Lightening my UDC 36

Okay I love my UDC 36 but I find that it does feel very heavy to me especially going uphill after 20 plus km. I would love to have it rebuilt to as light a uni as possible.Would love everyones input on the best way to do this or even whether it is worth doing; or should I consider another uni altogether.would i be able to get similar speeds on a 29 with short cranks?
would a geared 29 be the answer? I have trouble mounting my 36 so am going in circles deciding what to do and well geared unis are pretty expensive.Help!!! need advice!!

Is it the older steel or the newer alloy rim?

well i bought it second hand so i dont can i tell? my uni weighs about 8kg

If its alloy it will be a nimbus stealth and it will be written on the rim,if its steel a magnet will stick to it.

8kg doesn’t seem too heavy to me. Mine weighs about 8.3kg according to my scale, which might not be very accurate, though. And that’s with my long touring handle, aluminum rim, nightrider tire and alu cranks and bike seat, as shown in the pics.
Have you tried longer cranks yet? They make climbing a lot easier on 36er. But of course the smaller the wheel the easier it will climb too. Weight wise my geared KH26 is only about 500g lighter than the 36er. But it definitely climbs steeper hills.

As mentioned, if it’s a steel rim, a magnet will stick to it. (It’ll also be a chrome finish - possibly with bits of rust). If this is the case, then changing to an alloy rim will save a lot of weight.

If it’s already an alloy rim, there are a couple of threads on here show how people have drilled holes in the inner wall of the rim to save weight.

You can probably save weight on the tyre too. If it’s a TA tyre (look for TA in big letters on it), you can trim off some of the outside tread. These tyres last for thousands of miles, so trimming a few mm off all round might be worthwhile too.

I would assume that it’s got a 36" inner tube, which is very heavy. Swapping to a 29" tube will save a lot of weight too. Again, there are a few threads on here with details on how to do it and the pros and cons (to surmise though, pro: saves a lot of weight. Con: Very hard to do. Might take a few goes to get it to work. not feasible if you’re out and about a long way from tools).

You could also look at doing a tubeless conversion, which saves the weight of the tube entirely (well, except for a bit of goo).

Other things like swapping for alloy cranks or magnesium pedals are worthwhile too.

Despite all of those options, I traded my Nimbus 36 for a 29" Schlumpf unicycle. It’s much lighter, easier for me to ride, quicker in high gear, and better on hills in low gear. For me, it was the best decision I’ve ever made. ymmv :slight_smile:


If you have extra thick, 12 gauge spokes switch them for 14 gauge, use the spoke calculator at to work out the length you need.

The 29er tube is easy if you’ve the right tools and a nextra pair of hands: I was lucky it worked the first time I tried it - with a variety of methods I’ve saved over a kilo on the weight of an old steel 36" wheel (coming to you in an issue of Uni Magazine soon…)

I haven’t found it that hard (although you’ve certainly got to be a bit more careful than normal), and I promise I’ve only got the one pair of hands and normal tyre levers. What seems to make it much easier is leaving the tube over-inflated for a few hours to stretch it before fitting.

It does make quite a noticeable difference in weight compared with a proper coker tube, and I haven’t had any reliability problems (never had a puncture).

Like people have already mentioned, if yours is an old steel rim with 12 gauge spokes then upgrading to an alloy one and 14 gauge spokes makes an enormous difference (I think I saved about 1300g when I swapped mine).

Then there are more extreme things like shaving tread off the tyre (I think people have managed to lose a hundred grams or so that way) and drilling the rim. And cutting down the saddle foam or using a carbon base, but that’s not so noticeable because it isn’t rotating.


I really cranked on everyone a year or so back

I have a steel radial, the heaviest 36 going. I then proceeded to fasten 3 Velcro ankle weights evenly around the wheel, adding 4 lbs. Why ?, because it was easy to do and I wanted to see how bad it would suck.:wink:

Few seemed to believe me, when I posted the awesome results. For that matter, I didn’t believe myself either, and took off the weights after I was done bragging about them.

I will bring the weights to any uni event I go to because It will blow riders away. The weighted wheel wasn’t much harder to turn. The physics of it show that I must exert 2 % more energy to ride it up hill. Big deal. That wheel was as stable as a Segway gyro thing. Minorly harder to accelerate, it was super smooth and actually faster. No one seems to believe that, yet once I spooled that puppy up it flew.

So I guess my comment is that there is also a downside to making your wheel lighter. I would say just enjoy it as it is, or sell it and buy a lighter ride.
I can idle my 29 but not the 36, I guess a lighter wheel would help with that, but personally, I am going to keep my heavy 36 the way it is because I like it and it is a compromise. Lighter means more $ and less gyro stability. It doesn’t help on hills except that tiny % of the total weight of you and the uni. Actually, it is easier to pump hard into a heavier wheel, because it is smoother (flywheel) and more stable (gyroscope). I am not saying lighter 36 wheels are a waste of money, just that I wouldn’t expect a lighter wheel to climb hills noticeably better, and they are less smooth and stable than the set up you have now.

Yeah, that’s why you see Tour de France cyclists riding on bikes with tractor-trailer wheels.

Or, not.

The weight of a Coker wheel sucks. Reducing that weight will make it suck less. The fastest time on the Mount Diablo hill climb (1:13, which is at least 5 minutes faster than the known second-fastest time) was set by a guy (Glenn Drummond) who is not among the big names of unicycling–he just happened to have a carbon-fibre unicycle with a drilled rim, tubeless conversion, shaved tire and shaved pedals, bringing the total weight down to 13.5 pounds (6.1 kg), with most of the savings in rotating weight.

Yes. Heavy wheels feel nice when cruising along. They go straighter and are really stable. But try playing basketball on one, or doing some other performance-intensive activity and you’ll become very aware of your wheel weight!

By contrast, a lightweight wheel will feel squirrely, won’t seem to want to track straight, and will usually have a high-pressure tire that will ride like crap.

So if you want to cruise (or enhance your workout), go heavy. If you want to win races, go light.

thanks everyone youve given me lots to think about. I tested the rim with the magnet and it sticks no question so i definately have a steel rim. Im relieved to know at least im not being totally wussy complaining about the weight of a lighter 36 version. when i said its 8kg thats really rough as i measured on a very old crap pair of scales. I think i mite try some changes like the alloy rim, thinner spokes and 29 tube and see what difference this makes. Im sorely tempted to go a geared 29, still on the cards.( especially after some of the comments) BUt i am still curious to know on a non geared 29 with shorter cranks can you get comparable speeds to a 36? I want to cruise and race on my 36 so the decision is not so straightforward.But even if i just wanted to cruise i am deadly slow and need to half my riding times. Thanks for all your input so far,very much appreciated!!!

In general, yes you can go quite fast on a 29er - obviously you have to spin a bit faster than on a 36 to do the same speed though. There’s something about a 36" wheel that just feels very different though - probably partly because of the higher gear and partly because of the heavy tyre.

A guni feels very different from a big wheel to ride. In my limited experience of gunis (a few short rides on borrowed machines, 29" and 24") they feel much more skittish and take more concentration to ride than a coker. That feeling would obviously get better with practice, but from what I’ve heard from experienced guni riders it never really goes away.

When you get to the point where your top speed is limited by spinning speed, a guni (29 or 36) would help, but up to that point a normal 36 is probably nicer to ride. Personally my top speed on a coker is limited by bravery (I’m too chicken to go faster than about 15 or 16mph), but I can go very nearly as fast in a sprint on my 26" muni, so I can theoretically spin faster.

Some people can spin like maniacs on a small wheel and get up to quite high speeds (like people track racing on 24" unis) but it’s much nicer to be able to ride along on a bigger wheel at lower cadence.


EDIT: Sorry, that got a bit waffly, haven’t quite woken up yet… hopefully some of it makes sense :o

I actually found it no harder than fitting a correct inner tube, but I didn’t want to say that as so many people have had problems :slight_smile: I probably did pre-stretch the tube overnight though.

If you really are tempted with a guni, and can afford to do so, then whatever you do to your 36 will never satisfy you. A geared 29 is a very different animal, and for me personally, it revolutionised the way I look at riding any kind of distance. Sure, there is something very special about being up on top of a 36" wheel that you won’t get with any other unicycle… but then again, there’s nothing else like a 29" Schlumpf either!


Or a geared 26. I love mine with that nice fat Gazzaloddi. The dual hole cranks make it a 4 geared dream machine. The only thing missing are the brakes. But still I love to ride my ungeared 36er and KH24. They all have their advantages.

I think we have the same uni, a Radial 360, now off the market.

I would advise against upgrading the wheel. You can buy a whole new alum rim wheel set from Coker for not much $. If you take apart the steel wheel you will bin the parts. The UDC super wide square hub on the Radial is the only part you would be salvaging, and that’s not worth much. Better to have a spare wheel. Make a light ISIS knobby wheel for muni or hill riding, and save the smooth TA and not so strong steel wheel for levelish touring. It’s a waste of labor and parts to take apart a perfectly fine steel wheel just to throw the rim and spokes away.

I totally agree with ^ that having a 4 lb lighter uni is a 3ish % advantage in an up hill uni race. However, it won’t make riding uphill easy, or feel much different than before.