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Babas

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Discussion starter · #1 ·
I need a bit of a help to understand the situation - is it tire, is it rim, or me/setup...

So long story:
Some month ago, I've decided to try Continental Der Baron Projekt 2.4 x 29" as my "winter" tire set. Tubeless on setup on Ibis 942 rims (carbon, hookless, 35mm inner) was pretty easy, although I had to use charge function of my pump on one of the wheels (can not remember which). I did not have too many rides on it yet, but I really liked the way tires rode - good grip, albeit a bit draggy. And then I've noticed that tires leaked air pretty fast - in 2-4 days going from 35 psi to 10 or so, especially the front tire. So yesterday it was down to some 7-10 psi again, so I thought that maybe some additional sealant would help, but I was to lazy, so decided to pump it up a bit to keep it up. So pumped that to ca. 38 psi (rim max - 40 psi, tire - 58 psi), and left it. And then some 5 mins later tire blew off the rim with huge pop sound (and surely splashing sealant all over :( ). So there was no choice, as set it up again, so I've reinstalled the tire - was very easy, even felt too easy (I have to admit, with not much cleaning the rim or tire), put the sealant in and this time being cautious, I've inflated to 30-31 psi to settle. And in 2 mins, tire blew off the rim again, splashing even more sealant all over and leaving me one ear def almost for the whole evening :madman: Carefully inspecting rim, I found nothing strange, but the tire looks with deformed bead one one side.

So I was thinking if I did something wrong, or just had a bad batch of tires, or something else... And then by googling I found several mentions that this tire (or all Contis?) may not be compatible with hookless rims. And then speculating a bit - situation getting worse with wide rims (mine is 35mm internal)? So anyone can confirm or has more information on this? Or was it only with previous versions ? I bought tires on sale online, almost 50% off RRP price, but if production date coding for bike tires is the same as for cars, it should have been manufactured 26th week of 2017 - shall be a newer version then...

I really like the tires, but before I buy another Der Baron to replace - does anyone know the compatibility? Or shall I go the safe path and choose something like Magic Marry or Shorty (or maybe again experiment with something from Michelin, Specialized or Bontrager?)? Or is it again, me - doing something wrong..?

Many thanks in advance, as I need to order a new tire soon and got riding again!
 
This is a common problem with anything that isn't a UST style rim. There are no standards for hookless rim & tire profiles in the cycling world like there are in the automotive & motorcycle industry. Anything that isn't UST, UST profile, or designed for UST rims is a gamble.

I've seen pretty much every tire brand blow off on hookless rims which is why I refuse to run them on my own bikes. Maxxis is probably the best I've seen when it comes to not exploding, but I've still seen a couple failures.
 
IME, and I haven't had a Baron, so I can't comment directly, but conti tires have run on the small side. And your rim is on the wide side for a 2.4, so I'd think that is contributing, as well as the rims being hookless.
 
You overdid it with the pressure, but I agree that the rims are a touch wide for a 2.4 to begin with.

When setting up tubeless, especially for the first time for a tire, you're going to get some leakage. You've really gotta shake the sealant around to get it to seal. Might even be worth "painting" the rim with rubber cement or bead sealer made for car tires to encourage the seal to form at the bead.
 
Discussion starter · #7 ·
Ok, thanks all for replying. While I am not convinced that I used too much pressure (i have not reached the max, and was doing the same “stretch” with other tires), or that tire is too narrow (used Schwalbes 2.35 or Maxxis 2.4), it is probably combination of all this...

Now I need to choose some other set (debating between 2.6 MM or Bontrager SE5), and think whta I do with Conti’s - I am not sure I can sell them now...?
 
The tire bead could be damaged from blowing off of the rim so be careful. Most pumps are way off. If it reads 38psi, it could be 45 to 50 psi and without a hook it has less support to hold it on the rim.

If the tire leaks, find the leak with soap and water.

If air is leaking at the valve, then you have an issue with the tape.

If bubbles are forming on the sidewall or bead area then shake sealant to those ares and check again with soapy water.
 
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