New lightweight 36er tube!

It’s finally here! Just got mine today, and it is feather light compared to the standard black rubber 36er tube. These new light tubes are clear and apparently instantly seal around nail, thorn and other punctures. This gives the rider plenty of time to repair with a patch later on.

It is also supposedly “explosion” proof, but the best part is, it is 30% lighter than the standard 36er tube, and they say it reduces rotational weight by TWO POUNDS! I took my 365er for a test ride and I immediately felt the difference, could get up to speed faster and maneuverability and overall response felt quicker too.

This is great news for those who have been trying to save rotational weight by either trying to go tubeless, or stretching 29er tubes onto the 36er rim! This new tube is probably at least as light as a standard 29er tube. Big thumbs up from me! More inf here.

any reason for the bike?

Haha yeah, it’s my LBS! :smiley:

Fuzzy math

If the new tube is 2lbs lighter and that’s 30% of the standard tube weight, are the standard tubes 6lbs?

Maybe I’m unclear on the definition of rotational weight (mathematically speaking).

I still don’t see why anyone wouldn’t just use a Schwalbe 29-er tube, when it’s installed with a little bit of care, it’ll last quite a while. My original one is going on 2 years of mostly road but some light XC muni in there…and… they’re MUCH cheaper than this tube.

Similar Mt. bike tubes (clear) require sealant to be “instantly sealable”, is that true with these or are they somehow different?

This is a quote from the email I received from UDC:

[I]“Here are the specs of the tube. They are clear because the manufacturer makes them this way, perhaps because of the type of material used to make them. The 36 inch tube is 1 pound lighter by weight and almost 2 pounds lighter in rotational weight!


“These Nimbus tubes are lightweight and have taken the 36 commuter world by storm! These tubes are explosion proof and will form an airtight seal around the nail or glass, slowing down the leak. This gives the rider extra time before they have to fix the leak. ( We have even seen this tube fixed with a lighter.)”

Hmm, I read about several people getting punctures after less than an hour of riding. I like the reliability of my heavy 36er tube.

I see… I’ve never had a puncture flat on my 36-er… Actually, I’ve never had one on any of my unis… Only pinch flats.

There might have been reasons other than the tube quality that caused or contributed to their punctures. Too low psi, pinched tube due to improper installation, etc. Could have also been earlier versions that have since been improved. I will be testing mine with long rides over many weeks, and I’ll be reporting back on my experience.

Was the tube stem installed with a grommet to account for the narrower profile, or did they just center it in the same hole in the rim?


The tube came with a small square adhesive rubber strip, with a hole in the center, the same diameter as the stem, but we decided to put it inside the rim. for the outside, I just used a small strip of velcro–the softer, fuzzy part–and wedged it between the stem and the hole. I suppose another way would be to use a couple layers of shrink tubing to increase the diameter of the stem, taking up the extra hole space, and also “rubberize” the outside, since it’s bare aluminum.

a valve cap? come one lose some rotational weight for free!

My experience with the FOSS tube was that it was 8oz lighter than the 36" tube that it replaced (the fish scale I have has a 1oz resolution), but my 36" tube is one of the lighter ones I’ve seen.

I think the tube could use to be a little larger in its major dimension. It is a little tight, which makes it difficult to install without damaging it. Due to the material, it is very easy to damage if you’re not careful. The first tube I installed I nicked, and you can’t patch it with a regular patch kit. I would recommend getting one bead of the tire onto the rim, then installing the tube partially inflated, and then carefully working the other bead over. Partial inflation is necessary to be sure that all of the tube ends up inside the tire and none is caught herniated underneath the bead.

Fortunately, it comes with six “special” patches. Although they adhered well, and they didn’t bubble in a bucket of water, they did not hold air overnight. I removed the patches and followed the instructions on the web to use heat to melt-patch the tube and it has been good since.

I think those stick-on patches might be fine to get you home, but the real way to fix it is with heat. I used a butane-powered soldering iron with a “heat gun” tip, rather than a lighter.

If you’re running one of the older Airfoil rims, I would recommend carefully checking and de-burring the spoke holes on the inside of the rim and replacing the rim tape. I suspect these tubes are going to be a lot more sensitive to damage from bad rim taping, especially on these rims with the tight Coker tires.

So what is the pound of difference between rotational weight and weight? If weight is added by rotating the tire surely you could save weight by stopping moving. Strange logic. I think in the real world weight will shift in the opposite direction. Stationary riders will gain weight, while riders who keep moving may lose a pound over time.

I’ve quit riding, so it doesn’t matter to me now.

When I say “rotational weight”, I mean weight which is on the wheel, not near the hub. The rotational weight of the wheel is equal to the static weight of the wheel. However, as you decrease the rotational weight of the unicycle, it accelerates easier because the angular moment of the wheel is lower (the wheel requires less torque to “spin up” to a given speed). I think what is saying here is that the wheel FEELS as if you’ve saved two pounds (I couldn’t tell the difference). The “units” of angular moment are mass times distance squared, eg (forgive me using weight as a synonym for mass), pound-inches^2, so it is nonsense to say that the tube is 1 pound lighter but saves 2 pounds off the rotational weight.

That said, on a 36" wheel it is more valuable to cut the rotating weight rather than just the static weight. makes the unicycle “snappier”. This assumes you want it snappier.

I know what you mean by rotational weight, but when a Coker tube weighs just over a pound and you replace it with a tube that weighs over half a pound, I can’t see a pound or two pounds of savings.
Foss invisible 36" tube is 247g and £21
Coker visible 36" tube is 502g (supermarket scales) 480g (Uk) and £12.50
UDC 29er tube I assume is less than 250g and is £4.30.

So saving pounds in weight does not equal saving £ in money unless 29er tubes are used.

Snappier than what? If you are already running a 29er tube it doesn’t claim to be snappier does it? The new tube is claiming to be snappier than existing 36" tubes not snappier than 29" tubes.

My Cheng Shin 700x52/47 29er tube weighed in at 178g for NZ$18, and a Coker tube here costs $45. I’m not ready for a more expensive yet heavier than what I’ve got tube. 178g seems significantly lighter than 247g, and if it is true how finicky the new tires are, I think they may not be any easier than 29er ones which seem fairly easy. My 29er in the 36 has been reliable for over a year and I’ve not yet had a puncture. My valve thingy isn’t very well centered in the hole but no problem there yet.

I like it when new innovative products come out but I don’t like deceptive marketing techniques which seem to pretend to be ignorant and bend statistics to prove whatever selling point they’ve got. Be honest! Two pounds is 907 grams, which is a ridiculous claim of rotational weight to be saving.

The real savings are still to be had in 29er tubes it seems. Foss tubes are for spending not saving.

If you replace a one pound tube with a half pound tube, there are no units under which you’re saving a pound (never mind two) of weight. You’re correct. The claims others are making are wrong. The lighter wheel will accelerate faster for the same torque. I’m using the term “snappier” to describe this. If you’re already running a 29" tube, and going to a FOSS tube doesn’t save weight, then it won’t change the feel.

Myself, I don’t like the 29" tubes. I find them too difficult to reliably remove and replace in the field. I"m glad we finally have a 36" tube at near the same weight. The 29" tube, if you can deal with the fit, is a better value.

Btw, I have seen a significant variance in the weight of Coker tubes, up to around 1.5 pounds. I think it depends on who made them and when. The one I weighted at 17oz to compare to my FOSS was one of the lighter ones I’ve been able to find.

Here’s the thing. UDC, being the awesome company that they are, sent me three of these new tubes–one 36er and two 20’s–and wanted me to test them in real-world riding, and let them know my findings.

Today I did a little 1/4 century ride on my 36er, and did notice a lighter feel in the wheel. It seemed to turn easier, especially up hills, and had a “snappier” response and overall maneuverability. No punctures, no loss of psi, no issues whatsoever. So far, so good! :smiley:

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