Great idea! Especially for the 1x10 drive train.
Pull off your 17T gear and replace it with a 42T gear.

Go here: http://www.oneupcomponents.com/

...and here: http://www.bikerumor.com/2013/11/28/exclusive-take-your-cassette-to-the-next-level-with-oneup-components-42t-sprocket/#more-70079

The OneUp 42t sprocket is available in black or green with the MSRP set at $100. The first sprockets are shipping out in January and will ship anywhere in the world for free. As part of their product launch, OneUp Components is offering a special $15 discount for all of our readers, meaning you can pick up a 42t cog shipped for $85. To take advantage of the offer, email discount1@oneupcomponents.com with Bike Rumor in the subject line for a $15 discount code that’s good until Dec 18/13. Check out OneUp on the web for additional product info and to place your order.

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan

Ordered one for my SRAM X9 (PG-1070 11-36), using the $15 discount.
Review in Jan/Feb 2014.

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan

Here's an alternative product for $40. No ramps or pins tho...
http://www.ebay.com/itm/41-Tooth-Cog-for-Mountain-Bike-Cassette-41t-Sprocket-/261323976497?pt=US_Cassettes_Freewheels_Cogs&hash=item3cd81f6f31

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan

Mudd, that eBay seller is a local rider in El Cajon if I'm not mistaken. I dont see a city listing on his profile using my phone though. If its him, I met him for a purchase a year or two ago, good guy. He builds off road trannies and started off doing the MTB tools and sprockets for a little extra income and fun. The sprocket I bought worked great.

Very interesting. My mind finds the option to lose the front derailleur very attractive, but my legs & lungs question that. I'm going to have to plug some numbers into the Sheldon Brown gear calculator and think about it. Thanks.

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Thus, if we are to understand the world, we should live somewhere between judgement and amazement — Alfredo Lopez Austin

I switched to the SRAM 1x11 with the 11-42 cassette (30 tooth ring up front) and I'm never going back. I'll never have a bike without this set-up. Gearing hasn't been an issue at all and it runs flawless. Losing a derailluer and shifter is just an added bonus.

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If you don't go this year, you'll only be a year older when you do - Warren Miller

Couple years ago the 2X10 drivetrain came close to sliced bread when it came to convenience. Why? People were dropping their chains on the downhills and still continue to do so. Here comes the new, impossible to drop your chain derailleur; not good enough. Let's give 'em a single ring up front. I'd like to find out how many people can safely get the chain back on the front rings without dismounting, if they have a little momentum? This is for a simple chain drop and doesn't apply to the 1X9, 1X10, 1X11's.
I priced the 1X11 set up, damn! I paid less for my slightly used Stumpjumper, complete , but I'm frugal and fast on the flats with my 40 something up front.

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"Just stop this walking shit and let's get this done"
Avidtesty (Arch 2019)

Gonna try the 42 and convert my Hammerschmidt to 24T for now, then go with a 30T single ring up front eventually.

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan

24x42 - careful, too much torque.

Los, that's the guy - "mtbtools" on eBay. I bought a derailleur hanger alignment tool from him just over a year ago. Met him at his place in Santee for the pickup. A simple $10 tool that works fine for the once every year or so I need it (especially after a crash). Much cheaper than the shop-quality Park tool that goes for $60+.

A review article just got posted on empty beer. Generally positive, some little things to look out for like tension screw. I still mean to do some ratio comparisons with a couple of likely chainring sizes...

http://reviews.mtbr.com/just-in-oneup-components-42-cog-for-1x10-drivetrains

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Thus, if we are to understand the world, we should live somewhere between judgement and amazement — Alfredo Lopez Austin

Okay, gearheads, here are some results I got with some typical ratios (I used the 9-spd ratios I'm used to, but there are many other possibilities, and this gives you an idea. I realize OneUp says it is for a 10-spd 11-36). What it tells me is that the 42T grannygear gives a surprising spread. Yes, you give up something, but even my puny legs might be able to handle it with a 30 or 32T ring. Here's the website if you want to play with combinations:

http://sheldonbrown.com/gears/

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Thus, if we are to understand the world, we should live somewhere between judgement and amazement — Alfredo Lopez Austin

Or you could consider this other one and forget about the tension screw issue:

http://www.bikerumor.com/2013/12/15/abs ... sette-cog/

Dang! Only one left. You guys must be buying them like crazy!

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan

First ride today. The OneUp 42T performed flawlessly!

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"My favorite part of riding a bike is when I get off the bike." - Jim Gaffigan