Announcement

Collapse
No announcement yet.

Sun Electro Lite intermittent manual pedalling issues.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Sun Electro Lite intermittent manual pedalling issues.

    I recently inherited a Sun Electro Lite. I know nothing about electric bikes. I noticed after about 30 minutes of riding no matter if manual or pedal assist, the crank just spins freely like a chain popped, but the chain didn't pop, the crank is just not engaging with the back tire (whatever thats called). Anyway, before i take it to a bike shop, i am hoping someone can give me some idea's of what could be wrong with it. I checked the pedal assist sensor to see if it was free of dirt and within the right spacing with the rotor. Thats about all i have been able to read up on so far.

    Thanks

    #2
    Looking at what info I can find about that bike it appears to be a direct drive rear hub motor. This means that the pedal portion of the system is identical to a non e bike so there really isn't many places for this issue to occur. Most hub motors use what is known as a freewheel which is a complete assembly of the sprockets and the ratcheting clutch mechanism. This assembly then threads onto the hub which in this case is where the motor is. The other style is called a cassette and those differ in that the ratchet clutch mechanism is part of the hub and the sprockets are stack on that and are held on with a lock ring. Cassettes came out around 1990 and have been standard on every bike shop quality bike since the mid 90's. Its only your wal mart sort of bikes that for the most part use the older style thread on ones.

    The freewheel (or hub part of a cassette) has little spring loaded wedges that engage a ring of teeth. If things are moving in one direction they just ride over the teeth and nothing happens but you hear a clicking sound and the inner and outer parts can move independently otherwise known as freewheel. The other direction they basically wedge in the teeth so both the inside and outside of the unit have to turn together. In yours something must have happened that is keeping the teeth (technically called pawls) from engaging the teeth. Could be the lubrication is hard or dirty and they are just too sticky to pop up and catch. Could be wear of some of the teeth so it just depends on where you try to engage it and sometimes you get lucky and find a good tooth.

    I doubt you would find a shop that would want to take one apart and try to inspect and clean it. Even if they did its unlikely that there are any individual parts available and the labor would cost more than replacing the whole thing. A new one ranges from $15 to about $40. They were and I assume still are an item in high demand so may be difficult to find in stock and you may have to just take what ever model you can find rather than actually choosing a brand or price point.

    Even though this is likely a standard bicycle item (I don't know yours specifically but many hub motors use standard freewheels) you may have to find a shop that works on E bikes because most of the time the wires come through that end of the axle so not only do the wires have to be disconnected which may scare a non E bike shop many times the wires get in the way of the standard tool that is needed to remove the assembly off the bike so they could get it all apart and find out that their tool won't fit because of the wires. An E bike shop should have special or modified tools to do the job.

    If you want to take a shot at it yourself you could try shooting something thin in there like WD40 in hopes of flushing out crud or sticky grease but that may not be a long lived fix. Ideally you would remove the rear wheel to get a good look and access to it. If you look close you will be able to see where the gap is between the inner and outer parts and that gap is where you want to squirt the stuff. Just inside that area you should see splines, this is where the special tool engages to allow the whole assembly to be unscrewed off the hub.

    Comment


      #3
      Originally posted by 73Eldo View Post
      Looking at what info I can find about that bike it appears to be a direct drive rear hub motor. This means that the pedal portion of the system is identical to a non e bike so there really isn't many places for this issue to occur. Most hub motors use what is known as a freewheel which is a complete assembly of the sprockets and the ratcheting clutch mechanism. This assembly then threads onto the hub which in this case is where the motor is. The other style is called a cassette and those differ in that the ratchet clutch mechanism is part of the hub and the sprockets are stack on that and are held on with a lock ring. Cassettes came out around 1990 and have been standard on every bike shop quality bike since the mid 90's. Its only your wal mart sort of bikes that for the most part use the older style thread on ones.

      The freewheel (or hub part of a cassette) has little spring loaded wedges that engage a ring of teeth. If things are moving in one direction they just ride over the teeth and nothing happens but you hear a clicking sound and the inner and outer parts can move independently otherwise known as freewheel. The other direction they basically wedge in the teeth so both the inside and outside of the unit have to turn together. In yours something must have happened that is keeping the teeth (technically called pawls) from engaging the teeth. Could be the lubrication is hard or dirty and they are just too sticky to pop up and catch. Could be wear of some of the teeth so it just depends on where you try to engage it and sometimes you get lucky and find a good tooth.

      I doubt you would find a shop that would want to take one apart and try to inspect and clean it. Even if they did its unlikely that there are any individual parts available and the labor would cost more than replacing the whole thing. A new one ranges from $15 to about $40. They were and I assume still are an item in high demand so may be difficult to find in stock and you may have to just take what ever model you can find rather than actually choosing a brand or price point.

      Even though this is likely a standard bicycle item (I don't know yours specifically but many hub motors use standard freewheels) you may have to find a shop that works on E bikes because most of the time the wires come through that end of the axle so not only do the wires have to be disconnected which may scare a non E bike shop many times the wires get in the way of the standard tool that is needed to remove the assembly off the bike so they could get it all apart and find out that their tool won't fit because of the wires. An E bike shop should have special or modified tools to do the job.

      If you want to take a shot at it yourself you could try shooting something thin in there like WD40 in hopes of flushing out crud or sticky grease but that may not be a long lived fix. Ideally you would remove the rear wheel to get a good look and access to it. If you look close you will be able to see where the gap is between the inner and outer parts and that gap is where you want to squirt the stuff. Just inside that area you should see splines, this is where the special tool engages to allow the whole assembly to be unscrewed off the hub.
      I took it to the bike shop and the tech noticed right away there was no clicking sound when the tire was spinning. He did exactly what i highlighted in your post and whalla, clicking sound. He said this is common in colder weather (its in the 30's here). Anyway, im going on another hour bike ride and will report back sometime after the long nap im going to need after going 2 hours in one day. Thanks for your very detailed responce.

      Comment


        #4
        Well, bad news, it started doing it again after about 30 minutes.

        Comment


          #5
          I would guess have a chance of fixing it correctly it would have to be removed from the bike and the wheel then disassembled. Its been a long time since I have done this but from memory I would guess there are maybe 75 1/8" loose ball bearings in there that will just roll out as you take it apart. You can then clean and inspect things and if there is not actual wear or damage you then have to re assemble things.

          On the ones I did you gooped the stickiest grease you could find in the bearing races then stuck the bearings into the grease one by one and hoped they stayed stuck there long enough for you to get them all in then assemble the sections hopefully without loosing any in the process. On a warm day this didn't always go well. If you have the time and patience it can be done but paying someone to do it just doesn't make sense when you can likely get a new one for maybe half the labor cost. Labor for putting it on and off the bike is the same if its fixing the old one or installing a new one.

          Comment


            #6
            Assuming its a thread on freewheel here is one that looks like it should be a direct replacement based on a spec sheet I found on what I think is your bike, out of stock of course.

            https://www.universalcycles.com/shop...&category=1665

            For those that don't like links its a SunRun 8 Shimano HG compatible 13-28 $14

            Comment


              #7
              Now that i know what the part you were referring to looks like. I looked at the last sprocket and it is labeled ZF28T. That link you gave me says out of stock.

              Update: Found an exact match on ebay for $30
              Last edited by mikemikemike; 5 days ago.

              Comment


                #8
                I sprayed a bunch of WD-40 in right before i went for a bike ride this morning. I did not do it the entire 45 minute ride. Maybe i just need to keep spraying the crap out of it to prevent it from happening, but its still good to have a spare if it gets worse.

                Comment


                  #9
                  That does sort of imply its a lube and or contamination issue rather than actual damage at this point.

                  Like I said I'm not sure that is a replacement, I could have been looking at the wrong year or model online and they didn't specify its a thread on style. Im just guessing based on that is how hub motors tend to be.

                  Comment


                    #10
                    I think it could be contamination. The day before i took a bike trail that was partially paved and partially stone. The stone area had a few slushy areas of water and fine stone which made it like mud. I tried to go over it without splashing too much up, but i guess some must have got into that freewheel. I didn't notice this issue until the next day, but maybe it took time to work itself in.

                    Comment

                    Working...
                    X