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How do I measure frame?(3 posts)

How do I measure frame?mtnpat
Aug 13, 2002 8:03 AM
I believe it is from the center of the BB to the top of the seat tube? Is this correct, all the way to the top of the seatpost collar basically?

Just wanted to make sure the measurement wasn't to where the top tube intersects or anything.

Sort of an evolving process...Silverback
Aug 13, 2002 8:28 AM
Center of BB to center of top tube is the traditional way, but a lot of companies (maybe most) now use the TOP of the top tube, and at least one (can't remember who) goes to the top of the seat tube. It's not an insignificant difference, either. My son's old Bstone (only bike I have within reach right now) is a 58cm on the label, but 56 to 59 depending on how I measure.
re: How do I measure frame?Len J
Aug 13, 2002 8:54 AM
Like someone else said, it varies by company. It also varies by person selling the bike. For instance, I saw a Serotta CSI (Serotta normally measures center to center )listed on e-bay with a seat tube of 58Cm. When I e-mailed the seller, he was measuring center to top, so you have to be careful.

Trek measures center of BB to bottom of seat collar.

I have gotten to the point where I know what CtoC measure I need & I take a tape measure or verify the measurements when I am looking at a bike.