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Geometry explaination needed(6 posts)

Geometry explaination neededzooog
Apr 15, 2003 3:59 AM
I currently ride a 52 CM C-C frame. Top Tube is 52.8CM. Head Angle is 72.5 and seat angle is 74. Stand-over is72.6 inches. 100MM stem. 3.5 stack on stem.

The Bike I am looking at( calfee Tundra) measures Center of bottom bracket to bottom of seat binder.

52CM Frame:
Seat Tube Angle:74
Head Tube Angle:73
Top Tube: 53
Stand Over:77.4

50CM:
Seat Tube Angle:74.5
Head Tube Angle:72.5
top tube:52.5
stand over:76.2
My riding style is rec/fitness. Seat level with bars. Upright position(somewhat). Never ride in drops.

My question is... How can you compare my present bike to the calfee with different measurements of frame geometry. I want to be a close to my present bike set up as I can.
Is this comparing apples to apples or apples to oranges. Any advice/explanations are appreciated. Have not been to look/ride the calfee. About 2 hours away and weather been poor.

Thanks in advance.....zooog
errors in the info...C-40
Apr 15, 2003 4:19 AM
The standover height that you posted for your current bike can't be correct in inches or centimeters.

If you need 3.5cm of spacers on your current bike, you need a longer head tube and/or more stem rise to reduce amount of spacers, preferably to 1cm or less. Measure and post your head tube length. This is an important dimension that should not be ignored.

A 52cm c-c frame would be comparable to a 53.5 or 54cm frame measured center to top, not a 50 or 52cm.
updated info...thanks C-40zooog
Apr 15, 2003 8:13 AM
Current bike standover height is 30 inches. Could you explain this...A 52cm c-c frame would be comparable to a 53.5 or 54cm frame measured center to top, not a 50 or 52cm.
.......Headtube length is 110 MM on current bike. Thanks.
Correction.....zooog
Apr 15, 2003 8:50 AM
Present bike is 30Cm standover height. I believe that is 2.54 CM + 1 inch = 76.2 inches.. or am I doing the math wrong??? Will do an exact measurement after work.
explanation...C-40
Apr 15, 2003 9:02 AM
If your current frame measures 52cm from the center of the bottom bracket to the center of the topt tube, then it should measure somehwere in the range of 53.5 to 54cm to the top of the top tube (center to top measurement).

Calfee frames are essentially measured center to top.
The small difference to the lower side of the seat post clamp is negligible.

The standover height of 30 inches or 76.2cm is bit low for a 52cm c-c frame, unless you have a low bottom bracket height.

The closest Calfee frame to yours would be a 52cm. It is virtually identical.

Check the vertical height of your saddle above the top tube of your current bike. Take the measurement near the nose of the saddle. If it's more than 17cm, you should consider a larger frame, which would have a longer head tube so you can get rid of some steering tube spacers.
updated measurements...thanks C-40zooog
Apr 15, 2003 3:01 PM
Did some measurements this PM on my Silverton. Standover is 76.2. Measured center of bottom bracket to top of top tube and came out with 54CM. Vertical height of saddle is 16CM. Did not know how to measure bottom bracket. I will call Sampson tomorrow and ask. I measured my head tube length. I kept coming up with 130MM but Sampson site says 110MM. I may be measuring incorrectly. I am beginning to understand what you are saying about the fit of calfee. Thanks for the explanations.