Ben,
They were mounted with Tufo Extreme rim tape on new clean rims. At first I thought that there may have been a chemical reaction between the adhesive in the Tufo tape and the Panaracer tires. I asked the person at Tufo customer service and they said that they never had a problem with rim tape affecting the base tape.
On both tires it's a clear case of adhesive failure between the base tape and the tire. I have some Italian made tires from the 70s and 80s and you still need to use an Exacto knife (scalpel) to separate the base tape from the tire casing.
I have 20 some old sewups that came on bikes or wheels that I've acquired over the past few years. These tires are 5-15 years old and every one of them has base tape separation. They range from cheapos to fairly decent sewups.
I picked 6 of the best ones and sent them to Tire Alert in Florida to have the base tape replaced.
They charged me $8.00 USD each for the new tape including return shipping. I got them back yesterday and they look very good.
Chas. Colerich Oakland, CA
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