Originally Posted by
avrilboazmoss
I noticed many CX bikes back in the day (prior around 2010) came with 15C rims and had 35mm tires on them. Nowadays, these would be considered out of specs by ETRTO, some even publish more restricted ranges marking anything outside but within ETRTO as "non-optimal".
Does anyone understand how it became that universal regulatory body came to dictate these for the manufacturers rather than manufacturers defining what's permissible for their own products?
Also, what is the logic behind e.g. 35mm tire being out of spec for 15C rim, but 19C can take tire up to 62mm - more than triple?
Has the hook design changed over time (NOT talking about hook-less rims), or the tire beads or what caused the regulation to become necessary?
https://www.wtb.com/pages/tire-rim-fit-chart
It's not worth getting THAT worked up about. ETRTO came up with their specifications and recommendations many decades ago (longer ago than you realize). The recommendations are given to show what should reasonably be expected to work. Anything outside of those are not a "SHALL NOT", it just means you're on your own if the tire squirms or blows off. Your question about 19mm rims taking 62mm tires comes from the 1980s/1990s when people decided to start putting skinny rims on MTBs. Since it worked well enough, they extended the chart to reflect that.
For some reason, people have gotten really anal retentive about tire/rim combinations lately, and want to cede all of their thought processes to charts and graphs. It used to be that you would try it, and if it worked, you were happy.
