Bike Forums - View Single Post - how is this an 18" mtb?

12-19-09 | 04:02 PM

#3

bikinfool

I have senior moments...

Joined: Oct 2008

Posts: 2,151

Likes: 2

From: Woodside, CA

Bikes: Many

As Sheldon noted:

The old standard system was to measure from the center of the bottom bracket to the very top of the seat tube.
Some manufacturers have decided that this is too easy, so now many bikes are measured instead to the intersection of the centerline of the top tube with the centerline of the seat tube.
Some other bikes that have seat tubes that protrude farther than normal above the top tube measure as if they were measuring to the to the top of a seat tube with normal protrusion.
Some bikes are measured to the top edge of the top tube, even though the seat tube protrudes higher up.
Some bikes with slanting top tubes are measured as if there were a level top tube, they use the length that the seat tube would be if it was as high as the head tube.

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