Double crankset - what options

[brussel]

I am currently riding an xt crank on a 29er and I have a blackspire chain ring giving me a 26 38 combo which is perfect for my needs. The only issue is that the blackspire does not shift all that well. The little steel pins that help the upshift lose their edge and the shifting sux.

 

I have modified the pins and shifting is now better...but ultimately I need something more reliable. I race pretty seriously and I cannot have a drivetrain that does not accurately shift.

 

so what options:

x7 10 grams more than the x9 and about R600 cheaper

x9

X0 and XX are way outside my pricerange

the new 2012 XT only comes out in July and I have no idea on what pricing is going to be like

 

what else is there?

[Bat-ass]

is your current setup 9 speed or 10 speed?

[andretraut]

What are using at the back? I've got XTR 2 x 10 with 42/30 in the front and 11/36 at the back on my 29er. So far so good, will still see if I will be able to climb those steep hills.

 

Also look at the FSA Afterburner, read some good reviews.

[philip.maree]

What are using at the back? I've got XTR 2 x 10 with 42/30 in the front and 11/36 at the back on my 29er. So far so good, will still see if I will be able to climb those steep hills.

 

Also look at the FSA Afterburner, read some good reviews.

42/30 bliksem!

 

I am running 39/26 with 11/36 at the back. That sorts out 99.9% of steep climbs

[brussel]

running 9 speed but that makes no diffs on a crankset.

I run 34 on the back and where I ride I need 26 up front

[TitusTi]

The 9 vs 10 speed does make a difference up front, the spacing on the crankset side is slightly different.

I use the XTR 970 (with TA Specialites rings) and 960 to fulfill all my shifting needs, sometimes it's not great but it's mostly fine.

[brussel]

The spacing is minimally different..I have a mate (who because of stupidity) is using a 10 speed chain on a 9 speed setup

 

where do you get the TA rings?

[orbeaorca]

What i want to know is if I run 42/28 with a 11-36 cluster how many gears easy gears would i loose vs a triple crank? would 39/26 be better?

[brussel]

well look at it like this:

triple up front with a 32 on the back

lowest gears are:

22x32 gives 0.687

22x28 gives 0.785

22x24 gives 0.916

22x21 gives 1.047

 

with the double and a 36

28x36 gives 0.777

28x32 gives 0.875

28x28 gives 1.000

 

so effectively you will lose only one gear

 

my problem is that on on a 29er you have to add 10% because of the increased wheel diameter

so compared to a triple on a 26er you lose about 2.5 gears with a 28x36 combo as your lowest gear

 

personally I dont like a 36 as the gear ratio's are too broad, too much of a jump with each shift, I prefer 32 most.

[ichnusa]

Maybe this will help...

 

[orbeaorca]

do any one know if its possible to run x9 2x10 as 26\42?

[brussel]

should be able to.

shifting might suffer a bit.

sram also have a system where the chain can sit on both 26 and 39 tooth at same time making shifting very very good....you'll lose that with the 42