27" rims are 630 BSD 700C (29") rims are 622 BSD That is a diameter difference of 8mm which is a 4mm difference in radius - so the brake pad position is just slightly more than 1/8 of an inch off. The 27" is larger in diameter than a 700C (29").
650B (27.5") is 584 BSD So a 27.5" rim is considerably smaller than a 27" rim. When talking about rim diameters, using the BSD (Bead Seat Diameter) is the only reference that lets you compare relative diameters. There are more than one BSD for 26" rims. Ditto for 20" rims. Laing Delray Beach FL On Monday, October 26, 2020 at 1:16:13 PM UTC-4, Sam Perez wrote: > > Hi all I'm working on several projects at the moment, an old steel bike > had 27 rims /tires in the late 2000's I laced the old campy 5s hub to 700c > for more tire options. Just now I put an old 27 rim to see the difference > since I was told 27 is 650b. To my astonishment the brakes lined up exactly > with the 700c rim. On line there was conflicting information. With a 700c > I fit a 35c tire I was hoping to transfer my hetre tires to this frame > thinking the smaller diamiter would afford me a wider spot on the chain > stays... Thoughts / advice. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/49b719bc-cff8-41ff-ab9b-05638ccc30a3o%40googlegroups.com.
