tubular tyre pressure loss

[berksboy26]

Does anyone know how long the pressure should remain at constant levels in tubular tyres?
I recently purchased 2 Vittoria Evo Cx320 tubs with appropriate extensions (they are to be fitted to Campagnolo Shamal aero wheels).Because of the extensions i pumped them to 1 bar (15psi) and checked them in a bath of water to check for leaks - nil.After fitting to the wheels and finally pumping to150psi i rechecked the following day and they were visably softer and had dropped to less than 80 psi.I repumped to 160psi and the same think has occured.They were then left for 3-4 days and were by then virtually flat.
I have again pumped them to working pressure and there is no evidence of leaking in a waterbath!
I am new to sew-ups and would appreciate any advice.

Berksboy26

 

[alienator]

That's quasi normal. The Corsa tubulars have latex tubes, and latex is really permeable to air. With latex inner tubes, you need to pump your tires up each day.

FYI, I hope you're not going to ride those tires at 150 and that you only pumped up to that pressure to make sure the tires were seated well while the glue dried.

 

[Peter@vecchios]

Does anyone know how long the pressure should remain at constant levels in tubular tyres?
I recently purchased 2 Vittoria Evo Cx320 tubs with appropriate extensions (they are to be fitted to Campagnolo Shamal aero wheels).Because of the extensions i pumped them to 1 bar (15psi) and checked them in a bath of water to check for leaks - nil.After fitting to the wheels and finally pumping to150psi i rechecked the following day and they were visably softer and had dropped to less than 80 psi.I repumped to 160psi and the same think has occured.They were then left for 3-4 days and were by then virtually flat.
I have again pumped them to working pressure and there is no evidence of leaking in a waterbath!
I am new to sew-ups and would appreciate any advice.

Berksboy26

What alienator said and no need to run these at anything above about 100 psi. No pinch flats and cornering performance is compromised with rock hard tires. PLUS very uncomfortable, another advantage of tubies lost if they are run at 150psi.

 

[berksboy26]

That's quasi normal. The Corsa tubulars have latex tubes, and latex is really permeable to air. With latex inner tubes, you need to pump your tires up each day.

FYI, I hope you're not going to ride those tires at 150 and that you only pumped up to that pressure to make sure the tires were seated well while the glue dried.

Thanks to you both for that information - its saved me ripping them off the wheels and returning to the shop for replacements!
I did only pump them to the high pressures in order to assist the glueing process - many thanks once again.
Alan ( berksboy26)