A scene from the 1957 movie, “The Incredible Shrinking Man”
During a recent doctor appointment I was asked by the nurse what my height is. My answer was “Well, I used to be 5’6″, but the last time I was checked I was down to about 5’4 3/4″ I think.”. She told me to step up to the place where they measure patients and low and behold she told me I now measured 5’4″. In all fairness, I don’t think she measured me carefully and accurately. I just measured myself and I got 5’4 1/2″. I noticed a few weeks ago that I seemed to have too much leg extension while pedaling even though the boom had been adjusted correctly and was fine for a long time. Today I shortened the boom just a bit. I seem to be the victim of a cruel hoax … another ‘incredible shrinking man’, if you will. I sure don’t seem to be having any problem in my vertical measurement lessening, but the horizontal measurement is another story. At the rate I am going it won’t be long before my horizontal measurement is more than my vertical measurement.
I only am sharing this because this same scenario could be happening to others and they too may need to readjust their boom. In doing so remember that it may also me necessary to shorten the chain if your derailleur can’t handle the adjustment to the boom. Typically a rear derailleur can handle about two inches of “extra” chain length (which is about one inch of boom movement), but that is only when talking about from the one extreme to the other extreme … when both the chain and rear derailleur were set up correctly initially. If you are already near the one extreme when you move the boom the chain may need to be shortened. Having too much chain for the derailleur to handle will result in the derailleur not being able to move back far enough to take all the slack out of the chain and having the chain rub against itself while pedaling like in the picture below.
So if you find yourself experiencing what seems to be too much leg extension even though you had the correct boom setting in the past you too could be another incredible shrinking man or woman. No matter how short we get hopefully we can …
KEEP ON TRIKIN’
A FREE GIFT awaits you!
You can watch the movie here: https://archive.org/details/The.Incredible.Shrinking.Man