Another CB350 Tire size/wheel combo question

[x1rider]

OK, first I appologize for asking this. I've searched the site and read 10,000 different threads which has me even more confused.

Maybe I’m over thinking this and making it more complicated than it needs to be. Hopefully my ignorance will help some other confused people in the future.

I have a 72 CB350 twin with stock rims; 1.60 x 18 in the front and 1.85 x 18 in the rear. I’m not racing this bike, nor is it my primary ride. I got it to have a winter project and ride around town every now and then.

In numerous places I found people mentioning that a 90/90-18 is the correct replacement tire for the front wheel and 100/90-18 (or in some places 110/90-18) is the correct replacement for the rear.

Then in other threads I’ve seen people post the charts that compare tire size to rim width; which indicated the above mentioned tires are to wide for the stock rims.

Can somebody help me understand this better? Are people simply cramming these tires onto the stock rims because those are the sizes that are reasonably available?

I know is some cases people are replacing the rims, but that’s not what I want to do. So if I keep my stock rims, is it safe to install tires with the above mentioned size on the factory rims?

Or is there something else going on that I am missing?

Sorry for asking a question about a subject that I know has been beat to death, I do appreciate your help.

 

[teddpage]

https://www.denniskirk.com/help_center/tire-sizes.jsp

At the bottom of that page is a general guideline of what tire vs what rim width.
A 90/90 front and 100/90 rear should work OK on those rims. They may be "slightly" too wide, but im sure a majority of bikes on this site are running the same tire combo or even something bigger.
I made the mistake of putting a 120 on the back of mine, with a 1.85 rim. It squeezed the tire a bit and it has almost a crown at the top of the tire, not a nice curve. When it wears out its getting a 100.

 

[crazypj]

90/90 front is OK 110/90 rear works but is a little wide, 100/90 fits better on a 1.85 rim
80/90 is a little more difficult to get hold of so the 90/90 is a compromise
90/90 and 110/90 work a lot better on 1.85/2.15 rims but as your not swapping rims you won't have any problems (although tyres will wear a little faster than if you had 'correct' sizes)

 

[x1rider]

Thanks, I really think I was trying to make things overly complicated.

In the end, I just ended up ordering a set of Avon Roadriders in a 90 & 100. Everyone seems to be happy with those, and its the size Avon recomend for the 350four which has the same size wheels.