Continental GP5000 tubeless blow outs

[Sbudge]

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.

Obviously it might be an issue with my rims but I've not had this happen with the Pro-Ones I've been riding. For now I'll just stick to the Schwalbes I think.

 

[Milkfloat]

I have inflated some to over 110 psi. Whenever I fit tubeless, I always over inflate overnight to make sure they seal properly. Are you running them tubeless on tubeless rims?

 

[Sbudge]

I have inflated some to over 110 psi. Whenever I fit tubeless, I always over inflate overnight to make sure they seal properly. Are you running them tubeless on tubeless rims?

Yep, tubeless on tubeless rims. Not had any issues with Schwalbes on them but the GP5000s (tubeless version) on the same rims blow off at just under 80psi. I did a 100km with them at 70psi or so and they were lovely. Following weekend when I topped them up (they'd lost a bit of course) I overdid it and at about 78psi 'BANG'! I refitted them and checked with a different pump as I was surprised at such a low pressure, same result. They've now come off the bike as, even at the recommended 65psi, I don't fancy the potential results of hitting a ridge/pothole on a high speed descent and losing the tyre completely,

 

[Milkfloat]

Yep, tubeless on tubeless rims. Not had any issues with Schwalbes on them but the GP5000s (tubeless version) on the same rims blow off at just under 80psi. I did a 100km with them at 70psi or so and they were lovely. Following weekend when I topped them up (they'd lost a bit of course) I overdid it and at about 78psi 'BANG'! I refitted them and checked with a different pump as I was surprised at such a low pressure, same result. They've now come off the bike as, even at the recommended 65psi, I don't fancy the potential results of hitting a ridge/pothole on a high speed descent and losing the tyre completely,

That sounds a bit scary, difficult to know if to blame the rims of tyres. Certainly the ones I fitted for a friend (who loves them), were pretty tight to go on and sealed nicely. Conversely I needed an extra strip of tape to help my Schwalbe's seal on my carbon rims.

 

[Sbudge]

That sounds a bit scary, difficult to know if to blame the rims of tyres. Certainly the ones I fitted for a friend (who loves them), were pretty tight to go on and sealed nicely. Conversely I needed an extra strip of tape to help my Schwalbe's seal on my carbon rims.

They sealed just fine... it was the rather loud 'unsealing' that's the problem!

 

[Racing roadkill]

It’s also dependent on exactly how much, and which sealant you use. With the recommended amount of a more viscous sealant, I wouldn’t go above 60 psi. The less viscous sealants and I probably still wouldn’t go above 70 on a road tubeless.

 

[lane]

What rims are you using? I have 32s on my bike and initially inflated to 80. Am thinking of running around 70-75.

Some tubeless ready rims are more secure than others.

 

[lane]

It’s also dependent on exactly how much, and which sealant you use. With the recommended amount of a more viscous sealant, I wouldn’t go above 60 psi. The less viscous sealants and I probably still wouldn’t go above 70 on a road tubeless.

Not really sure about that the 5000s have an airtight layer on the inside of the tyre so can't see it would make that much difference although my experience with tubeless is admittedly limited.

 

[Racing roadkill]

Not really sure about that the 5000s have an airtight layer on the inside of the tyre so can't see it would make that much difference although my experience with tubeless is admittedly limited.

I’ve not tried them yet, but they will have to go some to beat the Mavic USTs. I’ll get some at the bike show later this month and run them back to back.

 

[dan_bo]

Sounds like a right pain in the arse to me. Is it worth it?

 

[Racing roadkill]

Sounds like a right pain in the arse to me. Is it worth it?

It’s always been worth it on mountain bikes. It didn’t used to be quite such a worthwhile exercise on a road bike, as the earlier attempts really didn’t work well enough to make it worth the effort when they went wrong ( punctured / burped / came off the rims ) but I’m using the latest Mavic USTs on one of my bikes at the moment, and the extra comfort afforded by the low pressure running, and the fact they seem to have sorted all the other issues out, does make it a worthwhile exercise.

 

[lane]

Jury is out for me because I haven't used them before. My thinking is I can can run faster (GP5000s are fast) but less puncture resistant tyres because most punctures will seal anyway. It is supposed t be easier to repair punctures on the road using a worm. So far set up went very well and tyres are holding pressure. They are faster than the tyres I had on previously. Time will tell how I get on with punctures.

 

[mikeymustard]

Not ridden mine yet, still setting them up but on Ambrosio P20 rims really, really, really tight, and similar to @Milkfloat I pumped one of mine up to 120psi to make sure they were sealed!
@Sbudge Conti say not to run them on hookless rims, could this be the issue?

 

[lane]

My are on H & Sons Hydra rims which are tubeless ready. Tyres were very tight to get on but did not need a lever. Cycleclinic says tighter the better and if you need to use a lever to put them on that is a good thing. @Sbudge how easy were yours to get on?

 

[lane]

The link below is to an article by the person who runs the cycleclinic who is something of an authority on tubeless and a wheelbuilder. He gives some insight into tubeless rim profiles and opines that some are better than others. Its an interesting read. Not all tubeless rims are equal in the opinion of the author.

https://www.cyclingweekly.com/news/product-news/tubeless-tyres-properly-406530