BRACKET 2738346 - Caterpillar

With conventional idlers, the grouser rise height will be reduced by about 7 mm (0.28 inch), at 100% undercarriage wear.For SystemOne with Center Tread Idlers, the initial rise height and change in height with undercarriage wear is much different. As an undercarriage (with CTI) wears, the grouser rise height changes with the difference between link and roller wear vs bushing and Center Tread Idler wear. The SystemOne rotating bushing and Center Tread Idler wear very little, compared to the link roller wear. This effectively lowers the grouser rise height, as the undercarriage wears. Below, Table 5 is an example of a grouser rise height loss at 100% wear of SystemOne undercarriage with conventional idlers.
Table 5
Combined, 100% wear of SystemOne link and roller.    
28.5 mm (1.12 inch)    
(Minus) Combined, 100% wear of SystemOne bushing and CTI idler.     Minus
8.0 mm (0.315 inch)    
Loss of grouser rise height due to wear     Equals
20.5 mm (0.81 inch)    As shown in Table 5, with Center Tread Idlers there is a greater loss of grouser height as the undercarriage wears. So, rise height of the grouser will be reduced about 13 mm (0.51 inch) at 100% undercarriage wear. To compensate for this loss of grouser rise height, two factors have been designed into the Center Tread Idler. These are listed below.
Center Tread Idlers are mounted slightly higher when new undercarriage is installed, increasing the initial grouser rise height.
An idler height adjustment shim must be removed at approximately 50% undercarriage wear. This increases grouser rise height by raising the Center Tread Idlers back up, halfway through the undercarriage life.Note: Item 2 above is the only interim maintenance required for SystemOne with Center Tread Idlers. It is critical for this height adjustment shim to be removed (at approximately 50% SystemOne undercarriage wear). This will maintain proper idler rise height and will avoid loader ride problems.As discussed previously, Center Tread Idlers will generally wear through 2 to 3 SystemOne undercarriages. However, CTI sealing and lubrication compartment is designed to be serviced/renewed at SystemOne undercarriage replacement. The individual parts of the Center Tread Idler are parts serviced. Therefore, it is imperative that Center Tread Idlers be resealed and lubricated when the SystemOne undercarriage is replaced.As with conventional idlers, Center Tread Idlers can be weld rebuilt when worn to the wear limit. However, with the extended life of these idlers (two to three undercarriages), hub and/or idler sidewall wear may be the limiting life factor. The requirement for idler weld rebuild be much lower.Conventional Idler
Wear Characteristics
Wear characteristics for conventional idlers with a SystemOne track will be similar to a conventional track, including tread wear patterns. Heavy side sloping and turning will increase idler center flange wear, just as with conventional track. Wear limits for conventional idlers are the same when used with SystemOne track. A wider outside link assembly spread has been designed into the SystemOne track. Because of this, the SystemOne links may slightly overhang conventional idler treads. This is cosmetic only, and