Shock short cranks can climb really well!

Unicycles and Equipment
37

My inseam is 32", femur measuring from center of knee cap to illiac crest (hip bone) is 21". I dom’t have very long legs, but I loke very long cranks :smiley:

Last weekend I did a brief pedal poistin swap from 165 to 137, this was on the trail, ridih some flowy singel track. I found the cranks to be a tad short, lost enogh control that transitons and obstacles became much more difficult and steep ups became steel walks, so I swapped back shortly.

So yesterda I swapped cranks on my 36er from 165’s to 150’s and rode a moderate single track loop that I’ve done often on 29er and 36er. It was akward at first, requiring a finer balance point than the big cranks, I couldn’t count on pedal pressure to slow down or power up, momentum was key but too much momentum with short cranks is not as controllable, spinning smoothly and thinking ahead were the name of the game.

By the end of the ride, fours later, I was pretty comfortable riding the shorter cranks, I even considered keeping them on for a while longer, that was until I hit some tough uphills and some even tougher downhills. Uphills that I normally think nothing of ridring were walks and the downhills on steep rocky terrain were supper duper sketchy; think out of control spin riding across rock ledges.

I could see running 137 to 150 for flatter terrain, more double track, gravel roads, that sort of thing, but for single track it’s just not reasonable to try and climb/descend technical single track on short cranks. I’d even go as far as to say it was dangerous doing so, had to force myself to walk things I normally ride :o

So i went home and swapped cranks, but instead of going back to 165’s, I went straight to 170’s :smiley:

Tomorrow it’s back to the single track on the36er, go big or go home!

38

Hi Ben,

All this crank swapping… :thinking:
How about a Schlumpf?
You have much more experience than a few years ago, when you had your first Schlumpf.
You will be fine in high gear on the easy trails, they will be fun again.

39

Just been out on my 36 which always reverts to 150s whatever else I try. About 22 miles including a single longish steepish incline and a more gradual descent with some steep sections. Always felt under control and I made it up the hill in one. I also ride the 36 comfortably on easy cross country including short but steep descents on 150s.

Swapping cranks is a simple 5 - 10 minute job if your tools aren’t hidden in several different parts of the garage.

40

I’ve always played around with cranks, it helps that I have lots of choices and a nice place to work.

I last rode a guni a year ago, my skills haven’t changed much, but then it really wasn’t a skill thing turned me off on the guni, it was the 50% gearing step. I’d like a 25-30% step, also some 165/150 cranks, but of course neither of those dreams are coming anytime soon…

I’m thinking about building a 29guni, but it would be more for double track and dirt/gravel road, extended rides, overnighters, that sort of thing. A guni really isn’t viable for the trails I ride, it’s just to variable, I’d be in and out of gear too often. When I rode bikes I was on a 29er single speed, which is a very popular mtb styler here, for the same reasons I ride a single speed uni.

I rode the 36er last night with the QuAx chromoly steel 170’s, but the Q factor was just a little too much for my already super wide hub (125mm), the power was better but the width threw me off.

@ Feisty: I think the Q factor may have been what made your uni ride weird when you ride the wider cranks. I’m on an Oregon, so I’m used to having a wide set up, but the addition of 12-15mm width made the ride wonky. Have you tried a K1 crank?

So I didn’t totally dislike the 150’s, though they were a tad short for climbing, so tonight I’m swapping out to some K1 160’s which have a Q factor in between the Ventures and Moments. If these are a nice balance of power and spin, then I’m going to order a new set of the K1 lights.

Last night was my first night ride of the season, single track, leaves, roots and rocks, so much fun :o

41

I bought a 29 trainer from UDC a few months ago. It came with 150’s. I switched to Coker 127’s and was much better. Curiosity got me and went to 102’s. These were even better. (totally flat road riding) I figured it would be too much, but I ordered a set of Nimbus Ventures 75’s anyway. Put them on and after some trying was able to ride down the road. I was thinking I was getting it, when I came to a stop and shot the uni out in front and landed flat on my back. Lack of torque and no brake. Little road rash was all, no biggy.
So a couple questions come to mind. Does anyone ride 75’s on a 29 regularly, or is that just too short?
Is there a “Too short” for riding due to not enough movement, resulting in leg muscle issues.
I was surprised at the speed difference between 75’s and 102’s…thanks

42

I ride a 700c, and 75mm cranks are what I use. It works fine where I live, which is pretty hilly. I recall riding the Unicon 15 marathon course (which was very hilly- ask anyone who rode it), and climbed up faster than I ever thought possible, and much faster than I did on a 36"/145mm Schlumpf in 1:1. The slideshow of the terrain is at the bottom: http://www.uniconxv.co.nz/participants/competition/venues/

Partly that is from having a lightwheel, but once you get used to it, the 75mm cranks are great for climbing. The grades where I ride get to 10-15%.

43

Wow, 75mm… Now that really is “heroic.” :slight_smile: How are they going downhill? That’s what I’m curious about.

The older pages of this exchange are mostly from before I joined the site, and there are some interesting and less obvious points going back there. What adelman has to say about a larger range of motion engaging more muscle fibers, making more stored energy available for long rides, is food for thought. But fighting the wobble from wonky pedaling on long cranks probably wastes energy too.

44

I find long cranks use more energy because of the greater range of motion and also because you tend to be using a bigger, heavier wheel.

At low resistance with short cranks, the movement is so small- it feels like you’re gliding with little effort/movement. I could ride all day with a 75mm/700c. On long cranks/big wheel (125mm/36"), I know my legs have had a good workout after a couple of hours.

I have a 32km training ride with a few climbs and I’m a few minutes faster on the 75mm/700c than my 110/36" record (which was set jsut before I won the Marathon at Unicon 13- I was quite fit then!).

Downhill- hard to answer- it depends on steepness, and the weight/momentum of the wheel/rider. The 75mm/700c feels similar to 110/36" in terms of controllability for me.

45

I have tested 75/700c compared to 125/36" on flat road. I was faster on the 36er. Going downhill with short cranks on a small wheel is harder than on a big wheel with long cranks. For me, a 700c uni cant beat a 36er.

46

Thanks for the comments. Mine is a 700x45c so a bit heavier than yours. I’m not looking for all out top end speed as in for racing, but more the fastest for cruising along for some distance. The rail-trail I’m riding is flat and smooth. I’m riding with my wife, her on a heavyweight cruiser and my 36 is pulling away from her. I prefer to spin than just dog along, so maybe 75’s are the answer in this case.

47

This thread reminded me of this thread:

48

giggle :smiley:

49

Crank Size for muni climbs - criteria to consider

For muni riding, people talk about hill climbing capability on various sizes of cranks a lot. In my opinion, it really depends on the slope and smoothness of terrain involved. And for slope, I think what is relevant is how close the slope is to the max slope you can climb with your skill and endurance.

On a paved (or smooth) climb with a grade shy of 20 percent, you can actually get a smooth climb on a 125mm crank on a 29 inch muni - which is a bit of a large wheel and somewhat of a small crank size.

But as the hill gets steeper than that - like say 24 percent or higher, the capabilities of wheel size and crank size really dramatically differ, and the climbing technique has to be spot-on.

The smoothness of the terrain is almost more of a determining factor for crank size as well - especially when the terrain forces you to slow down almost to a stop for moments - where you have to restart your momentum.

So the more you are pushing your climbing to your personal limits, I think you end up using 150mm cranks, and perhaps a muni wheel as small as 24inch. But for muni, it would seem that the Kris Holm recommended 150mm cranks on a 26" muni - can ride the largest variety of terrain with decent speed. And to ride with a smaller size crank, they can be fun but you have to make sure you are not riding close to the limit of your capabilities for climbs - as the limited motion of the leg with smaller crank size creates fatigue in that area of muscle quicker. 165mm can feel good and very controlled, but not at high speed for great durations, and I don’t think it has a lot of sustained top-speed potential.

50

I’ll go out and experiment with the 165s again. High cadence for 8-10miles and track my time vs the 150s, for a week and see how my legs adjusts to them;)

51

Upd

Curious, UPD. How did your legs adjust to them?

52

Oh, jeeze its been awhile since this last post…hmm let me try to remember what I was trying to accomplish…

Oh right, I was going between 165s and 150s, funny of all the people, you would ask me.

I determined, Im definitely a long cranker. Im no good on hills less than the terribly long 165s. 150s on the 36er on flat and slight incline is ok, but I like to climb steep for miles on the 26er and even contemplating on going longer like a 175 or 180.

Too some that might sound ridiculously long, but really, I dont mind it;)

53

Dang what’s wrong with me…while everybody’s going shorter, Im going longer…just bought a pair of 175s Truvative to try out, I ll let you if I like it:D

54

This I also found out. I have a KH26 and just this week put variable cranks on it for 127 and 110mm sizes. Though it was ok to ride on flat asphalt with the 110, when I tried 127mm in the forest, it burnt a lot of energy and going up really hurt my knees. I might change it back to 150mm. Then again now that I have an Oracle 29" with 150mm cranks, it is more comfy that the 26" also in the forest with climbs. As long as the wheel keeps rolling, climbs are very well doable.

55

Thank you for that, UPD.

I’m likely buying a Nimbus 29er strictly for road, brakeless (until I can afford the brake), handlebar-less, and live in relatively flat Illinois; that said, when there’s a hill there’s a HILL. This thread has helped me, yet every time I think to go short on cranks, an experience like today’s three posters on here gets me thinking twice.

I have 150mm on my KH24, and 150mm also on my Torker Street 26 (cheap, slow). I’m thinking, esp since brakeless, I should go with 125mm minimum on the 29er, but I’m open to suggestions. It’ll be all road, Schwalbe 2.0 slicks. Can I brake with legs on 125mm cranks? I’ll likely be riding 10 milers, tops, and usually less. I’m just not a distance nut (I usually ride MUni on my Brakeless KH24 at forest preserves, county parks, and in the woods).

I’m coming back to uni after riding as a kid, been at it for 2015 only, so fairly basic, but I can ride. Im 5 foot 8.5 inches tall, (gotta get that half-inch in there…lol),176 pounds.

I’m not really into 36ers, for some reason, as I just ride alone for cardio and enjoy my strength training, guitar-playing, and other sports (ultimate frisbee) enough that I really don’t want a face-plant from ten feet in the air to break an arm from a high-seated uni. Lol.

Thanks for any and all suggestions. Please don’t feel bashful to tell me what’s what. ��Steve

56

You can also get the Spirit cranks in 137/117 (or 137/110 if you can find some old stock). I find that 137mm is a really nice balance between power and spinability. I have them on both my 26er and 36er at the moment.