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  1. #1
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    Compact double - less than 50-34?

    I am riding a compact double crankset with 50-34 chainrings, which seems to be the normal road replacement for a road triple. I have an 11-32 cassette in back. I live in a mountainous, and more importantly, a windy area, and find that the 34 is not low enough for uphill-into the wind climbs. Add any load to the bike, and considering I am a Clydesdale, I need a lower option. I rarely spin out the 50x11 or -12, or even -13, unless downhill. I spend most time in my 50, but usually in the middle or bigger cogs on my cassette. Loaded I will never be able to push existing gearing up hills into the wind, at least not without losing 50 pounds or adding an engine.

    I checked my gear inch charts and ran a few scenarios, and believe that a 48-32 or even 46-30 chainring set would serve me well and make better use of my smaller rear cogs. Is this a possible setup? I am using a SRAM Apex 50-34, and would like to just swap chainrings. But I am wondering if I will need new arms and bottom bracket, too. Any suggestions, experiences, or (dare I say) opinions out there? I see that SRAM offers a 42-28 mountain double, maybe that is an option? Thoughts?
    Last edited by tntmoriv; 06-01-14 at 09:32 AM. Reason: Forgot one thing

  2. #2
    coprolite fietsbob's Avatar
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    Probably have to work with the Inner 2/3 of a Mountain or other triple,

    as you cannot fit a chainring on, smaller than it's Bolt circle diameter ..


    Another option. shopping fans, White's Variable Bolt circle crank
    and Compass cycles Singer replica cranks and
    the old TA cyclo tourist ones, each have small bolt circles
    The VBC machines their outer chainrings with a slot in all 5 arms
    and has a custom machined bolt set to fit in that slot. Clever USA Manufacturing .

    Un roadie.. I use a Planetary Crank on my Brompton.. reduces a 50t chainring to act like it's a 20 tooth ..

    the crank arms rotate faster than the chainring ..
    Last edited by fietsbob; 06-01-14 at 12:13 PM.

  3. #3
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    Quote Originally Posted by tntmoriv View Post
    I am riding a compact double crankset with 50-34 chainrings, which seems to be the normal road replacement for a road triple...

    ... Thoughts?
    A compact double is a replacement for a road triple on a road bike, but not so much on a touring bike.
    Quote Originally Posted by gaucho777 View Post
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  4. #4
    coprolite fietsbob's Avatar
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    Any How I See people riding the Pacific Coast on compact doubles, still as the bikes came out of the carton, Touring, all summer long .



    Touring is the thing you Do, not the bike you have to own to even start.

  5. #5
    Have bike, will travel Barrettscv's Avatar
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    A super-compact double with a 46 and 30 is an option. Here are two sources;

    http://store.somafab.com/suoxcrarwcu.html


    http://store.velo-orange.com/index.p...kset-mkii.html
    Last edited by Barrettscv; 06-01-14 at 12:23 PM.
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  6. #6
    Senior Member bikemig's Avatar
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    sure it's possible. Here is one crank that will do the job: VO Polyvalent Crankset - Cranksets - Components

    A 46-30 is a smart choice for hilly terrain if not racing.

    TA copies are also good:

    Grand Cru 50.4 BCD Crankset MK II - Cranksets - Components

    The Sugino OX601D is expensive but you can really tweak the chain rings on this thing:

    Sugino OX601D Cranks Arms w/BB Cups

    I think I'd go for the 46-30 VO copy of a TA crank or get a triple.

  7. #7
    coprolite fietsbob's Avatar
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    NB: The Sugino OX601D is using unique outer rings as you see its pretty much like the middle ring on a triple .

    VO is accessing similar facilities, over there.. http://store.velo-orange.com/index.p...-crankset.html

    the shift details on the face of the chainring are on the same side as they machined out around the hole so the ring nut is Flush

    other, Standard Outer rings the shift aide features are on the Opposite side.



    Last edited by fietsbob; 06-01-14 at 01:08 PM.

  8. #8
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    Quote Originally Posted by tntmoriv View Post
    I checked my gear inch charts and ran a few scenarios, and believe that a 48-32 or even 46-30 chainring set would serve me well and make better use of my smaller rear cogs. Is this a possible setup? I am using a SRAM Apex 50-34, and would like to just swap chainrings. But I am wondering if I will need new arms and bottom bracket, too. Any suggestions, experiences, or (dare I say) opinions out there? I see that SRAM offers a 42-28 mountain double, maybe that is an option? Thoughts?
    Your compact crank probably has a 110mm BCD (Bolt Circle Diameter). In order to install replacement chainrings, you need to find rings with the same BCD and the same number of crank arms (5 for Apex?). I took a quick look through my favorite online vendors and didn't see anyone offering 5-bolt 110mm BCD chain rings in anything smaller than 34-teeth. Which probably means you're going to need a new crankset and possible a new bottom bracket to go along with it if you want chainrings smaller than 34 teeth.

  9. #9
    nun
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    Quote Originally Posted by sstorkel View Post
    Your compact crank probably has a 110mm BCD (Bolt Circle Diameter). In order to install replacement chainrings, you need to find rings with the same BCD and the same number of crank arms (5 for Apex?). I took a quick look through my favorite online vendors and didn't see anyone offering 5-bolt 110mm BCD chain rings in anything smaller than 34-teeth. Which probably means you're going to need a new crankset and possible a new bottom bracket to go along with it if you want chainrings smaller than 34 teeth.
    You can make a super compact double by just using the middle and inner rings of a triple. I've been riding 42/26 on a Sugino 110/74 triple for ages...it works well. There are also the mountain doubles which are good solutions. I just lowered the gearing on a bike I have with a compact double by replacing the outer ring so I have 46/34 and going to a 12/36 rear cassette. This give me a good range of 103" to 25"

    TA does a 33t ring for the 110 BCD but that's the smallest.

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