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Shimano Nexus 3 Speed or Alfine 8 Speed on BBSHD build?

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    Shimano Nexus 3 Speed or Alfine 8 Speed on BBSHD build?

    Which of these two IGHs would be most efficient and cost effective for a hill climbing BBSHD commuter build?

    Based on the gear ratios on Sheldon Browns website the Nexus 3spd ($110 at lbs) gears are basically the same as 3rd, 5th, and 8th on the Alfine ($230 at lbs). I'm planning to use the bike as a daily driver because most everything I do is within about 5 miles of my house. There are significant hills in the area though and I'm wondering if the lower gears on the Alfine would be worth the extra $120. Also from what I've read the Nexus 3 may last longer because it has less moving parts. Does anyone have any knowledge of the longevity of IGHs on a BBSHD build?

    Also in your opinion is it worth switching from a derailleur system to an IGH?

    #2
    I have the Nexus 3 speed hub with the bbshd on my fat bike. I use it for road and trail riding. I found the 3 speed covers pretty much any terrain. You can also change the front chainring to suit your particular situation. The 42T is a good all around set up. I tried the 30t and it was way too small for the road. If you have a lot of hills a mid 30t would work out better. I went with a offset rear sprocket ($30) which gives me more front chainring choices.
    My lbs charged $150 to convert the wheel, $60 for spokes, $60 labor, $20 for a disk brake converter, and tax. Add the cost of the hub and your at $260+. I also switched to a KMC igh chain for another $20.00.
    What I like is the simplicity, no chain line issues, and I shift a lot less vs the 8 speed cassette.
    The down sides are, your stuck with that wheel, and the cost of the conversion.

    Comment


      #3
      Many feel the 3speed IGH's are more durable and as the above poster states "covers pretty much any terrain". I don't completely agree, but that is for me & my riding style personally, YMMV.

      I run a Sram8 with the Luna 42T & BBSHD on my original mnt bike build. I also live in mountainous country with a lot of elevation change doing both off-road (30%) & road (70%). I have ridden 3speed IGH's and wouldn't consider them for my riding needs. With this set-up I can do 22-24mph before cadence is too fast for me, 30mph throttle only on flats while being able to climb up to 50%+ grades before I feel the system is stressed (I weigh 235#). That said I also prefer more rider input, using assist only when I either can't or simply don't feel like putting out the effort needed for a particular scenario.

      I have well over 1000miles on this system with no issues but I also am cautious not to stress it by running in higher gears simply because I can or shifting under power. If I have a complaint it is the low gears are not low enough for my riding style but I would not want to change the 42T front chainring because that would make the high end less than I would want since I'm on the road more than off. I'm using a Sram dual drive for a total of 24 gears on my new build but that is on a FS bent trike which doesn't have the chainline issues of a DF.

      The Shimano Alfine is probably a better choice than the Sram if for nothing else more shops & mech's are familiar with it. Everything is a compromise and you need to fit your personal preferences.

      Comment


        #4
        I made a dual front sprocket set up, 38/42 for the igh. It's set up as a manual change. I figure the 38 is better for the trails, and 42t for the road.

        Comment


          #5
          Harold possible to post up some photos.

          Comment


            #6
            I posted a short write up and photos in the diy section. https://electricbike.com/forum/forum...inring-for-igh.

            Comment


              #7
              I have an Alfine 8 on a Surly fatbike with BBSHD and a couple thousand km without any issues. I do a lot of hill climbing and love the range of that IGH and my Eclipse 42. I never shift under load and would use this setup again without hesitation.

              Comment


                #8
                I have a Rohloff Speedhub 14 with a Luna 42T. BBSHD motor. From a price perspective, it's overkill. But it's amazing how well the hub pairs with the motor. The power of Pedal Assist 1 overcomes all gears on flat land. The 3 speed should be fine for you.

                Comment


                  #9
                  Hi, though all of the topics on using IGH's are quite old, I hope the topic isn't stale. I chose this thread over https://electricbike.com/forum/forum...icular-rohloff to continue the conversation mostly because the 3-speed IGH is probably more relevant to my question.

                  I have a Luna Folding bike with 20" rims and a BBS02. The rear hub ratchet gave out after 18 months, and I have been thinking for a while that I would like an IGH better for several reasons. I just don't know whether it's possible to do with the 20" rim - matching the number and length of spokes.

                  As far as tradeoffs go on the number of gears, I have to add this - Yes, I find myself usually only using 3 gears out of 8, with these caveats:

                  when I am going a short distance (6 miles or so with an 18-month-old battery) with no concern of running out of juice, I can go full speed and I don't shift at all. When I need to go further, I can only go pedal assist, which means I need to downshift before stopping, or I can't get across an intersection after a red light without hitting the juice and shortening my range by a lot. BUT the big "but" : when I kill my battery, I absolutely need those lower gears I otherwise never use because the bike just feels too heavy and it's exhausting to limp home without using the lowest two gears, even on flat Florida terrain.
                  Last edited by j.b.shirk@gmail.com; 07-06-2021, 05:16 AM.

                  Comment


                    #10
                    Originally posted by j.b.shirk@gmail.com View Post
                    Hi, though all of the topics on using IGH's are quite old, I hope the topic isn't stale. I chose this thread over https://electricbike.com/forum/forum...icular-rohloff to continue the conversation mostly because the 3-speed IGH is probably more relevant to my question.

                    I have a Luna Folding bike with 20" rims and a BBS02. The rear hub ratchet gave out after 18 months, and I have been thinking for a while that I would like an IGH better for several reasons. I just don't know whether it's possible to do with the 20" rim - matching the number and length of spokes.

                    As far as tradeoffs go on the number of gears, I have to add this - Yes, I find myself usually only using 3 gears out of 8, with these caveats:

                    when I am going a short distance (6 miles or so with an 18-month-old battery) with no concern of running out of juice, I can go full speed and I don't shift at all. When I need to go further, I can only go pedal assist, which means I need to downshift before stopping, or I can't get across an intersection after a red light without hitting the juice and shortening my range by a lot. BUT the big "but" : when I kill my battery, I absolutely need those lower gears I otherwise never use because the bike just feels too heavy and it's exhausting to limp home without using the lowest two gears, even on flat Florida terrain.
                    Without a in-person closer look and just based on the photos, I suspect if you want to convert to the Shimano Nexus disk 3-speed IGH, you'll need:
                    1. the hub (only available 32-spoke)
                    2. new spokes
                    3. new 32 spoke rim
                    A new rim and spokes would be required if your bike has the stagger step pattern 28 spoke rim. If you have a normal 32 spoke rim, I suspect you'd still need new spokes because of a difference in the hub flange diameter / position. With the Nexus 3-speed I'd go with a two-cross spoke length. If you instead decide to step up to either the 5-speed Nexus or 8-speed Alfine, I'd go 1-cross with no interleave.
                    Last edited by ncmired; 07-06-2021, 06:00 AM.
                    BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

                    Comment


                      #11
                      Thank you so much for the detailed reply. I just looked to confirm that I have staggered 28 spoke rims.

                      I think that it will be worth getting different rims, as I've been told several times that it's quite difficult to get gatorskin tire beads in (I consider those a must). A different rim might make a difference. I could never get those tires on myself.

                      Comment


                        #12
                        For easier tire battling I'd look for a rim with a nice "dipped" center, then make sure the opposing side tire bead (to the side your working on) is down in that dip when starting on or off the tire. I like the Velocity Cliffhanger rim, if the frame can clear it:
                        Click image for larger version  Name:	Cliffhanger_3_450_432.png Views:	0 Size:	105.8 KB ID:	131430



                        I'm able to wedge Schwalbe Super Moto X 2.4 inch tires on these rims, that are on my mini-bike build. For thinner than usual rim tape, I use fiberglass packing tape.
                        Last edited by ncmired; 07-06-2021, 12:25 PM.
                        BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

                        Comment


                          #13
                          Niiice! I'll take that advice. I noticed my stock hubs have no center ridge to speak of.

                          Comment


                            #14
                            I see a lot of people asking about the durability of different IGH's. I'd think that would be the number one reason to convert to belt drive. There is no doubt in my mind that if the BBS02 can shred a hub ratchet it's not going to be kind to an expensive IGH - why wouldn't someone want to protect their investment?

                            Comment


                              #15
                              Originally posted by j.b.shirk@gmail.com View Post
                              I see a lot of people asking about the durability of different IGH's. I'd think that would be the number one reason to convert to belt drive. There is no doubt in my mind that if the BBS02 can shred a hub ratchet it's not going to be kind to an expensive IGH - why wouldn't someone want to protect their investment?
                              Going or converting from a chain to a belt is ... complicated. On my first e-bike conversion I was initially going to retain the belt, thinking of all the nice belt features, as well as the possibility of the belt cushioning the motor start up. But pretty quickly you find out about the gotchas of going belt drive:
                              1. The front to back belt pulley alignment has to be spot on. With the BBS02 motor it's supposedly possible to hit the tight Nexus/Alfine belt line, but I've not ever seen the how-to specifics. With the BBSHD, it is not possible using standard off the shelf parts, no custom machining, and unmolested BB - as far as I know the only IGH hubs that are known (with the details) to work are the Sturmey Archer psuedo 3-speed CS-RK3 and the Rohloff.
                              2. If the belt has to pass through the chain / seat stay triangle, the frame must have a splitter. AND, the frame has to be rated for belt drive, with the frame lateral deflection staying within a limit (which you can bet is further stressed by >1HP of motor pull).
                              3. Belt drive needs to be set to a fairly precise tension, complicating setup and component choices.
                              4. Cost - unless your lucky / very careful with the belt pulley ratios, changing the overall "gearing" can get very expensive. Gates has patented their system and charges a hefty premium.
                              With either belt or chain drive, the frame still needs to be up to the task of dealing with the IGH's axle twisting motion - some are not and broken dropouts are the result. I've stuck with chains (much easier to deal with), and all of my builds are IGH (Nexus / Alfine 3 and 8 speed, one Rohloff).

                              As an aside, one way around fretting about becoming stranded after grenading an IGH hub is to get a frame with interchangeable front and rear wheel spacing (usually 135mm), like the Surly Pugsley and my Scapegoat. Then, put a single speed freewheel on the front wheel that matches the rear cog tooth count. If discs, the rotors have to be the same diameter. So, as long as the IGH's axle can still spin, swap the wheels and you're set to go.
                              Last edited by ncmired; 07-07-2021, 09:09 AM.
                              BBSHD / BBS02 IGH Builds: Nexus / Alfine 8: 1 2 3 4 5 6, Rohloff: 1

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