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  1. #1
    A little of everything
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    Close ups of aluminium cassettes...nice

    Check this out, more pictures here: http://terrengsykkel.no/?1235

    The text says they will be riding it on their trails in Norway. This is a country where it rains 200 days a year, so lets see how long it lasts. They says to stay tuned for the massacre. I'll let you know how it goes


  2. #2
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    I have an NOS "Real" cnc-aluminum cogset that is a work of art! It weighs like a feather, but lasts like one, too (I've used one).

  3. #3
    Max
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    although i'm a fan of WWism, i really cant recommend alloy cassettes, esp. for racing. they are light, but i would sacrifice weight for shifting performance. although there are some cassettes that really perform well on the workstand, they fail in real life hardcore riding with shifting under pressure and condition you usually face in races
    for pure weight savings ok, this cassettes will let you down in a race any day :-(


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  4. #4
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    What a boat anchor.. Hardly optimized for wieght. If you see my illustration, you'll note that thos areas scribbled over in red offer nothing in strength, so they very well should be machined off. For shame......
    Last edited by Ultra Magnus; 07-29-2009 at 10:09 AM.
    "I've come to believe that common sense is not that common" - Matt Timmerman

  5. #5
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    It was a joke... I'm sorry you missed it.

    I could do an FEA, but I really don't have the time to model that part right now. It would take a while. At least a couple of hours, and it would probably help to have a part in hand, of which to reverse engineer and make a model. Maybe I could model up a simplified example to illustrate the point, but then you'd argue something about the inaccuracy of the comparison of my part to the actual cassette..
    "I've come to believe that common sense is not that common" - Matt Timmerman

  6. #6
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    Wink

    Quote Originally Posted by bmadau
    It was a joke... I'm sorry you missed it.

    I could do an FEA, but I really don't have the time to model that part right now. It would take a while. At least a couple of hours, and it would probably help to have a part in hand, of which to reverse engineer and make a model. Maybe I could model up a simplified example to illustrate the point, but then you'd argue something about the inaccuracy of the comparison of my part to the actual cassette..
    So, you're saying that's an actual cassette, huh? Like we're supposed to believe that.

  7. #7
    POG
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    Not only that, but where are the holes?

    Major weight could be saved with a drill bit! They are clearly not serious about weight reduction.

    Quote Originally Posted by bmadau
    What a boat anchor.. Hardly optimized for wieght. If you see my illustration, you'll note that thos areas scribbled over in red offer nothing in strength, so they very well should be machined off. For shame......

  8. #8
    jonny_mac
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    i would like

    to see you model that in CAD in a couple of hrs. i work with UG and a cassette
    is way more than a "couple of hrs"

  9. #9
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    To draw it in CAD wouldnt be too bad. You could just draw the largest cog and copy m any of the parts from it for the other ones. The teeth could also be copied from one cog to another and arrayed around each individual cog. You guys get what I'm saying? Doesn't sound like more than a couple of hours of work to me, but maybe I'm wrong.

  10. #10
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    Hmmmm.. I feel challenged. Back when I was using Inventor I would enter "honor system" modeling competitions and always finished in the top 5 (in the Inventor usesr group on autodesks website). I'm not anywhere as fast in Solidworks (I HATE SW, passionatley, but moreso do I hate CAMWorks!!!!! POS), but now I'm curious just to see how long it would take. I've modeled Spur gears and sprokets before, but never a cassette. I've got a spur gear model I part on cbliss.com. It's not a 100% accurate spur gear. I used arcs instead of involute splines, but at the point the arc intersects the pitch diameter of the gear, the tangent is at the correct pressure angle for the gear.

    http://cbliss.com/inventor/Parts/PowerTransmission/
    "I've come to believe that common sense is not that common" - Matt Timmerman

  11. #11
    A little of everything
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    Here you go bmadau...

    Couldn't resist either. It's in SolidWorks 2004, but I don't have the stress software, but I can upload it to my site and give you a link, then you can do it. It took about 2Ĺ hours and it's about 3.2MB
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  12. #12
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    I'm impressed. That's pretty good. I also have SW2004. I have to ask, did yours come wiht cosmos express? Our install did. It's a little cheesy, and very limited, but it works for simple problems. Check your tools menu, should be somewhere near the top...

    If you don't have it, maybe you could email it to me. I'll PM you with my email address.
    "I've come to believe that common sense is not that common" - Matt Timmerman

  13. #13
    A little of everything
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    Thanks...

    I found the Cosmos tool. Didn't know it was there and very easy to use, but a limited as you said. Here is the stress test. I have put 100N on 6-7 teeth, but I don't think it says anything about it, only if something wa terrible wrong.
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  14. #14
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    Well, it shows that that little piece of material I suggested be lopped off doesn't carry a whole lot of load (if any at all).. Looks like you applied your load to the 2nd largest cog?

    (None of use here at work knew it was there either until one day I was bored and started clicking buttons I'd never used before to see what they did....seredipity baby!)

    BTW, in the first dialog box, there's a box for options and you can change the units to english if you so desire. Newtons mean nothing to me, I have to convert to lbf every time, same with pascals.... I've become relatively fluent with metric units of measure, but that's a far as it goes.. Oh, and grams to lbs. As a WW, you gotta know that!
    "I've come to believe that common sense is not that common" - Matt Timmerman

  15. #15
    A little of everything
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    Yes it was the 2nd one. I'm in the metric mode, as I'm living in Denmark. The only problem I have regarding this is regaring people post their heights. I'm lost there.

  16. #16
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    problem with this is you're forgetting the stress on the inside where the cassette touches the hub cassette body.

  17. #17
    A little of everything
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    I'm not following you. This is the static point, where it is attached. The weight is 154g by the way. It's a 11-34 cassette.

  18. #18
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    Either way, that wasn't the point of this excersize. It was to determine whether or not load is carried by the material described in an earlier post. Also, when doeing FEA, it's good to isolate the one part or feature of a part that is in question. All computes much faster that way, and to accurately FEA the whole hub interface, you'd need to model the freewheel body, and the splines on the ID of the cassette, and test it in an assembly. Cosmos exrepress doesn't do assemblies and it only does simple "rigid" restraints (which I hate because it is not accurate, nothing is rigid), linear forces and pressures.
    "I've come to believe that common sense is not that common" - Matt Timmerman

  19. #19
    nightriding is fun !
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    Quote Originally Posted by Anders
    Check this out, more pictures here: http://terrengsykkel.no/?1235

    The text says they will be riding it on their trails in Norway. This is a country where it rains 200 days a year, so lets see how long it lasts. They says to stay tuned for the massacre. I'll let you know how it goes

    Looks nice indeed but I want to see that same cassette when it has a 1000 hard K's on the counter. I think the teeth will be badly worn by then
    Titanium or Bust !

  20. #20
    Boj
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    I'm currently riding one of those cassettes and when it gets worn badly (which shouldn't take too long) I think I'm going to spring for a dura ace.

    I only have 3 rides on mine and recently I disassembled the bike and noticed cassette has already worn. I can see multitude of wear spots on all the teeth shining through the anodizing and, low and behold, a tooth has broken off on a 15t cog. Granted there was lots of climbing on those 3 rides but this was not racing.

    If it was just for the wear I could live with it but I don't want my cassette breaking up spectacularly. That's why I'm kind of reserved taking this cassette to a race as I shift 10 times harder under power in a race than JRA. Still will see how it goes nonetheless.


    I forgot to add, shifting is actually pretty good on mine and it gets ridden on dry trails only.
    If in doubt - pedal harder!!!

  21. #21
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    Pardon my lack of materials knowledge, I was a math major

    why can't they coat or plate an aluminum cassette like this to increase wear resistance?
    Also I do think the stress from the hub body will come into effect, its where the frictional force from the ground/tire relationship will be pushing against the force from the chain, no? So wouldnt you have to specify that in cosmos? Like I said I'm no engineer but I've fooled around with solidworks and I seem to remember something about equal and oposite forces. The chain has to have something to pull against on the cassette.

  22. #22
    Max
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    they do "coat" the cassettes: AFAIK they are all hard-anodized. just like chainrings. but as soon as that coating is worn off, the cogs will be eaten away with a glance


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