I think if you like walking so much, you should get a crossbike !!

What are the options for 20x36 gearing?

im assuming you mean a 20t/36t chainring combo on a double crank...
you can pretty much only do a 20t on a 94/58bcd (and old suntour 56bcd) "compact" 5arm spider. even then, 22t was more common. Action Tec still make some, in ti of course. then you are just left looking for a 36t 94bcd chainring, which might be harder to find. action tec stops at 34t, then jumps to 42t.
looking at action tec's website a little closer, they DO make a 20t in a 4bolt 64bcd size. you may need to grind/file down the tops of the inner ring spider where the chainring bolts fit, though. with that, even shimano makes a 36t 104bcd "middle" ring to match it.

hope that helps.

I was thinking 20t chain ring and 36 on the cassette. For my low gear.

For most people, I think a gear that low will only be useful in a few places on the LT100 course. And only if you are off the front or off the back.
The very steep parts are very crowded and everyone is walking. Not because it is unridable but because the mass of humanity.

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TIME RXR

Yeah, but I like to ride. From what I can tell it seems the options are to run 3x9 with a Deore 12x36 but that is heavy. Or, to run SRAM and run 12x36 with 20,30,40 chain rings from Action Tech. I suppose keeping the stock 32 is an option. Was wondering what other people do.

9 speed or 10 speed?
10 speed's easy, just run any 11-36 cassette, and then a triple crank with a 20t from one of the various manufacturers.

If you're running 9 speed and want 20/36 without using the heavy deore cassette, you could try and purchase one of the FRM 36t cogs to use on the back. You just remove the 11t cog and put this one at the end of the cassette.
http://www.dulight.fr/product_info.php? ... anguage=en

For a 20t chainring I'd contact this guy, http://andersenmachine.wordpress.com/, his website doesn't list a 20t cog, but one of the picture's captions mentions a 20t chainring.

i ran a 12-36 in 9sp back in the day. i used an xtr cassette (xt would work too of course) in 11-32. it has to be that range. removed the 11t cog, the next one up is a 12t, serrated for a lockring. got a 12t lockring, a cassette spacer, and an action tec 36t cog to put behind the largest cog. worked perfectly with my x.0 rear derailleur using a longer b-screw.
small note- youd think that a 9sp cassette spacer would be perfect, but i got some chain rub in the second-largest cog. the sides of the chain would just be sliding along the 36t. so i used an 8sp spacer instead, no problems.

thanks for the info. I never would have thought of taking the Cassette apart.

I was thinking of going to 10 speed but was told the 20T actiontek chain ring would not work with the new shimono 10 speed and had not been able to contact anyone who had done it or knew someone directly that was doing it. After digging around quite a bit it seems like people are doing it the SRAM XO series.

I just bought a deore cassette with a 36 tooth cog since I have a big ride (100 Miles 20K footies) this coming weekend.

It is good to know the options