Seems counterintuitive as MTB seems to need much wider gear range than road, yet many MTB'ers are going to 1X10, so what's the deal?

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A couple of thoughts.

MTB's in general use don't tend to need the same top end gear? I guess one could argue that most roadies don't either.

MTBers don't tend to mind large gearing gaps as much whereas roadies do?

i've often thought that a single chainring would work great for me... where i ride, i rarely ever drop down from the big ring, even on climbs.

a 1x10 sram setup with wifli cassette surely cannot be too far away.

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Terrain is so different, I know guys who do singlespeed MTB and others who do triple road (in different countries). All those setups and everything in between has their place.

That said my 1x10 build is forthcoming ...

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I've gone 1x10 on my Pitch, but that's mainly to gain a shedload of ground clearance as it only needs to run a 32t ring, anything faster and it's time to stop pedaling and start pumping for extra speed.

My XC bikes would be 2x10 though to keep the gearing range wide enough for flatter courses.

I've got a singlespeed MTB too, difficult to compare it to geared bikes as it's not intended to be ideal, it always makes climbs almost unbearable, and always spins out on gentle downhills, it's like that for the simplicity of there being nothing to break or go wrong or wear out, and a bit of masochist training. I can't remember the last time I wore out a road drivetrain quick enough to worry about it, or had a ride ending drivetrain mechanical on the road. I get through a rear mech once a month on the moutainbikes!

I can't see 1x10 working on the road, there's no reason to ever stop pedaling, unlike MTB where above arround 36-11 you're either working the terrain for more speed or riding a really dull crap course.

I think as a truck driver I can relate to very close gear ratios ( Very Very Heavy oversize loads).
Things I consider are Total weight and gradients.
If you have a consistant gradient, then you pick a gear and sit on it (Pedal)!!!
But if you have a heavier total weight (ride/bike combined) mixed with gradients that change (Hills that get steeper, or less steep) through out the climb then you want as many gears and as close as possible that you can.

So to sum it up on a flat ride fewer gears may suffice,
But on a ride that has many hills with varying gradients through out the climb, mixed with maybe heavier total weight, or less than ideal endurance/ fitness/ strength levels, then I would take as many gears as possible.

In my truck I have up to 72 gears that I can choose from, thats allows loads of 600-700+ tonne loads. Like a bike I dont need to use every single gear throughout my acceleration. But it allows me to choose the most appropriate gear the the given situation. It also with get me a higher top speed/acceleration uphill from a standing start. E.G. If I have only 2 gears on a very steep incline, chances are I wont get out of first, if 2nd gear is to wide, revelent to 1st gear.
But if I have 20 gears, I can go throughout the most appropriate gear for the climb and eventualy get to a gear close to or exceeding the gear ratio that a 2speed choose would have given.

sorry for the long winded response, I sincerely hope it helps.

Austke

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Certainly in my locale I'm never out of the 50, and there's only one hill which benefits from the 34- though I have done it in the 50- I think certainly 50 x 12-36 would cover any eventuality, the problem being to make the freewheel both light and durable.

Now I have started using close ratio 8 speed cassettes 12-21T I will not go back to wider ratios unless I want to climb an alp. The 10 speed 11-25T just has the bigger 2T gaps just were I don't want them. That 10 speed will be replaced by an 11-23T or an 11-21T if I can find one. I really want 11 speed now to have 11-23T with the 2T jumps only on the last two cogs.

Close ratio all the way for road and even for off road. Although I do ride single speed MTB's but when they back on gears it will be a 2x10 with a close ratio cassette. I really don't get the 34T and 36T big sprokets on MTB cassette. in the inner ring your ratio will less more than one turn of the cranks to 1 turn of the wheel. That is a silly ratio even for a 29er and it would be quicker to get of and pick the bike up and run/walk. Also riding a bike up a steep hill in that sort of gear ratio is quite difficult every time I have tried it I have had to move to a higher gear.

11-28T 10 speed (or maybe 11-25T) with a 28/40 chain rings is all I would need on a 26" wheeled MTB. In fact I can't imagine a trail that I could actually ride in a 28:36T ratio on a any wheeled bike without stopping. Maybe I am out of touch with MTBing these days. Maybe I am old.

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I am always on my 53t , I have climbed most of the tour climbs on my 53t. The wifli has really made me think about just using one chainring on my next build. Not sure if there will be much of a weight advantage given that my current Red RD weighs just over 100grms and the wifli RD weighs 169grms + cassette weight.
It does not look like you can tune the wifli that much .

I run a 1x10 set up on my cross bike. Given the terrain of most cross courses, there is little need for two rings up front - and in races I rarely shift gears anyway.

Also, you have to remember that mtb cassettes generally span a much larger range. An 11-34 or 11-36 is a common cassette for mtb. Sram even makes a 10-42 for its 1x10 setups.

Conditions on mountain bike trails typically vary so frequently, there isn't opportunity to shift often enough to finely tune the gear ratio anyway. So a predictable step between gears, even if that step is wider than roadies would accept, is fine. The relative success of single speed mountain bikers riding together with multi-geared bikes suggests that much more than 11 usable gears is likely overkill. The advantage of 1x11 is the simpler mechanical design, with the rear derailleur no longer having to take the big jumps in chain tension associated with front shifts, is more important than an extra 30% or so useful gear ratios.

The SRAM x1 system, in my view, is brilliant. It's totally optimized for a single ring up front, with alternating tooth widths on the pulleys and chainring, and a clutched rear derailleur given the easier job it has only needing to handle rear shifts. I was super-impressed when I saw it in the flesh @ Interbike last week.

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elviento, this is a great question.

While looking at options to upgrade my mt. bike I was looking at 2x10 or 1x11 options to replace the current 3x9. My conclusion there was a 2x10 with a 1.6:1 ratio on the chain rings would be optimal. I also concluded the 1x11 would not work on the hills I ride here.

Out of curiousity, I did some calculations of a 1x11 on my road bike compared to my current 2x10 (50/34 and 12-23). Much to my suprise, it would work great! I could keep the same top gear and my lowest is stepped up by a very small amount. I came up with a 46 up front and a 11, 12, 13, 14, 15, 16, 17, 19, 22, 25, 30 cassette out back. That gave me very tight resolution in my critical 19-24mph range where I spend most of my time.

Potential weight savings are significant, especially if a SRAM XX style cassette was available. I have no clue why this is not common.

I think MTBers don't want the chance of a mechnichal issue (dropped chain) on a front shift (a good chance with bumps) and as a bonus they lose the weight of all the unneeded parts and are simply prepared to put up with the "gaps"

MTB is for stupid kids seeking the latest bike fad.