Crank length and hill climbs

i wanna try some 89mms. these in particular.

My ungeared 29er (Zippy) which I’ve used for the Diablo climbs has the BA 2.0; my 29er Schlumpf (TD Jr.) has the Marathon Supreme when it’s set up for road.

I really don’t notice a lot of difference in handling between the two; they’re both nice tires. The rim on Zippy is narrower and lighter, so I don’t think I notice the extra weight of the BA.

For me, the BA 2.0 doesn’t seem too great on camber, which is funny because I never noticed any issue with the 2.35. I wonder if the marathon supreme will handle camber better, or if I am just used to a fat tire.

Yeah, I used to run 125s for my 36er and you can definitely climb a lot of hills with that set up (even the 114s), but doing long hill climbs on a 36er is so much harder than a 29er. In a hill climbing event where gradients are 6% or more, it makes much more sense to climb on a 29er. Although, I haven’t timed myself on my old hill set up which was a 36er with 150s, so I am curious how much slower or faster that will be. I know that it works my muscles a lot more though, and I wouldn’t be able to keep a good pace for a long event (27 mile climb).

Odd. I think the BA 2.0 is outstanding on camber, totally able to carve turns with no concern for the tilt of the road. What pressure are you using?

definitive 36" speed standards by crank size?

Does anyone know the average AND top speed(s) of a 36" for every crank size? Like 150, 127, 114, 102, and 89, as well as the level of control for each?

I’m about to get some new cranks for my 36er for the upcoming LBI Unithon. I normally use 125 (127mm) but have had two bad UPDs while trying to top my speed on it. I wiped out at 17.6 mph, even though I previously got to 18mph w/o UPD. My right crank got bent so now I’m buying new 125s and I’m getting some 114 for fun. I might go lower, if it’s worth the risk.

The top speed is whatever setup Chuck Edwall is riding. It’s much more about the rider than the crank length.

Klaas’ idea of Total Gear Ratio will give you an idea of how much speedup you can expect with a given setup, based on how fast you are with a different setup:

The level of control is a personal thing as well. It’s safe to say that there’s not much control on a 36 with cranks shorter than 125mm; descending and turning can be smoother, but any sort of situation where you have to fight your momentum is a losing battle.

I agree w/Tom here. The BA2.0, pumped up really hard, is fantastic on off-camber or tilted surfaces, whereas the 2.35 was simply awful on the steeply tilted hairpins on Whiteface.

I am running 55psi on the B.A. 2.0.

From what I recall (although it has been over a year) the 2.35 felt a lot better on the camber and I actually liked turning with it more.

I will have to put the 2.35 back on and see if this rings true, or if I am just not used to the 29er since I have been riding a geared 36 for quite some time.

I wouldn’t go lower than 114s for the 36er. I was using 114s for quite a while and it is probably the lowest (110 or 114) that I would want. 125mm was my comfort size on the 36er though, it seemed to be a good size for most everything (especially around VA/DC).

hmm…i thought a lot of people used 100’s

ima still try 89s

i think if i practiced for a few days on 89s i could really fly…i’d just be worried about stopping.

I rode 36/114s in Ride The Lobster training and most of the race, and I found mounting difficult, though maybe being short (5’6") contributed to that. I also did a lot of riding with 36/125s, and with both of those “shorter” lengths, I had some serious knee-aches on long descents (this was my pre-brake days). In fact, accelerating on the smaller cranks hurts my knees*, too.

I now keep 150s on my Coker for the easy control, since it’s my around-town/5-or-10 mile uni, and I use my KH29 guni for real distance riding.

My KH29g has the 125/150 and I like 150s on that, too, both geared-down, for big, long climbs, and for the leverage when geared-up.

*My knees are quite old in knee-years; too much ultimate frisbee - 27 years and counting.

I am the same way, using the 125s on a geared 29 on a descent with no brake definitely hurts my knees, I prefer the 150s for that if I do not have a brake.

I also, have never really been good at slight braking on a downhill, I wish I was good so that I could just run 125s.

And your still so young!

True, Joe, most of me is 47 years young :roll_eyes: , but my knees, ankles and shoulders are at least 50% older from all the ulty.

Do you have a brake? or is your town really flat? because 89mm cranks are really hard to brake with… I say that but I only have like 30 seconds of experience, I rode my 89mm cranks and they stripped after a little loop in the road:( I might try them again though, I haven’t got any problems with them on my 12" uni lately:p

I dont think I’ll even go longer than 114mm cranks on my Coker, I climbed a 20% hill with them so I think they are pretty much perfect for me:)

Check out the “Fastest Speed on a Unicycle” thread. Page 10 may be especially helpful. Fastest speed on a unicycle

wherein it is written and graphed what sort of maximum speeds can be achieved on different unicycle set ups (wheel sizes, crank lengths and gears). All hail the uni geeks!
If you’re looking to break speed records you should probably consider a geared 36" with 125 mm cranks, although 150 mm cranks might do it too.

If you’re looking for issues of control, efficiency, likelihood of pedal strikes etc then you might want to check out the “New Concept: Total Gear Ratio” thread. (New concept: Total Gear Ratio) Eric made some beautiful graphs that make me want to laminate them and put them up on the wall.:slight_smile:

My personal preference? For climbing big hills with an 8 to 10% grade I like to ride my 36" guni (in low gear) with 165 mm cranks. That’s the configuration that I rode up the Mt. Diablo Challenge with, including the last super steep part.
For distance riding with less extreme hills I use 150 mm cranks.


I thought the geared 36er with 165s was indeed a pretty good climber. I think I have fallen in love with the geared 29er again though as climbing with a geared 29 in low gear with either 125s or 150s is a breeze - and that really comes in handy for road rides out here in Colorado.

Kh29/137 !

Well, I have a long, hilly race coming up (, 40 miles, lots of steep, dirt roads. Just a few minutes ago I swapped a pair of 137s (I had 150/125s) onto my KH29/Schlumpf and quick-tested it out in the street. It rides great, and the shifting is the easiest length I’ve tried yet.

I think ungeared KH29/137 will still be fine for climbing (after hearing tholub’s 29/110 climbing feats, I’d be ashamed to think otherwise), and this uni has a brake, to minimize knee-stress on descents.

I’m trying them out on a long ride tomorrow and I’ll report back.

Very cool, I think 137s would be a very good overall crank length on the KH/Schlumpf 29er. I probably won’t be experimenting with swapping cranks, it is more of a hassle with the KH/Schlumpf as it takes a few rides and lots of tightening of the bolts before the cranks become settled and those crank bolts round out too easy, which is why I prefer the dual hole cranks on the guni - no need to mess with all that.

That is the major complaint I have with the KH/Schlumpf, the crank bolts are either made of too soft a metal, or the hex hole is slightly larger than 6mm so those bolts always deform with constant tightening. I wish the bolt was designed differently so it wouldn’t deform.

Oh and let me know how the brake treats you, I always had issues with using a brake correctly on descents.

I’m loving the 137s after the ride. I only did 18 miles, but I did a hard hill, one of the steepest around here, and pretty long, as well.

With the 29er in 1:1, the 137s are a good climbing length, I only had to stand on the steeper parts. I may try some big climb races with that setup. Also the 137s are a good compromise for leverage vs spinning when just riding along in high-gear, and I was able to smoothly run out some hills because they were easier to spin than the 150s.

I also rode several of the miles on a often-rough dirt railbed that still has the rail ballast in places, so big gravelly parts. This is only place I missed the 150s, but it was “totally doable”, just more effort to crank though those bits.

I’m definitely leaving the 137s on this wheel.

I just had a couple new bolts shipped from Schlumpf because I rounded one out. I might have partly been due to my not getting the allen wrench seated in the bolt deeply enough a few times in the past and possibly the upper part of the bolt-hole stripped first, then the whole bolt-hole. I’m being very careful to get the hex-wrench in there all the way now. I hope I don’t strip any more of these suckers. They ain’t cheap.

I really learned to brake on an 8 mile descent down Whiteface and now I never descend a steep hill without it, it’s just much easier on my knees. Especially on a short-cranked guni, a brake is a must-have for me now. I’m putting brakes on my non-guni Coker and KH24 ASAP.