Difference Between 285/70 and LT285/70?

I'm about to pull the trigger on some bigger tires and I've found both of these in 10 ply. Whats the actual difference?

Also, for those who have used Discount/Americas Tires, are the certificates worth it? Got the certs for my car and haven't had to use them yet. Been about 3 years already. Did not get them on my truck and haven't had any tire problems with that either. Truck currently has Falken 265/70's 10 ply.

Any input would be appreciated.

 

LT = light truck metric size. Designed for heavy loads or heavy trailers. Simple explanation.

 

look up the tires on tirerack.com
the specs tab will show the max load. My tires are 760lbs higher for the LT. that equates to 3040lbs more the tires can carry safely. LT are usually tougher as well, but weigh more.

I only go to Discount, and always get the certs. I had a trailer come off the ball behind my jeep, destroyed the spare. They didnt even ask what happened, replaced for the cost of a new cert. Cheap insurance as far as I'm concerned

 

I ordered the regular 285's and the LT285's showed up. Maybe it was just a listing error? Idk, they showed up early too. Either way I'm happy. 10 plys all around, haha.