So after some Whistler and Bike Park days I returned home for more XC oriented riding and decided to lose the extra weight and rolling resistance of my Kryptotal DH tire and go for something that would require less effort to pedal uphill. My local trails don't have much dust and if it rains here things are unridable so I decided to try the new Magnotal in the trail casing for the rear (still running Kryptotal trail casing up front).
Immediately made the bike (Scott Ransom 900 Tuned) feel a lot more spry. It literally saves about a 1/2 lb and rolls much better. Made doing long rides with wife (who races a lot of MTB endurance stuff) way more tolerable. I didn't feel like I sacrificed much grip on most trails. On steep loose stuff it was noticeably more sketchy, but for 98% of the riding I didn't feel like I was sacrificing much.
HOWEVER …. It's been a struggle keeping the tire inflated. If I leave the bike for a few days I'd come back and pressure would be down to 10psi (I usually run about 21-22 in back with insert). I tried the "bath" trick prior to find the leak but clearly didn't spend enough time doing it. After riding again today my frustration got the best of me and decided I really want to get to the bottom of things. Pumped the tire up to about 37 psi, filled the bath so I could put about 1/4 of the wheel in the tub and started watching. Nothing … at least initially. I went to put stuff back in my shed and came back to tire sitting in the tub and noticed lots of little bubbles coming from the sidewall (see link for video)
https://share.icloud.com/photos/0a6TG4k1019z4Exeq_kKSGSbg
I had already put the usual amount of Stans in the tire (100ml) when I mounted it, and put anther 100ml in the first attempt to sort the problem (about a month ago). So this time I put an additional 120ml in the tire and made sure I spun the tire so the sidewalls would get a good coating. Seems to have reduced the leaking, but there are still some small areas of bubbling, which means it's still leaking, just slower.
I've been running tubeless on my MTB since it became common (10 years?) and I've never had any problem like this.
Has anybody else run into this issue?
I like how the tire rides, but I think I'm going to put in an inquiry with Continental since this is not acceptable.
by Surfbreak_Tiger
2 Comments
You need to do a fresh tape job. Sealant isn’t a magical cure. Your tires should hold air with no sealant at all if tape is done properly.
It’s normal that a lighter casing tire loses more pressure than one with a thicker casing.
If you have to pump once a week, that’s acceptable in my book, especially if the bike hasn’t been ridden.