My dealer uses the caliber plastic ones. Said he has had them for a few years and finally the tiers are giving up. He drives every sled he sells and and services over gravel with them. Pretty impressive actually.
FEATURES Fully adjustable from 177mm (6.8") to 272mm (10.7") designed to fit most Ski applications Adjustable Arm retracts to 556mm (21.9") and extends 683mm (26.9") allowing it to lock easily into most Ski loops The 30-degree lateral sweep adjustment ma
The Canadian Tire ones work better than the other cheap ones. The main issue with the cheap ones is the wheels separate when you turn because there's no solid connection between the two sides. The Canadian Tire version addresses this.
They all work well though. I can ride out of my garage, down the driveway, and up my sled deck or in to my trailer with them on. They even stay on going across grass or gravel.
I even got in trouble at the Alberta Sled Show this year for riding too fast when I pulled the wife's machine out of the building if that means anything.
As per the original post. I have a set and they work good but if you want to drive around a gravel driveway they do spread apart when trying to turn. There is an upgraded version that has more support that probably is better. I have the cheap ones though and set up 2 very short ratchet straps that I hook over th back of the ski and down to each metal part of the rear part of the brackets. The strap pulls them tight to the bottom of the ski so the don't move. I don't use them often as I have my Gripper Ripper axle brackets that my wheel axles slide in to.