When 28 – 23 does not equal 5…

I rode my 38c tired cross bike earlier in the week followed by a ride on one of my road bikes with 23c tires. I have to say that the 23c bike felt much faster (could have been the sweet tail wind). I came back with a plan to put on a set of 28c tires. A nice compromise. I thought those 28c tires would look big compared to the 23c tires that previously occupied space on my wheels.

Before I took off the 23c Vittoria tires, I measured their actual width – 24mm. Hmmm, that’s pretty fat. I thought that the 28 Continentals would then be the bee’s knees and look all fat on the wheels. Got them installed and … well, my hopes were dashed. They looked no fatter than the 23’s I just took off. A quick check with the calipers and lo and behold, those 28’s are actually 26! Huh?

So, I’m still trying to comprehend. Try this: attemping to get a 5mm fatter tire, I go from a 23 to a 28 and only gain 2mm. 28 – 25 = 2. New math. I don’t like it.