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Oversize crankset/chainwheels

Started by Risto Varanka · · Last activity · 11 posts · 945 views

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01 / Original postOversize crankset/chainwheelsRisto Varanka · 6 Apr 2003 02 / This pagePosts 1–11Page 1 of 1 · chronological order 03 / Latest replyPost #11Rorschandt · 10 Apr 2003

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Original section
Recumbent bicycles
Published
6 April 2003
Last activity
10 April 2003
Original author
Risto Varanka
Posts
11
Discussion status
Public discussion
Total views
945
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0
Topics
Front derailleursRear derailleurs

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  1. Original post
    Risto Varanka
    Archived post
    #1

    Suppose you want high performance from a 20" rear wheel. Logically you need at least 63 teeth
    chainring. Maybe more with a fairing. Suppose you are into sprinting and want to beat the national
    record or something 😉

    How can you go about getting one? Is best way to go to webstore and separately order custom and
    standarad parts and put together a crankset yourself? Or can I just take a standard Shimano roadset
    and change the largest chainring? At least on Shimano parts you have asymmetrically shaped teeth to
    make shifting work better. Would it work smooth even if you have right form factor etc? How about
    large jumps, like 39 teeth ring to 65 teeth ring. Can it work at all, would you need a MTB front
    derailleur? I think Challenge Taifun has something like this, and maybe RANS.

    --
    Risto Varanka | helsinki.fi~rvaranka varis at no spam please iki fi

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  2. Torben Scheel
    Archived post
    #2

    <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    Suppose you want high performance from a 20" rear wheel. Logically you need at least 63 teeth
    chainring. Maybe more with a fairing. Suppose you are into sprinting and want to beat the national
    record or something 😉

    An intermediate step-up drive could solve the problem rather elegantly :
    dalliegerad.comshark.htm

    I'd go with that.

    Regards, Torben

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  3. Dave Larrington
    Archived post
    #3

    Alligt in Eindhoven advertise big rings - the Challenge Taifun I was prodding at the races yesterday
    had an Alligt-inscribed 65.

    alligt.nlalligt.nl - Tandwielen.

    For much filthy lucre, Highpath in Wales will machine any size you want.

    argonet.co.ukeggs.htm

    Dave Larrington - legslarry.crosswinds.netlegslarry.crosswinds.net
    ===========================================================
    Editor - British Human Power Club Newsletter
    bhpc.org.ukbhpc.org.uk
    ===========================================================

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  4. Rorschandt
    Archived post
    #4

    For a bit more flexibility: pictures.care2.com733339897

    rorschandt

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  5. Joshua Goldberg
    Archived post
    #5

    U know everytime U time you park this, you'll have people asking more about the massive mid-drive
    than any other part of the trike. Apart from the added weight a Chromed Cowl over it might be cool
    for that Retro-Hog look especially if you do the frame in a purple Metal Flake (Hamster optional).
    ----------------------------------
    "rorschandt" <[email hidden]> wrote in message
    "]news:[email hidden]...

    Quoted message said:

    For a bit more flexibility: pictures.care2.com733339897

    rorschandt

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  6. Risto Varanka
    Archived post
    #6

    rorschandt <[email hidden]> wrote:
    : For a bit more flexibility: pictures.care2.com733339897

    With such close distance, I'd think there would be chainline problems? Could sacrifice some
    performance and durability 🙁

    Would work better if the other cassette was rotated 180 degrees lateral 🙂 But the derailleur would
    have to work in reverse. Hello Shimano, are you listening? ;p

    --
    Risto Varanka | helsinki.fi~rvaranka varis at no spam please iki fi

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  7. Rorschandt
    Archived post
    #7

    [email hidden] wrote in :"]news:[email hidden]:

    Quoted message said:

    rorschandt <[email hidden]> wrote:
    : For a bit more flexibility: pictures.care2.com733339897

    With such close distance, I'd think there would be chainline problems? Could sacrifice some
    performance and durability 🙁

    Would work better if the other cassette was rotated 180 degrees lateral 🙂 But the derailleur
    would have to work in reverse. Hello Shimano, are you listening? ;p

    The distance between cassettes is approximately that of an ordinary DF bike, so chain angles are no
    worse than for what it was designed. I'm sure there is some more friction because of TWO separate
    chain systems. Primarily, this was an engineering challenge for me, and I've managed to do it (~:
    Also, I placed the mid-drive shaft so that it doubles as the rear suspension pivot. This de-couples
    any pedalling action and suspension movement. It does nothing to neutralize the movement of
    mass(legs) from giving suspension movement, but that has been no problem so far.

    rorschandt

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  8. Risto Varanka
    Archived post
    #8

    rorschandt <[email hidden]> wrote:
    : The distance between cassettes is approximately that of an ordinary DF bike, so chain angles are
    : no worse than for what it was designed. I'm sure

    Would think rear cassettes are wider than front ringsets :-/ Also the most useful gears come from
    the most extreme chainlines.

    --
    Risto Varanka | helsinki.fi~rvaranka varis at no spam please iki fi

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  9. Rorschandt
    Archived post
    #9

    [email hidden] wrote in :"]news:[email hidden]:

    Quoted message said:

    rorschandt <[email hidden]> wrote:
    : The distance between cassettes is approximately that of an ordinary DF bike, so chain angles are
    : no worse than for what it was designed. I'm sure

    Would think rear cassettes are wider than front ringsets :-/ Also the most useful gears come from
    the most extreme chainlines.

    I think you may misunderstand how it works, as in the pics there are no chains.The front cassette is
    offset from the rear cassette,has a chainring on the back of it, which is connected by chain to the
    rear cassette. The front cassette is driven by a chain coming from the front of the trike. Each
    individual cassette and derailleur operates exactly as it would on a bike with only one cassette.
    Individual chainlines are as they would be on a bike with only one chainring. Check the website for
    new pictures. pictures.care2.com844656287

    rorschandt

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  10. David
    Archived post
    #10
    Quoted message said:

    I think you may misunderstand how it works, as in the pics there are no chains.The front cassette
    is offset from the rear cassette,has a chainring on the back of it, which is connected by chain to
    the rear cassette. The front cassette is driven by a chain coming from the front of the trike.
    Each individual cassette and derailleur operates exactly as it would on a bike with only one
    cassette. Individual chainlines are as they would be on a bike with only one chainring. Check the
    website for new pictures. pictures.care2.com844656287

    rorschandt

    This is very ingenious...I was having a bash at working out the gear range. I came up with (assuming
    2 x 11-32 cassettes and 2 x 22 drive rings, one on the boom and one on the back of the mid drive
    cassette) a range of 6" - 150". Is this correct? If it is, this is an excellnt way to solve the
    small drive wheel problem. The low gear will be very useful on a trike. How is the chainring
    attached to the back of the midrive cassette? Are you using two 9sp bar end shifters, I would be
    interested to know as I think I may be able to add a bolt on midrive myself...TIA David

    Report
  11. Rorschandt
    Archived post
    #11

    Subject: Re: Oversize crankset/chainwheels Newsgroups:
    newscache3.freenet.de:alt.rec.bicycles.recumbent To: David <[email hidden]>

    On 10 Apr 2003, you wrote in alt.rec.bicycles.recumbent:

    Quoted message said:
    Quoted message said:

    I think you may misunderstand how it works, as in the pics there are no chains.The front cassette
    is offset from the rear cassette,has a chainring on the back of it, which is connected by chain
    to the rear cassette. The front cassette is driven by a chain coming from the front of the trike.
    Each individual cassette and derailleur operates exactly as it would on a bike with only one
    cassette. Individual chainlines are as they would be on a bike with only one chainring. Check the
    website for new pictures. pictures.care2.com844656287

    rorschandt

    This is very ingenious...I was having a bash at working out the gear range. I came up with
    (assuming 2 x 11-32 cassettes and 2 x 22 drive rings, one on the boom and one on the back of the
    mid drive cassette) a range of 6" - 150". Is this correct? If it is, this is an excellnt way to
    solve the small drive wheel problem. The low gear will be very useful on a trike. How is the
    chainring attached to the back of the midrive cassette? Are you using two 9sp bar end shifters, I
    would be interested to know as I think I may be able to add a bolt on midrive myself...TIA David

    Hello, Yes, both units are 11-32.Try wisil.recumbents.comgearinches.asp I brazed a
    steel plate to the rear of a cassette body, and machined some inserts for the cassette body to
    accept some cartridge bearings. As I recall, the gear inch range is 14 to 123 or something like
    that. I'm using a 22th ring at the back and 34th at the crank. I could also use a front derailleur,
    total 3 shifters, a potential of 243 combinations!...The shifters used are a regular set of Shimano
    9spd bar-ends. The "left side shifter" will move a rear derailleur thru the complete range, it
    merely is not indexed. It is a bit confusing to shift at first because both shifters run the
    derailleurs identically. "Now I just shifted that one into the second smallest gear...wait, that was
    the OTHER derailleur..."

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