Is anyone going to be lacing a Nextie 36" carbon rim to a qu-axle hub or an aluminum hub? Would be interesting to see a super duper ultra light set-up!
You can tell when a website is using the same code, because the figure will be identical. That calculator has a fudge factor of -0.2% to seemingly account for approximate spoke stretch under load, whereas other calculators that don’t have this will measure a fraction of a mm larger.
I know this because I hassled my brother to write me a calculator to figure out every spoke length for a unicycle wheel with an off-axis hub, and he went digging around all of the existing calculators:
Is this the kind of spoke failure that brass washers are good for?
I’m a bit off topic, this happend monday on my G36 with a brauss carbon rim and the first prototype of the brakefast.
The spokes were tensioned hard between 110 and 120 kgf (24-25 on my parktool TM-1), fortunately the BF has nothing. I rode 1000 km before I had this failure.
Based on how bent the head of the spoke we can see on the right is I’d say yes (/maybe).
Based on the drawings I’ve seen, the Brakefast adapter is 3mm thick with 2.6mm holes which sounds close to the thickness where you shouldn’t need one/wouldn’t be able to fit one in though.
A sure way to decide though is when you loosen off one spoke so that it can move slightly in the flange, if it has side to side play (the head can move away from the flange) then washers would be a good idea.
I do note that it’s an outside spoke which has broken though which makes me wonder whether a levering force could also be a factor.
The Brakefast adapter is straight on both sides, whereas many hubs have at least the outside of the flange at an angle, so that the spoke does not rest on the flange much (if at all). If the spoke is resting on the outer “corner” of the flange then the force of it being pulled in to the centre of the rim could perhaps introduce a very large force pulling on the spoke head (and on one side of it as they’re not sitting flat).
I’d not expect it to be so much of an issue on a 36" wheel due to the small angle we’re talking about, but perhaps it is a contributing factor. The long side of the lever would after all be ~357mm and the short side of the lever being ~5mm, making the force theoretically ~71x larger (ignoring every other factor like spoke bending etc.).
Thank you for your explanations. I put the spoke back in place, I still have 3 spare spokes just in case… I took the opportunity to check the tensions of all the spokes.
On the same occasion, I noticed a bigger problem on the external splined bearing of the hub :
To be honest, I was expecting to see tyre blowing problems with this rim.
Of course, unicycle rims have always been designed to be wider than bicycle rims. This seems fine to me when it comes to off-road riding (low pressure), and we’ve seen the trend towards wider tyres for 2-wheelers.
Except that 36" is the size where speed freaks (like me) will want to reduce rolling resistance and unnecessary energy loss by inflating the tyre higher (3 bars and more).
I am not an engineer, but it seems to me that there are things to respect (rim width, tyre width and pressure) if you don’t want to take too much risk of tyre blowing.
Without going to the extreme of thin tyres like those on racing bikes (which I think would bring their own set of problems), a 25mm internal width rim (with hooks) would seem to me to be more appropriate for road use.
EDIT : The 36" brauss rim has an internal width of 28mm (without hooks), which already seems more appropriate for my road use.
By tyre hasn’t blown of the Nextie rim, it’s been on there since Friday 10th September.
It’s inflated at 35psi which is 2.4bar and so far no problems.
Nextie hooked rims, need a minimum order of 6 units. To be able to have hooked rims in 36” from them.
It is not a high pressure. On my 36" I run at 3 bar (45 psi) and some go to over 50 psi.
Nine years ago, I first had many problems with 29" rims with 40+mm internal width and slick tyres. I had less problems with my 36" wheels (I only had one heat related tyre blowing, the unicycle was left in a car in the sun).
This kind of problem usually doesn’t happen right away, but in my experience there are some contributing factors: rim too wide, pressure too high, heat, tyre wear (tyres that have already had a blow problem are damaged, even if you can’t see it), of course the absence of hooks on the rim…
I don’t think that 29" tubes are to blame, but some tube models are not suitable (the 29" tube has to increase its overall diameter when inflated empty 29=>36, otherwise it will deform too much). I use the reference given to me by @bouin-bouin (michelin butyl airstop 700x35-47, available in europe only?) and I never had any problem. Many people use tubes without paying attention to this. Most of the time, they have a lot of trouble with the fitting (risk of pinching the inner tube).
Six units doesn’t sound at all unreasonable. What’s the price going to be?
I agree with @toutestbon. I have had many issue trying to fit another inner tube into my carbon Braus rim (pinching a few tubes and damaging my NightRider Lite tire ). When I switched to a Michelin Butyl Airstop 700x35-47, it became pretty easy to fit the tire onto the rim.
In Gpb Sterling they are just under £300 plus postage.
That doesn’t sound bad at all. Aren’t the hookless ones pretty close to that as it is?
I recently ordered one of these beauts (hasn’t shipped yet) and sent an e-mail asking if my specific order could be made “hooked”. Here is the response:
I’m sorry, but the 36-inch rims are now only available with the Hookless Version.
The NXT36XU42 rims are tubeless Compatible. It is no problem for you to run a tube or non-tube. Please feel free to let us know if there is any question.
That’s what they should have made in the first place. There are no tubeless 36er tires.
Not yet, but there has been talk about it for years and years.
But I think you make some good points in your Nightrider lite video to why Not run a tubeless setup.
The liquid will weigh just as much as a light tube.
Tried tubeless and the bead set solid and held 30psi over night so I decided to risk it…
I know people make these work but I am going to have to shelve the carbon rim for a while in hopes we get a tubeless tire in the future. I like to ride fast and it’s not worth the risk for me to have a blowout at speed