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What chainring for 11-46 rear in "east East Bay"?

  • 30

    Votes: 14 70.0%
  • 32

    Votes: 6 30.0%
  • 34

    Votes: 0 0.0%
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Discussion Starter · #1 · (Edited)
Thanks to a new job in the bike industry, wife approved N+1 and I'm building my first MTB in years. It's going to be more XC centric, frame is a 2015 Wheeler Falcon full suspension. Edit: It's a 29er.

Going with Shimano XT 1x11 drivetrain. Rear is going to be 11-46. I'll have 30, 32, and 34 chainrings, wondering which to put on. Hoping for locals' input/suggestions.

Majority of riding will be in Mitchell Canyon/Regency area of Mt. Diablo, and Black Diamond Mines. So some pretty steep stuff if I want to summit Diablo, etc, but a lot of rides won't be that extreme and will be just tooling around the flatter sections. Will also ride Morgan Territory, Redwood/JMP and some South Bay locations occasionally, and wherever NICA NorCal races are.
 

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Coming back after years is what I did, and I liked these combos:

30 - 11-46
34 - 11-51

36 - 11-51 (e-bike, would go 38 if I could, will swap for 12-50 cause I wanna try box9)

But my final settle point was:

30 - 9-46 cause I went XD when I rebuilt my rear wheel, and its awesome. 9 is so overkill I could drop to a 28 tooth ring. Which I would do except 30-46 is enough climb, and I think I would appreciate 30-9 rather than 28-9 when riding back down to the Rincon trailhead.

Caveat: I ride SouthBay only, nothing in the East Bay. Not sure exactly how similar our trails are.
 

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I live in Danville, and I like to climb. I prefer the 32 on my XC and also my 130 mm bike, and the lowest I go is 42 in any climb around Mt Diablo. With my son's Ripmo AF at 35 pounds with attached gear, it's so heavy and long, the 30 feels better.
 

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Discussion Starter · #5 ·
I don't have a climber's build, but that's what I like to do and most of the time I've been on a road bike for the last 6 years. Road gearing is 53/39 + 11-28, CX/Gravel gearing is 46/36 + 11-34. I can climb steep stuff on the CX bike, but it can get pretty brutal.

It seems like most people are on SRAM now and can go with 50+ in the back, but for now I'm invested in this Shimano groupset with the 11-46. Just curious what others with same cassette might run.

Thanks much, all!
 

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I don't have a climber's build, but that's what I like to do and most of the time I've been on a road bike for the last 6 years. Road gearing is 53/39 + 11-28, CX/Gravel gearing is 46/36 + 11-34. I can climb steep stuff on the CX bike, but it can get pretty brutal.

It seems like most people are on SRAM now and can go with 50+ in the back, but for now I'm invested in this Shimano groupset with the 11-46. Just curious what others with same cassette might run.

Thanks much, all!
For 1x11 I'd personally run a 30t up front. But I also only ride long travel bikes.
For you, I'd recommend 32t.
 

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Also consider that a 30t on a 29er will be similar to a 32t on a 27.5 or a 34t on a 26er, so you'll have to comment what tire size you have and take that into consideration when reading recommendations. Your fitness and riding goals also come into play.
 

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Discussion Starter · #9 ·
Oh, it's a 29er, it'll have 100mm travel front and rear. Not sure what the weight will be but it was originally an XC race type bike. I'll be running a little wider wheels/tires. 30mm tires and Maxxis Ardent Race 2.35".

I'll definitely start with the 30 or 32, and keep the 34 clean for if I ever sell the crankset/parts.
 

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Start with 34 chainring and see how you fare on the trails you want to tackle. You may be fit enough to not need the smaller gears. Also, its simple to go down to 32 and 30. You can always take off links on the chain. Adding links is not always easy.
 

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It only depends if you’ll have road sections you ride. 34-11/29er is completely pointless on any dirt sections. It’s only useful on road parts. Despite what some people like to believe they never need to pedal on dirt faster than 35 mph. I’d stick with the 30t. The tens of minutes youll be slogging in your lowest gear is more important than the 5 seconds you might want a higher gear for Each ride.
 

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If you actually have all of the chainrings, just try them all. Personally I would use the 30. I have XT 1x11 speed with the 11-46 cassette on a 29er and I have a 28t ring. I spin out on fast downhills (this happens only on the road) at 23 mph or so, and I'm content to coast at that point. I went with 28/46 to match the 22/36 that I was used to with 2x and 3x ten speed bikes I've had. I could live with a 30t if I had to. I don't ride in the east bay but I do encounter some steep hills, e.g. 0.6 mi with average 9.6% gradient--some sections quite a bit steeper--where I trade off between the 46 and the 37.
 

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Asking what size chainring to run is almost like asking what color shirt to wear. It is a function of fitness, preferred cadence, and terrain. Just to give an example. As a nearly 50yo decent shape rider (can climb about 1500 feet an hour, comfortable up to 3,000 foot climb rides), I regularly use my 30/50 combo on the steep climbs in Briones. On my trail bike, I use a 30/52 and need it in Tahoe when climbing at 8,000+ feet. My buddy has an 18 year nephew that is a competitive swimmer. We have him on a 34t front, 11-36 cassette and he virtually never uses the 36t. The kid can leave my buddy's house on the Concord/Clayton border and ride to the top of Mt. Diablo on the trails in less than 1.5 hours. When it gets steep, he just stands and pounds out the climb (I blow up if I try and do that, so sit and grind away).

You have all three. Pick one, try it and go from there.
 

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Discussion Starter · #19 ·
Forgot about Briones (maybe on purpose), will have to go there when the rig is done, too. I understand the frustration some people have with questions like this, but appreciate all the feedback which has been very helpful.
 
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