24T Chainring for XX Cranks???

Discuss light weight issues concerning mountain bikes & parts.

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rouleur1
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Joined: Tue Jun 13, 2006 1:04 am

by rouleur1

I've been looking for a 24T chainring as an option for my XX 2x10 set up. Currently running a 39/26T front chainrings. Anyone know of aftermarket suppliers that fit the XX BCD pattern? Are these even available in cranks other than OEM offering from Specialized and Cannondale? Thanks!

PS For that matter, I can't seem to find exactly what the BCD is for the XX small ring. NOT LISTED anywhere on SRAM/TruVativ website...

by Weenie


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stephen@fibre-lyte
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by stephen@fibre-lyte

I think the XX is 120/80 bcd

boots2000
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by boots2000

24 is too small for that bolt pattern.
Apparently Mattias Hellore can make a 25 tooth. I paid him for one and waited 6 months- he never delivered.
Finally I had to ask for a refund.
FWIW I use a Rotor 3D+ with 74/110 bolt circle and run 24/38 TA rings.


tompho
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by tompho

25 is the smaller you will find.

crohnsy
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Location: Canada

by crohnsy

Your best bet if you need a 24 would be to get a X.0 AM double 24/38 or 22/36

http://www.sram.com/truvativ/products/truvativ-x0-10-speed-crankset#/path/term-id/267

sstefanov
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by sstefanov

+1 on the X.0 crankset, but with spiderless rings from FRM. You can even go down to 22/36. I am running this combo since 3 months and it is lighter than XX, (around 680 grams, including the GXP bb) and shifts flawlessly.

The English version of the FRM site seems down, so here is the FRM 36T NS ring this one:
http://r2-bike.com/FRM-Kettenblatt-XGlide-NS-36.

Stefan

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Mattias Hellöre
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by Mattias Hellöre

24T on a XX is no go as it will not be above the chainring bolt holes.

By the way EP has stopped producing chainrings, of some causes, one of them is unreliable supply of titanium chainring and cutting quotes, often end up zero profit or negative.
The other stuff is intact as it´s made in house.
Experimental Prototype

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stephen@fibre-lyte
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by stephen@fibre-lyte

Agreed, 24 on to an 80bcd won't go. 25 will.

Matti
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by Matti

sstefanov wrote:+1 on the X.0 crankset, but with spiderless rings from FRM. You can even go down to 22/36. I am running this combo since 3 months and it is lighter than XX, (around 680 grams, including the GXP bb) and shifts flawlessly.

The English version of the FRM site seems down, so here is the FRM 36T NS ring this one:
http://r2-bike.com/FRM-Kettenblatt-XGlide-NS-36" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;.

Stefan


What is the BCD for attaching the 24 ring on the 36?

sstefanov
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by sstefanov

Matti wrote:
What is the BCD for attaching the 24 ring on the 36?


64mm

Stefan

UpFromOne
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by UpFromOne

Older SRAM XOs have a 104/64 spider (i think) that can fit 24 rings, but that would be getting a whole new crankset. And I think the X.O is a 167 Q Factor, wider than the 156 XX (unless you already have that width on your XX).

EDIT 10/26: I just ordered one of those ti 25t rings from r2bikes. If that won't do it, then a whole 'nother crank is in order.
FWIW, the difference between 25 & 24 rings with a 36t cog is about 3% in the gear-inch difference with a 29er.

VMac
Posts: 12
Joined: Sun Mar 08, 2009 5:40 am

by VMac

UpFromOne wrote:
EDIT 10/26: I just ordered one of those ti 25t rings from r2bikes. If that won't do it, then a whole 'nother crank is in order.
FWIW, the difference between 25 & 24 rings with a 36t cog is about 3% in the gear-inch difference with a 29er.


UFO, any update? Did this arrive?

by Weenie


UpFromOne
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by UpFromOne

Oh hey, sorry i forgot about this thread, yes the 25t arrived (seattle) and bolted right on to the XX spider (80BCD).
Works great, and yes there's a difference from the stock 26t. Enough where I'm not worrying about a 24t and a whole new crank anymore.

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