oh, this is not a simple answer I am afraid and I am going to be a bit vague. The problem is the tubeless standard(s)… yes there are 3 of them! Tyres and rims work with ERTO. This is a figure that is the inside of the tyre bead and the outside of the rim. Tyre stretch and need to fit on to the rim that does not. Traditionally there is about +1mm between the tyre and rim. The distance from the ERTO surface on the rim to the outside of the rim is traditionally 7mm, this allows the tyre to fit over it and holds the tyre in place. One of the expensive tools for rims is the one used for cutting the rims. This is like a big steel drum. Its inside dimension is ERTO + 2*7mm+cutting blade thickness.
Then come along the tubeless tyres. These require a compression fit, so the tolerance is about -2mm. So… there are 3 ways to make them work:
You can either make the ERTO of the rim bigger or the tyre smaller.
If the tyre is made smaller then it wont fit on non tubeless rims as they don’t have the smooth ramp to get the tyre seated.
If the rim is made bigger to fit the tyre at -2mm then it wont fit in the cutting drum… now you get to the fun bit, the solution that quite a few manufactures do is they increase the ERTO but leave the outside the same size, so the lip is only 5mm! Yes this works… mostly, but I am guessing you can see what happens here.
Another solution is you make both rim and tyre bespoke and you see this with tubeless only rims and tyres.
Carbon rims can do this, but… they can’t do hooks so they make hookless. This again works mostly. The problem is that the rim can not be too big or you can not get your tyres on, so they tend to be only just big enough and I suspect they are made around 27.5 rims where they work really well. On 29" they work, mostly but have more problems.
The 36" version should work as they can make the rims to fit the tyres, but there is a problem in the tyres are not made by a process used by most modern tyres, so they have a bulky bead and require to be held in more than modern flexible beads, so they are not made at -2 but at 0.
All in all… no easy solution. Just be careful when you put your tyres on rims for the first time.
no damage! It just blew the bead off the one side.
@mowcius i will likely try a Kenda tube. I would happily run a 36” tube if a presta version were available. I have drilled aluminum presta rims for shrader valves so i may consider that route if its ok to do with carbon
Carbon tends to splinter and make very fine splinters when drilled or cut into. Make sure to clean up the hole and make everything smooth again, 400 grit is what I have used on various carbon tubes for other projects to smooth them out (as carbon rims are gonna have to get a lot cheaper before I end up with one), or those splinters might end up puncturing a tube. I would also wear gloves, as it is very annoying to have those splinters in fingers for a few days while your skin attempts to digest carbon fibers and they are too small to see and remove with tweezers(ask me how I know)
I would not blame the tube. I had exactly the same thing happen on a 36" stealth rim because the tire was not installed/centered correctly on the rim. When correctly installed the tube is fully contained in the tire and rim and can not burst. If the line on the tire near the rim is located the same distance from the rim all the way around the tire, all is good. If the tire is even slightly lopsided, the bead can pop off and the tube will explode out of the opening. The tube will be destroyed but it is not the fault of the tube.
Is this something where they’d need a minimum order quantity to create the flexible tooling for it, or just an additional cost per unit and something they could have as an option?
Something like an extra $50-100 per unit for a hooked version wouldn’t seem totally unreasonable for that extra peace of mind.
(Edit: Additional discussion on the carbon rim should probably go in here: Nextie 36" carbon rim)
I wouldn’t overthink it. I’ve been running whatever 29er tube my LBS had in stock (maybe Continental?) for the last few years with no problems. I’ve even removed and replaced the same tube when changing tyres.
Remember that a blowout is caused by explosive decompression, ie the tyre either being gashed or coming off the rim and therefore being unable to support the tube. If the tube fails by itself it’s rarely very exciting.
Yeah I’m not super concerned - I’ve previously helped a friend stretch a random 27.5" onto a 36er after a catastrophic tube failure when out on a ride (none of us had spares - 27.5" was the largest the local bike place had) and he ran it for months without issue.
It’d be nice to know which is the best to go for though if there is a best option.
The best from what I’ve seen on these threads of late seems to be this one:
Admittedly these are likely on the Braus rim but this brand seems to have a good reputation as was in the video above on this thread being show it inflates evenly
