Tubeless MTB riders complain that sealants like Stan's No Flats must be scraped out and replaced every 2 months. Slime claims it'll work for up to 2 years in an inner tube. After a month on hot asphalt it's already drying out.

Water vapor permeates through butyl rubber 2 orders of magnitude faster than air. You can easily check this with kitchen scales. Weigh a sealant filled front wheel every 2 weeks this summer.

I tried this today and apparently discovered a violation of conservation of matter: The weight _increased_ by 6 gms or 1/4th an oz.

Either that or the kitchen scales are suspect.

Polypropylene glycol is non toxic and greatly lowers the total vapor pressu

https://dowac.custhelp.com/app/answers/detail/a_id/7412

Coolant might also reduce the coefficient as well as the driver. The sealing characteristics should be just as good..

Has anyone heard of a sealant w/ coolant already added?


Bret Cahill