You have 2 canistors mounted to the axel near each rear wheel. It looks similair to a maxi can for air brake equipped trucks. Well anyway, when the canistor recieves air fron either an on board compresor or air supply from the truck it is mounted on, it engages a rubber wheel to the drive tire. As that wheel spins, it throws short length on chains, under the tires providing traction.When you are done, you just turn the switch off, and the canistor retacts. go to http://www.onspot.com
Ok How they work. They are held up by a air cylinders, and are spun around so there is always a some lengths of chain under the tires. They can only be engaged when the truck is traveling over 5 MPH, so if you don't have them engaged when you get stuck they will not help you. You can't travel over 25 MPH, with the chains on.
How well do they perform. I used them last year for the first time on my F 650. I got them because I have always doubted the performance of a 2wd plow truck big or small. The driver tried plowing roads with and with out the chains. His report was the truck did fine at the start of the route with a full spreader. However the performance wasn't as good with out a load in the body, when the chains were added, the truck was fine.
The chains also helped in over the road operations, when the road was covered in deep snow. The chains proved very benneficial when starting at an intersection. I believe the truck would perform fine if the v-box was always 1/4 or more full, even with out chains. However when you are not sure what the road will be like, it is good to have them.
My recomendations, if you have a med duty truck, like the F 650, and you only have one. On spots are a must, on spots will get you though the areas that you would get stuck with out chains. The work as well as standard chains, but they aren't as good as 4X4. The reason why i say if you only have one med duty truck, you should have chains is simple. If you don't have chains and you get stuck, i doubt your 3/4 or 1 ton pick up will pull you out. The cost that you will recieve from a tow from a towing company, in addition to the lost time, equals lost money, and maybe your paying an employee just to sit there. All this adds up and if you add it up, and think what if it happens 3 times in 2 years, well, thats a lot of money. If you had chains, you wouldn't be waiting for a tow company, wouldn't have lost money, and wouldn't have an employee sitting around doing nothing. So don't think of them as an extra expense, because even the best driver will get stuck after enough hours (if you think that you the owner will just drive the big truck and not get stuck, you will probably get stuck as fast as your driver would or be so afraid of getting stuck the truck wouldn't be used to it's full potenetial.
Now just as a side note. The med duty trucks are generaly used to accomplish long runs, ie road plowing. Where the chains shine are in the hammer head turner rounds, at the end of private roads. I will also admitt that if you are in an area, where there are very little hills, and the roads are maintained very well, 2" or less of snow left on the road. Then you probably will be fine with out chains. However they really shine on ice, that was the major reason i went with them. They help to elliminate slidding, keep traction on ice, and are just great.
[Edited by GeoffDiamond on 10-23-2000 at 01:48 AM]
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