Towing capacity is a measure of how much weight your vehicle can tow. The gear ratio is the number of teeth on the ring gear divided by the number of teeth on the pinion gear. A higher gear ratio means more torque and a lower gear ratio means less torque.
For towing, you want a lower gear ratio so that your engine doesn't have to work as hard. A lower gear ratio also means that your vehicle will be slower on the highway, but this is not necessarily a bad thing when you're towing a heavy load.
The best gear ratio for towing will depend on the weight of your trailer and the power of your engine. If you have a powerful engine, you can get away with a highergear ratio because your engine will be able to handle the extra load. However, if you have a weaker engine or are towing a very heavy trailer, you'll want to go with a lower gear ratio so that your engine isn't overloaded.
Experiment with different gear ratios until you find one that gives you good power without overworking your engine. And always consult your owner's manual before making any changes to ensure that you're not exceeding the capabilities of your vehicle.