What is the top of the line Semcycle?

I’m looking at Semcycle’s website. I’m a little unclear about something. Which is the top of their line unicycles? The Semcycle line or the XL line? Specifically, I’m wondering about their 28" unicycles. I think that part of my confusion is based upon the following facts:

The Semcycle 28 Inch is $100 more expensive than the XL 28 Inch. The Semcycle 28 Inch also has a longer warranty plus a lifetime half-price trade in. However, the Semcycle 28 Inch is also three pounds heavier than the XL and seems to be two half-tubes bolted together. Finally, the Semcycle 28 Inch seems to only allow seat adjustment at regularly spaced intervals.

So, how do you guys think these unicycles compare? Am I missing something obvious about either of these that makes one worse/better than the other?


The more expensive one uses the old Schwinn-style frame, which I don’t think anyone sane would develop today. If you’re going to buy a Semcycle, the XL 28" at $200 looks like a reasonable deal.

But I would choose either the Nimbus ISIS 29er at $300 or the KH 29er on special at $350 over the Semcycle XL. They have better hubs (ISIS) and seats (if you ride any distance, you’ll have to upgrade the Semcycle seat).

That said, one of my favorite unis is “Zippy,” which is a Semcycle XL-W frame, 700c rim, Schwalbe Big Apple 29x2.0" tire, Primo Rod seatpost with rail adapter KH Fusion Freeride seat, and 110mm Bicycle Euro cranks. The frame is pretty decent–but none of the other parts are stock on the Semcycle.

Thanks for the reply. I’m definitely heading in the direction of either a 29" or 36" uni. It doesn’t appear that there are many 28" unicycles (perhaps Sun and Semcycle, only?). Perhaps 28 inchers are a holdover from a earlier era of unicycling?


In theory, the semcycle line is their top range. In practice I think the XL is probably a better unicycle.

I’ve owned both kinds of semcycle and have reservations about the semcycle split frame design. It looked kind of cool and was very convenient if changing tyres BUT as you pointed out, you are limited to certain seat positions and I don’t think the frame design is a particular strong one. I have seen the frames bend where they join the post and holding your entire frame together with one bolt seems like a weak point just asking for trouble.

I originally had a semcycle frame on a freestyle unicycle which worked well until I started worked on 1ft skills. At this point an XL frame would have been a better shape to rest my other foot on. I also used a semcycle frame to build up my first trials unicycle (way back when there were no off the shelf trials unicycles). It was an excellent frame for this is it had the required clearance for a fat tyre, which many other frames lacked. I eventually sold it though as I was worried I would break the frame on big drops. These days there are purpose built trials unicycles and a large range of frames available which will accommodate fat tyres.

I built up a lovely 29er with the semcycle XL-W frame. I got the wider version so that I could throw wider 29er tyres in there as well as skinnier tyres. It worked really well for road riding and was good for cross country too. For more serious Muni you probably want an ISIS hub, which doesn’t fit too well in the semcycle XL frame, as it is designed for 40mm OD bearings and ISIS hubs come with 42mm OD bearings. It may be possible to get 40mm OD bearings which fit on an ISIS hub though.

I have found that when it comes to bicycle/unicycle wheels, 28-inch, 29-inch and 700c are all the same. I bought a 29-inch unicycle with a Big Apple tire. The tire says 28-inch on it. I bought a new 700c tire for my same rim and the tire says 29-inch on it.

These measurements make no sense. Seat post diameters are measured in milimeters when in fact they are exactly 7/8-inch and one-inch in diameter.

Welcome to the screwy world of cycling standards.

The Semcycle debuted in 1985. Back then, the brand choices in the American unicycle market were Schwinn, Miyata and cheapies from Taiwan (and worse stuff from department stores). The frame design is based on the simplicity and durability of the Schwinn design, but with improvements. The original Semcycles also had radially-spoked wheels. These were very stiff laterally, but very flexy in the drive direction. If you didn’t maintain them constantly, you could break several spokes in a single game of basketball.

Today the Semcycle web site still shows the Semcycles coming with a cross-1 spoke pattern, which they went to after the first year or so. Great for indoor and basic riding, but still not great for high-torque riding.

The XL frames came later, to provide a less expensive but still solid unicycle in a variety of sizes. Simple Taiwan frames.

Fast-forward 24 years and the original Semcycle has changed very little. They are more expensive than the XLs because (I believe) the parts are made in smaller batches and some high-end components are used. The original Semcycle hubs were the best you could get at the time. But unfortunately being stuck with 1" seat height increments is just a deal-breaker for serious cycling. It matters less for playing around in small areas, but for any kind of distance riding it’s a big problem.

So the higher price of the Semcycles is based on parts which are a mixture of better, and more expensive.

An earlier era of wheel sizes. Today the most common wheel size (for bikes) is 700c, which gets you a 27-29" wheel depending on the tire you put on it. There was a 28" rim size, which required a 28" tire to fit. That’s probably not what you get on today’s Semcycles though (contact them to be sure; the site doesn’t specify). For best results these days, a frame that fits 700c will offer you tons of tire choices.

As others noted, 28" vs 29" is [usually] an arbitrary distinction, based on the size of the tire; tires with 28" or 29" markings can [usually] be used with the same rim. In fact, I think the Schawlbe Big Apple 2.0" I have on Zippy is marked as 28", while the 2.3" more commonly seen on unicycles is marked as 29". The rim diameter for 700c, 29", and most 28" tires is 622mm.

The caveat is that there is also a designation 28" on some “roadster” bikes (similar to those still used in Amsterdam and some developing-world countries) where the rim diameter is 635mm. So if you’re buying a tire with 28" stamped on the side, make sure it’s right for your rim.