MODE V6 - APPENDIX: INSPECTING CHAIN WEAR; Measuring Wear on the Chain; 1 VISUAL CHECKS; 2 Measure link thickness (d)

7/2015
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APPENDIX: INSPECTING CHAIN WEAR
Measuring Wear on the Chain
Note: The chain should be inspected regularly for wear, rust and corrosion.
1
VISUAL CHECKS
Examine visually for gouges, nicks, weld splatter, corrosion or
distorted links and slacken chain. Check bearing surfaces between
links for wear.
A chain with excessively pitted, corroded, nicked, gouged, twisted or
worn links should be replaced with a factory approved chain.
2
Measure link thickness (d)
Measure the dimension (d) at several points of the chain and
calculate the dimension (dm).
dm = (d1+ d2) 12 < 0.9 * dn
dn = nominal
t = pitch
Criteria:
Chain size
d*t
4x11
5x14
7x20
dn
4
5
7
dm max
[mm]
(in)
3.6
(0.142)
4.5
(0.177)
6.3
(0.248)
Note: Use only a "knife-edge" caliper to eliminate the possibility of false
reading by not measuring full pitch length.
Measure elongation (P)
Measure (P), the pitch over 11 links, at different regions of the chain.
Criteria：
Chain size
d*t
4x11
5x14
7x20
dn
4
5
7
dm max
[mm]
(in)
123.42
(4.859)
157.08
(6.184)
224.4
(8.835)
*NOTE: 2% elongation as per ISO 7592.
Note: If these limits are exceeded, the chain must be replaced immediately. In
this case, wear on the guide chain and chain sprocket should also be checked
and they should be replaced if necessary.