>>1017701>MTB bros seem to regularly put huge tires on nature rims and pump then up to high pressures without issues. I don't know about MTB but it seems stupid and is probably not goodThe source of these charts is ETRTO, and for some reason, ETRTO likes to put HUGE fat tires on skinny rims.
That may have been the fashion back when they started this bicycle-tire-measuring standard (1969) and they have refused to change it to avoid breaking the standard system.
In short--the ETRTO rim/tire charts are shit. Ignore them.
Here is a better rule to follow:
The tire width should be at least as wide as the outside rim width, and no more than 1.5X the external rim width.
That cuts the available tire sizes for any rim way down, but it cuts it down to the combinations that work well.
Fat tires on skinny rims don't work well, and some of the ETRTO combinations say it's okay to use a tire that is almost 2.5X as wide as the rim.
It's also a lot easier to get wide MTB rims now, in the era of disk-only wheels.
It's not hard to find wheelsets for $150 that have 40mm [aluminum] rims, and you can get fairly-cheap aluminum rims up to 80mm wide.
>>1017709>The Schwalbe table posted in >>1017640 is more accurate than the conservative one on Sheldon's site.The page claims it's an ETRTO chart too. It may be a later-edition one than the one that's been on the Sheldon site forever.
The funny thing here is, the newer one is more ridiculous: it advises using even fatter tires on skinny rims...
On the old Sheldon chart, the tire width range for a 17mm rims was states as 25mm to 37mm.
On the (newer?) Schwalbe chart, for the same rim the range is given as 25mm to 52mm tires...? 52mm is 3X as wide as 17mm!
The ETRTO regulations cost a couple hundred bucks for a copy.
From bits I've seen posted around online, they're very silly.
