masi61

I’m trying to convert 2 of my existing road bikes and a new disc build to road tubeless this winter. I have managed to get 2 different wheels to hold air. The 3rd wheel, a Dura Ace 7850 that is supposed to be tubeless, leaks air out of the valve no matter what I do - just maddening!

But back to the “good” installations -

1) Mavic Cosmic Elite disc UST with proprietary Yksion Pro UST matching tire. I had it up around 90 when I used my Airshot pressure canister to get it to hold air. I then put 60 ml of Stan’s sealant in there, put the valve core back in, reinflated to about 90 psi and gave it a spin. This seemed to work really well so now I feel like I’m “getting” this whole tubeless thing. After 24 hours the pressure was still at 88 psi. After 48 hours the pressure is now 77psi, I’m now not quite sure of what to think about this - I mean my latex inner tube wheelset loses pressure at about the same rate and it is a lot less hassle...

2) Next up a DT Swiss R460 rim brake front wheel that have set up for tubeless with 2 layers of Kapton tubeless 18 mm tape and a universal type tubeless valve (with cone shaped rubber grommet). I used Panaracer Race A EVO3 tubeless tires. Mounting these Panaracer tires held much excitement for me - you can see that they are well made and likely to be a very grippy, great cornering 25mm tire. I did the same procedure with the airshot, then removed presta valve, instilled sealant 60 ml, inflated and spun to distribute sealant. Pressure loss on this one is much worse. I went from 80 psi on install to like 35 on day 2, re-inflated back to 80 or 85 and by (the second go around) day 2 pressure is now 54. So I have lost 31 psi in only 24 hours.

Now these are wheels and tires I’m just setting up and have not ridden yet. Maybe the secret is that when you ride them, they continue to seal up. Please enlighten me if you know. Poor sealing of tubeless valves seems to be a big issue and so far I am not impressed and would probably not be confident in the air holding ability of these tires for everyday road use.

I’m doing this as a winter project figuring that I’m not missing out too badly on riding due to the cold. Working with these road tubeless wheels seems like a worthwhile skill to develop. So far, the fails outnumber the success - basically I’m not off the ground to even go out for a test ride yet.

Please share any any wisdom on this topic about whether keeping at it is a worthwhile endeavor or not.

pdoege

My experience with the Mavic wheels is that they lose about 5 PSI/day until they reach ~40PSI and then they stay there for a long time.

Roval and Shimano rims are all over the place in my experience. 10PSI/day, maybe 20 on a bad day. I used to overfill with sealant, eg, 250ml or so and then rotate the wheel throughout the day. Drained and then refilled with the correct amount. Tires treated in such a fashion lose around 1PSI/day until remounted.

It was a lot of faffing about and I just standardized on Mavics and a puff of air in every morning.

masi61

DowneasTTer

Not to be dumb but are you sure the leak is at the valve stem? Have you put the wheel into a water bath to check for air bubbles? If it truly the valve I have had great luck with a little RTV or silicon around the stem and let dry before putting in sealant.There is also a possibility it's leaking from the spoke nipples.If so check the tape close to the valve stem to see if air is entering the spoke channel. Good luck.

masi61

DOS

DowneasTTer

Good to know.

alcjphil

My experience with road tubeless has been using Campagnolo Shamal 2way fit wheels. Rate of air loss is about the same as if I were using butyl inner tubes, even without sealant. I run these wheels without sealant more than half the time for the last 7 years