Measuring a bike
06-29-13, 11:15 PM
#1
Member
Thread Starter
Measuring a bike
I'm about to sell a bike and don't know it's size. Where or what exactly do I measure? Is there a site with a photo or drawing showing precisely where to measure? (Nothing on the Sheldon Brown site) It's a 1980 English bike and there is no decal with the info.
For example, I presume that I measure one of the tubes (top, down or seat). Is it the inside measurement from the joint to joint? The entire length on the outside? Something else?
Thank you.
For example, I presume that I measure one of the tubes (top, down or seat). Is it the inside measurement from the joint to joint? The entire length on the outside? Something else?
Thank you.
06-29-13, 11:18 PM
#2
Really Old Senior Member
Center of the BB to.....
You can specify top of seat tube, top tube or ??
Stand over height is also informative for people that think size has something to do with the tires.
You can specify top of seat tube, top tube or ??
Stand over height is also informative for people that think size has something to do with the tires.
06-30-13, 06:20 AM
#3
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Most bike manufacturers post "Geometry' charts on their web site for their bikes. These usually show where they take their measurements from and you can follow their lead. Here is an example from the Surly web site:
https://surlybikes.com/bikes/pacer/geometry
https://surlybikes.com/bikes/pacer/geometry
06-30-13, 09:42 AM
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With traditional geometry having a seat tube that ends at the top of level top tube, the size is from center of BB to top of the seat tube.
Some frames have a seat tube that extends above the top tube about 1/2" where a clamp collar rests. Traditionalists measure these to the top of the top tube, or include the seat collar and add a note saying it includes a 1/2" extension above the top tube.
With the advent of mtn bikes and their sloping top tubes seat tube length alone was less informative. The measurement is still the length of the seat tube (from center of BB), but some other info is helpful, such as measurement to the top tube intersection, but this is often not included.
Some frames have a seat tube that extends above the top tube about 1/2" where a clamp collar rests. Traditionalists measure these to the top of the top tube, or include the seat collar and add a note saying it includes a 1/2" extension above the top tube.
With the advent of mtn bikes and their sloping top tubes seat tube length alone was less informative. The measurement is still the length of the seat tube (from center of BB), but some other info is helpful, such as measurement to the top tube intersection, but this is often not included.
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Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
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FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
