@prendrefeu - HBC don't do 20/22 tooth counts and even if they did, I don't like your chances of getting one before the 2013 hill climb

That means it's pretty much E.P. or Fibre-Lyte for weenie custom stuff. There are a few other options for low tooth count, spiderless cranksets (mostly trials or BMX) but those will generally be quite a bit heavier than anything normally mentioned here.

Honestly, the S-Works cranks are hard to beat.

Imagine that without the 32 tooth ring and bolts. That is also the MTB version, the road version is slightly lighter again thanks to the shorter spindle. You could even cut the 104mm bcd tabs off if you're not really looking to re-use the spider for anything else.

Look up the MTBR thread on homebrew components before you decide to order one of those rings, hundreds of disappointed customers. I don't even think the guy is taking any new orders anyways.

Thank you everyone for all the great information.

I'm leaning towards the Extralite with a standard 20T ring because of the price and availablity.

The Lightning looks very nice, but is close to 50% more expensive for not much weight saving.

The Cannondale is awesome too, but also expensive and I'd need a custom ring to make it work.

Given the test weight load used in maddog's comparison (250lbs) I don't think flex will be an issue in a seated hillclimb at my ~250 watts.

Any further thoughts are welcome and appreciated.

The Cannondale doesn't need a custom ring at all, just the 104/64 spider which is pretty cheap and easy to find.

If you live in the USA the S-Works is cheaper than all of those and the lightest.

Also, which 20 tooth chain ring are you thinking of using? You know you'll almost certainly have to file down your spider to make it fit?

I agree that a fixed gear would be a bad idea without practice. Varying cadence is something you can get used to. You also get a slight drivetrain efficiency boost, in addition to the weight loss.

How fast do you plan on going, and what cadence do you like to use on a steep climb? Might want closer gears at the ideal for a 12% grade... since you are going to have gears anyway.

_________________
formerly rruff...

I've run the Extralite w/ a Fiberlyte ring on a SS MTB for probably 8 or 9 years now. It can be a bit flexy, but that has never stopped it from being functional. And my wife who pretty much co-opted the bike a few years ago says she can't notice it at all. It has some finicky tiny threads for bearing preload(?) and proprietary aluminum bolts, but if you take some time to install properly, it should treat you well.

And it certainly is light.
-Cory

Speed will largely depend how much weight I can lose. Normally, I climb at ~60rpm-70rpm, but am going to try and make a concious effort to increase that to 80 over the next 6 months. I think the practice ride (which I'll do with a full cassette) will tell me a great deal about what is correct.
I made a Gear Chart
The 34/30/26/23 gives me a range of 2.8MPH at 60 rpm to 5.5 MPH at 80 rpm which pretty well brackets the possible finishing times for me.(1:29-not likely to 2:40-I hope not likely). I probably don't need quite that range on the low end, but better safe than sorry.

I had considered using closer gears at the top, but i'd need to buy single Ti cogs rather than using the top 2 spiders on the XTR (which I already own).

Thanks for the input. I apologize, but I am just getting back into weight weenie stuff, and am unfamiliar with where to get components. I have no idea where to get a Cannondale 110/64 spider. I do live in the USA and will search for an S-works.
I've seen a number of 20 and 22T chainrings, and I do realize I may need to machine the spider. Extralite makes some as does Actiontec- any manufacturer you recommend?

22 tooth rings are still pretty much standard for MTB triples so weenie replacements are plentiful.

20's - There are a few around but Carbon-Ti make a nice 20 tooth chainring for 64mm bcd cranks. It's probably one of the easier one's to find too IMO.

Making the chain run smoothly isn't a huge deal for most cranks, the pic below shows that a little work with a file is needed for clearance and that's about it.





The S-Works crank could be bought direct from the website at one stage, US$300 for the arms but unfortunately I think you have to get them from a dealer now. Last I heard, the pricing was the same or similar. The spider and chain ring spacers can be bought from Lightning, the spline pattern matches the S-works cranks.

If you want to look at Hollowgrams at all, IMO your best bet is to spend some time on eBay or similar sites and look for some bargains. Being Modular, it doesn't matter if you find road/MTB versions, you can swap spiders and spindles to suit your needs.

The Hollowgrams are likely to cost more than the S-Works because they have such a cult following. The S-Works can also be found on eBay at great prices, often barely used or even the occasional new bike take off.

Rennen Design Group machined a 21t spiderless ring on a Lightning SL crank and 18t cog on a singlespeed C'Dale EVO bike for Mt W. They were able to work it without a tensioner.

Why so low? Your highest gear is a fair bit lower than a compact mated to a 32T bail out gear. Plus the cmaller the chainring the less efficient the set up due to the chain's articulation.

Because I will require gears in that range to achieve the target time I figured at analytic cycling. A 30/32 would not be anywhere near low enough for me. (think old and fat, although I'm working on the latter)

Quick question about the S works crank- are they all the same throughout their production (mtb/road variants excepted) or have there been design variations?