36" paved, 29" if dirt.
I have never been to Whiteface Mountain. Sounds fun!
If the steepest pitches don’t exceed 15% I would choose to ride a 36 with 125s. Longer cranks slow me down on steeper pitches but that can also help keep the heart rate down.
I’ve done similar rides on 110s just for the challenge.
Bellingham Bay to Artist Point
When I was newer to hill climbs on a 36 my favorite length was 140s.
JM
I like the leverage that big cranks give when climbing big hills. Judging from the advice of the others, I am probably more out of shape than they are - but I would favor a 29" wheel with 165 cranks.
The Coker Non-Skid tire has a very round profile. Also very good traction, but still has pretty low rolling resistance. I love it for the mixed road & off road riding that I do. For climbing, however, the Nimbus tire has advantages of lower weight and higher tire pressure.
I think a 36 with whatever cranks you’re comfortable with would be good, but agree that if it’s dirt, or if you’re pushing your personal limits on the steepness of the climb, then a 29 might be better.
Slick IMO is not going to greatly benefit you efficiency wise for most conditions. (For the record I ride slick.) However, with a long steepish gradient you will likely have to do a bit of zig-zagging. And each zig is at the time that you push the maximum load onto the tyre. So knobbly and soft and sticky will make it a lot harder, having to exert considerable extra effort at each zig.
Nothing too knobbly, pump up fairly hard and use a normal non-tacky compound is my advice.
I’ve read several of Steveyo’s write-ups of his races and a couple of years ago a guy did it on his 36. I don’t remember the crank size (125?) but it prooved too much. The ideal setup seemed to be a 26 or 29 w/ 137s, I think.
It wasn’t that it’s too steep, it just never levels off. Nice and steady won.
I’m too lazy to reread but here’s a few:
2011
http://www.unicyclist.com/forums/showthread.php?t=88909&page=2
2007 and link to 2005
http://www.unicyclist.com/forums/showthread.php?t=41177
Thing about 36-ers though, is that they’re always going to be heavier than 29/26/24, and, when it comes to continous climbing, weight is an enemy.
I know that climbing on my 29-er was made much easier when I switched to a lighter tire.
Tyres and wheels are rotating mass, and, whenever the climb becomes steep enough that you’re having to go up in half revolutions, that’s when any excess rotating mass really makes it’s presence felt, because, with each 1/2 rev, you’re accelerating that mass from static, to moving.
I have not done one of the long uphill rides. I have climbed hills regularly in my road riding. If I were doing the ride, I would look for a setup where I could ride almost the entire route without having to get out of the seat. That might mean a 29" with moderate cranks, or a 36" with longish cranks. As long as I can stay in the seat my efficiency is good. As soon as I have to stand up on the pedals to apply more leverage, my efficiency plummets.
It would be helpful to find a long stretch of similar grade and see what combination of cranks and wheel diameter lets you stay in the seat and keep up a good pace.
Scott
I welcome the stand up time on hills, even if I don’t need to stand. If I sit the entire ride my fleshy, crotch bits cry. standing is more relaxing for me, but only when going uphill.
#1 rule is, ride with what you trained with. If you don’t have time to change unicycles and train for at least a month on the new setup, stick with the unicycle you’re used to.
Weight sucks on hill climbs, so I’d prefer a 29er with shorter cranks to a 36er with longer cranks. Your personal preference depends on your own strength and riding style. For Mount Diablo, 12 miles that varies from 5% to 9% (with a short bit of 14%), I typically use a 29er with 110s if I know I can get a ride down. Otherwise I use a geared 29er with 150s. My time is not significantly different on the two setups.
I’ve used my KH 24 for steep road climbing, using the standard drilled rim, but a much lighter kenda “K-Rad” 2.3" wide tire. So I’ve been wondering if a narrower, lighter rim, such as the “Alienation” 24x 1.75 rim would be better for this purpose which, at 375g, is nearly 200g less than the kh drilled rim. But my worry is, I may lose some stability with the much narrower rim.
The steepness of some of the hills I’ve been training on (all paved streets) require a great deal of torque, so I’m wondering if I should just stay with the kh drilled rim, or go with the one mentioned above.
I’m asking this question also because my current kh rim is pretty old, and has had a very noticeable flat spot for some time, and my LBS was unable to pound it out completely. And I want the wheel to be as perfectly round and true as possible. Thanks in advance for any suggestions and opinions on this. 
I don’t think that weight difference will make that big of a difference. Are you planning on using this rim for muni too? Since your 24 is now your dedicated techy downhill ride, since you’ll take your G26 or bigger wheels for other rides, I think you want to keep as much rim width as possible. If you’re looking for a rim to use on your 24 for purely road climbing, then I would go even smaller and lighter. Something more like the wheelset here: http://www.unicycle.com/hot-products/nimbus-e-sport-24-inch-basketball-unicycle.html/
Thanks for that info Scott. Actually, the paved hill climbs are done with a different wheelset than for MUni. When I use my 24 for that I switch back to my LM wheel with Intense 24x3 tire. That Nimbus looks like it would make a great hill climber and weighs only 10lbs! My 24 is a mere 11lbs when running the lighter wheelset, and might even come down closer to 10lb with the narrow K-Rad and lighter rim.
Edit: Since I won’t be doing any drops or offroad with this setup, would it be better to go with the folding bead vs wire, and save even more weight?
I would definitely go for the folding bead tire. Since it is just for paved hill climbs, I would go for an even smaller rim than that one.
The super narrow rims are good for track racing, but I’m not sure about super steep climbing where you are standing on the pedals, half revving all the way up. But I guess there’s only one way to know for sure, and that’s to try it.
“UP” - Climbing with road bikers. From 12/1/12.
PS: The narrow 700c rim and tire are plenty stable and super light. Perfect for long sustained road climbing!
When climbing steep hills, you are “lifting” the weight of the entire uni as you go up, so it’s not just rotational weight involved. For example, it would be harder to climb a 20% grade with a 3 pound wheelset, if the rest of the uni weighed 15 pounds. Conversely, it would be easier to climb the same hill with a 5 pound wheelset, if the rest of the uni weighed only 8 pounds.
I think this is unlikely; rotational weight is much more important, especially when you’re doing something like a slow-paced, one pedal at a time hill climb. I’ll take the light wheel and the heavy frame over the heavy wheel and the light frame, any day.
Rotational weight is definitely a factor, but when climbing really steep hills, every ounce counts, no matter where it is. Yes, I’d rather have the least weight in the wheelset, but that wouldn’t help much if I was carrying a 50lb backpack while riding up a 25% grade! That’s why I also believe that trimming down a few pounds in body weight (if the rider has some extra body fat to lose) would make for more efficient climbing than losing 100 grams from the wheel.
Hill climb
Anyone who claims they can climb 8 miles at 8% with a 36" and 110 cranks is either on the same juice Lance was on, a mountain goat or has actually never done it.
I’ve done Whiteface on a 36" with 170 cranks and a 29" with the same 170 cranks. 10 minutes faster with the 29"
The record for Mt. Washington (12.5%) was by Johnathon who did it on a 20" wheel. The second best time was on a 25" with 170 cranks.
Climbing a 1/2 mile long hill is a whole lot different then 8 miles. You can not maintain momentum for 8 miles so you have to rely on pace, and cadence. It kills time to have to stand out of the saddle
Best thing to do is to go to a mountain and try your options before you race it.