If your Bob® 325 serial number is 514011001-514012999 or 511820001 through 5118299999 this idler will not fit.The arms on your idler should extend out to the length of your idler wheel, whereas this replacement idler has arms that extend beyond the diameter of the idler wheel. If they are short and square we do not offer the idler you need. We do not carry an aftermarket idler for those specified serial number break downs, but this idler will fit every other serial number series.

If your track is coming off on the same end on a regular basis the culprit is likely a worn idler or tensioner. If the idler is worn down it isn't fitting tightly into the guide system on the track and the track can easily slip off. This idler is designed to keep tension on the track and the center flange fits into the guiding system to prevent de-tracking.