road speed question

OK, I’ve only been at this for 4 months now, and have been enjoying the h@ll out of my custom Hunter/Coker.

In the search for speed on roads and paved trails, my newbie question is this: what would be overall a faster uni: a coker with short cranks, or one of the big 48"+ retro wheels?

Wouldn’t the 48" with a thin solid tire be capable of faster top end speeds? If so, why aren’t there more of them? Are those really big wheels (w/ 60 spokes) too heavy?

I would guess that the Coker is more popular because its more popular. There is some market and replacement parts and others have it.

A coker is better than other big wheel unis due to it’s pneumatic tire which gives it a smoother ride than a hard wheelchair-like rubber tire. Also, the coker’s tire is pretty heavy which gives it more momentum and less wobble. All of this makes it a faster unicycle for long rides because it’s a more comfortable ride. For a short ride, such as a mile or two, a bigger wheel would probably be faster, assuming enough training were done on it.

Borrow UniBrier’s Tom Miller big wheel and you’ll discover why. :slight_smile: The hard wheelchair rubber tire does not get along very well with uneven pavement. Bumps are a big problem. You have to keep more in reserve with the big wheel so that you can recover from bumps.

The big fat pneumatic Coker tire is very forgiving of bumpy pavement.

Plus they’re a b!%@h to freemount for shorter-legged non-experts. I suspect better technique on a smaller but superior tire (the Coker) would lead to higher roadspeed. I’d say in the Coker vs. Big Wheel debate, however, speed would be one of the lesser factors in choosing.

If you’re asking about road speed rather than theoretical maximum speed, then the most important consideration is control. For real world high speed riding on uneven surfaces, you need to be able to regain control immediately following the most minor hiccup in your balance.

A pneumatic tyre (Coker) will smooth out the small bumps.

The right length of cranks (neither too long nor too short) will maximise your control, therefore your confidence, therefore your speed.

Within certain limits, a bigger wheel will always be faster than a smaller one. Those limits may vary from rider to rider. However, the weight an the lack of a pneumatic tyre would (I guess) make a big wheel slower except in ideal conditions.

In the real world, there is maximum speed, cruising speed, average speed (when riding) and average speed (including stops). A Coker or a 28/29 will provide a good combination of 2 or more of these.

Well, a 48" wheel would be faster I think, mainly because I find myself limited at speeds to how fast I can move my legs round, I’ve got plenty of strength left to push it round. A coker with short cranks will probably still have the same limits of how fast your legs can go round, with the exception of fear.

With shorter cranks you can move your legs round faster, because they have to move a shorter distance to go in a circle.

I think the 48 would only be any faster on a very smooth running track and even then it’d be debateable. I’ve definately upped my speed loads on the 29er by going to a wider tyre, not quite a third increase, more like 20%, but that’s only with a slight increase in tyre width and both with pneumatic tyres.

The other thing to bear in mind is that solid tyres supposedly have more rolling resistance than a normal tyre of the same width and hardness, because the whole tyre has to flex, not just the outside of it. Apparently that’s why solid rubber tyres for road bikes are so terrible.


Thanks for all those thoughts. My assumption was that with 5" cranks on both the coker and a 48", that the 48" would be faster hands down. Maybe not because of the tire?

Has anyone ever tried fusing together 2 tires to make a 48" clincher or sew-up tire? Is that too wacky to try??

I bought a 43" Sem solid tire uni a couple of years ago. Before I got it I asked these questions of several people who had ridden different solid wheels. Most everyone told me to just get the Coker instead because of the rough ride of wheelchair rubber. I still had to give it a try. I thought I would learn to ride progressively larger wheels faster and faster until I couldn’t reach the pedals or couldn’t duck under all the trees. At this point I had logged many thousands of Coker miles.
The 43" Sem is a lightweight, beautiful, fun ride; but every time I got it up to speed I would have to shut it down for some reason (road surface,wind,sloped surfaces and hills were all more work than I could believe). The tire never fit as tightly on the rim as other skinny tire big wheels I have seen(but not ridden). I would think that a Tom Miller would have been better for speed because of the fatter rounder more snugly fitting tire and the fact the uni is much heavier(which I think is a good thing in this case). I don’t have an opinion on rideable bicycle replica or any other brands. Also, keep in mind, that it’s much worse falling off a bigger wheel, and don’t forget about head clearance issues where you ride.

I ended up selling the 43" Sem to John Drummond. I think he told me it doesn’t get ridden much anymore.

So, have fun whatever you ride, and if you like something bigger than a Coker, let me know.

Tom Miller has done this. You might ask him.