I am not bashing Bergstrom's or his idea but I replaced both of my sleds (dual carbides) with a set of his single carbides (his thoughts on dualy's) unexceptable, my god I couldn't believe the darting problems we had with em, I used the shims then took em out no difference, I tried my darndest to make these carbides work, spent all of last winter season adjusting front shocks (more spring pressure to no pressure, limiter strap adjustments etc to make em work but nothing changed, Posted my problem on this forum & got many, many, ideas on how to fix it (thanks to the guys who tried to help) I mean the darting was unbelivable didn't want to go past 30 mph cause of the sever darting issues. Went back to the dooly's & the darting issuse faded away. Just my 2 cents