranty, but I can't even find the page to register my product so I could be covered.

    They have I think 2 or 3 versions of the 360,get the 2015 or 2014 version, whichever is the actual latest edition, can't remember the year but anyways it has a slightly different mechanism for the shifting on the hub, which includes an insert in the manual that describes the slightly different installation.

    From what I heard a few people had some issues with the earliest versions, namely the transmission fluid leaked from the hub, which of course can't be refilled, and that leads to failure of it.

    I will also note that the cam arms that make up the freewheel internals, you know the part that let's it run only one direction, and freewheels if spun in reverse, have like next to no grease, at least in my opinion, I opened it and slabbed in a nice blob of red automotive bearing grease, synthetic type. That just helped me feel happy that it wouldn't fail and need replacement for a part at this point might not even be replaceable.

    That's my feel of it, it's a really good idea and I still can't get over how buttery smooth shifting actually is. Rode a shift kit bike a little while ago that had a derailleur, felt almost like i was in the stone ages with that clunky feel, and the need to ease up to the gear to not over strain it. Oh yeah there's none of that weird issue where you need to ease your way onto the gear when you up shift, like hitting the gas too hard and getting a jolt sent through the entire drivetrain, I can shift up and hit the gas as hard as I like and it seems to just flow to the setting instead of hitting it like a rock. It's probably because as you spin the sprocket faster the semifluid becomes stiffer as the bearings transfer more energy to the outer hub. So at a lower speed the freewheel is doing its thing untill it catches up, then the energy transfer builds up smoothly, even if it's in a small fraction of a second, and that just cushions the entire action that would otherwise be a heavy jolt on a standard bike derailleur. Amazing really, if it's not even a design feature but simply a side effect of the technology. Sorta like sitting at a stop light in a car, let off the brake and you just ease into the idle speed, or hitting the gas hard will throw the rpms off the meter untill the speed catches up to where the transmission should change gears in an automatic.

    Sorry for the novel, but now you and everyone else who plans on using the nuvinci is well informed and knows what to expect out of the box.
     
  7. gary55

    gary55 Active Member

    Quite alright it's it's a novel issue. I got the hub and had it laced up to a new double wall rim, mounted it on the bike, and it has set in my tool shead for nearly a year. I read that the tolerances are so precise that when the fluid in the hub passes between the ball and cone assy. it is brought down to a molecular level and at that precise point it becomes solid then as it passes through it becomes liquid lubricant again. Science is so bad assed. I have seen nothing but trouble with j shafts to derailleurs. tTo manny working parts, tension and allignment issues. I like my internal geared hub, but I do take it real easy on it when shifting. Thanks for all the info. I'll post a pic. when it's done
     
  8. Frankenstein

    Frankenstein Active Member

    You're welcome, I assure you that the hub is going to improve your experience tri-fold, what's even better is if you do bust a chain, you have no derailleur to work around, in the middle of the night in pouring rain you can repair and reinstall a chain in under ten minutes.

    Yes science, and all its semifluid molecular solidifying insane black magic of physics is incredibly bad to the freaking ass.

    Enjoy it and be safe.
     
  9. Fabian

    Fabian Well-Known Member

    When you have the heavy duty SickBikeParts jackshaft, you can do all of this and more:



    and this

     
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