125 vs 150 cranks on KH29 comparison (dual hole moment cranks)

125 vs 150 cranks on KH29 comparison (dual hole moment cranks)

Since getting my KH 29-er, despite paying extra for the dual-hole cranks, I’ve ridden it only in the 150mm mode.

The majority of my riding over the years has been with 150’s (either on 24x3 muni or various 29-er/700c unis).

The reason being that 150’s seem better suited both to the steep road hills round here as well as being better for any mild off-road terrain.

Previously I’d found that I actually completed journeys faster on 150’s than 125’s, probably cos I felt more in control and happy about spinning fast on the longer cranks, combined with less dismounts/remounts or UPDs.

Recently though, having decided to experiment with a thinner tyre on my other (Nimbus) 29-er, when the lesser mass of the tyre, as well as assisting on steep uphill climbs, also left me with a feeling that shorter cranks could work well on the set-up.

( the 700c slim tyre riders thread
the 700c slim tyre riders thread )

Before switching the (square taper) cranks on the nimbus, I figured I’d switch the KH to 125 mode and see how that worked out.

Ride 1- 150 and 125

First ride was on Tuesday- I started with the 150s and waited till I got to a length of cycle path that I know well, is fairly long and with a mild downhill slant.

Spanner out and the switch was straightforward- on mounting, the uni initially felt very wrong- I had a strong feeling that my feet were very restricted and, as expected, the wheel had a lot more momentum.

However, only a few seconds later the ride felt more fluid and the cranks started to feel ‘normal’.

The ride felt strangely slow, probably because I was reluctant to spin the cranks at the same speed as I would with 150’s: it’s difficult to tell if the actual forward speed of the uni was slow as it’s quite subjective without the use of a speedometer of some kind.

Soon the cycle path ended and a short steepish uphill stretch appeared- the 125’s were no problem on this.

Continuing into town I found myself feeling quite comfortable on the shorter cranks- just having to be alert to the extra momentum of the wheel and the fact that it can’t be stopped dead like with the 150’s.

Getting closer to the town center and with more pedestrians, I switched back to 150’s.

They felt very long! After a few seconds riding I got used to them again.

My feelings on the comparison was that the 125’s were better than I expected on hill climbs, but that were was no speed advantage- that almost certainly being due to my inexperience- I’m sure that with more riding on them, I’d get to the point were I’m happy to spin them fast,which would yield more speed than with the 150’s.

Returning home, I called at the local supermarket- usually I carry the uni in, but, this time, I’d brought a bike chain and put it on the rack outside.

Shopping finished started unlocking the uni as a biker was just chaining his up- he did a double take and asked something along the lines of ‘where’s the other wheel…’.

In this case I could see he was genuinely confused as he really thought it was a bike, so I took the time to explain to him that it was a unicycle that I used as transport etc.

As he seemed interested I even went into details of the double-hole cranks and how they acted as a primitive gearing system.

He watched as I got the uni into position and jumped into the free-mount, riding off I heard ‘F*cking hell!’ behind- clearly he’d never seen a big-wheel unicyle going about it’s daily business before.

It’s good to chat to a member of the public who can express an interest in unicycles without the usual stupid/disrespectfull comments.

Approaching home I come out 1/2 up the steep hill just before my place- it’s a challenge with 150’s, I usually succeed but it’spretty close to my physical limit.

Unexpectedly, I found the 125’s OK, infact, for an instant, I had the strange feeling it was easier?! Almost as if the gear was lower. I could think of no physical reason why that should be so- obviously the foot circle is smaller with 125’s, but, the wheel moves the same distance.

Later that evening, I went out in 150 mode and called by the local unicycle hockey team and let them have a go on the big wheel.

They all ride 20"-ers and I was impressed by the fact that the good riders could hop on the 29-er and ride it straight off, with one of them even attempting a wheel-walk on it.

I wanted to test my theory that they’d actually find the 29-er easier to ride in 125 mode (as 125’sare the standard on 20" unis) and so switched the cranks to 125.

My theory seemed to be disproved as, everyone who tried it found the momentum of the wheel to be very difficult.

(On reflection though, that’s to be expected, it takes more than a few yards riding to aclimatise to the length change)

Ride 2- 125’s and a bit of 150’s

The hill outside my place is really, really steep- my personal rule with steep road hills is that I don’t ride down them until I can ride up them.

With 150’s it’s a good workout riding up and, straightforward to ride down (though it’s a good idea to take care).

I didn’t feel confident about riding down with 125’s, so walked the uni down.

Ride was OK, a bit squirrely at times, but that’s probably going to go away with practice. Uphills seem very doable, any UPD’s feeling more down to inexperience with the cranks size, rather than any actual limitation with the size.

Downhills are more of an issue with the shorter cranks, but, with care, they’re no problem.

For me, the big selling point of shorter cranks wasn’t necessarily the speed increase, but the lessening of saddle chaffing, due to the fact that the legs move less.

While I can happily ride for 1hr+ with 150’s, on occasion I do come back pretty sore and, during periods when I’m riding every day, the soreness can build up.

These initial rides with 125’s do seem to be leading to less saddle chaffing.

On this ride, whilst switching the cranks, a lady on a bike pulls up and asks ‘Are you with Greentop?’ (Greentop is the local circus)

She’s not being delibaratly rude, but, I’m tired after a hard ride and, I find the public’s irrational association of unicycling with circus somewhat tedious- yesterday’s encounter has shown that it’s possible for some of the public to enquire about unicycling in an intelligent and respectful fashion, so I don’t see why they all can’t :slight_smile:

With a tone that isn’t rude, but isn’t particularly pleasant either, I ask her why she’d assume that I’ve got anything to do with Greentop. She looks at my unicycle (a big wheel top-of-the-range KH, clearly being used for transportation, not entertainment) then looks at me confused, mutters something that sounds like an apology and rides off.

Ride 3- today, pure 125’s

I decide to attempt the initial really steep downhill, but lose control of the wheel and have to dismount.

Rest of the ride is really good, ride through town, managing to manouver through pedestrians, uphills are no problem and I find myself able to spin the cranks more, on one occasion, being aware of a bike coming up behind me, I push the speed and find, by holding the handle, that I can really go fast and end up leaving it behind.

Indeed, the cranks no longer feel short and, bizzarely, at a couple of points they actually feel too long.

There’s plenty of students around and, as it’s end of term, they’re in good spirits (drunk or in the process of becoming drunk) and, by the comments as I pass the various groups, the sight of a unicycle is a positive experience for them :slight_smile:

The ride as a whole seems to have been more physically challenging than it would on 150’s, but, as I’m trying to get fitter and lose some wieight, that’s a good thing.

Arriving at ‘home hill’ I come out at the halfway point and decide to head down it and see if I can get to the bottom without UPD-ing.

The force on the wheel is extreme- I have to pull hard on the handle to keep control and, at one point, almost fall off backward (which would be bad) but, regain control and then make it to the bottom.

To celebrate I ride around a bit more, before arriving home feeling somewhat proud of tonights efforts with the 125’s.


  1. KH dual-hole moments 125/150’s are very good- they allow an easy comparison between the two lengths on the same ride.

  2. 125’s are surprisingly good on uphills- seemingly able to tackle most hills that can be done on 150’s (that’s road hills, I expect that anything rough/off-road will be harder with 125’s)

  3. Speed- difficult to tell without a speedo- I suspect that I’ll gain the speed advantage of 125’s after a few more rides, when I’ve got the practice and confidence to spin the cranks at the rate I can do with 150’s

  4. Seat chaffing- I’m hoping that this will be lessened with the shorter cranks due to less leg movement

Hey, what a mega writeup. But very nice reading. I would suggest getting a magura brake and a spooner. You will have more confidence on the downhills, especially with the 125 setting.

From my experience with road and XC riding on my buddy Ed(frogy130)‘s KH29, I’d say I agree with the sentiments in both munirocks’ suggestion re:125mm/brake and with the majority of your write up, right down to your guess on how the short crank length would behave off-road.

29er/125mm, especially compared to 24x3/145mm seems to be an exercise in momentum. When you get “in the groove” and work WITH the momentum rather than treating it as something you can take or leave as you choose, it does seem to have that magical “wow, I thought this’d be harder” feeling to it. In fact, I have a feeling that riding the 29er off and on for a month or so was part of the difference in my 24x3/145mm climbing ability, taking the “use the momentum” lesson to heart.

I also loved that feeling of going from 125mm to 150mm after a long ride on the shorter length… the main trail I was practicing on has a solid 5 miles or so of flowing semi-technical XC riding before you get to the “tough stuff” in the back of the park, and switching over was always an interesting experience. I call it “tractor mode”, as you suddenly get the same big rollover momentum, plus “bonus” torque beyond what you’re used to having available… slower to start, slower to stop, but you feel like you could pull stumps out of the ground like a big diesel rig :slight_smile:

Here I’m rivalling your wall-of-text, and I’m only replying to your post, so I’ll cut this off here ;D

Call it +1/me too/I agree with the OP,

John M

Making the swap and trying the125 hole tomorrrow

OK,nice thread guys! I bought the on special KH29 last month and I have yet to swap the pedals to the 125 hole. I do like the feeling of being able to strongly accelerate and decelerate, and the 150’s length I’m comfortable with. I’d tried some 125’s on my 36er, and really felt like I couldn’t affect the wheel enough starting or stopping.

You’ve peaked my interest, and as always, psyched to get out there tomorrow!

Great post. My KH29 came with 137/165 cranks and I quickly found the 165s to be far too long for riding on roads, even bogging down a bit on climbs. I had 137s on my KH20 and felt they’d be too small for the 29 so I never bothered and ordered 150mm cranks which worked quite well with the big fat knobby wheel. Once I outfitted the KH29 with a narrow slick tread tire (Schwalbe Marathon Supreme) the cranks instantly became too long.

It was only at this point that I tried the 137s and I’ve never looked back. They climb just as well as either the 150s or 165s (even on steep 8-10% grades) and allow me to spin much faster on the flats increasing my top speed markedly. I’d say the 137s require some getting used to on the downhills (I have no brake) but after a few days I couldn’t tell the difference.

I think the 137mm cranks offer a nice compromise between torque and control. I’m going to try a 700X25 tire wheel this week and I’m thinking that a 125mm crank will be in my future.

I think 137’s would be an excellent compromise between 125’s and 150’s.

Scott has kindly contacted me by pm and offered to measure the grades of some of the hills I’ve been climbing- the results are:

  1. the hill near me which, in the old days, I’d climb at the end of every ride on my 24x3 with 150’s: grade is 19.6% and length is 225 ft.

On the 29-er with 150’s I tend to come in on a side road and so only climb half of it- I’ve found that on the 29-er with 125’s it’s surprisingly not harder than with 150’s, but I’ve yet to tackle the whole hill with 125’s

  1. Blake Street- this is what I always considered to be the real deal in terms of extreme road hills, turns out the grade is 16.8% for the first 333 ft and 8.3% for the next 278 ft.

Though I wonder if those lenghts are correct cos it doesn’t seem that long? Still, it’s longer than the road above and that probably accounts for why it seems harder despite having a slightly lower gradient.

I used to climb Blake street at the start of most roads on the 24x3/150’s, I have climbed it on a 29-er/150’s but have yet to attempt it on 125’s

  1. the Crookesmoor road section that I describe as not-harsh, but long, comes out at 8.8% at a length of 2085 ft- doable on both 150’s and 125’s but, if riding the whole length,legs will be burning at the end.

Agree with you on this one. I got my 29’er about 6 months ago with dual 125/150’s, and as yet have not tried the 125’s. I’ve been very comfortable with the 150’s and have felt the struggle with controlling the momentum on some downhills with the 150’s. I’ve been reluctant to swap to 125’s fearing a loss of control. I had a 2nd hand Magura brake fitted and was on for all of about 1hr into it’s first ride when the Uni landed on a rock and smashed a neat hole into 1 of the pipes, rendering it useless which has added to me being reluctant to swap to 125’s.

However after reading the original write-up, it has picked up my interest and makes me think that I should at least give it a try. Was even talking just this morning about trying the 125’s on my 24x3 MUni just for kicks :slight_smile:

With dual-hole cranks the chage-over is so much easier that it’s worth trying it out.

I’d say it’s best to try the shorter setting on a nice long flat bit of road/pavement and be prepared for the fact that, initially, it’s going to feel a bit difficult- after pedaling a few hundred yards they’ll probably feel fine.

Then, it’s a matter of doing several rides for you get at ease with them until you’ll start to feel the benefits of the 125 setting.

With dual-hole cranks the chage-over is so much easier that it’s worth trying it out.

I’d say it’s best to try the shorter setting on a nice long flat bit of road/pavement and be prepared for the fact that, initially, it’s going to feel a bit difficult- after pedaling a few hundred yards they’ll probably feel fine.

Then, it’s a matter of doing several rides for you get at ease with them until you’ll start to feel the benefits of the 125 setting.

29er brake drag or wheel flex

ONe thing I’ve noticed aboutmy 29er. I do quite a bit of urban city riding, but also have a MaguraHS33 installed. I’ve noticed that one of my pads hit the rim when idling from back to forward and vice versa. Almost like the rim is flexing. Not sure if I have my brake piston adjusted too close to the rim, or whether I need to tighten the spokes a uniform amount all the way around to limit the flex.Any suggestions on which is better? Kind of aggravating that I feel drag and sometimes fall out of idle because of this…

Also problem seems more pronounced with the pedals in the 150 hole. More leverage? :thinking:

You clown! You should consider circus comments to be compliments. It is not at all irrational for public to associate unicycling with circus- that is where I first saw a unicycle. Circus people tend to be very talented entertainers, and to assume you are in the circus maybe she thought you looked entertaining. It is a pity you can’t answer “Yes I am with Greentop”, because maybe you aren’t skilled enough despite your top of the range KH big wheel. You can’t define what other people find entertaining, and your form of transport is entertaining to others!

I have only changed to the 150mm hole twice since December when I got my 29er. I have only regretted not changing a couple of times while doing steep offroad stuff, but I usually can’t be bothered cos it involves changing the seat height as well as the pedals. I would never want to ride 150mm for on the road, I much prefer my 36" with 114mm cranks for that- 125mm max. The 29er is good for short journeys and mucking around with staircases and stuff that might bend my other softer unicycles. I miss the bounciness of my 24x3" Gazzaloddi but since I love the big wheels the 29er seems like a logical choice for an XC MUni for me- I hardly ever go offroad any more.

You’re definitely seeing flex, either in the frame, the wheel, or both. If the spokes seem loose, tighten them up. If the spokes seem tight, it may just be that your frame is flexy. It could also be that your bearing holders aren’t tight enough.

That’s a debate that’s been done to death on here in years gone by :slight_smile:

Personally I’ve mellowed over the years and reckon it’s pretty much done to the individual rider as to whether they’re going to laugh off circus comments or react by trying to educate the public.

I go for the second approach.

As you believe that the fact that a member of the public’s view that “unicycling = entertainment”, then I’m sure you’ll allow me the same right to personal opinion when I believe that 'the public’s view on unicycling = irrational"

I’m glad you mentioned that, as I’d forgotten to. The change does indeed involve a seat height change.

However, on the first change (going to 125’s after several months of 150’s) I felt the seat height to be OK.

Then, when I left the 125’s on, I raised the height a bit and, after a few days riding, when I switched back to 150’s, the height was unridable.

So, the height used for 150 setting seems compatible with 125’s with no seat height change, but, not the other way round?

As a member of a circus it’s always nice when people recognize me on my wheel :slight_smile:

Crank lengths are a funny thing though. It seems to me that they require experimentation and time to figure out what length is right for you. Right now I’m doing all my distance riding on a 36 with 110s, which I find is a great balance for hill climbing and spinning away on the downhills, provided you don’t encounter more than a 15-20% grade. After that point it’s just not possible to ride up.

The more you practice with shorter crank lengths, the more you’ll see what is possible even with less control over the wheel’s momentum, because you learn to work with it instead of muscling over it as you might with longer cranks.

The biggest thing to know is that different body types (leg lengths, fitness levels, skill levels…) will all have a different ‘ideal’ crank length for a given route. It just takes some experimentation to find yours and how you work within it.

Interesting ride on saturday, as-

  1. i wasn’t alone
  2. tackled a couple of the really steep hills with the 125mm cranks

I was riding the KH29 with cranks on 125 setting, joined by Andy who runs the local uni hockey team- he normally rides a 20"-er, but today he used my Nimbus with 700x40 tyre with 150mm cranks.

Also present was Chris- a non-unicyclist who uses a longboard, he’d brought a camera to get footage of the ride.

First part of the ride was just heading into town, riding flat/mild downhill road as Andy got accustomed to the big wheel.

I tried to do a bit of filming by just holding my camera- the resulting footage was pretty shaky.

Chris on his longboard was swooping around, also filming and some of his footage was pretty good as he could squat down on the board and get some nice low-down shots.

We decided to ride through Sheffield’s tourist feature, the ‘Peace Gardens’- we knew we’d have to be in and out pretty quick as the security down there are highly averse to anything remotely ‘unusual’.

My plan was to just ride through the area with giant reflecting sphere and get some footage of the unicycles reflected in it.

However, within seconds, the security/‘city center Ambassadoors’ had appeared and were trying to wave us down.

Normally, i deliberately avoid these situations as I know that no amount of rational discussion/reasoning has any effect when it comes to these kind of officials.

On this occasion, I just got a bit annoyed- years of frustration at the way this country is going and the way that over- keen health and safety and a host of petty officials constantly getting in everyone’s face just seemed to build up and I thought f*ck it, I’m going to ride this bit and get footage and not waste my time trying to talk to these people.

And that’s pretty much what we did, we were going fast enough and were manouverable enough that they couldn’t actually stop us and, each time I got accosted with a ‘excuse me sir!’ or ‘can you stop riding that for a minute please’, i just said ‘hi’, smiled pleasently and, rode on.

I continued into the seated/fountain area, which, originally I had no intention of, but, seeing as the petty officials had harassed us while we were ridng through the reflective sphere area (which was virtually devoid of members of the public and so, even if we’d been not the excellent and safe riders we were, there would have been no danger to anyone) me and Chris (on the longboard) continued riding and getting footage.

Then I saw that Andy had been forced to dismount by the security, so I called it a day and rode over, then dismounted.

The security guy then said something along the lines of ‘do you realise…’ and I butted in with, ‘do you realise how safe we are on these things?’ and, as always,would have been happy to prove that to him with a small demonstration.

But, all he was interested in doing was reciting his standard script about endangering the public, so, realising there was not going to be any l constructive dialogue, we walked off, at which point the security guy said something about us not respecting him.

Having rode on further, i started to question the wisdom of my actions- there’s a good reason I usually avoiid these scenarios and that’s because, currently, I don’t seem to get any hassle while riding on the roads/paths of sheffield.

Of course, there’s no reason I should, i make a point of riding responsibly (the fact that I were helmet etc probably helps there as well) and, personally, I’m not into the ‘riding stairs/grings/stunts’ that can attract the attention of officials.

I’m aware of the fact that the ‘city center ambassadoors/private security/council security/restrictions/regulations’ is, in the near future, only going to get worse, not better and, I didn’t want this guy reporting back to his team manager that there’s a stroppy unicyclist which could lead to possible hassles/restrictions for all unicylists in the city center in the future.

I also genuinely didn’y want him to feel insulted- at the end of the day, in his eyes, he was only doing his job and, I expect that it’s a job which has more than it’s fair share of hassles from the public.

The upshot was, having rode around and thought about it for a while, I decided to go back and offer a apology- not an apology for wanting to ride round the sculpture/spheres area, but an apology for the dialogue and any feelings of disrespect it may have brought about.

So, I did- I went back, rode up, dismounted and, said I didn’t intend any disrespect,that I understood he was doing his job as he saw it etc.

of course, he soon went into ‘public education about the dangers of wheels’ mode, which I didn’t want to get into, so, I stuck out my hand, said ‘are we OK then?’ and we shook hands and left it at that.

Which i thought was a good result for everyone.


Then it was time to head home and we took the opportunity to attempt a couple of the monster hills I’ve mentioned previously.

First, Blake street with a grade of grade is 16.8% for the first 333 ft.

With me on KH29 with 125mm cranks and Andy on the 700c with 150’s- I’ve ridden up many times before on my 24x3 with 150’s and, I think,in the past may have done it on a 29-er with 150’s.

For me, this is the first time with 125’s and, for Andy, he normally rides a 20"-er and,I believe, hasn’t tackled any steep hills.

Surprisingly, i do actually made it up the first half of the hill, then I encounter a rough patch of road at the same time as a car appears in front and i dismount.

Then, it’s on to the really steep one near my house- grade of 19.6% and length is 225 ft.

After a short period of looking up at it and feeling an appropriate amount of respect for this majestic mountain, me and Andy start our ascent.

Andy soon pulls in front of me- very impressive for someone who’s not used to either hills or big wheels to go up with such confidence- I certainly didn’t do anywhere near as well the first time I tackled this hill.

In the near future I’m going to upload a short video clip of this climb- I’m not sure the steepness is apparent on the video, but, the fact that there’s handrails on the footpath should be a giveaway.

On the clip you can actually see the difference in the crank lengths- Andy, on the 150’s, is pedaling quite smoothly with no hands on the seat- in contrast, with me you can see some of the characteristic ‘pendulum/momentum’ effect of the 125’s and, my hand is very definitly on the handle, in fact, clutching it and pulling up as if the climb depended on it (which it did).

Andy, now if front, gets stupendiously high up this hill of hills, before wavering, moving into increasingly zig-zaggy motion and, finally, UPD-ing.

At this point I’ve pulled of in front- what the video doesn’t convey is how close to dismounting I was- I think the only thing that kept me on was the fact that it was being videoed and I just wanted to get it over and done with.

The end result is that this hill, is doable on 125’s, but, I’m not sure you’d want to do it as anything but a stunt. In terms of practical riding, you’d probably either get off and walk,or, find a different route.

But, it’s good to know that it’spossible.

Another positive is that, as I’ve previously mentioned, my personal rule for steep hills is that, if I can get up it, then I’m happy to try riding down it, so, in the rides since, I’ve been riding down with the 125’s, something I wasn’t totally happy with before.

The other thing about this ride is that I had a lot of fun- pretty much 100% of my riding over the past years has been alone and, it was a nice change to have a couple of riding buddies for the afternoon.

(I’ll try and get the video clip up tonight)

I agree, I went out for an hour today and, the 125’s now feel completely ‘normal’, i would expect the 150 setting to feel very clunky now if I switch back.

In terms of riding, I’m happy with the 125’s- I can still feel the pendulum/momentum effect on really steep stuff (I rode down the steep hill today and, though it was fine, I definitly needed more focus and handle control than with the 150’s).

I’m feeling now that 125’s are going to be my standard length on the 29-er for the forseesable future.

I’m even thinking about digging out my 110mm square tapers and putting then on the 700c.

Here’s the link to the movie clip I promised of the hill climb-


it’s 2.8 Mb- please do a right click and download it to your pc, where it can be yours forever- I’d much prefer you to do this rather than streaming it, as that will eat into my bandwidth.

here’s the text relating to the climb from my previos post-

Great write up…good enough to make me buy some dual 125/150 cranks for my KH29.
I’ve only had the 29 for a week, and have only been Unicycling for 6 months, so am really inexperienced and all changes are really felt.
My weeks worth of 150mm crank cycling (probably no more than 30 miles) has been great, freemount ok (70%) and loving the greater speed (compared to my 24")…so I then swopped over…AWFUL, really awful - it felt like I had gone back several months on my learning curve. Struggled to freemount, kept UPD’ing (forward for some reason!) and generally it felt all wrong. How 25mm can make this difference is beyond me.
…however by the end of 5 miles I began to get the ‘feel’ of them - that lovely point where it all comes good. Checking with my GPS my max and average speeds over a compared 2 miles was about 2 and 1.5 MPH higher, it felt more. Hill-wise they seemed about the same (wrong I know, just my first impression).
I think 125 will be my Length of choice, so thanks for the inspiration.

Great thread! I was just looking at the Nimbus 29" and upgrading the cranks to dual holes would increase the price by 20%. I’m pretty sure I won’t be changing the settings during a ride. For road and fairly mild XC it looks like most people started with 150 and after trying and getting used to the 125 hole they end up using 125.

For a beginner like me coming from a 20", is there a point in starting with 150 to get used to the bigger wheel or should I just go strait to (a single hole) 125, which is the default configuration for the Nimbus?

If you’re riding on roads, just go with 125mm. It’ll only take you a little bit of practice to get used to it.

I would not bother with the dual-drill unless you are planning to do real MUni on it.