The Worlds Heaviest 36’’ Unicycle Wheel, a Weird Experiment

Unicycles and Equipment
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Some unicyclist go to great effort and expense to reduce the weight of the unicycle wheel. But is less weight really better for normal use? Just for the fun of it, I added 10.5 lbs (4.8kg) to my 36er wheel. The current Nightrider tire weighs 2.9lbs (1.5kg), that makes my tire and added weight about 3.5 times more then a “normal”36er tire. Changing from an aluminum rim to a carbon fiber rim reduces the wheel weight by about 1.3 lbs (600g). I would think if reducing the wheel weight by 1.3 lbs makes a huge positive difference in unicycle performance, then adding 10.5 lbs would have an enormous negative affect on performance. I did not find that to be the case.

Anyone that has reduced the wheel weight will immediacy notice that the uni feels more responsive and quicker to get up to speed. Sometimes it is helpful to push things outside of the normal range to clearly identify the advantages and disadvantaged of the issue. I have seen many riders working to reduce the wheel weight but there is a limit to how much weight can be removed. On the other hand there is no real limit on how much weight can be added and my testing may help to identify the advantages and disadvantages of wheel weight.

The weight I added can be installed and removed in a couple minutes so it is quite easy to evaluate the difference in handling that the weight causes. I used some very thick walled heavy rubber tubing for the weight and it is attached with inner tube bungees.

I rode about 20 miles (32km) with the worlds heaviest 36” uni wheel and my impressions are:

  1. The added weight makes it easier to mount, the wheel is more stable and less likely to roll during mounting.
  2. The added weight makes it slower/harder to get up to speed. This added effort is not wasted, it is just energy stored in the wheel’s rotation. This added effort to get up to speed accounts for about 0.5% of my normal ride time.
  3. The heavier wheel results in less wheel wobble when riding. This accounts for 99.5% of my normal ride time.
  4. The heavier wheel rolls over bumps and dips easier with less chance of a UPD.
  5. The heavier wheel provides a more relaxed and more energy efficient ride because there is significantly less need to correct for forward and backward balance. The added wheel weight essentially eliminates the need to apply any pressure on the pedal’s upward stroke. Any correction of balance that requires pushing on the pedal as it moves up is wasted energy. This added benefit accounts for 99.5% of my normal ride time.
  6. The approximately 5% increase in total unicycle plus rider weight is not noticeable but does cause a slight increase in rolling resistance. This increase in rolling resistance can be easily eliminated by increasing the tire pressure a little.
  7. The unicycle corners more uniformly and less jerky with the added weight.
  8. My ride included a total elevation gain of about 600ft (182m). I did not notice the added weight.
  9. The maximum grade on my ride was 12% grade (with 109mm cranks). I did not notice the added effort but did notice the smoother more uniform force to ride up a bumpy incline. I did not notice the required additional braking required on the downhill grade but did notice the more uniform speed and less need to correct for forward and backward balance on the down hill grade.
  10. Because the added weight is close to the vertical axis of rotation there is a small but noticeable affect on the ability to make sharp turns or pivots.
  11. The added weight would very likely make some tricks like one foot riding and freewheeling easier and other tricks like high jumping harder. I don’t normally do tricks on my 36er.

My conclusion;
For sprint racing on a smooth surface and some tricks a lighter wheel is an advantage. For normal road touring, mounting and riding over rough surfaces a heavier wheel is an advantage. Because of the cumbersome nature of adding weight I will not leave the weight on my 36er and will definitely not go to any expense or effort to reduce the weight of my wheel either.

A Video

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Well dang. How are we supposed to justify the carbon farkles we want now? :laughing:

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I appreciate your detailed format and experimental responsibility. I think it would be interesting to see a full technical report on this experiment. I’ve thought about the benefits of the increased angular momentum of a heavier wheel, with benefits mostly enumerated in your report above. I’d be interested to see a similar experiment performed with a power meter and a larger dataset(maybe more rides, multiple of each distance), as this would allow for better data analysis. It’s great to see that someone is out there doing this sort of experiment with this level of analysis!
Kudos to you!

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I second this notion. If you have a power meter, it would provide some great empirical data! I believe your subjective account is an accurate representation of the truth, but I would love to see the empirical evidence showing exactly how much it affects riding speed, power input, and energy expenditure in real-world conditions. Of course, these factors are not everything, because as you noted handling characteristics are probably the most important thing for a rider’s enjoyment of the ride, but I would love to know.

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@JimT Did I ever mention that you are awesome? Because… well… you are. :wink:

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I‘m pretty sure that my first UPD on my new 36er was due to me not being able to accelerate the wheel quickly enough whilst riding on a bumpy stretch of a gravel road (I was actually riding on the grass strip in the middle because of puddles to the left and right). I‘m also pretty sure I would‘ve managed that obstacle without issues on my 26er fatty or the 29er, both with obviously smaller but lighter wheels. I‘m willing to blame my inexperience with the big wheel, though.

I apply pressure on the pedal‘s upward stroke to bring my center of mass to the front and regain balance (or rather: overshoot…). Two factors come into play when doing so: 1. Slowing down the uni while my body keeps the speed. Me being faster than the uni puts my center of mass towards to front. 2. By building a „more fix unit“ between the uni and the rider when applying back pressure, I have the inertia of the rotating wheel rotating my body towards the front (like the brake caliper builds up pressure towards the frame, thus rotating the frame to the front, when braking). Lighter wheels may favour the first process, while heavier may favour the second. But both require you to push on the pedal when it‘s moving upwards. If you don‘t, you will fall on your back, no matter the weight of your wheel. Is there a physical (as in physics, not body related) reason why the second process is less tiring than the first?
So far, I‘ve preferred when the wheels of my unis got lighter. To be fair, my sample size is 2, and there was always a change of tire type involved, so your experiment clearly has a more robust setup than my experience, which was formed more randomly. And it may simply be a question of things like experience, personal preference and riding style. While I‘m usually riding on pavement, I‘m not into long distance riding and prefer a more agile handling of my uni(s), at least up to a certain point.
Who knows, maybe I‘ll give your experiment a go one day.

I did some other experiment, lately. I timed how long it took me to ride to the next town and back to go shopping. Note: I take different routes to go there and to come back home. Took the 36er on friday and the 29er today. I was a bit faster with the the 36er (14.4km/h on average vs. 13.6km/h) both from my home to the shopping centre (13:45 vs. 14:00) as well as the other way round (15:00 vs. 16:30). But the difference was greater when riding the route with less elevation gain. I attribute this to the heavier weight of the bigger uni slowing me down more when ascending a hill. I still managed to be faster than with the smaller uni, but not by much. Whereas on the way back home (with less elevation gain) I could better take advantage of the bigger wheel. So, in my book, weight still matters, and I prefer it to be less. (…and yes, I‘m not a particularly fast rider, especially on the 36er. But I‘m thinking of putting slightly shorter cranks on the 29er - this will help to better keep up with the progress I hope to make on the bigger wheel :wink:)

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This is brilliant! :smiley: I’ve reduced my 36’er wheel weight twice. First the Foss tube and after that with the Nightrider Lite. Both times the feeling was great for a week until I got used to the weight reduction. After that things felt like before and this is the reason I never had any interest in getting a carbon rim.

What Jim has done here, is inventing the ‘weight vest’ for unicycles. You put it on, train for a month, take it off and ride like superman. :rocket:

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Thanks for this experiment!
I must say that this is not a big surprise to me. Martin Charrier once said that we don’t care whether a uni is heavy, as it will only make it hard to start, which you don’t do often.

However, as you point out, there are some downsides about a heavy uni and I don’t think your results apply to all rides.
As per my experience, when riding in town, it is better to have a light wheel as you accelerate and slow down most of the time. In your experiment, you say that you accelerate or slow down approximately 0.5% of your normal ride time. That’s definitely not the case of someone who rides in town, as I do. I spend probably around 50% of my time accelerating or slowing down.
Similarly, sharp turn and agility are required to ride in town, so a lighter wheel is better.

Both elements also apply to XC or DH rides, where you don’t have a long, straight and clean road. You’ll want to be agile, and able to quickly jump, accelerate and slow down.

Last but not least, if you’re going for a long uphill ride, then a light wheel makes more sense than a heavier wheel. There’s no clear mark for defining such a ride (100m, 1 km,…?), but going up for a long time with a lighter wheel makes it easier to save energy for the rest of the ride.

To conclude: on a long, flat, clean and straight road, the wheel weight does not really matter. And that’s probably what most 36er riders do.
However, if you’d like to push your limits on technical rides, then a lighter wheel is usually better.

Anyway, thanks again for this analysis! That’s always great to gain knowledge on our sport!

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On a completely different topic altogether, I noticed you have a mechanical disc brake on your unicycle. Would you care to create a topic on your experience with that brake set up.

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What a cool experiment and simple to implement. I love seeing people do stuff like this.

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Posted a few years ago. In the time I have been using it, it has works well.

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Very cool experiment, Jim, and especially cool that it refutes some of our preconceived notions and things that seem obvious.

One thing I’d probably benefit from with the added weight is the apparent ease of mounting. My knees are approaching 60 (they’re far older than I am!), and to avoid putting too much stress on them, I mount while holding a stationary object like a lamppost. But with the added weight, it looks like your running (walking?) mount would be the way to go (from the video). In either case, you’ve inspired me to try a few walking mounts to see if my knees don’t complain too much. (That’s typically how I’ve always free-mounted unis of any size).

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Yeah, i noticed that also. I didn’t tested in so extreme way, but when changed from a light folding Continental tire to a cheap version of Smart Sam (29") I’ve noticed the uni got much easier to ride on bad surfaces. And much less likely to roll over.

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@ Jim, thanks for this post, I like the way yout think and work.

For the uphill - weight discussion, as in here

I’d like to add a thought. Carrying weight uphill costs energy, and for a 2wheel bike, that’s the end of the discussion. For my (compared to Maxence so very little) experience with uni / muni uphill riding, I find going up mild slopes makes balance easier, I can control speed and balance better than on level grounds. As It gets steeper, for me the work for balance goes up so much more than the work for climbing, that I wonder if with my limited uphill skills there could be a benefit of added rotational momentum by reducing balance costs more than I would loose for working the extra weight uphill.

What are your experienes with uphill and balance?

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Hi JimT

Nice experiment. I have always thought that in the future I would get a big carbon rim. Now my standard Nimbus 32” seems to have some advantages that a lighter wheel does not have. Noticed any change in camber sensitivity?

Claus

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I noticed no difference in camber sensitivity due to the weight difference. However I have seen a huge difference in camber sensitivity as well as the ease of riding with both hands on a handlebar and the ability to make smooth uniform turns due to tire model/brand differences. With the 36er the old Nighrider (non-light version) is quite sensitive to camber but is very easy to ride with both hands on the handlebar and does smooth easy turns just by leaning into the turn. On the other hand the new light weight Nightrider is not sensitive to camber but takes more effort to ride with both hands on the handlebar and is near impossible to make nice smooth turns just by leaning into the turn. The old Coker non-skid is similar to the new light Nightrider.

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Is the Nightrider Light marked as being „light“? I seem to remember to have read that it had thinner sidewalls. The tire on my Oracle has in my opinion rather thin sidewalls, but it is just labeled „Nimbus Nightrider“.

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No, not marked other then this:

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Thanks, Jim. Precious information, that I just had to bookmark. Turns out I’ve got the light version on my Oracle :relieved:.

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Thanks JimT
My 32” night rider has the same text so it is probably the light version.
No need for me to get the standard version then… :grinning:
My lower back is struggling with the camber sensitivity and the hard pumped tire.
On my My 26” Muni I hardly notice camber anymore.