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
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
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.
KH dual-hole moments 125/150’s are very good- they allow an easy comparison between the two lengths on the same ride.
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)
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
Seat chaffing- I’m hoping that this will be lessened with the shorter cranks due to less leg movement