I’m looking for a 29" unicycle. As an alternative to mountainbike and racebike. I want to ride on street as well as trails. I have just once tried a Kriss Holm 29" with two-speed gearbox, but only for 200m.
I’m 190cm tall and have a inseam of 91,5cm.
Until now I have found just two interesting products:
Where you live is a factor in what unicycles are easy to get and what vendors are available to you. Sounds like Europe.
To use the same uni for on and off-road, you will have to compromise. You won’t want a really knobby tire, since it will be poor to terrible on pavement. But you’ll want to have some tread on there. I used to do just fine on a Schwalbe Big Apple (2.3") on dry trails, though it’s probably not very good in the wet or mud. But it’s excellent on the road.
Then get a pair of multi-hole cranks. For muni you will probably want in the 137-150 range, and for road you will probably want shorter. Both depend on the amount of hills you will be on, and whether or not you have a brake. A brake allows for shorter cranks. For my riding tastes, the dual-hole cranks from KH don’t have a wide enough spread for a Muni/Road setup but if I had to pick one, it would be either 127/150 or 117/137. Neither of those is short enough for Road riding (for me) but the long holes would work on the trails. For Road I’d want something like 100 or 110.
If you plan to upgrade with 2-speed hub (Schlumpf) you shall be more interested with KH setup due to brake fittings on frame and cranks.
The cranks length depends on many factors including your skills.
I would suggest 117/136 (road/muni) cranks. Recently I use 110/125 (road/muni) while being geared and I find it too short at some conditions.
Both KH and QX you can use in hard Muni. For difficult muni I prefer Q-axle built wheel (QX). It has inside disc, less prone for damage, and shorter Q-factor (distance beetween pedals) allowing better maneuverability.
QX is lighter and cheaper but upgrading to Schlumpf means purchase of new cranks and new frame with brake mount on right side.
Some people might try to disagree, but first things first: no unicycle can ever really be compared to a bicycle. (I don’t know how much unicycling background you have, so maybe I am telling you old news, but I’ll put this here for you to get your expectations straight) There are only two things a unicycle can beat a bike in, wich are transportability and fun.
The QX and KH are both good unicycles, the previous commenters already made the points to be made for comparing between the two. Maybe consider the Nimbus and Mad4One range too, they offer good unicycles as well. Most manufacturers have now reached a standard of quality so high that I have a hard time recommending a specific one, I don’t think there is anything major wrong with a new Nimbus oracle, QX Qaxle disk, Mad4One, or KH unicycle. I’d add a pair of dual hole cranks to any of these, and whatever saddle you prefer.
Probably more than starting with the general and subjective question “which unicycle is best”, it’s probably better to try and figure out exactly what your needs are. As I do more muni than road (and I also have a 36 for road), a good grippy (and wide) tire is very important to me. Other than the Schlumf (geared hub) limitation, about the only technical limitation of the different options is tire width. From my memory, the new KH has the most width, then the Nimbus Oracle, then the Qu-ax (don’t have one, but I think it has less tire clearance) (and Mad4-One I don’t know but probably similar to the Oracle). And actually the new Nimbus Hachet is the widest, but is overkill for road/touring. IF muni is a priority to you, then I would want width for a 2.5" to 3" tire. I also use 125/150 duals.
If you want more all-round, that’s good on the road and can be ridden off-road, then you can go with narrower and less knobby tire and probably 110/137 dual cranks.
As has been said, all these are high quality unicycles and none is a bad choice.