Continental GP5000 tubeless blow outs

[lane]

I wasn't aware of the recommended pressure but now am so I will run my 32s at 65psi should be good for comfort and better for sealing punctures as well.

 

[lane]

Following on from the link above, I have conducted a test deflating my tyres. This appeared to cause the tyre to unseat because there was a poping sound and some sealent leaked out at the rim. The good news from this is that I was able to reflate and presumably reseat my tyre using my frame pump that I have when out cycling. so in the event of a full deflation I should be able to reinflate providing I can seal the puncture. My thinking is on the downside my rims are not the best profile for tubeless (despite being tubeless ready) or they would not unseat in the first place based on the link I posted. Having checked out my rim profile I already suspected this because they do not seem to conform to the best practce listed by Malcolm in the link. Also I have seen some reports on the web of tubeless blowing off Hydra rims. I will still be happy to use at 65psi and and reassured that I can reinflate on a ride.

 

[lane]

This is probably a better link than the one I posted earlier. Re reading the tyre not being retained when flat is a different issue than blowing off the rim. Still the more you know the better if you are going tubeless.

https://thecycleclinic.co.uk/pages/tech-page

 

[lane]

This link specifically deals with tubeless blowouts. They don't recomend re using a tyre that has blown off the rim and also don't recommend funning over 60psi. That is just thier opinion ofcourse but worth a read.

https://janheine.wordpress.com/2017/05/29/the-trouble-with-road-tubeless/

 

[aintegrate]

My GP5000 TL on ZIP 303 blew off of the rim with 80PSI pressure 5 miles into a ride after over a 1000 miles on this tire. This surprised the heck out of me and did not know this was an issue. I booted the tire and pumped it up to 80PSI. I hit the tire on the ground a couple of times and the tire can off of the rim again. I had to replace the tire. Will Continental take these tires back and replace them?

 

[lane]

Interesting. It is going to be influenced by rim choice - what rim are you using?

edit - can see you already stated zip 303. Quick Google designed to be run at high pressure road tubeless. Would be interesting to get some more info on what may have caused this.

 

[Drago]

Anyone tried the new(ish) Conti tubeless variant? I've been trying a set out and while they ride well they do seem to be particularly sensitive to pressures. The Conti site quotes a recommended 65psi (for 28s) and a maximum of 94psi. I inflated mine to 78 psi in error and they just blew off the rim (tried it a second time with a different pump just to be sure, same result). If that's the real (rather than theoretical) maximum then it doesn't leave much of a margin over the recommended pressure.

78 is a full 20% over the recommended max, and I would suggest that 20% is a considerable margin of excess. If it were 5 or even 10 percent then I'd agree there wasn't much of a margin for error, but 20 is definitely considerable. Try taking a submarine 20% beyond crush depth and the. complaining it wasn't much of a margin.

 

[lane]

I can't see that @aintegrate has stated the tyre width - if it's a 25 I think the pressure is OK but agreed if a 28 it's high. I stated previously I think tubeless work better wider tyres / lower pressure. Just been googling tubeless blowouts - not much on the internet but those that are seem to be running at 80psi plus.

 

[Milzy]

Pro ones are a lot more delicate I don’t rate either. Sounds like they hate your rims though.

 

[aintegrate]

I can't see that @aintegrate has stated the tyre width - if it's a 25 I think the pressure is OK but agreed if a 28 it's high. I stated previously I think tubeless work better wider tyres / lower pressure. Just been googling tubeless blowouts - not much on the internet but those that are seem to be running at 80psi plus.

I was using 28mm tires. The low pressure setting is 65psi. So do you think 70psi will work better. A further note is that I'm riding at 6 to 8,000ft elevation. That may make a difference.

 

[lane]

Yes recommended PSI is 65 max is 87. Personally I would always run tubeless near the lower recommended pressure. I run my 32s at 60-65. In theory should be OK at higher pressure but most tubeless blowouts seem to be at high pressures. Also punctures are more likely to seal at lower pressure and will be more comfortable. You give up a little bit of rolling resistance but they still have very low resistance at the lower pressure.

 

[Ajax Bay]

A further note is that I'm riding at 6 to 8,000ft elevation. That may make a difference.

At 8000 feet, the air pressure is about 11psi (cf 14psi at sea level). But you'll be inflating your tyres to a pressure which is 'compared' to the 'ambient' air pressure (not a vacuum at 0psi) so I don't see riding at altitude/lower air pressure would be a factor in your tyre blowing off the Zipp rim. And anyway the differential is only 3psi: minimal when the tyre's inflated to 75psi+.

 

[lane]

If you look at continental recommended pressure they seem to have a lower "recommended" and a higher "max" rather than a min and max. This kind of suggests they anticipate people will inflate to the lower pressure but I have also seen that they suggest that most people will be somewhere between the two which would be around 76psi. This doesn't help all that much if you were running them at 80psi would still expect them to be OK.

"We usually recommend choosing a pressure level somewhere between the recommended and the maximum pressure. The maximum tire pressure indicated on the side of the tire may not be exceeded." This seems strange in itself as if a pressure was "recommended" you would think it was what they suggested you use - but no for most people they suggest a higher pressure than their own "recommended" pressure which seems a bit bonkers.

Still I would always use the lower "recommended" pressure with tubeless.