Originally Posted by
1989Pre
50psi is what I run my 26x1 3/8 tires at, but I don't think I'd ever go that low on 27x1". Not when I'm doing 60-mile rides on them.
27x1" tires can be as narrow as 21mm or as wide as 26mm, the tires I reported on above say 27x1-3/8" and also "37-630", so are much wider at an actual 35mm inflated. About the width of your 26x1 3/8" tires!
I run my 27x1" Paselas at 70-72psi. 27" Paselas run large, so their 27x1" measures a full 26mm wide on touring rims as shown below.