Tandem Tom

Just posted a note on C&V looking for a rim suggestion. But I just thought I could use some advice.
How does one determine what range of tire widths will work on a given size rim?
I Googled this and came up with Images showing some charts. and for instance the Schwalbe site show that for a 21mm wide rime I can use 35-50mm. Am I reding this right?
I was thinking of using a Mavic Open Pro,I have on another bike and they measure 21mm but there site says 28mm max for this rim.
Thoughts??

desconhecido 

"Official" ISO rim width is the inside width. The outside width for a 21 mm ISO width is on the order of 25 mm, or so. Not all rims have the same difference between outside and inside width. An Alex rim (Adventurer, I think) recently discussed in another thread was 25mm out and 19 mm in while the CR18 is 19 and 22.5.

I'm not looking at the Schwalbe catalog, but my recollection is that it refers to ISO width.

FBinNY 

I gather you searched "bicycle rim and tire widths" or something similar and found the guideline charts. Keep in mind that the rim width generally used is the inside width, and the tire width is the nominal or overall width. Otherwise you seem to be reading it right.

These are only guidelines and there's a decent amount of fudge room, especially to the wide side.

If you go wider than suggested you'll tend to get wallowing if the pressure is low. OTOH, much narrower than suggested can give you a harsher ride because the sidewalls are straight up and down and have less room to flex.

So if buying rims or wheels keep in mind the general range of tire widths you plan to use and buy accordingly -- be careful, many rim specs are for outside width, and the charts are for inside width, which means a difference of 3-4mm or so.

Bill Kapaun

CR-18 is 17.5 & 22.5mm

https://sun-ringle.com/wp-content/upl...files_rev_.pdf

desconhecido 

Oops. Thanks for the correction -- sorry for the error.

GravelMN

I've got Open Pros on my road bike and even if I had the clearance, I wouldn't run more than a 32mm on them. If you want to run wider tires look at the A719 which has plenty of room for tires 28 to 40+mm. I've got those on my gravel grinder and they work great with my 40mm Schwalbe Smart Sams.

cny-bikeman

How did you miss Sheldon's page and chart on that exact topic? I don't know of a search including bicycle, tire, rim and width that would not yield his page as the first result. Scroll down for the chart

Tire Sizing Systems

Tandem Tom

I think I did not scroll down far enough. But I do have a question on this chart. Is it the "X"'ed box that indicates what size?

Bill Kapaun

Yes-
You wouldn't use a 57mm tire on a 13mm rim or a 18mm tire on a 25mm rim would you?

bradtx

The top of the chart is the tire width and the interior rim width is on the left hand side. The X marks a compatible pairing.

Brad