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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

2400.0. "Cassette Cogs, who sells them?" by TEMPE::HUFFAKER () Fri Aug 28 1992 19:24

    I want to do some cog trade outs on my hyperglide-90 cassette but I
    cannot find anyone who sells individual cogs.  My local bike shops
    dont and I have tried performance,nashbar and rei.  Colorado Cyclist
    used to sell individual cogs but now they dont.  I hate to buy an
    entire cassette just to get one or two cogs.  Is anyone aware of a mail
    order company that sells cogs???
    
    Mike
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2400.1KEEP LOOKIN'WMOIS::GIROUARD_CMon Aug 31 1992 10:415
     That's strange...I can get Campy cogs and the That stuff is not easy
    to get (indivudally). Try some non-local bike shops, e.g. Gamache's,
    "let your fingers do the walking..." They should be available.
    
     Chip
2400.2PIPPER::GOODMon Aug 31 1992 12:185
    
    	Try Landry's in Westboro. I have purchased them there recently.
    They had what was needed in stock.
    
    	Roger
2400.3proceed with cautionTFH::REEDThu Sep 03 1992 18:299
    Are you sure that you would like individual cogs.  When I first started
    with hyperglide cassettes I beleived that I could mix and match my own
    combinations.  In reality the cogs are cut according to the cassette
    they are meant for.  Although some cogs are common to several cassettes
    many are unique.  For instance, the 15T cog on a 12-21 is not the same
    as the 15T on a 13-23 nor as on on a 13-26.
    
    					beware !
    					Ken
2400.4I can confirm for 7-spd.ODIXIE::RRODRIGUEZWhere's that Tour d' France thang?Thu Sep 03 1992 19:0511
2400.5LIKE NEW ENGLAND WEATHER...WMOIS::GIROUARD_CFri Sep 04 1992 10:206
     That's Shimano for ya... They rev stuff more often than DEC
    software!
    
     :-)
    
    
2400.6PIPPER::GOODFri Sep 04 1992 13:037
    
    	RE-1
    		I think that -2 is inaccurate. I don't see a problem
    swapping cogs on Shimano. If anyone needs help on this and you are
    near Marlboro MA send me mail. You need a couple of tools to do it.
    
    	Roger
2400.7I imagine 8-spd is the sameODIXIE::RRODRIGUEZWhere's that Tour d' France thang?Fri Sep 04 1992 13:3719
2400.8PIPPER::GOODFri Sep 04 1992 15:365
    
    	Are you referring to hyperglide casstettes? That may be the source
    of my confusion.
    
    	Roger
2400.9Wish I could draw a picture...ODIXIE::RRODRIGUEZWhere's that Tour d' France thang?Fri Sep 04 1992 17:3024
    Nope.  The regular twisty-tooth non-hyperglide that you slide
    down the freehub (except for the threaded one, of course).
    Unlike the loose, "add-on" spacers, the fifteen tooth's spacer
    is "notched" along the inside to help the whole thing "stay-put".
    
    These "notches" are facing the hub-side.  If you used a regular
    spacer and 15T, it would fall off.
    
                7 6 5 4 3-2 1  Note: 15T "hangs" over narrow end slightly;
                bbbbbbbbbb           a normal cog would be very unstable
                         bttt        because a fused spacer makes the cog
          <HUB           bttt        effectively wider.  
                         bttt
                bbbbbbbbbb                               c
                                                        c  cogs without
    b= Freewheel Body                                 ssc  spacers have
    t= Narrow threaded end                            ssc  a it added to
                                c=cog                 ssc  the opposite
                                                      ssc  side; except
                                s=spacer              ssc  for no.3 which
                                                        c  wouldn't need
                                                        c  one because of
                                                           no.2's (15T).
                         
2400.10keep hypergliding !TFH::HERBIE::REEDFri Sep 04 1992 19:1849
    I Have HG90 cassettes on my Ultegra 600 8 speed equipped bike.  On
    this freehub it does not have a step and the outermost cog is not
    threaded. The innermost 6 cogs are fastened together with three small
    diameter hex head machine screws with spacers between them.  The next
    two cogs have the spacer cast on to the cogs.  The whole assembly is
    fastened onto the freehub with a very thin threaded lock-ring.  I
    expect other cassettes are different.  But you were referring to HG90's
    I believe. I expect others are different.  When you purchase a cassette
    it's cog combinations are indicated by a letter appended to the part
    number.  A 12-21 is an S, a 13-23 is a T and a 13-26 is a V.  The cogs
    that comprise the cassette must have the letter in their part number.
    Although you the wrong cog will easily assemble to your freehub it will 
    degrade how well it shifts.  If you dissassemble two cassettes that
    have some cog sizes in common you will find that the teeth are shaped
    differently and/or oriented to the index tab differently.  The numbers
    stamped on the cogs indicate which cog they are suitable for.  A 14T
    cog on the 12-21 cog is 14T-s-u indicating that it is cut for the
    12-21 (s) or the 12-23 (u) cassette.  Inspecting a 14T on a 13-26 cassette
    reveals that it is marked 14T-t-v since it is used on the 13-23 (t) or
    the 13-26 (v) cassettes. 
    
    	The following table list the cogs that comprise 4 of the HG90
    cassettes
    S		T		U		V
    12-21	13-23		12-23		13-26
    -----	-----		-----		-----
    12T-s-u			12T-s-u
    13T-s-u	13T-t-v		13T-s-u		13T-t-v
    14T-s-u	14T-t-v		14T-s-u		14T-t-v
    15T-s	15T-t		15T-?		15T-v
    16T-s-t	16T-s-t				
    17T-s-t	17T-s-t		17T-u-v-w	17T-u-v-w
    19T-s	19T-t		19T-u-v-w	19T-u-v-w
    21T-s-t	21T-s-t		21T-?		21T-v-w
    		23T-t		23T-u-v-w	23T-u-v-w
    						26T-v
    
    I don't have the 'u' cassette so it's cogs are a conclusion on my part. 
    So, if one expects to convert a 12-21 cassette to a 13-23 you can
    expect to buy at least 2 cogs if you don't care about smooth shifting.
    One 14T since the 12-21 14T is clustered with 6 others and you need a
    slide on, and a 23T of course.  On the other hand if you would like to
    keep your hyperglide shift feel you will be buying 5 cogs.  A
    questionable frugality since a whole cassette can be had from Colorado
    Cyclist for about $28.
    
    					Best of Luck
    					 Ken
    		
2400.11some assembly requiredTFH::HERBIE::REEDFri Sep 04 1992 19:3915
    I may not have been clear how it assembles.  The 6 largest cogs are 
    fastened together by machine screws to form the 'cassette'.  This 
    assembly is not normally taken apart.  It is slid onto the freehub
    first.  Then each of the two smaller cogs are slide on ( with their
    integral spacers ). Then the locking ring is spun on and torqued down
    with the so called 'freewheel tool'.  
    
    Assembly requires a wrench ( adjustable 'crescent' will do ) and the
    'freewheel tool'.  Add a chain whip for holding the freewheel still for
    removing the cassette.  The whole thing takes about 5 minutes including
    removing and replacing the wheel from the bike.  This is great for
    changing the cassettes between hilly training rides and fast races.
    
    					Ken