Specialized BICYCLE Owner's Manual page 50

• SIGNIFICANT SCRATCHES, GOUGES, DENTS
OR SCORING CREATE STARTING POINTS FOR
CRACKS. Think about the cut surface as a focal point
for stress (in fact engineers call such areas "stress ris-
ers," areas where the stress is increased). Perhaps you
have seen glass cut? Recall how the glass was scored
and then broke on the scored line.
• SOME CRACKS (particularly larger ones) MAY MAKE
CREAKING NOISE AS YOU RIDE. Think about such a
noise as a serious warning signal. Note that a well-
maintained bicycle will be very quiet and free of creaks
and squeaks.
In most cases a fatigue crack is not a defect. It is a sign that the part has been
worn out, a sign the part has reached the end of its useful life. When your car
tires wear down to the point that the tread bars are contacting the road, those
tires are not defective. Those tires are worn out and the tread bar says "time for
replacement." When a metal part shows a fatigue crack, it is worn out. The crack
says "time for replacement."
Fatigue Is Not A Perfectly Predictable Science
Fatigue is not a perfectly predictable science, but here are some general
factors to help you and your dealer determine how often your bicycle should be
inspected. The more you fit the "shorten product life" profile, the more frequent
your need to inspect. The more you fit the "lengthen product life" profile, the less
frequent your need to inspect.
Factors that shorten product life:
� Hard, harsh riding style
� "Hits", crashes, jumps, other "shots" to the bike
�
High mileage
� Higher body weight
� Stronger, more fit, more aggressive rider
� Corrosive environment (wet, salt air, winter road salt, accumulated
sweat)
�
Presence of abrasive mud, dirt, sand, soil in riding environment
Factors that lengthen product life:
� Smooth, fluid riding style
�
No "hits", crashes, jumps, other "shots" to the bike
� Low mileage
� Lower body weight
� Less aggressive rider
� Non-corrosive environment (dry, salt-free air)
�
Clean riding environment
SIMPLE RULE 4 : Do not
scratch, gouge or score any
surface. If you do, pay fre-
quent attention to this area or
replace the part.
SIMPLE RULE 5 : Investi-
gate and find the source of
any noise. It may not a be a
crack, but whatever is caus-
ing the noise should be fixed
promptly.
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