Rotor crank 30mm or 24mm axle (3D+ or 3D) what's better?

Discussion in 'Cycling Equipment' started by Doncantador, Mar 5, 2013.

  1. Doncantador

    Doncantador New Member

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    Anyone can address what stiffer and lighter between the 2? After all with rotor press fit caps you can use both on a frame with bb86 shell. What would you go for and why? Thanks
     
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  2. alienator

    alienator Well-Known Member

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    The 3D weights about 531g while the 3D+ weighs about 503, both without chain rings and BB bearings/cups. All things being equal, the 30mm axle on the 3D+ will make for a stiffer crankset than the 24mm axle on the 3D. Whether you would notice the difference is an entirely different matter. I've heard zero complaints about the stiffness of the 24mm axles in Campy and Shimano cranks.
     
  3. alienator

    alienator Well-Known Member

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    Please remove, mods. Somehow I got a double post.
     
  4. Doncantador

    Doncantador New Member

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    What you mean by saying "you heard zero complain on the 24 axle in Campy and Shimano"; I am interested to know about the Rotor cranks. So you saying basically that it doesn't really matter if I use for my BB86 shell's frame the 3D+ or the 3D both of them stiff while the 3D+ is little bit lighter?
     
  5. alfeng

    alfeng Well-Known Member

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    Sorry, but (based on your follow-up to alienator) is there a real question here?

    FYI. If your current bike already has a BB86 crankset, then there really is not any reason to change the crankset if you simply want to use ROTOR chainrings unless you are buying the actual crank, itself, for cosmetic reasons ...

    • NOTHING wrong with that, BTW

    Because 99% of us will probably never be capable of experiencing the mechanical advantage between spindle sizes of 24mm, 25mm, 30mm or almost anything else in a beneficial way, the practicality of the choice should be YOUR BUDGET ... now, and in the future ...

    So, if your current bike has a BB86 BB shell BUT does not have a BB86 crankset, then if you think that you may ever plan on selling the ROTOR crankset, then the crankset with the 24mm spindle is probably the better option since you will increase the potential number of buyers by a significant number ...

    BTW. Just to clarify a point, Campagnolo's Ultra Torque & Power Torque cranks use a 25mm spindle ...

    • BUT, having said that, in 99% of the Shimano/-compatible external BB cups, the bearings have a 25mm inner diameter but the plastic seal makes up the 1mm difference ...
    • there ARE some Shimano-compatible BB external BB cups which actually have bearings whose ID is the smaller 24mm
     
  6. alienator

    alienator Well-Known Member

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    What I'm saying is that it's unlikely you'd notice the difference in stiffness or in weight between the 3D and the 3D+. It's almost assured you won't see a performance difference. You're not likely to be disappointed by either, unless you're put off by their gaudy laser etched graphics.
     
  7. Doncantador

    Doncantador New Member

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    Alfeng I use currently the ultegra di2 with the ultegra 6700 crack. I mainly look to shift to Rotor because of A. Weight (will save about 200 grams) B aesthetics - my bike are black and white and the Rotor colour will fit the entire set up ( picture very soon will be posted) C I am curious to use something different and in this case the oval Q Rings option. I wanted to check regarding the two options of cranks (30 and 24 of Rotor) just to see if on the market people have any valuable experience and a preference for any of them, which I find that there isn't.
     
  8. alfeng

    alfeng Well-Known Member

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    Okay ...

    I look forward to seeing pics ...
     
  9. Doncantador

    Doncantador New Member

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    [​IMG] Ill post better one soon
     
  10. alienator

    alienator Well-Known Member

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    The head tube reminds of the head tubes on Principia's CF bikes and one other company's frames whose name I'm struggling to remember.
     
  11. Doncantador

    Doncantador New Member

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    Btw I wanted to ask if it is necessary to use an adapter of Rotor for their crank or I can use any adapter which fit my bb86 shell? I.e I am using now the adapter of Shimano inside my bottom bracket (86.5mm shell width on 41mm dimeter), that means I can't use neither the 24mm axle of Rotor nor the 30mm with this adapter?
     
  12. Doncantador

    Doncantador New Member

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    I'm am so happy with the ride of this bike, it is German company and the ride's feeling, the stiffness all is so perfect. I had Cento Uno, Scoot CR1 Pro, Felt F3, Felt F2. I found this bike the best ride.
     
  13. alienator

    alienator Well-Known Member

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    You won't be able to use the Rotor 3D+ on your bike because BB83 only accommodates a 24mm diameter BB axle, so that leaves you with using the 3D. I think you can use the Shimano bearings you have in place, but I reserve the right to be wrong on that point. I'm sure someone will chime in with a definitive answer.
     
  14. Doncantador

    Doncantador New Member

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    alienator You meant BB86 not 83. But anyhow I am a bit confused since my frame shell is what considered to be called BB86 isn't it? In order to use the Shimano I'm running right now, I need the Shimano press fit adapt which create 86.5 width with 41mm in dimeter. So what the case of the 4130 adapter that Rotor claims can make their 3D+ crank works with BB86 shell?
     
  15. alienator

    alienator Well-Known Member

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    BB83 and BB86 are used interchangeably. If Rotor says their 4130 adapter will allow the 3D+ to work with your BB, then you're golden. Note however that the bearings in that will be pretty small, so don't expect to get great life out of those bearings. You'd get much better bearing life by using the 3D crank set. As you might expect, you'll have higher bearing friction with the smaller bearings.
     
  16. Doncantador

    Doncantador New Member

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    Alienator I have just read a bit and saw that what is called BB83/86 is a patent of Scott/Shimao which takes 24mm spindle inside 86.5 wide shell and 41mm ID. so mine called either or BB83/86? You might be right, in this case a 30mm spindle crank won't fit? But if this is the case why Rotor advertise their adaptor for BB86 press fit they called 4130 (would this cover what also called BB83?)? It's clear it has the 41mm ID but can it be different shell width and not one that will go with 86.5mm? I assume the 30mm is the inner width of the bearing's dimeter, right?
     
  17. alfeng

    alfeng Well-Known Member

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    BTW. I think that the ROTOR chainrings may be problematical on a frame which has a braze-on mount for the front derailleur ...

    • I think the diameter of the ROTOR ring is effectively the same as for a ~60t chainring, +/- depending on the actual tooth count of the outer chainring ...

    So, before-you-buy, you may want to confirm that re-mounting your front derailleur at the necessarily higher point on your frame's seat tube is viable!!

    Of course, if you frame uses a clamp-on front derailleur, then never mind ...
     
  18. alienator

    alienator Well-Known Member

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    Any adapter will place the bearings in the correct position. 30mm would be the axle diameter and approximately the bearing inner diameter for the 3D+.
     
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