Schwalbe Ultremo blowing off rim

[Comedian]

- You're not using nitrogen.

Strange comment since the air is 78% nitrogen.

Did I miss anything there?

Yes.

- Rims not able to handle the pressure.

I'm sure I read that at least once.

Sssshhhh... I'm pretty sure I made the one up about the nitrogen... and the Ultremo bondage props.

Yep, I forgot the one about my $2000 durace wheels allowing tyres to blow off at less than 8 bar - 2 bar under the stated max.

[Comedian]

For those with Ultremos with the threads hanging off this may be of some interest.

Currently in email conflab with Dave the man at Schwalbe - very helpfu - have sent him photos but beforte he received them he sent me this, which is interesting so I thought I'd share (I didnt realise that the ultremo ZX HD were essentially race tyres with minimal armour - d'oh - I thought they were actually meant to be heavily armoured)


"The HD SpeedGuard is our very lightweight puncture guard protection
for competition tyres. Although effective against small shards and
thorns, anything larger will of course penetrate the puncture guard
layer. Something like the Durano Plus will have faired better but the
weight compromise is substantial.

If what you can see are loose threads that you can pull away from the
sidewall then this is part of the chafer. It's made up of woven cotton
material, which prevents the carcass chafing on the rim. Some of these
cotton yarns are not clamped in between the rim and tyre bead and
become loose, because of insufficient rubber coating. You can simply
cut the yarn and go on riding

It is not dangerous because the chafer is a separate part of the tyre
and doesn´t belong to the carcass. Some tyres don´t even need a
chafer. Even if you completely remove the chafer (and this is only
possible if the tyre is off the rim), the bead is still completely
hidden by the carcass."

[Comedian]

For those with Ultremos with the threads hanging off this may be of some interest.

Currently in email conflab with Dave the man at Schwalbe - very helpfu - have sent him photos but beforte he received them he sent me this, which is interesting so I thought I'd share (I didnt realise that the ultremo ZX HD were essentially race tyres with minimal armour - d'oh - I thought they were actually meant to be heavily armoured)


"The HD SpeedGuard is our very lightweight puncture guard protection
for competition tyres. Although effective against small shards and
thorns, anything larger will of course penetrate the puncture guard
layer. Something like the Durano Plus will have faired better but the
weight compromise is substantial.

If what you can see are loose threads that you can pull away from the
sidewall then this is part of the chafer. It's made up of woven cotton
material, which prevents the carcass chafing on the rim. Some of these
cotton yarns are not clamped in between the rim and tyre bead and
become loose, because of insufficient rubber coating. You can simply
cut the yarn and go on riding

It is not dangerous because the chafer is a separate part of the tyre
and doesn´t belong to the carcass. Some tyres don´t even need a
chafer. Even if you completely remove the chafer (and this is only
possible if the tyre is off the rim), the bead is still completely
hidden by the carcass."

[jules21]

i made a discovery on this tonight!

i just fitted a new GP4000s to my new roadie. it is a tight fit on the rim. what happened to me was that the tube got snagged between the rim wall and the tyre bead. as i was in a hurry, i got a tyre lever and levered the tyre over. now with other tyre/rims combos which i've used and which have been a looser fit, this hasn't been a big problem. but in this case, the tight fit meant that the tube remained snagged under the tyre bead, even after the bead was seated properly in the rim. it is very difficult to un-snag it once it is seated.

now due to a combination of being late and stupidity, i inflated the tube, hoping that the pressure would pop it back under the tyre bead. i was wrong. about 10 minutes into my ride, the tube exploded - splitting along the section which had been snagged under the tyre bead - and popping the tyre off the rim along the same section.

so there you go - that's one way to blow a tyre off a rim.

[Comedian]

i made a discovery on this tonight!

i just fitted a new GP4000s to my new roadie. it is a tight fit on the rim. what happened to me was that the tube got snagged between the rim wall and the tyre bead. as i was in a hurry, i got a tyre lever and levered the tyre over. now with other tyre/rims combos which i've used and which have been a looser fit, this hasn't been a big problem. but in this case, the tight fit meant that the tube remained snagged under the tyre bead, even after the bead was seated properly in the rim. it is very difficult to un-snag it once it is seated.

now due to a combination of being late and stupidity, i inflated the tube, hoping that the pressure would pop it back under the tyre bead. i was wrong. about 10 minutes into my ride, the tube exploded - splitting along the section which had been snagged under the tyre bead - and popping the tyre off the rim along the same section.

so there you go - that's one way to blow a tyre off a rim.

Good work on the research!

Since replacing rim tape I've not had one blow off on any rim. In fairness the c50's haven't had a lot of miles... but the tyres are still firmly stuck on.

[VRE]

I haven't read this entire thread, but in case anyone wants to know: I had a Schwalbe Marathon Plus tyre blowing off its rim 3 times in about that many weeks last year. After some discussion with others, I found that it was actually the tyre that was defective. It looks like the tyre bead wasn't tight enough, and so it was coming off the rim under pressure. After replacing it with another, the problem vanished. This is the only Schwalbe Marathon Plus tyre I've ever had this problem with, though: all the others have been great.

[Jono L.]

FYI,

I've only just seen this thread, but about 4 years ago at the VIS the local schwalbe rep sent us a pile of Ultremo tyres to ride. They had been having problems with the tyres having 'eggs' develop in the sidewall and then being blown off the rim. So we got about a 50% chance I reckon of getting a great tyre for free or an excellent lesson in bike handling

Interesting to note the problem hasn't been nailed..

Having said that I have since bought some ultremo's for crit racing and they've been great...

[jules21]

about 4 years ago at the VIS the local schwalbe rep sent us a pile of Ultremo tyres to ride. They had been having problems with the tyres having 'eggs' develop in the sidewall and then being blown off the rim.

what a guy

[eeksll]

Since replacing rim tape I've not had one blow off on any rim. In fairness the c50's haven't had a lot of miles... but the tyres are still firmly stuck on.

anyone have any theories as to how rim tape causes the tyre to blow off the rim?

[bosvit]

Since replacing rim tape I've not had one blow off on any rim. In fairness the c50's haven't had a lot of miles... but the tyres are still firmly stuck on.

anyone have any theories as to how rim tape causes the tyre to blow off the rim?

Over time the edge of the rim tape (only the plastic type) chaffs and can get a sharp edge, causing the tube to split and explode unlike if it was just a puncture.

The quick release of air causes the tyre to blow off of the rim.

It's happened to a couple of the guys who race at Whyalla. It was one of the other members that told both of them to change their rim tape and neither has had a repeat of the problem since.

[macca33]

Good to see that so far, so good is the verdict Comedian, but I'm with others, I cannot see any necessity whatsoever to inflate to 130-140psi, then lower pressure. The tyre ought to be well and truly beaded - if correctly fitted - with no more than 50psi in it, the rest is then getting it to your desired pressure. I reckon you're stressing the tyres / rims without any real purpose.

I'm not having a crack - each to their own - I simply cannot see any reasoning in the methodology.

cheers