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11-28 cassette for RS compact double?

Last post 05-06-2009 8:23 PM by carhillclimb. 20 replies.
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  • 05-04-2009 1:26 PM In reply to

    Re: 11-28 cassette for RS compact double?

     You can change the intermediate sprockets of a cassette, by buying several of the less expensive Shimano cassettes.  The one caveat is if you want to remove the 12 t cog from an 11-xx shimano 10 speed cassette, you will need either an IRD cassette or a cycle dynamics 11 t cog (and cycle dynamics appears to be out of business).  The 11 t Shimano cog sits a little too close to the Shimano 13 to be guaranteed to work.

    I set up all my bikes (except the P3 and now P4 TT bike) with an 11-13 jump (these are downhill gears for me, and I have no need for close ratio gears going downhill).  10 speed cassettes with the 27 or 28 tooth large sprocket also jump from 13 to 15, - the 14 is deleted.  For me the 14 is either a downhill gear or a gear used on the fast lunch group rides.

    Cost?  You just spend between $5000 and $10000 on your bike and you will avoid getting the gears that will make the bike a true joy to ride because of a few extra dollars on cassette cogs?

     Yes you will HAVE to do this yourself, EVERY bike shop person I have talked to will not think of doing this.  (Yet they will freely recommend someone do a custom frame for $8k.)

    My preference for chainrings is 30-47, but that is extremely non-trivial.  I at least used to be able to pedal a 47-11 to 52 mph.   I am planning to move to 24-47 11-27 on one bike so it will be suitable for general New England riding and Mt Washington hillclimb with no gearing change.  Yes I could swap gears; that is not the goal here.

     

    Michael Wilson

  • 05-04-2009 4:02 PM In reply to

    Re: 11-28 cassette for RS compact double?

    carhillclimb:

        I am planning to move to 24-47 11-27 on one bike so it will be suitable for general New England riding and Mt Washington hillclimb with no gearing change.

     

    Michael Wilson

    Michael,

    How do you get a 27-47 chain ring onto a road bike (without going to a triple, I got Red so no triple for me, not easily anyways)?

    I'm going to do Mt. Washington this year and I'm thinking of putting a mountain bike crank on my bike with a 28 or 30 tooth single chain ring with a 11-28 cassette on my R3 SL as suggested to me by a bike mechanic.

    Paul
  • 05-04-2009 5:41 PM In reply to

    Re: 11-28 cassette for RS compact double?

    Small chainring crank options:

    1) Almost all road triples, both compact and 130 bcd, are 74 mm bcd inner ring, minimum size 24 t, chainrings available from Vuelta or Ta or Sugino.  Use one, 2 or 3 chainrings as desired.  Old square taper cranks allow fine-tuning of chainring position.

    2) Mountain bike cranks, as above.  I have a Clavicula set; it has a ridiculously long bb spindle so the chainline may be very hard to achieve.  Chainline and Q (frame centerline to pedal center distance) are the major issues here.  Square taper is your friend here.  I think the minimum is 22, but it might be 21.

    3) TA Carmina which have an interchangable spider, and a wide variety of available sprockets.  For example, 94-58 spiders are available.  Use the pedal washers if you use TA cranks.

    4) TA 5-pin from Velo-Orange - long spindle (117-124 mm) square taper 51 mm bolt circle, only go down to 26 tooth stock; harder to set up with just a single small ring; very narrow Q, will not take a modern triple front derailleur with the stock sprockets due to too little space between the large sprocket and the crank arm.  But the easiest way to get a double with almost any pair of chainrings 26 t or larger.  Use the pedal washers if you use TA cranks.

    5) 94-58 compact mountain cranks go down to a 20.  94-56 Suntour compact mountain cranks may go smaller yet, if you can find the parts. 

    Custom sprockets are in principle available from Highpath.net or Fibrelyte and possibly action-tec.us .  I have not searched for other sources recently.

    The first few hundred yards of Mt Washington are FLAT.

    The new XTR rear derailleurs (shadow??) are NOT compatible with road shifters unless you use a J-Tek pulley.  I know; that is what I did last year.  No he will probably NOT know what pulley to use.  I might be able to figure out what I did and tell you what you need.  I actually use campy shifters; the jtek pulley I was using for the Dura-Ace was not the same as the one needed for the XTR.

    For reference purposes:  I am 54, last year I did Mt Washington in 1:19:08 (or was it 1:19:13?) 30-47 chainrings, 15-34 cassette.  I never got off the saddle.  I used the 30-34 in about 5 places.  The younger and the faster you are, the taller the gears you can accept.

  • 05-05-2009 3:19 PM In reply to

    Re: 11-28 cassette for RS compact double?

    I realized that I did not answer the question.  All bikes listed are road bikes.

    For Mt Washington I used a 30-47 on a clavicula road compact - custom chainring and bolts on the Trek Madone SSL.

    I have a 26-46 on TA 5 pin with Campy 68-SS120Z bb axle on one the Dahon Allegro

    I have 30-46 on Ritchey 94-58 mountain compact cranks, not using the 58 bcd, on the 1972 Paramount.

    I have 24-39-50 ultegra triple crank shifted with a campy triple front derailleur on the 15 year old Centurion.

    Michael Wilson

  • 05-06-2009 12:54 PM In reply to

    Re: 11-28 cassette for RS compact double?

    Michael,

    Thanks for all gearing info!---I presently use a compact 34/50 and 11-28 cassette on my 2009 SRAM equipped RS.---This gearing is perfect for my "old" 66 year old body while climbing most of the high mountains here in Colorado.-----HOWEVER, I will be participating in the Mt. Evans Hill Climb (Idaho Springs Colorado) this July 18th, and want to gear much lower for this specific race of 27miles at 12-14% grades and finishing altitude of 14,500ft.

    I am looking for specific reccommendations for crank and cassette options which I can go to for this one race!---Any help from the "peanut Gallery" would be appreciated!----Or possibly a specific bike shop or individual who might have experience with these unusial gearing options!

    Thanks for any help!

    Bill

    Durango, Colorado

     

     

  • 05-06-2009 8:23 PM In reply to

    Re: 11-28 cassette for RS compact double?

    Short answer - put on road triple cranks with a 24 tooth sprocket (probably purchased by you over the internet from amazon or loosescrews or Peter White or some such).  Long answers follow:

    First you need to decide how low to go.  I figured that out by talking to people, analyzing what I had done and a test hillclimb at Mt Okemo VT a week before.  I realized that 1:1 was going to be used a lot, and would not be low enough for the 20-22 percent maximum grades on Mt Washington.  But I am not skilled enough to ride much lower than that without falling over either sideways or backwards.  New England is steeper but lower altitude and shorter distance than things like Mt Evans.  Mt Washington is 4600 feet elevation gain in 7.5 or so miles, Okemo is just about half that in distance and elevation.

    Second decide whether you are changing the cranks (and probably the chain and a good chance the front derailleur) or the cassette and rear derailleur (and probably the chain).  For some reason I chose the latter.  Thus I chose the 30 t chainring and the 34 t rear sprocket.

    If you are a campy rear derailleur person, changing to a triple crank with the 24 (or 26 or 28 or 30) inner sprocket and your choice of 0, 1 or 2 other sprockets is the way to go.  Front derailleurs will be interesting; they all expect a big ring; modern triples may not work well as a double; most modern doubles do not have a wide tooth count range.  The Ultegra 6600 front has a wide tooth count range; I am using that for the 26-46 on the Dahon and the 34-53 on the Cervelo P4 (yes I have some hills to climb on the way home from the time trial, and no energy left for high power).

    If you are a one-bike-to-rule-them-all-and-in-the-darkness-bind-them guy, then again I would work on the cranks (and the cassette) to get the low gear I needed without a rear sprocket over 28 or 29 teeth.  If you can tolerate triples (I cannot tolerate the way they shift) then you could simply get a compact triple or an IRD triplizer 36t compact sprocket (and larger chain capacity rear derailleur and triple front derailleur and probably chain) and be done.  Otherwise work on getting the smallest large ring you could use for downhill to allow more useable uphill gears on the big ring.

    If you really like your cranks (SRM for example) then large rear sprockets and a mountain rear derailleur is the plan.  IRD makes 10 speed shimano 11-30, 11-32 and 11-34 cassettes.  Mix and match probably works for this if you want to do gearing; I have not bought one and tried.  As previously mentioned the Shimano XTR Shadow derailleur does not shift properly with road shiftes and no ShiftMate.

    If you are a campy shifter person and want to use the wide-range rear cassettes anyway, (which is what I did) - use a Shimano mountain rear derailleur and a shiftmate.  That even works with the XTR Shadow if you choose the correct ShiftMate, which is not listed in his table - this is what I did.

    If you use a ShiftMate, then you are no longer restricted to 10 speed cassettes; any mountain cassette can be made to work with any road shifter and any mountain derailleur and the correct JTek ShiftMate pulley.  Speak to me if you do this; one of the pulleys for campy/campy interchange is the wrong ratio for the job he claims and I have the ratio tables somewhere.

    Once you use ShiftMate, then you also have the freedom to use action-tec.us Ti rear sprockets which he wants to be used for 9 speed applications (and you will not get 10 on the back with 10 speed spacing because there is no offset inner sprocket available until I get someone to make tooling).  He offers a 38 tooth rear sprocket; I do not know how they set up a rear derailleur for that.

    Non-gearing comment:  It is VERY useful to know the road well enough that you know exactly what is coming up at all times.  When the grade will be less, when it will be more.  Where the potholes are.  That was a significant advantage for me at Mt Okemo - it was the first official bicycle hillclimb there, but I knew the road cold from the car days.  For example, I saw someone stopped for a water break on a steep stretch a few hundred yards below a level patch.

     Michael Wilson

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