Hello,
I’m sure there’s a thread for this but I can’t find it.
I am wanting to build up a 29" road only Uni. I see a Mtn bike rim with a hub from UDC in the future. Possibly even building with a road bike rim and tire of 700c?
I’m looking for a very light wheel. Have these been attempted before?
I worry about the strength and only plan to ride streets.
Thoughts or concerns are welcome!
Thanks.
I assume that a road bike rim is not strong enough to handle all the weight and force. But I am no expert.
Thats what I’m thinking as well. But I too do not know. Some of these road rims are pretty tough.
Earlier this year I built up a light weight 29"* uni based on this thread: 29er rim options?
I used a Velocity Dyad rim, 700x45 Resist Nomad, 32 hole Nimbus ISIS hub, and Qu-ax lightweight 114mm cranks. Even with a cheap steel frame the whole thing weighs around 10lbs.
It’s great for rides around the neighborhood, short trips to the store, etc. You could go narrower on the rim/tire (search for road razor or bacon slicer) but I think the 700x45 tire is a good balance between light weight and still having some cushion; it rides nicely and still feels quick.
*Technically, the diameter of the 700x45 only measures 28.5" so it’s not quite a 29er.
YES thats what I’m looking for, thanks!
I have just started remembering, when you said “cushion,” how harsh a roadbike can feel…
The guni I’ve just bought is specified as something kind of like what you’re after, with a narrowish rim and 2" tyre - see spec. and pics at
Curious, so UDC doesn’t stock road unis in 29 similar to the customs that you are speaking of? What about those racing unis, or are those only in 24"?
I’m also curious as to how much of a difference in worl weight makes on the road compared to muni. More critical or less critical?
Any decently built road bike rim will work for a road uni. You probably want a wider rim if you want to run a 29er tire on it. The Velocity Dyad mentioned earlier is a great option, one of my faves; it’s not super-light but it’s a lot lighter than the MTB-oriented fat 29er rims. For tire I’d go with the Schwalbe Big Apple 2.0 or the Schwalbe Marathon Supreme 2.0, which are both an excellent mix of cushion and nimbleness, with no road camber issues.
For road-only, I’d go with 125mm or shorter cranks. My road 29er has 110s which I really enjoy.
I can definitely second this sound advice. I have a Schwalbe Marathon Supreme 2.0 on the Nimbus Dominator rim. Even at the high end of recommended pressure, 70 psi, the tire is very comfortable to ride.
I have a 29er which has the old narrow Nimbus rim on it, and I put a 700x35c tire on it, Vittoria Randonneur (rear tire I think) with Double Sheilding (I hate punctures). I’m using 89mm cranks and a Shadow handle on it and it goes pretty fast on the road. I love the way the tire and rim are so light compared to the 36". You have to pedal like crazy to get it up to speed but it feels pretty smooth and the handle helps with the twitchyness.
I still mostly ride my 36 because I find it is faster over longer distances, and slightly more comfortable because of less leg rub from less rapid pedal motion, and it feels like a natural wheel size for going places. Also the puncture issue- more rubber makes for seldom punctures. I guess that is why I am ordering a geared 36, would love to be able to try a light weight 28" schlumpf to compare maybe with 700x23c.
I have a pure road uni that has a standard hub, 36 spokes and a narrow road rim from a sports bicycle. It runs a 700c x 23mm tyre (I did go down to 700c x 20mm for a while) at about 120 psi. The uni is as light as I can get it without spending silly money. It’s fun to ride, challenging on uneven surfaces, and good for a bit of light farmtrack and byway as long as the ground is dry. Normal riding will not damage a good quality bicycle rim.
My more common road rides however are on the 36 and the KH29. The extra bit of weight and a wider tyre actually help the unit to go faster and smoother than a super lightweight wheel with a skinny tyre.
Thanks everyone for chiming in, I’m getting a lot of the info I needed.
I wondered too why I have not seen a 29", “race” unicycle in a similar fashion of the 24" nimbus on UDC.
Thats what I’m going to try to put together then I will let everyone know how it went.
Because the Std Racing Unis are 24"/125mm cranks. Not many people race 700c wheels because it is not an IUF standard (although I think John Foss did try to introduce a 700c class).
700c wheels can be competitive against 36" Ungunis…I recall the 10km at UNICON 12 being won with a 700c/65mm cranks, against quite a few 36ers; and some very fast times in Japan on 700c wheels.
Personally, I love how lightweight and simple my Std Uni is. I packed it in my bag with a weeks worth of clothes, shoes, tools weighed less than 11kg and checked into the normal luggage belt rather oversized 
If the Std class ever changed to 700c, I would love to have one built with a light rim/tyre combo. It feels so light and responsive! A 36" Unguni feels like a tractor in comparison, and a Schlumpf 36" feels like riding a cement mixer. A Schumpf 700c would be amazing though…I’ve only ever seen one of those built up, but sadly I didn’t get to ride it.
Unfortunately, most unicycle hubs seem to come in 36 hole, which limits your top end rim choices, as they usually have half as many spokes.
That’s right. A 700c class is available, but so far it hasn’t caught on. 24" is the well-established standard, but it doesn’t make sense for anyone tall enough to ride a larger wheel. Why pedal your brains out on a little wheel? Once upon a time, that was the biggest size of unicycle you could buy, but that hasn’t been the case for many years now.
Racing unicycles are limited by tire size, which for 29" wheels is set at 768mm (yes, really!). A skinny tire would be at a disadvantage over wider tires of larger diameter. But it would look sexy. 
Can’t you just skip half the holes?
That actually seems very big for a 29" wheel (for a start it’s over 30"!) By my calcs that would be a ~2.9" tyre - ie larger than anything made, hence the optimum would presumably be whatever tyre comes out largest?
It is actually quite fun to pedal really really fast on a std uni I was pretty stiff and sore after my first ride on one.
The appeal for me is that it means everyone is racing the same gear/equipment, and it is unicycling in the most basic form- no gear, no brakes…it’s just a wheel and how fast you can pedal.
Having said, that. I think having a standard that is based on what unicycles were available historically makes little sense.
700c wheels are used for road bikes, and gives us far more choices than a 24". It would take a big shift to make a new standard, but something I support because it vastly increases the equipment options available.
In terms of speed, it gets us a little bit faster than running speed. The fasted 10km standard times on a standard uni are only marginally faster than than the fastest 10km running times, and likewise for the Marathon and Half Marathon distances.