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  1. #1
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    Large Spoke Holes - Special Spokes Needed?

    Hi There,

    I recently purchased a SRAM Automatix 2 Speed Hub.

    I want to use it with a SUN CR18 rim, to build a wheel for my around town MTB.

    The SRAM hub has really large spoke holes, they seem like they are about 3 mm or maybe slightly more in diameter. Will this cause an issue if I build the wheel with spokes with regular sized heads?

    When I say regular, I am using the spokes I used for the front wheel as a basis for comparison. This is a CR18 Rim / Deore Front hub combo, with some wheelsmith double butted spokes. When I thread pokes I have left over from this wheel, through the SRAM hub, they do catch inside the spoke holes in the SRAM-flange, it just seems like there might be a lot of pressure put onto directly onto the spoke-heads.

    Any thoughts or recommendations on spokes would be helpful. I'm not sure if this is a problem or not - don't have the experience to know.

    Thanks.

  2. #2
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    If the head is long enough on the spoke,put spoke washers on them.....
    Everything should be as simple as possible...But not more so.---Albert Einstein

  3. #3
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    Thanks - sounds good - will try it.

  4. #4
    Senior Member mrrabbit's Avatar
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    1. Try at least to not go more than one guage lower than the hole itself. I.e., it the hole is for 2.34, try not to go less than 2.0.
    2. If you experience excessive elbow lean + non-flush head seating...seriously consider using spoke head washers as suggested above.

    The more you can get the spokes to "hug" the flange on the way to the rim - the better.

    =8-)
    4000+ wheels built since 1984...

    Disclaimer:

    1. I do not claim to be an expert in bicycle mechanics despite my experience.
    2. I like anyone will comment in other areas.
    3. I do not own the preexisting concepts of DISH and ERD.
    4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
    5. My all time favorite book is:

    Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life

  5. #5
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    If the spoke hole itself is actually "3mm or larger," I'd probably be looking for an alternative hub. Maybe you have a "normal" spoke hole diameter, but with an overly deep countersink? Your only choice is to use spoke washers, to ensure- as mrrabbit says, the spokes "hug" the flange. I'd probably take a pass on this hub unless it has really thick flanges.

  6. #6
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    Hi All,

    Finished the wheel and got a question about it - I can't Private Message yet, so I thought I would post an update:

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    Q: SRAM Automatix Hub - Did you ever build your wheel with the SRAM Automatix hub? If so, what sizes did you use for your front chainring and your rear sprocket? Has the hub worked well for you? - Thanks!

    A: Yes I did - thanks for asking - it works well.

    The rear sprocket that came with the SRAM Hub is a 19 tooth, which I am using.

    There is a triple ring in the front, 48-38-30, and a rear derailleur in back to keep the tension on.

    I live in Pittsburgh, so there is a lot of up and down hill riding, the 30 is good for moderate up-hill to stand-up riding. The 38 is good for general city riding and brief moments of stand-up riding. There is a long flat section of my commute to work, and I tend to use the 48 for that, but it also has a slightly downward grade....coming back I stick with the 38.

    If I had to have just 1 front ring, I think I would go with something like a 38 or 40 tooth ring...2 reasons for this - 1 - I like easy pedaling and 2 - with a larger sprocket, like the 48, the wheel gets up to speed and shifts very quickly, so the first gear is shifted through almost immediately.

    My wheel is 26" so that probably effects things somehow.

    Someone had a post somewhere that said there was a way to adjust when the hub up-shifts. If I could control this, I would like to adjust it to up-shift at a higher rotation speed. Right now, if I use the 48 ring, it tends to upshift almost immediately, as the wheel is spinning so quickly...the 2 speeds are more distinct with the 38 ring. With a bigger ring, it is almost like a 1 speed hub.

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    In case anyone is interested in doing a similar build, along with the SRAM Automatix hub, the wheel was built using a 36 spoke, Sun-CR 18 Rim (559mm), 256 mm length straight guage spokes (2mm), and I did use spoke washers, as Booger suggested. I probably could have skipped the washers, but they look really cool, and made me feel comfortable putting a lot of tension on the wheel, which does have large spoke holes.

  7. #7
    Saving gas on my commute Scooby214's Avatar
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    Thanks for answering my questions! I was looking at using a 38t front chain ring. I am deciding whether to go the simple route and use this hub, or go with one of the new 5 speed Sturmey Archer drum brake hubs.

    I will also be using a Sun CR-18 rim, though mine will be a 700c wheel. My commute is relatively flat. I am currently using a Shimano Nexus 3. Based on my commute, the 38x19 gearing should work well with the Automatix for my small hills.

  8. #8
    Senior Member mrrabbit's Avatar
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    What size were the hole on the hub you used...

    2.8mm or 3.0mm?

    =8-)
    4000+ wheels built since 1984...

    Disclaimer:

    1. I do not claim to be an expert in bicycle mechanics despite my experience.
    2. I like anyone will comment in other areas.
    3. I do not own the preexisting concepts of DISH and ERD.
    4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
    5. My all time favorite book is:

    Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life

  9. #9
    Senior Member mrrabbit's Avatar
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    God I hate my computer...

    =8-(
    4000+ wheels built since 1984...

    Disclaimer:

    1. I do not claim to be an expert in bicycle mechanics despite my experience.
    2. I like anyone will comment in other areas.
    3. I do not own the preexisting concepts of DISH and ERD.
    4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
    5. My all time favorite book is:

    Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life

  10. #10
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    I measure 3 mm, maybe plus a little more. Other folks could still post about this though, I do not have a spec sheet.

  11. #11
    Senior Member Bill Kapaun's Avatar
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  12. #12
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    Quote Originally Posted by mrrabbit View Post
    What size were the hole on the hub you used...

    2.8mm or 3.0mm?

    =8-)
    How would a person measure this on a flange?
    Nobody slower, and nobody lovin' it more...

  13. #13
    AEO
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    Quote Originally Posted by Rubato View Post
    How would a person measure this on a flange?
    mitsutoyo or vernier calipers.
    Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
    http://sanfrancisco.ibtimes.com/arti...ger-photos.htm

  14. #14
    Senior Member mrrabbit's Avatar
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    As AEO noted, calipers. Most are double sided...one side does outside, the smaller alternate side does inside. Quality steel ones will usually be just small enough that you can measure holes as small as 2mm.

    The reason I asked earlier is that while I do recommend the use of spoke head washers for thin flanges - spoke head washers however are not really hole fillers. They're head spacers...you can get away with them in most cases with holes drilled for 2.34mm and even holes tightly drilled for 2.6mm spokes in some cases - but as mentioned earlier if you are working with 2.8mm and 3.0mm holes, perhaps a different hub or same hub drilled smaller is really called for?

    =8-)
    4000+ wheels built since 1984...

    Disclaimer:

    1. I do not claim to be an expert in bicycle mechanics despite my experience.
    2. I like anyone will comment in other areas.
    3. I do not own the preexisting concepts of DISH and ERD.
    4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
    5. My all time favorite book is:

    Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life

  15. #15
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    Thanks. I never would have thought it possible to be that precise. I just measured a couple of hubs for both inside and outside spokes and they are consistent. I'll have to start tightening my working tolerances.
    Nobody slower, and nobody lovin' it more...

  16. #16
    Charles Ramsey
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    I'm surprised they are that large. Shimano used 2.6mm spoke holes and they work with 1.8mm 2.0mm and 2.3mm spokes not 2.6mm I have tried it. Assuming they are 3mm then you should use 2.2mm 2.3mm or 2.6mm spokes. Sapim and wheelsmith make 2.3mm spokes at the elbow and 14 gauge at the nipple. Pillar makes 2.2mm spokes at the elbow and 14 gauge at the nipple. They also make 2.5mm at the elbow and 14 gauge at the nipple but these are not available in the US. If you want to use the fat spokes ignore this forum and get on the ones that deal with motorized bicycles. Stainless steel spokes can be bought in 13 and 12 gauges you may need to enlarge the holes at the rim.

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