Hi ya' Monkey Boy...
Yep, I'm running a 2x9. I have a Race Face bash guard where the big ring used to be.
I adjusted the limit screw on the front der to where it wouldn't move past the middle ring.
Advantages:
- Don't have to worry about high centering and crunching your sprocket/chain on the rocks here in NJ.
- You can run a shorter cage dérailleur; a little more ground clearance for the dérailleur and crisper shifting. I'm running 36/24 w/11-34 and dropped to a medium cage. I could run a short cage with this setup if I was careful to keep off a few of gear combos. If I was running a 32/22 w/12-32, or so, I could certainly run a short cage.
- I've gained about 1.5cm of ground clearance with my 36T setup; you'd get even more if you went with a 32T setup (dunno' how much, another 3-4mm?)
Disadvantages:
- No big ring (duh!). Of course, this isn't a disadvantage if you never or rarely use your big ring. Though I didn't use my big ring much, I found that 32T was a little low for me as I was running some of the smaller cogs on the rear on the flats (I'm a masher, not a spinner). I decided to try a 36T to give me a little more gearing on the top end and straighten the chain line out a little more on the flats (picked up some good RF rings on fleabay for cheap). So far, I like it. Also by running the 36T, I only loose two gears on the high end (see chart). And by running 24T for the small gear, I only loose one on the low end. Granted, I loose some granularity in ratios...but I feel this is a so what.
- It might be a tad heavier; I didn't weigh 'em but it wouldn't surprise me if my bash guard is a little heavier than the 44T sprocket I took off. Plus, the 36/24 rings are probably heavier than the 32/22 rings I took off...but I'm sure we're talking weight weenie delta's here.
Here are the ratios comparing my 36/24 + 11-34 setup with my old 44/32/22 + 11-34 setup. The first nine rows are small ring, second nine middle ring, etc.
Code:
2x9 3x9
0.71 0.65
0.80 0.73
0.92 0.85
1.04 0.96
1.20 1.10
1.41 1.29
1.60 1.47
1.85 1.69
2.18 2.00
1.06 0.94
1.20 1.07
1.38 1.23
1.57 1.39
1.80 1.60
2.12 1.88
2.40 2.13
2.77 2.46
3.27 2.91
1.29
1.47
1.69
1.91
2.20
2.59
2.93
3.38
4.00