Hey I'm a manager of a shop that services and sells road bikes 99% of the time so my mountain bike knowledge as related to equipment is especially limited and I would love whatever feedback or opinions you all have. I am building up a hardtail for my girlfriend and am in the process of choosing the details of my group and the chain ring option are blowing my mind. I understand how gearing works, I just don't know exactly what gearing is good for what situations.

The bike is going to be built for mostly singletrack trail riding. It won't be used for jumping or climbing mountains but it won't really be used for the wide-open XC style terrain either. What's a good combination with an 11-36 cassette? Is there a better cassette range to have? I've always just used whatever mountain bike I could get my hands on and was never sure what gear combinations I was using. The group is going to be Deore 10 speed. Also, what's the big difference between doubles and triples? With road, doubles are cleaner, lighter, and generally preferred plus the shifting always seems to be nicer. Is this pretty much the same with mountain components as well? Every triple I've ever ridden has been at the Acera/Claris level so I don't know how the mid to high end stuff behaves. The trend everywhere seems to be to use less chain rings thanks wide range cassettes but I'm not really concerned with the cool thing to do, I just want functional and I understand that there might be "no real right answer" I'm just looking to see what you all have to say. Thanks!

I have 3x9 with an 11/34 cassette 22/30/40 and while I have never used the highest gear even on pavement, I have used lowest gear on single track hills when I'm getting tired. 2x10 with 11/36 with 24/38 is the standard upgrade for my bike, but does not have quite the same overall low.. I actually like the overall wide range of the 3x9,, if I am riding on the hard pack or pavement I use mid and high range, when on single track I use mid and low range.

It depends on the legs and terrain it will be used on. Of the options I see for Deore (38/24, 38/26 and 40/28) I would go with 38/24.

I have used 2x10 with 39/26 and 38/24, not a night and day difference but the 38/24 is a bit easier on the legs. 40/28 is a race setup.

I haven't really used a triple in years. And when I did, the big ring was mostly a bashguard. Meaning, I never really used the big ring.

Go with a 38/24 double. The 38-11 is plenty of top-end speed, since the higher drag of MTB tires slow you down. The 24/36 is great for hills.

one thing that hasn't been asked and does make a bit of difference is, what size tires? 26, 27.5. 29, 27.5+,or 29+?

I started on a 29er Hard Tail with a 3x9 set up,,stripped it to a 1x9 pretty quick,, running a 32 ring up front and a 12x36 cassette.
Them big heavy 29er hoops,,,I just did not have the engines for that set up but I hated front derailleur's and all that noise..
sold it.
I move to a 25.5" wheeled full suspension,,wow,,now I could accelerate big time !!!
It started with a much better 3x9 SLX system,, and,, you guessed it ! stripped off all the front junk and for three months ran a 32 ring out front and a 11x34 cassette out back,,

Then came just what I needed,, the Newly updated Shimano Deore XT M 8000
I am now Running a Race Face Narrow wide 32 tooth chain ring up front,
(NO chain guard/keeper and I never drop a chain),,
and the 12X42 toothed 11 speed cassette out back,, Very affordable
shifter $75
Cassette $130
Derailleur $120, with the new user externally adjustable clutch !
Chain Is some new fancy super slick refuses to pick up dirt Shimano chain for $40..

Shifts perfect, I'm told It shifts just like the now over priced Sram X01 stuff,,you know,, the system with the
$350 Cassette,
the $350 Derailleur,,and so on,,,,

1x9's repeat so many gears so 27 is really what,,15 ?
2x10's are still noisy and still have some repeats right ?

Cleaned up my handle bars, dropped a pound of junk off the bike by loosing the front gear system,,,, Just sayin..

Right and I'm glad you said this because I forgot to mention it. It's a 26 frame with canti brakes but I'm taking it to work tomorrow to see if I can fit 27.5's in it. If so, then it looks like I'm going to have to build a set because I can't find a rim brake 27.5 wheelset from any of my distributors. Any ideas for that?

Not bad. Thanks for the input. I don't think I'm going to go 1x just because of the limitations. Some extra weight and some extra stuff is worth the extra gears. My girlfriend loves single track but is not a gear nerd like me at all so I just want her to be able to have the gears she wants when she needs it. She would gladly just stick with the 3x7 thats on the bike now but since I need to burn up some S-TEC discounts I am going to hook her up.

By the way, what made you decide to go 1x9 instead of just 2x9? I know it's the trend and all but before it was in magazines and at interbike I feel like nobody was doing it. It's funny how the world spent decades trying to get more gears and now all the sudden instead of make a 12 speed cassette they just made a long tooth chain ring haha.

I'll hijack...

Easy: no need for anything else. My old bike was a 3x9 and I NEVER used anything but the middle ring (unless you count using the big ring as a bash guard). Was planning on going 1x9 but my bike wasn't worth upgrading. New bike with 1x9 and I am not in need of anything else. I'll probably drop to a 28T ring for Christmas, as I'm in bad enough shape to want a little help on the bottom end. Ha. But that's more of a refinement thing, I think. And a mild tinkering addiction.

Understood. I have no experience with a 1x so it seems like that's the bulk of my skepticism. That and they all seem to be expensive because demand is high, but I haven't looked too hard.

People started going 1x for the same reason people started going 2x : cassettes are providing better range. When cassettes got to be 11-36 a 2x system became viable range-wise and 10spd meant the gaps weren't that bad. Front shifting is better with a double. People also started to realize that, for the most part, they didn't need the range a triple provides.

When SRAM came with the 10-42 11 speed cassette a 1x system became viable (a 30t paired with a 10-42 cassette gives you about the same range as a 39/26 with an 11-36 cassette) and you lose the front derailleur entirely. Now people have realized that they don't even need as much range as with a double.

Cost wise, I don't agree that demand for 1x is what is keeping prices high. Demand for 1x systems is the reason why SRAM started making lower end 1x parts.

Demand or not, the willingness to pay is what keeps the price up. I find it hard to believe an 11 speed cassette costs 2 times as much to produce as a 9 speed cassette. Seeing as my center ring is already 30 tooth, if I have not bought a new bike by the time the rear needs to be replaced I will probably go 11.. But I went 3x9 because I don't see occasionally having to shift the front worth the $600 more for the upgrade to 2x10 on my bike (and for that $600 all that was different was the 2x10 and a remote cable for the fork lockout) , let alone the $3000 more for the lowest price bike in the line that has 1x11 available.

also speaking of the ranges, I find it interesting that KTM is going with 3x10 and 2x11 setups.

I run 1x10 Shimano XT+Raceface crank on my MTB with a 32T chainring and 11-36 cassette. Works great for my needs and uses which is XC type riding. Theres no way I would run 1x on my road bike, but for a mountain but it makes sense and I think is the way to go. With larger range 10-42 cassettes its a no brainer.