Any info on expected internal width? I hope we’ll have something pretty narrow
When driving back from the Mont Ventoux Unicycle Challenge, we were discussing with @muni_ben about narrower 36er tires. It’d be great to be able to have better, lighter and slightly narrower (~2") tires in the future. Having a rim that’s ready to receive such tires would be great… And may help manufacturers to go this way
My next task (now done) is now to send a message to Vee Tire. They may help us in making such a tire
We could maybe ask Innova as well, but I’m not sure they can produce a modern 36er tire (or we should already have modern NightRider & King George, right?). @rogeratunicycledotcom, any idea on that point?
I think not, but I can ask. One of the problems is MOQ. Typically this is 600 tyres, but we have ours running at 300 at the moment as there are 3 tyre types using the same base tools. Most “modern” tyres have an MOQ of 4000.
If you are wanting a new tyre, we need to find a use for it on a production unicycle or bike to use them. This will help the numbers. I think V- Rubber are a good option for doing small MOQ, but they are not good for using on production.
That’s why it won’t happen before 35 years. But let’s get through how I would do it:
Step 1: take control over the world.
Step 2: impose 36er as the only authorized vehicle.
Step 3: create the 36" wheel lobby.
I still have to figure out step 1, but the rest is pretty easy
I am seriously no longer worried about tyre blow offs even at 50PSI with the TPU tube.
When it came taking the King George Ultimate tyre off. Its bead was super well locked onto the rim. I mean sealed tight. Tighter than the hooks on the dominator2 rim in my view. I had to really roll it hard to get it off.
Indeed, this tire is much harder to remove than to install. It acts like a suction cup on the rim. I’m trying to get some air into the valve to make dismounting easier.
I haven’t tested TPU tubes yet. I don’t know what difference it makes to the tire’s performance.
I tend to think blow off is more a question of rim and tire than tube. But I do wonder when I see the very significant differences in spoke tension when the wheel is inflated or not. When the wheel is inflated, there’s a significant force going from the rim to the axle.
In any case, with the 70g to be saved compared with my 29" butyl inner tube, it’s tempting.
I don’t know the science behind it but my gut says that somehow thanks to the TPU being not as stretchy as a butyl tube it is going to help remove the chances of a blow off by a small amount.
It seems to match the inside of the tube more precisely and when I took it out it felt like it have created a custom fit for the rim and tyre - so much so that I imagine it is perhaps providing a more uniform support structure or all the pressure gets loaded into the tyre.
I like them so much I am tempted to convert my aluminium rim to Presta and try one there. Less for the weight saving but for the general confidence I have over how it fits and inflates.
I can totally see the logic here - and I think the blow offs may have come from older tyres or when they become generally slacker around the bead. But I still find myself thinking the TPU side of things helps avoid any stretch and distortion to the tyre when they hit bumps or even as the pressure gets applied. The tube also seems massively harder to get trapped and pinch due to how the material is less sticky and more crinkly.
As you can see I am a fan now. Just wish I could have continued riding the King George using this TPU tube without the camber issues as I liked it a ton in other areas.
That’s a common thing with TPU tubes. It is generally said that you should not use a same TPU tube with different tires as the tube takes the shape of the first tire. But we can assume that for similar-section tires, this should not be a big deal.
I agree. It’s much easier to set up a TPU tube in Braus rim as we can apply more force on it without being afraid of pinching it
I also noticed that the wheel had shifted slightly to the non-disc side.
I think the tube induces a force that goes from the rim to the hub. This force is probably correlated with pressure, and is greater with a 29" tube (for the same pressure). I don’t know if this force can modify the rim’s external diameter… and the tire’s fit on the rim…
Tension on my spokes drop from, say, 120kgf to 90kgf, after inflating a tire. That’s a 30kgf change. The only way all the spokes lose tension is if they shorten, which means the rim compressed (or shifted to one side and the other side tightened/lengthened).
With the Young’s modulus of stainless steel of 190GPa, we can calculate a 2mm diameter steel spoke’s change in length given the kgf change.
That means the rim diameter is getting compressed by about 2 * 0.17mm = 0.34mm
If the rim is stronger and stiffer, then it will compress less. If it compresses less, then we will measure less change in spoke tension. Doesn’t really matter what material, but more in the design+material. We can have super stiff and strong aluminum rim, or super weak carbon rim; or the other way around.
I agree the tube/air will compress the rim. It would be interesting, but I doubt the type of tube would have a significant effect. If you were to inflate inly a tube, how much pressure can it withstand before popping [or at the shape/volume inside the tire]?
If it is 2 psi, then the pressure on the rim would be 2 psi less than the air pressure in the tube. If TPU is stiffer than the butyl tube, and withstands 3psi by itself, then there would be 1psi less pressure on the rim.
Currently in the process of building a 36" and had carbon questions.
Does someone make one that’s reliable/good yet? I’ve bought from light bicycle in the past and love their rims on my 29 and 26. Are they good and available?
TPU tubes, where can I get the 36" one? And is it well reviewed?
I think you should read this thread you replied to for info about the Braus rim and the thread about the Nextie Nextie 36" carbon rim and make your own jugement.
Light bicycle does not make a 36" yet.
Also just for the record, I’m reporting yet another blowout for my friend. He’s using an NR Lite on a Nextie rim, no exact pressure gauge read but should be less than 40 psi.
