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Surley Ice Cream Truck - A bridge too Far

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    Surley Ice Cream Truck - A bridge too Far

    Guys, Girls fellow ebike enthusiasts I want some advice before I start destroying a perfectly good bike. (everything I've done up until now I can undo.

    I bought a Surley Ice Cream Truck with a desire to convert a Fat Bike into an Electric Fat Bike. I liked the fact that the Surley bike had great quality components and was steel frame and very strong. I bought it online from a distributor who was selling up his business so I got it at a great price. Once he bike arrived I realized it was going to be a tough convert. A 132 MM bottom bracket being the biggest challenge but I hoped to be able to trim the BB down enough to be able to make it all fit together. Anyway I thought I'd give it a go.

    After removing the Press fit bottom bracket and sliding in the 120 MM BBSHD I discovered that there were a number of things that were going to make this build very hard so before I started doing anything that I couldn't put back together I thought I'd put this out to the wider masses for advice.


    Firstly the Bottom Bracket is 41 MM in diameter and so the BBSHD has wobble room as the shaft is much smaller than the Bottom bracket. I could probably solve /fix this with a shim - any ideas where to get one from? If I pulled the BBSHD forward as far as possible in this oversized BB I really doubt that BBSHD mounting bracket be able to take all the stress?
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    Secondly the chain stay. On the drive side, the housing for the gearing on the BBSHD has only 3 MM of clearance from the chainstay. This does not allow any chain ring other than a Luna Cycle Mighty Mini to fit without the teeth hitting the drive side chain stay, however the chain line using the mighty mini would possibly be on too great an angle as there is little offset. I was hoping to be able to take 5 MM off the drive side using a facing tool and 5 MM off the non drive side to get me too the 122 MM (loose 10 MM ) overall and not fit the second locking nut for the BBSHD. But I am wondering if I'm dreaming.

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    Drive Side


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    Non Drive side

    On a very close inspection I only have 4 MM on the non drive side to be able to remove before I start eating into where the chain stay welds are attached to the BB. If I push the BBSHD unit to the front of the oversized BB then I could get 6 MM from the drive side and end up with a better chain alignment but I couldn't do this by fitting a shim on the shaft.

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    There is not much of the oversized BB I can shave off wothout hitting the welds where the chain stay attaches to the BB.

    Lastly and probably leastly I chucked a standard issue Bafang Crank Arm on the non drive side to see how the chain stay clearance was. Don't forget this is before any alteration to the facing is done. Given that I may get a few MM off each facing this problem will only get worse or stay the same. So I'll probably also need offset crank Arms from somewhere. The original crank arms form the surley are offset but the have a different fitting than the square one that Bafang uses. I notice that Luna Cycle doesn't sell offset crank arms them so hopefully "IF" I go ahead I can score some from California Ebikes.

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    So there you have it - please advise - "a bridge too far" or do you recon I should go ahead and shave as much off each of the BB facings that I can before I hit the chain stay welds , Shim up the Bottom bracket so the BBSHD Axle fits in snuggly and whack on the Mighty Mini as a chain ring.

    Please let me know.

    Chur

    PS - I am using the Mighty Mini on my other bike and I love it.




    #2
    Here are photos of the Surley Pressfit Bottom bracket that came out of the Ice Cream Truck. Enduro SEMR 2487
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    Last edited by neilio; 02-20-2016, 05:05 PM.

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      #3
      Thanks for posting this. This is one of the reasons that these forums are so very important. There may be a frame that is similar to the Surly Ice Cream Truck, and that might save another builder these same issues. I'll look for an answer, but it may take a while...(if I even find a solution at all)

      Comment


        #4
        For anyone who is having these issues then I suggest reading this article several times.

        http://electric-fatbike.com/2015/11/19/get-a-bigger-hammer-bbshdbbs02-installation-problems-fixes-for-non-standard-bb-intrusive-chainstays/

        I have contacted a local bike builder in Pukekohe NZ (yes someone actually builds bikes here still). Using an industrial 40MM Nylon heat shield lagging for protecting 15 mm pipe (bought from a plumbing supply store) I will create a "bush" (what I refer to as a shim) for the BBSHD axle which will enable it to nest nicely into the empty 40MM Pressfit BB shell. I did think that removing and replacing the bottom bracket could be an option but I am told is like a trying to replace a human spine or something equally important and not recommended. I did a bodgy job on my own to see if my shim or "bush" using the Pipe Heat shield would work. It has a 15 MM inner diameter and a 40MM outer so I started boring out the middle using a 32 MM Quick Drill bit and my electric drill then finishing it off to fit perfectly using a wood rasp. Once i slipped it on the BBSHD Axle and pushed it into the BB shell it was nice and tightly nested just like a bought one. Using a lathe to get the internal diameter would get the diameter perfect but the drill bit and rasp works fine too.

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        Now that I've read Karl's article properly for the forth time I see I need 12 MM of thread showing to fit all the BBSDH's locking rings and brackets. I have 3 MM at present - this means that once the triangle bracket for holding the engine up against the frame is on there is only half a thread showing which is nowhere near enough to even start fitting the first lockring. Tonight I will visit the bike builder who will see how much I can gain with a reface of the non drive side of the bottom bracket - I have small balls so I'm not going to try the angle grinder and the Hose Clip method Karls uses. I am thinking I will be able to get 4 to 5 MM. This will mean ditching the second lock ring which I know is common (loctite liberally applied to the first one will have to hold it on).

        I have noticed that the drive side chain stay is not round where the chain wheel comes close to the chain stay. It has been pushed inwards (by Surley) and is a "U" shape. If I do the same thing to the non drive side I will gain some breathing space and may not need an offset crank arm. Shipping to NZ via Lectric cycles costs 4 x what the crank arm does !!! I'm looking at $125 USD for an offset crank arm if I can't get enough clearance. At $1.52 NZD for every $1 USD that turns into $190 of hard earned for a crank arm you'd have to be kidding me.

        I'm getting closer - Fingers Crossed.......

        Comment


          #5
          Wow, good luck! I suspect by the time your done building this bike your balls will be larger as well, maybe not Karl sized but hey. ;)

          Comment


            #6
            Well after visiting the bike builder I am saddened to report that due to the Bafangs gearing house being approx the chain line was never going to work. This was exacerbated by not being able to fit a chain wheel other than the mighty mini which has no offset. This only left one option and Mike the Master bike builder is going to go down the un-recommended path of altering a chin stay and taking 20mm off the bottom bracket on the drive side. It'll cost me around $300 NZ to do the alteration and it will be professionally done. On the plus side I won't need any offset crank arms afterwards which has saved me up to $190 NZ. The drive unti will set nicely n the middle where it should be and the crank arms will be equidistant on each side of center. He will also build two bushes one for each end of the bottom bracket to "bush" out the BB so the BBSHD axle is snug - my green sheath won't be needed anymore.
            This is hardly a "self build"anymore but it highlights two things. Do your homework before you buy a bike to convert and that some Fat Bikes are strange pieces of equipment with all sorts of weird and wonderful designs and sizes. If you read the article i mentioned in the above post it will highlight any potential pitfalls of any bike you may ne thinking of converting.

            Luckily for me I got the Surley for a bargain price and even with the costs of the alteration I still couldn't by a similar machine on today's NZ market with the same components. For any of you looking to convert a Fat Bile in NZ the only one I can see that will take a 20AH 52V Traiangle battery is the Reid Boss at $549 NZD from evolution cycles. Its low spec'd bike of course for that money but has disc brakes. I'll post some images of the finished beastie on here once its been blooded.

            Comment


              #7
              Hi Neilio, did you complete the ICT e-bike conversion? I have just bought a ICT hoping to convert to a mid-drive, I didn't do my homework on the BB size either! Would be great to hear how you got on with yours.

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