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Rockrider ST530 + BBSHD

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    Rockrider ST530 + BBSHD

    Hello everyone,

    My father has a Rockrider ST530 size M ( ) that i would like to make an ebike so he can have more fun in the hills and i have some questions to ask since this would be my first ebike build !

    This is the kit i would like to use ( ), i would get the 42T 750C Bluetooth and i would most likely change the chainring for a 42T Luna Eclipse ( ) to get a better chain line.

    By searching on Aliexpress, i found a frame bag made especially for Rockriders ST500+ it seems and it's waterproof : ("color" PT0713) Click image for larger version  Name:	H7e015350162041cd9466531786954a25R.jpg Views:	170 Size:	130.2 KB ID:	117726

    I also found a seller that sells specific triangle batteries for frame bags and the mesurement looks good, the V/Ah too :

    Now my questions are :
    -Is everything should work together from what i chose ?
    -Are those Chinese batteries reliable ?
    -If not do you know a seller that make this kind of batteries with the same shapes/mesurements and V/Ah ?
    -What max V/Ah battery can i run with the BBSHD it's controller without burning everything and having a good "battery life" ?

    I think i'm gonna get the specific hydraulic connected brakes and the gear sensor with this too !

    Thanks in advance !
    Last edited by bezen; 12-08-2020, 10:26 AM.

    Seems like a reasonable plan. Since the chain ring is coming from a different place I would not order that right away. Try the stock one and see how the alignment is and how the gearing works out for him. The Eclipse 42 and 48 has about 6mm more offset than the stock and Lekkie ones which is good if you have the frame clearance but you don't always have the clearance.

    Another item I would want is an assortment of spacers for the bottom bracket. I would check the sellers selling the main kit so you don't have to pay extra shipping. You will also need special tools to remove the old crank and bottom bracket or take the bike to a shop and pay to have it done. It can be nice to have those tools since they are often the same tools needed to remove the Bafang crank arms which you may have to do in the future to change chain rings or tighten the whole unit if it comes loose. Tools are not usually that expensive especially if you can get them from a vendor you are already getting parts from so you don't have to pay extra shipping.

    EM3EV has a pretty good reputation for quality batteries so it may be worth checking with them to see how much it would cost to get them shipped to you. The amp hours don't effect the motor. You could have a 10,000 amp hour battery and the motor would not care other than how heavy it is.


      Thanks for the reply.

      I actually think i'm going to go for the BBS02B 48V 750W option rather than the BBSHD (mostly due to cost/performance balance) and i don't think i'll ever need the 1000W and 160Nm ;D

      As for the spacers i found some cheap ones on aliexpress but it was for BBSHD, i wounder if they are the same for the BBS02B, they should be, the shaft going through the BSA BB should not differ right ?
      As for the crank and BB tools, i already have them, since i'm already a "DIY" bike mechanic, i'm just starting with ebike stuff and i'd rather do it my self than by a brand name and be fucked in 2 years when you can't have replacements parts anymore ! :)

      I'll ask EM3EV if they ship to Europe, but their website has the option to choose french language and Euro as a currency (but weirdly it doesn't work when you choose these options).


        I would think the spacers would be the same, like you said they are fitting the same BB size. If you don't need the wider spacing, extra power, and extra water resistance then might as well spend the money in other places to make a better bike. The 02 has a slightly smaller gear case so that can help fitting on some bikes. The 02 and HD use different chain rings so when you are looking at those remember to pay attention to what they fit. If you don't think he will need power and speed will he really need a big battery? Going fast and or hard up hill is what eats up the range.

        Being based in China I would think EM3EV would ship everywhere but who knows. Batteries is a tough call because I'm sure as you have seen you can spend $300 or $600 for a packs that more or less look the same on paper. Even packs that use identical cells can be quite different in quality. Some packs each cell is individually fused and other packs don't have any fuses at all. You take something like the lack of fuses and just use some hot glue and shrink wrap you could have a very unsafe pack. A little vibration and things shift slightly and you get a short you can end up with a fairly quick chain reaction and a big fire pretty easily. A pack that is completely sealed in epoxy should not have the vibration issues but may be impossible to service when it gets old and cells start to fail so if you buy that style you hope they are using the highest quality cells.

        I currently have 3 systems, only one I bought new and it was a Luna Wolf pack which is a good example of being able to get something with similar specs for half the price. The Wolf packs appear to be completely sealed in epoxy so should be very rugged. I don't know if they have fuses or not. My first used system also had a wolf pack. My latest used system came with an EM3EV triangle pack and my first issue with it was how to mount it since its just shrink wrapped. The Luna Wolf's have a metal plate in the bottom so you can use magnets which I think is pretty nice. My frames are on the large side so the bags don't tend to fit well. The bags to work well and have some vibration resistance need to mostly be hanging from the top tube but you don't want them too far away from the bottom so they want to swing either.

        When you are thinking about mounting another thing to consider is will it have to be removed very often? If its going to live in a freezing climate you will want to remove them when not in use. Does the bike have to ever be carried? Like to load on a car rack or maybe up some steps into a flat? Getting rid of the weight makes a big difference not to mention the triangle bag tends to bock access to the top tube so less places to grip the bike to lift it.


          Well we live in a really hilly/mountains area, basically the only flat sections are the big roads which you do not really to be on your bike because of huge traffic, so yeah i need a pretty big battery i think (atleast over 600Wh would be good) if he want's to be able to do more than 40-50kms (where you can easily get 1000meters plus of elevation).

          I was thinking doing this build for christmas so idk how it's going to end up because i see that pretty much every battery that you get directly from china you have to wait atleast 1.5 to 2 months to get it in europe, so i think i'm going to look what's in stock in europe and go with it.

          As i said the frame is pretty small for a medium size due to the seatpost beiing really small so a triangle bag would be snug especially when i see the mesurements on most of them, they would fit pretty well and i think i would use some foam between the frame and the bag to absorb the virations, otherwise i think i'll have to get a pack and fit it the best i can, knowing i can really remove the battery without removing the whole thing (might have to use some plombers hoose tightenners that you can screw and make them hole like zip ties, idk how they are called).

          In term of removing the battery would it be a pack or a triangle bag frame, the only reason he would do that is to change the battery if he had a second pack on the ride to go further, but that would not be possible without tools and a lot of time lost for the change, otherwise the bike would not go when snowing or in freezing temperatures (it hardly get that bad here) and it does'nt rain that much either, the weight might be an issue to put it in a car maybe in 5 years from now but i doubt he'll travel alot with the bike and the bike will not go upstairs nor will sleep outside, plus he takes care of his stuff so i don't really see any weather/premature wear beiing a problem, so that is not really an issue i think !


            50km is about 30 miles so with hills involved you will likely want a battery in the mid teens to be comfortable on the range. Finding something in stock in Europe does make sense if you don't have time to wait. Its a big enough area there has to be some options for you.

            With the hills I do wonder if you should consider the HD? Does your dad ride now so he will be able to do a decent amount of pedaling? If not then I again lean to the HD.


              He rides from time to time but not alot, this is why i want to make him an ebike so he can ride more without feeling tired/broken !

              Yeah but i saw some example on this bike where the chain line was not good at all with the BBSHD where it was ok with the BBS02, might be due to the rear skewer being only 135mm and the chainstay being short and not really made for MTB, the max 1x ring you can put with a standard GPX/Shimano/Dub is 34 apparently (with standard 1x crankset atleast).

              That and i'm not sure how log the pawl in the rear wheel will last with a 1000w 160nm motor, might aswell take a bit less, if he does more kms i'll see if i can manage an other batterie or a second battery or even buying him a more recent MTB with boost (BBSHD chainline seems better with boost 148*12 since the cassette tend to go further on the right side) or even a frame with a bafang motor mount we will see !


                I think the BBSo2 will surprise you in the power department. I have had my BBSo2 on 2 different bikes and as long as I don't use any bottom bracelet spacers on the drive side the chain line is great with the stock Bafang 44 tooth chainring. The first bike was a 68mm bottom bracket with 7 speed freewheel, and the second bike is a 73mm bottom bracket with 8 speed cassette, both are 135mm spacing. A 52v 15ah or larger battery should allow him to go farther than 50km. But for that range, pedal-assist is a must. The more effort the rider provides the loner the total range, and this means that you need to use the lowest assist level possible for the amount of power your pedaling can provide to meet the goals of your ride. With my BBSo2, 750w, with a 48v 20ah (960wh)battery I can get 90km range on relatively flat ground averaging around 17 km/h. And I can get 63km easily with battery to spare in steep hilly terrain with careless battery management.
                I wouldn't worry about the rear freehub/freewheel failing with either motor unless it already has a severe problem
                Last edited by Dshue; 11-15-2020, 10:44 AM.


                • Dshue
                  Dshue commented
                  Editing a comment
                  And your bike has slightly better rear gearing than mine. My current 8 speed has an 11-40 cassette, Decathlon lists the Rockrider as having a 9 speed 11-42 cassette.

                The 135 rear hub isn't really a factor its all in the frame design and how fast the chain stay kicks out after the bottom bracket. If you can get us some photos looking down at that area and tell us the current size of the chain ring(s) we can give you our best guess on if it will be a problem or not. Its when tires get wider than 2"/50mm and stock chain rings are smaller than 40t that things can get difficult, basically plus and fat bikes. And I'm talking about original size or max tire size. Doesn't usually matter if you have a bike that can take 5"/125mm tires and run 1 1/4"/30 mm's. Frame is the problem because it was designed for a specific tire width and chain ring diameter.


                  Yeah i plan to get a 42 chainring (with approximativly the same offset than the stock 44 chainring) and maybe get a 11-46 cassette since the derailleur can apparently take it easily, so the motor probably will never have to use all the torque (except maybe on really steep 15%+ rocky/gravely uphill).

                  I will probably have to put a 2.5mm spacer from what i've seen while searching because the chainring and the round part of the motor (idk how it's called) are way to close to the chainstays (it clears but i'd rather have a little more space) for my liking :)

                  Click image for larger version

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                  As for the battery i went with a 48v 17.5ah shark pack type (Helion ~367*110*90mm), i found a seller in eu with Samsung batteries and if the battery does not fit in the frame i can send it back for free, the seller will pay the return fee ! :)


                    Here are some pics of my build.


                    • Dshue
                      Dshue commented
                      Editing a comment
                      But if the chainring won't clear the chainstay then spacing the bb may be the only choice. And a 42 tooth ring won't hurt at all in hilly terrain.

                    Grinding the part down is an other option, i will see, if the chainline is bad, i might try it too, i would paint the metal back tho so it does not rust ! :)


                      I'm not sure what these are made of but there doesn't appear to be any iron in em so no rust. Also doesn't seem like typical aluminum either.

                      Looking at the photo of that other install doesn't look like grinding would do any good since the chain ring looks like it barely clears. Maybe if a smaller ring clears then it would help and be worth the trouble.


                        Yeah, i'm going to get a 42T chainring and a 2.5mm bottom bracket Bafang spacer, then if the chain line is too bad, i'll think about grinding the motor, but i think that with a 42T narrow wide, there is almost no chance the chain is going to drop.


                        • Dshue
                          Dshue commented
                          Editing a comment
                          It's not all about chain drops, if the chainline is too far out you have the problem of being able to get into first gear as well as the chain putting a tremendous side load on that cog.

                        • 73Eldo
                          73Eldo commented
                          Editing a comment
                          Its a weird game you have to play. One of mine with a like new 8 speed cassette I just could not reliably stay in first gear using the stock cheap Bafang ring. Chain would climb off the ring sometimes so my fix was just lock out 1st and order an Eclipse ring that had more offset (like 6mm) to get in as tight as possible. The Eclipse has a narrow wide too and even with the extra offset was not even close to working with the 8 speed setup. With the Eclipse ring 2nd gear was like 1st with the stock ring, really crunchy and you could tell it wanted to climb off. I wasn't that big a fan of the 8 speed that bike had on it anyway and I had a well used 10 speed laying around so threw that on and over 200 miles now its been great. Hope I don't find out the secret is that you need a chain that is just about shot which mine is.

                        Bike is comming along nicely, i'm just missing mudguards and rack and getting the tires to tubeless !

                        Attached Files


                        • Mike_V
                          Mike_V commented
                          Editing a comment
                          Hi B,
                          You're a good son.
                          Did you ask what style 'throttle' Dad prefers?
                          Nice eBike !

                        • bezen
                          bezen commented
                          Editing a comment
                          Hi, thanks !

                          What do you mean by "what style throttle" ?
                          Thumb or grip throttle ?

                          I did not ask anything since it's a "surprise" christmas present, so he'll get the throttle, i was kind of hesitant to put it since it's not "ebike" legal here in france, but the motor is already not legal so...
                          Plus i got to unmount in a steep singletrack rocky/rooty uphill in yesterday test and the throttle actually help massively at getting you back on the back with balance !

                          I just hope he'll use his legs more than the throttle, he won't go far only on throttle anyway ! :)

                        • Mike_V
                          Mike_V commented
                          Editing a comment
                          just L/R thumb ; 1/2 or full grip ' speed control ' not a big deal.

                          You're doing great, I'm glad to read your story and see a nice and stealthy eBike you created.
                          Way to GO !