New guy with a question...

[StylistDave]

So how do I figure out if some of the fat tires will fit my frame? I have an old OP 26" beach cruiser that I wanna make a project out of. Is there a lot of mods to do, or do they fit most standard size cruisers?

 

[Bicycle808]

How fat do you wanna go? Remember: the surest way to find out is to measure. If it won't fit, there are ways to get more clearance in the frame, too.

 

[StylistDave]

I want those copper rims on this site with the BOA-G tires. I'm just not sure if all I measure is the triangle area or if I need to measure chain clearance too. I don't wanna order something that pricey +shipping and have them not work. They are 57mm, so what, about 3 inches I guess.

 

[Wildcat]

The 57mm rims will fit a beach cruiser frame, it's the tires that may be too wide. I used 2.125 width tires on those rims with no problem with clearance. From the ad here: Width of rim and fully inflated tire is 3.5". Diameter of wheel with fully inflated tire is approximately 28".
If your old frame is the standard beach cruiser type, then like Bicycle808 said, it can be modified a little to take a fatter tire too. You'll need 4 inches of width for the BOA-g tires listed, leaving 1/4" clearance on each side. The chain spacing can be helped by flipping the cog and/or chainwheel to give a little outward spacing.