WTH is alfine mu-s705b di2 8-speed motor unit???

Discussion in 'General Questions' started by autowood, Nov 17, 2013.

  1. autowood

    autowood New Member

    What is an alfine mu-s705b di2 8-speed motor unit? Is it a motor? I've searched the net and found plenty of them for sale, but not one description, explanation, picture assembled on bike.

    I like the concept of the internally geared rear hub for mid drive(chain wheel drive) bikes. No front or rear derailleur and option to use of a heavy BMX chain or even Gates Carbon Belt drive.

    I like running my motor through the gears.:confused:

  2. IbedaYank

    IbedaYank Member

    8 speed internally geared hub
  3. autowood

    autowood New Member

    The hub is different from the motor unit. What is the motor unit?
  4. IbedaYank

    IbedaYank Member

    autowood likes this.
  5. autowood

    autowood New Member

    I get it now. The motor unit is an electronic shifter for the hub. Has anyone used this in an off-road mountain bike application?
  6. tom-fishing

    tom-fishing Member

    This thread has caught my interest. Is this a auto shift or does it have a gear selector to shift with? I've never seen one of these and information about them is kind of hard to find. In the pictures they don't show any wires or gear selector. Anyone with firsthand knowledge out there?

  7. autowood

    autowood New Member

    Tom-Fishing. Go to the link above. It shows one installed and how it works. No, it is not an automatic shift, it is an electric shift that uses wires instead of mechanical cable to shift. It has a nifty lighted gear indicator on the handle bar and push button shifting.
    tom-fishing likes this.
  8. LR Jerry

    LR Jerry Well-Known Member

    From advice given by KC Vale with these internal geared hubs more gears more things to go wrong. The parts in the larger number geared hubs are thinner and aren't as strong as the ones in say a 3 or 5 speed hub. The Nuvinci hubs are very good but even they have their torque limits.

    As for shifting gears automatically there are some electronic shifters and mechanical shifters as well. My bikes shifts 5 gears automatically with a mechanical shifter.
  9. IbedaYank

    IbedaYank Member

    another post where somebody has to brag.... offers NOTHING to what the OP asked about
  10. LR Jerry

    LR Jerry Well-Known Member

    The hub you're talking about is somewhat expensive. I wouldn't want someone on here spend a lot of money on one just to find out it couldn't handle the torque of an engine. KC also has his own forum "KC Kruiser's". He should be able to tell you what the hub can handle.

    If what you're asking is more about automatic drive systems then I have knowledge on this.
  11. IbedaYank

    IbedaYank Member

    get your FACTS straight first... what he was asking about was the MOTOR for that does the shifting NOT the hub... you built ONE bike hardly means your an expert. Maybe when you hold pattents on something YOU designed from scratch and sold a few thousand of them
  12. LR Jerry

    LR Jerry Well-Known Member

    First of all you don't know me or what I've built. You don't know what I've researched either. I don't need pattents on anything to figure out a way to make something work. Nor do I need to smelt down the iron ore turn it into steel then pour it into a mold. My talent lies in taking what is available to me and combining it a way to make it work. There are many builders on here who build the exact same way. Example: take a White Industries Trails freewheel and change it from a single gear to a multi gear freewheel. I'll be doing a tread soon on how to do this.

    All I was trying to do was direct the OP to somebody who would know whether or not they should invest in this product. When we're opened minded things are discovered. When you're narrow minded things always stay the same. Just because somebody else's way is different doesn't make their way wrong. This is a place we should be trying to learn not talking trash to one another. So in the future if you don't have anything good to say to me then don't say anything at all and I won't say anything to you either.
  13. IbedaYank

    IbedaYank Member

    and again what does your bike have to do with what he asked about??

    multi speed freewheel to singlespeed conversion.. ... already been done MANY times nothing new here!!

    Conventional Freewheel-type Hubs

    The cheapest way to convert a multi-speed bicycle into a singlespeed is to use the original rear hub, assuming that it is made for a conventional threaded freewheel. A single BMX freewheel will thread right on. Unfortunately, the chainline is likely to only work with your granny gear unless you re-space the rear axle and re-dish the wheel.
    Cassette Hubs

    It is easy to convert a Shimano cassette Freehub ® for singlespeed use. The simplest way is just to remove the derailers, shorten the chain and thread it onto the chainwheel and rear sprocket of your choice. This is less than ideal, however, because you've got the extra weight of the unused sprockets to deal with, and the chainline will probably be crooked. The sprockets used on multi-speed cassettes are designed for easy shifting, which is not a good thing on a bike that isn't supposed to shift!

    The better way to convert a cassette Freehub ® is to remove the 7-, 8- or 9-speed cassette and replace it with a single sprocket. You will also need a bunch of spacer washers to hold the single sprocket in place. You can often get a suitable number of spacers by taking apart a couple of discarded, worn-out cassettes.

    Having a single sprocket sandwiched in a stack of spacers makes it easy to get the sprocket properly aligned for perfect chainline with whichever chainwheel you choose to use in front.

    You can use one of the old sprockets from your taken-apart cassette, but it you are less likely to have accidental derailment if you use sprockets made for single-gear use. The best choice for this is to use BMX cassette sprockets. These sprockets are quite inexpensive, and are available in a range of sizes. They have taller teeth than sprockets designed for derailer use.





  14. LR Jerry

    LR Jerry Well-Known Member

    I wasn't talking about converting a multi speed freewheel to a single speed. Just the opposite, converting a super strong single speed freewheel to a multi speed one. Open your mind look for ways thing can connect instead of the ways they don't. Then a whole new world will open up to you. Lose the anger and replace it with a desire to learn.

    I did electrical work for 30 years and still learned new things from green helpers. If you have some problem with me then PM me. Ibedayank stop starting petty fights on these post. Like I said if you can't say anything nice then don't say anything at all.
    Last edited: Nov 21, 2013