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11-17-02, 07:42 AM
Using the formula at this site, I should have a top tube of 55cm. My current top tube is 58.5 cm and seems pretty close. Could it be that far off? Thanks.
http://www.cptips.com/bkefit.htm
"The top tube length of your bike should be proportional to a combination of your trunk length and arm length. For these measurements you need to be seated with your back pressed firmly against an upright surface such as a wall. Trunk length is measured from the seat you are sat on to the top of your shoulder with you sitting fully upright. The forearm length is measured from the back of the elbow (with the back of the elbow pressed against the upright support and with the forerarm horizontal) to the centre of your clenched fist. Total arm length is obtained with your arm straight out in front and measuring from the upright support to the centre of your clenched fist (keep your back firmly against the support). The measurements are used in the following equation: top tube length = 75.25% trunk length + 7.8% forearm length + 7% total arm length - 1cm (1/2"). The answer should be rounded out to the nearest 1/2cm (1/4")."
http://www.cptips.com/bkefit.htm
"The top tube length of your bike should be proportional to a combination of your trunk length and arm length. For these measurements you need to be seated with your back pressed firmly against an upright surface such as a wall. Trunk length is measured from the seat you are sat on to the top of your shoulder with you sitting fully upright. The forearm length is measured from the back of the elbow (with the back of the elbow pressed against the upright support and with the forerarm horizontal) to the centre of your clenched fist. Total arm length is obtained with your arm straight out in front and measuring from the upright support to the centre of your clenched fist (keep your back firmly against the support). The measurements are used in the following equation: top tube length = 75.25% trunk length + 7.8% forearm length + 7% total arm length - 1cm (1/2"). The answer should be rounded out to the nearest 1/2cm (1/4")."