TPU Tubes and sealant

After riding too far on a flat my Gravel King rear tyre stopped holding air in a tubeless setup. Revoloop tubes were cheaper and more readily available than the other TPU tubes (Tubolito, Aerothan) so I bought one to try. However, the American distributor’s FAQ states that they’re not compatible with sealant-imbued tyres because the acetone in the sealant will melt the tube.

  • ・ Stans told me that their sealant doesn’t contain acetone but they don’t have long term tests results for compatibility
  • ・ The Japanese distributor reports that the sealants they tested didn’t react with the tube (but provide no details)
  • ・ The first ride on a tube caused a pinhole puncture towards the rim side of the tube. Refitting it with a good helping of talcum powder stopped it from happening again. [1]
  • ・ The tube turned yellow after a day or so inside the tyre
  • ・ Both Revoloop patches and Park glueless patches seem to work equally well. Park are much cheaper.
  • ・ After another few hundred km the tube hasn’t given me any problems.

Finding pinhole punctures is a pain because they leak very slowly - even submerging the tube didn’t show the usual stream of bubbles. Inflating the tube to the limit (4 PSI) and stretching it very slightly by hand helped.

Just in case: I can’t guarantee sealant won’t melt your tubes. Especially if you use really old Stans.

UPDATE 2021-10-01 (or so): On a big ride the tube took a sharp chunk of gravel and the tube punctured. A stick-on patch (Revoloop? Park? Panaracer? didn’t check, they’re all the same) fixed it up for the rest of the day but there was another slow leak somewhere. The next day the leak sealed itself up somehow but went back to leaking after that. Gave up and threw in a Maxxis lightweight butyl tube instead.

[1] Panaracer make a dedicated tyre powder for seating tubes.