David- I tell my customers that it's a size label, not a measurement.
List- I was rooting through old stuff and found some Specialized Turbo Infinity/SK4 tires marked 700x25. I was going to toss them, but decided to do a trial mounting and see how they would do. Great, as it turns out, but I noticed the actual size of these 700x25 tires to be smaller than the current day 700x23 tires I removed, which were Conti Grand Prix 3000s. Both measurements, across and off the rim, were smaller. Why is this? Have the numbers come to represent something different? They could be mis-sized, but I recall back in the day during the introduction of skinnier clincher tires that 25c would be the narrowest I would want to ride on the road, and today I'm riding 23c tires with no consideration. Well, I guess because they're bigger. So, have tires come to reflect the overall cultural obesity situation or is there some other "inflationary" cause for this? Anyone else notice this in older tires? Was this a gradual change or did I miss a tire sizing revolution somewhere?
Dave Boston Tucson AZ USA
Andrew R Stewart
Rochester, NY