"Motorbike" - style frames as Rats?

[bombshelterbikes]

I need some help from the family. I have a great build in mind (hopefully for RRBO3 ), but I am unsure which frame to use. See, I would really like to use an old motorbike style frame from the teens through 1930's (you know, sharp top tube bend - like the Schwinn B-10). Generally had 28" wood wheels. Not sure what tire size they ran. Lots of bike companies made them very similar.

My problem is that I have never seen one in person, and have no idea how much width there is available for tire clearance in the rear. I would be using a different fork, but want to put at LEAST 26 x 2.125 tires on it, and possibly run a 24 or 26" x 3.0 in the rear. If my understanding of RRBO rules is correct, I can't alter the frame, so I need to know before I go and find one. So please help....is this even possible? If anyone has a frame like this, could you please measure the frame gap and let me know what that is?

My other option is to use something like a later 30's Schwinn C-model frame that was made for baloon tires, but it has a more curved top bar and loses some of the "vintage" character.

Oh yeah, if someone has a frame like this and wants to sell (or trade stuff!!! - even better), please let me know. Thanks all!

 

[sensor]

cant tell you about 24x3's but i know someone that had a 22 mead that originally had 28" wheels on it and balloons fit with out any problems
btw....the schwinn b-10e's were balloon tire bikes to begin with.......
you might ask oldy57 what size wheels and tires he used on his massey boardtracker.it was a 28" wheel bike and it looks like he put balloons on it also(and the original 28" tires were 28x1 1/2)
hope any of this helps

 

[skoda]

You can run 24x3's on most frames that will accept 26x2.125 balloon tires, but the frames that would have had 28" wheels barely accept a balloon tire, sometimes will not even do that without stretching. You'll need a 35 or so Elgin or a B-10E frame to be sure it will work without stretching or modifying.