If your bike rear end is fully sprung as opposed to standard with the seat supported off the RFM you will probably need the additional strength of the sidecar spring gauge, especially if you take a pillion passenger frequently, I have run the petteford sidecar variant for years, fully sprung it makes for a very comfortable ride with either KONI or AVO, the only downside being it makes the seat hieght a little tall for my short little legs, but now they have repaired and straightened I am hoping that I have gained a little, it won’t be much, but every little helps! Now what else could I do with being a little longer?