rim replacement option for Mavic?

Discussion in 'Cycling Equipment' started by dabac, Mar 25, 2010.

  1. dabac

    dabac Well-Known Member

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    Hi guys,
    I've got a Mavic ksyrium Elite rear with a badly busted rim, and is deb ating whether to bin it or to replace the rim.
    Replacement rims from Mavic are dangerously close to what a whole wheelset would cost 2nd hand, so I'm fishing around for options.

    I can get a rim for a shimano R500 front, for about a quarter of the cost of the Mavic. It's the same spoke count and current research indicates that the ERD is close enough to make it work. Question is: is it worth trying?

    The Shimano r500 wheelset use a 24H rear, with the Mavic hub I'd have to settle for a 20H rear.
     
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  2. tafi

    tafi Member

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    If you buy proprietary (factory built) wheels, this is what you are stuck with when things go wrong. You pretty much have to buy the factory spare parts.

    Trying to combine two different designs together could be asking for trouble. Usually a manufacturer will design their factory wheels so that there is almost no chance of interchange. They want you to buy their spare parts alone.

    I'd first be concerned about the nipples. The R500 appear standard enough in this respect, but Mavic don't seem so. The Mavic nipples look big and chunky in comparison. If the nipples and holes are not specified the same then it won't work.
    I know that the Ksyrium SLs had/have nipples which thread into the rim rather than onto the spokes. If this is also true of the Elites then there's no way it would work unless the Shimano system was the same (ie: precisely the same thread pitch and hole diameter)

    Aside from that, there is no way of getting different length mavic spokes to cope with any change in ERD. Normally you need to get within 2-3mm of the right length spoke so you have a decent range of tension adjustment and the ability to re-true later. It's unlikely that factory wheels will give you that much leeway.

    In short, you're walking straight into a mine field.
    Purchasing the Mavic part would probably save a lot of heartache.

    Otherwise, consider some hand built wheels with J bend spokes. Then you can chop and change rims, spokes and hubs to your heart's content.
     
  3. dabac

    dabac Well-Known Member

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    Right now, it looks doable. The stated ERD of the R500 rim is 593 mm, and the reach of the Mavic spokes are, best as I can measure it, 598 mm. They also have a longer-than-average threaded part, so if I switch to a generic nipple I should be able to hit the mark with margin to spare.

    Seeing the prices they run, I don't think they want to sell anything but wheelsets...

    The Elite use the same concept as Mavic UST rims. There's a "grommet" with a left hand thread that goes over the nipple and into the rim. The actual nipple looks pretty much like a regular nipple, although longer.

    They do come in a few different lengths, but certainly not as many increments as generic spokes.

    Besides, having to buy new spokes would pretty much trash the economy of the idea.

    As far as I can measure, I'm in the zone.

    I got these for free from a neighbour who was about to scrap them, and at that I couldn't turn them down. But sure, if it was my money from the start it would have gone to another design.

    I've got the geometry figured out as far as my measuring tape can take me, and it looks doable from that point.
    My main concern is if the 20H Shimano rim can take enough spoke tension to build up as a serviceable rear wheel laced to this hub.
     
  4. tafi

    tafi Member

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    The fact your neigbour was scapping them is evidence of this being a false economy in the first place. Put it this way, the Mavic part is the only way of being 100% certain you'll have a functioning wheel when you get to the other side of this.

    Then why are you asking:confused:?
    Are the nipple/spoke threads still 2mm standard?
    IF you have made your measurements correctly and IF the measurements actually match in the real world then it might go together.

    IF that all works then....

    The shimano rim is completely unproven in this application so this is the one question you probably won't get an answer to.

    If the sections of the front and rear Shimanos are the same then I would hazard a guess that they would have the same strength. You could guess that with 4 fewer spokes the wheel will need about 20% more spoke tension than standard. But this is an approximate guess.

    The reliability of your frankenstein wheel afterwards is also an unknown quantity.

    You won't get an answer from either company (for the reason I described in the above post and becasue they wouldn't want injuries on their conscience) and I don't know of anyone adventurous enough to try.

    It makes an interesting exercise, and you seem pretty set to go ahead but you really are on your own.

    Good luck and let us know how it goes.
     
  5. swampy1970

    swampy1970 Well-Known Member

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    The only question you need to ask is:

    Should you manage to build a 'hybrid' wheel of unproven parts and actually make it out onto the road, will this accomplishment help offset the feeling of your face grating along a rough asphalt country road when you're out of a cell service area and it's going dark.

    Have at it bucko.

    Personally, if you want to go custom building wheels stick to regular hubs and rims.
     
  6. vspa

    vspa Active Member

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    and the other question is from where do you get the ksyrium spare rim ?
    or for that matter any other specific spare part for factory-built wheels ?
     
  7. tafi

    tafi Member

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    Dealers all have spoke kits from Mavic to service these wheels. They also have access to other parts like rims. You just have to ask.
     
  8. vspa

    vspa Active Member

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    spokes yes
    haven't seen rims though
    i have factory built Mavic's myself
    as you said might be a good idea to ask in the store
     
  9. dabac

    dabac Well-Known Member

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    Because the 20H Shimano rim is supposedly for a front wheel, so I'm wondering if it is likely to hold up under the higher spoke tensions and loads it'd see when used as a rear wheel.
     
  10. dabac

    dabac Well-Known Member

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    Cyclecomponents - Skandinaviens största Internetbutik för cyklister can get me the Mavic rim, but at a decidedly enthusiasm-damping price. They can also provide spokes, nipples, hub bearings and whatnot.

    Bicycles | Bikes | Mountain Bikes | Road Bikes | MTB Bikes | Bike Parts | Bike Frames | Road Frames | MTB Frames has the Shimano R500 rim, at a quarter of the cost for the Mavic.
     
  11. alfeng

    alfeng Well-Known Member

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    FWIW. I don't know if it is a suitable rim, or not, but the ALEX EA38 (622-14) is available with various drillings ... as low as 16h ... so, I would presume the 20h drilling is strong enough that you should not have to worry about it collapsing if you were to lace it to the MAVIC Kysrium Elite hub.

    My recollection is that the Ksyrium Eclipse is laced with 14g spokes, so you probably don't have to use MAVIC's spoke nipples if you don't want to ...
     
  12. dabac

    dabac Well-Known Member

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    Well, I have looked into other rims as well, but 20H isn't that common. And with what's happened to shipping prices and customs I'm pretty much restricted to European stores if I want to beat the Mavic price.

    Right, threading is the same - I can use dead stock DT nipples.
     
  13. alfeng

    alfeng Well-Known Member

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    HMMmm ...

    FWIW. Considering I would be tensioning all the spokes on the front wheel at about 100Kgf (straight 14g, BTW) ...

    And, also about 100Kgf (again, straight 14g) on only the driveside of the rear wheel, I guess you could say that the front rim would be under more stress (though more evenly distributed) than the rear rim would be.

    Is the front rim more robust? Probably not.

    Is the rear rim less robust? Probably not, too.
     
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