biketampa

First time I’ve setup tubeless tires on my gravel bike. 700x42 tires at around 40psi. I’m assuming a psi or two loss is normal overnight.

u235

All of mine average some loss and some more than others and it randomly varies. If I had a tire losing 2 a week or 2 a day I wouldn't think anything of it. I check my tires and adjust pressure before leaving the house so it is what it is.

biketampa

I'm mainly keeping an eye on more closely as this is the first time I've set them as tubeless. And last weekend taking them out for the first time one of the tires lost most of it's air in the first 30 minutes so there was a leak somewhere but I'm not sure where. so I've reset the bead and have been checking the psi daily over the past couple days. so far it's losing ~1-2 psi each day which seems reasonable. I'll see this weekend when I take it out again.

dsbrantjr

A quick dunk into water will show where, or squirt some Snoop or detergent solution on the suspected areas. https://www.swagelok.com/en/product/...-Leak-Detector
Make sure your valve cores are tight.

biketampa

thanks. I suspect the valve core. But I’ll definitely try dunking in water if I have issues.

dsbrantjr

A valve cap should pretty much eliminate leaking through the valve even if the valve leaks a bit.

ThermionicScott 

If the tire was a reasonably tight fit, I wouldn't worry too much about a few psi per day. What you don't want are tires that might come unmounted if you forgot about the bike for a couple of weeks.

jadocs

As mentioned a few PSI overnight is nothing to be concerned about. What is concerning is that you experienced significant air loss (made no further modifications beyond adding more air - did you tighten valve cores, check rim tape if applicable?) and do not know what the reason was.

biketampa

I actually fully removed the tire and reinstalled it. And I tightened the valve core. wheels are a few months old and rim tape is in good shape. so can't be sure where the leak was at this point. It's funny as this tire when I originally dry mounted it popped on easily. The other tire was slightly more difficult as I had to pull on the tire in a couple of spots to get the bead to set in. But that tire gave me no problems. I'll be taking it for a ride this weekend and keep a close eye on it. Last time it become quickly apparent when I felt the rear become bouncy.

jadocs

...Gotcha

biketampa

It's my first time attempting to run tubeless ever. Few months ago, on a different set of wheels and with some panaracer gravel kings I tried to get them dry mounted and couldn't get them fully seated no matter what. used soapy water. used handsanitizer. I don't have a air compressor but have one of those airshot inflators. These wtb resolute tires seemed to be far easier on some dt swiss rims.

biketampa

Had a 3.5 hour ride with no issues with this install. Noticed today, day after ride, when cleaning bike a few sealant streaks on the sidewall so I assume some minor burping on the ride and assume things settles in quickly as when I checked psi tire only lost a 3-4 psi from previous day.

Darth Lefty 

If the tire weeps sealant out the sidewalls it's also going to lose air. It IS a problem if you're losing air overnight like that. Because it's a leak and not permeation, it's taking humidity and ammonia along with it and you're putting dry air in to replace it. The sealant won't last nearly as long. The first set of tires on my bike did this with Stan's and Truckerco sealant but Orange Seal did them right up, no further problems, and the next set of tires were Schwalbe with Snakeskin and don't weep.

HerrKaLeun

Temperature changes and the air loss from hooking on and off the chuck easily explain 1-2 psi. You need to observe over some more days.

the higher the pressure, the higher the pressure loss at a given leak.

not sure if it matters, for my tubeless hybrid (35psi rear, 18 psi front) i typically adjust pressure weekly. Maybe there is not a real need, just want to be consistent.

More importantly, always use the same gauge.

bitpuddle

In addition to what other people have mentioned, some tires have more permeable casings than others. After initial setup, there can be some extra loss while the sealant works into the sidewalls.

DrIsotope

Might lose 10psi on the first day after mounting. After the first ride, maybe 5psi. Once it's fully seated (after a few rides) and the sealant has done it's thing, most tires will fall into a pattern of 1-2psi a day down to a certain number, then it will just sit there.

I had an unridden backup tire drop from it's normal of 60psi to ~40psi over the course of two weeks or so, then just sit @ 40psi for six weeks. Some tires and rims are very happy together, and might not lose any pressure at all over a 24 hour period.

Pressure loss depends on so many variables-- the tire and rim, how well the rim tape was applied (if there is rim tape) the type of tubeless valve, etc. Unless a regularly ridden tire loses +10psi in one night, everything is quite likely just fine.