Most MTB cranks these days use a 4 bolt 104/64 bcd which won't allow for a 29 tooth middle chainring. The old compact 5 bolt 94/58 bcd would allow for the smaller 29t chainring in the middle position. As far as I know, only Middleburn still offers a spider in the old compact 5 bolt pattern. I'm sure there are some 5 bolt Race Face Turbine cranksets still floating around on E-Bay if you want something other than Middleburn.
Blackspire offers a 94/58 5-bolt BCD crank in Octalink form that can take a 29t middle, but you'll have to track down the 29t middle ring elsewhere (they do offer an unramped 30t 94bcd ring though, which would work in a 44/30 combo as you only really want the pins & ramps on the bigger ring)
Personally, I think a 38/24 or 36/22 combo makes much more sense for general riding. 44t is too big for most riding (unless you race XC and your local races don't throw in any really tough climbs)
I see Nashbar has an Ultegra Triple Octolink on sale for $75. It's a 30-42-52. Remove the big ring and replace with a cyclocross bash ring / chain retainer and you are good to go. I agree that 2x9 doesn't make much sense for weight savings, but if you can go with a road crank, then you can get a better Q-factor.
Personally, I think a 38/24 or 36/22 combo makes much more sense for general riding. 44t is too big for most riding (unless you race XC and your local races don't throw in any really tough climbs)
I am in this camp. You will only lose the 44 x 11, and 12 using a 38 "big ring" (also the 13 with a 36 which gets gained back a bit on my 29er.) I would guess that even strong riders end up with more of a need for a small ring with the 26-34 range of the cassette much more than a 44 with the 11 and 12.
Another option would be a 28 granny (truvativ makes them) and a 42 big in the middle position.
All these choices would end up easy to do with readily available current cranksets. Good Luck!
I am in this camp. You will only lose the 44 x 11, and 12 using a 38 "big ring" (also the 13 with a 36 which gets gained back a bit on my 29er.) I would guess that even strong riders end up with more of a need for a small ring with the 26-34 range of the cassette much more than a 44 with the 11 and 12.
Another option would be a 28 granny (truvativ makes them) and a 42 big in the middle position.
All these choices would end up easy to do with readily available current cranksets. Good Luck!
Depends of the bike, it's intended use and where you ride. A very light racing bike and a strong rider don't use a 22 front x 34 rear combo much. On my old hardtail, 23.5lbs, my lowest gearing was 24 x 27, never had the need for easier gears and it's not because I don't climb steep climbs... It has a lot to do with your pedalling style too. If you like to spin fast, 29/44 might not be for you, if you like powering taller gears though, no problems.
I had my All-Mountain FS bike setup with a 22/36/bash ring and I often missed the 44 ring, I broke the bash ring, put back the 32 and 44 rings and I'm happy again...
As for the 28 granny and a big ring in the middle position, that's a great idea. You must first check that your frame has enough clearance at the chainstay though.
For XC, I'm running a RF Next LP with 29/42 (FRM 29) and 11-34 rear in Marin, where there are plenty of long FR climbs. Like the smaller Q factor better. Not really much lighter or more clearance, but it's simple: climb = 29t (20-34 cogs), flat/descent = 42 ring (11-20 cogs). Not much overlap on gears.
Also, would probably prefer 12-34 as the 12-14-16-18 seem preferable to 11-13-15-17 on the smaller cogs (20-23-26-30-34 same on both).
N.B. - you may want to run a big ring without pins & a SRAM twister on the front to trim to avoid hitting the pins with this set up. Others have had success with spacers. Search prior posts.
29t not too common, but l found some FRMs.
I have a Phil BB and like it. If you can find a UN72 (or, a UN 73 in a pinch) those are fine. The Phil is way more expensive, but it's got a somewhat adjustable chainline. I have a 108mm length spindle.
I don't use a special front der; just an XT. That said, a twister for the front is nice because you can trim it.
29t not too common, but l found some FRMs.
I have a Phil BB and like it. If you can find a UN72 (or, a UN 73 in a pinch) those are fine. The Phil is way more expensive, but it's got a somewhat adjustable chainline. I have a 108mm length spindle.
I don't use a special front der; just an XT. That said, a twister for the front is nice because you can trim it.
Depends of the bike, it's intended use and where you ride. A very light racing bike and a strong rider don't use a 22 front x 34 rear combo much. On my old hardtail, 23.5lbs, my lowest gearing was 24 x 27, never had the need for easier gears and it's not because I don't climb steep climbs... It has a lot to do with your pedalling style too. If you like to spin fast, 29/44 might not be for you, if you like powering taller gears though, no problems.
I had my All-Mountain FS bike setup with a 22/36/bash ring and I often missed the 44 ring, I broke the bash ring, put back the 32 and 44 rings and I'm happy again...
As for the 28 granny and a big ring in the middle position, that's a great idea. You must first check that your frame has enough clearance at the chainstay though.
I am running a 24/36 right now and do not miss the 44 big ring at all on my 29ers. I suppose my gearing is similar to a 26/40 on a 26" bike which I wish I would have tried when I was riding my Sugar. I really like the 2x set up for mtbing now and always ran the standard triple on my Sugars.
There are 2 reasons I like a little smaller 24-26 small and 36-40 big ring than the std 29 or 30/44 2x set up . 1. Better gear selection in the small ring for tight techncal ST. In these types of trails my observations are that most riders are in too big of a gear to quickly get through those sections. They would benefit by having a gear allowing them to spin a bit more. 2. Very seldom are the 44 x 11,12,13 are used. I'd bet that a bigger end of the cassette is used much more even for strong riders.
#1 is the biggie for me it is not so much the climbing part that determines what is needed.
disclaimer: my observations are from riding just a bit better than mid-pack in sport series racing. Of course everyone elsed MMV.
I debated between the road-triple-with-the-outer-taken-off and the Middleburn Duo. Installed the Duo (29x44) a couple of weeks ago, and it's been all good thus far.
FSA is going to have a 2x9 version of their new top-end MTB crank; it'll have a 29t inner and, like the Duo, its own bolt pattern and spacing. It will be made of carbon, and it'll have outboard bearings.
The Duo uses a square-taper BB, and I'm very stoked to be back on a nice UN-72 again. It's smoother and less draggy-feeling than either of my modern, external-cup BBs.
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