There are two reasons I know of to have the chains loose.
First picture a car tire with a tight chain. This is good. Because the tire is relitively flat with a tight tread design compared to the chain link size. No matter what the tire rolls over the chain will have a tire backing. The tire will support the vehicle not the chain and the tension in the chain will not increase.
Now put a tight chain on an ag tire where the chain bridges big void spaces between the tire lugs. When the chain rolls over a rock between two lugs there is a hole there so there is no tire backing behind the chain. Now the weight of the tractor is being held up by a short piece of chain bridged across two lugs. The tire is no longer supporting the tractor the chain is. The tension in the chain increases to many times the weight of the tractor. Think of it this way - tie a 20' rope to a tree about 3' off the ground. Run the rope thru a concrete block lying on the ground 10' away. Grab the other end of the rope about belt high and pull horizontally to pick up the block. The pull or tension in the rope has to be much, much greater than the block weight to pick it up. Basically the same thing happens to tight chains on ag tires, there is tremendous pressure on the lugs and high tension on the chain. If you loosen the chains they can collapse down between the lugs and be supported by the tire. The chain tension will not skyrocket. You get your traction where the chain goes over the top of the lugs.
Adding tensioners lets then run tight but also allows the chains to stretch down between the lugs.
The second reason for loose chains is so they will be self unloading of packed snow or mud. The loose chain shakes the packed snow off the chain/tire so it won't build up an reduce traction.
Edit - I don't t run tensioners on mine, I have plenty of clearance so the chains don't hit anything. They stay centered just fine.
gg
I'm with Gordon on this one.. I also have the Tellefsdal (pronounced tell- effs- doll or dahl since you asked
) chains, they were marketed under the name Super Tractor and sold by Norse, but made by Tellefsdal . I have the cast steel couplers with the drive pin to link the ends of the center links, but each set of chains (per side) only has 2 of them, they aren't used between each section of center links.
I've had them for 4 years now, zero problems, and I do mean zero! No appreciable wear, even running a few miles on asphalt every winter. My Kubota dealer had them, Nova International, paid around $550 IIRC. I run mine loose as a goose, as per the instructions. They need to be loose to grip and shift around properly, according to Tellefsdal, they should actually rotate around the tire to prevent undue wear and stress. They say 30-50 cm rotation is desirable after driving a distance of 1 km.
A direct quotation is "Right tightening is very important for not getting damages on the chain or tire. Check the chain fitting by driving 1 km. During this distance the chain should move about 30-50 cm on the tire. If the chain doesn't circulate it will cause extensive wear." That's from the manual that came with my chains. Like Gordon, I don't use tensioners of any kind.
I've never had them come off, even under some pretty severe snow and brush conditions in the woods. Running them loose also makes for a much smoother ride on hard surfaces like concrete or asphalt. All you get is a very merry jingling noise, with the occasional hop as the chain bunches up and goes under the tire.
YMMV as might be expected.
Sean
