I had been thinking of converting my CX bike to tubeless for a while and having now done it, thought I’d post on my experiences, as much as anything because I couldn’t find much about it on google when I was researching it and I know that google will pick this thread up.
The background is that I don’t use my CX bike for racing but rather for riding on trails that would probably be a bit dull on an mtb (though not always!) but that are great on a CX bike. Being a big and pretty heavy (16+ stone) rider, pinch flats were a constant problem which meant I was running my tyres (Conti Speed King 35mm) at 85psi and even then I’d occassionally get pinches. Based on my own positive experiences of running tubless on my mtbs with no problems since, I thought I’d give it a go on my CX bike.
So, it started off as per this thread:
http://www.singletrackworld.com/forum/topic/random-tubeless-problem-on-cx-bike-leaking-after-a-ride-but-fine-during
Summary – Stans cyclocross rim strip, Halo Aerorage (19mm wide) rims and Maxxis 32mm Small Block 8 kevlar beaded tyres. They inflated easily enough but seemed to leak air slowly and particularly after I stopped riding.
After that, I took the tyres off, cleaned them out and cleaned with meths to ensure that any release agents/etc on the tyre were removed.
I put it all back together (both @ 70psi) and the rear one now held air very well but the front was leaking slowly but not from anywhere obvious.
I did a ride like this and they held up fine but the front was noticeably soft towards the end of the ride. The final rocky descent with the front at 40psi-ish (eg less than half what I used to ride at) was fine though – I was a bit worried that it might dent the rim but luckily not.
Back home, I pumpded the front wheel up again and held it in a bucket of water to find the leak, found a small one (pinhole in the sidewall), gave the wheel a shake to get sealant there and it sealed.
The next day it had lost pressure though not as much as previously. I pumped the tyre up to 80psi(!) and some sealant came out around the valve hole and then sealed which now seems to have done the job and it’s holding air properly now.
So, in summary, CX tubeless works but for me at least, it’s much fiddlier than on my mtbs, presumably because of the higher pressures. I think I’ll drop the pressure to 60 and then even maybe to 50ish as I reckon that will work fine.
It’s certainly cured my pinch flat problems and I’m pretty pleased with it now – I certainly can’t see myself going back to tubes.
