cold air and cx tubular pressure loss

[sparky33]

Does anyone notice a dramatic loss in air pressure when running cx tubulars in freezing temps?
I'm using near new Clement MXP tubs with a bit of Stan's sealant (as a preventative). I drove to the trailhead and pumped to about 30 psi. After an hour in the freezing cold I notice a dramatic softening of the tires. Feels like 10 psi loss. I can't find a leak - no sealant squirting out. Is it just the frigid temp (30F) cooling the air in the tires? Do tubeless tubulars (i.e. Clement) lose air in the cold? I'm stumped
Same thing happened at a race this weekend (also very cold).

This is a question of curiosity mostly. I do still love these tires.

[eBAUMANN]

Does anyone notice a dramatic loss in air pressure when running cx tubulars in freezing temps?
I'm using near new Clement MXP tubs with a bit of Stan's sealant (as a preventative). I drove to the trailhead and pumped to about 30 psi. After an hour in the freezing cold I notice a dramatic softening of the tires. Feels like 10 psi loss. I can't find a leak - no sealant squirting out. Is it just the frigid temp (30F) cooling the air in the tires? Do tubeless tubulars (i.e. Clement) lose air in the cold? I'm stumped
Same thing happened at a race this weekend (also very cold).

This is a question of curiosity mostly. I do still love these tires.

Having raced the same tires in temps in the teens without noticeable pressure loss (over a few hours)...i don't really know what it could be.

Did it happen in BOTH tires?

As I'm sure you are aware, the clement/tufo tubeless construction holds air MUCH longer than any latex tube-based cotton tire, so its surprising to hear that.

[sparky33]

Having raced the same tires in temps in the teens without noticeable pressure loss (over a few hours)...i don't really know what it could be.

Did it happen in BOTH tires?

As I'm sure you are aware, the clement/tufo tubeless construction holds air MUCH longer than any latex tube-based cotton tire, so its surprising to hear that.

Good to hear that this is not normal...because these tires have been so good to me and I'm not looking for alternatives.

yes...both, I think, but more noticeable in the front probably because I give that one fewer psi to begin with.
I'm thinking that I should CLEAN the tires before inspecting them. It is hard to see any real defects with a layer of mud and such.

[45K10]

I had it happen to me a few weeks ago. Pumped up the tires to around 30 psi drove an hour and a half to the race. Pulled the bike off the rack starting pre-riding the course and I could tell they were low. Checked the pressure and they were down to ~25 psi.

However the race location was about 2,500 ft in elevation higher and about 15 degrees colder than when I pumped up the tires. So not really the same situation as yours but I thought it was interesting.

[sparky33]

yes...both, I think, but more noticeable in the front probably because I give that one fewer psi to begin with.

Yeah, I'm crazy because the back tire is holding.
... but the front was dead flat when I just checked it after letting it sit several hours post-ride. While cleaning it, I found the tiniest white mud glob of sealant. Must have been a really slow leak. I'm curious if it will seal up properly if I let the sealant pool overnight at the leak (rotate the leak to the 6 o'clock position etc).

Thank you all for humoring me.