The only problem I had with them apart from finding space between the elephant trunks was the wheels coming off. The retaining washers (push on fasteners) are not the most reliable, though this could in part be due to me fitting / removing them several times.
In the end I drilled a small hole through each of the axles, and fitted a stainless steel R clip to retain the washer and wheel. Since then they have been fine.
I haven't tried them on soft sand, but they have been fine on other surfaces.
Brought the same and had the same issues as chris123, think they may have changed the design. Another thread on here discussed this issue. Once you have sorted it out though they are great wheels and make my SIB a lot easier to use. Would not be without them TBH.
