With all my modifications, my 2 door Tracker with me in it weighs 3,020 lbs. Technically a 6000# winch has twice the capacity to lift my Tracker off the ground. That capacity is only at full spool, then the capacity drops with each layer of line off the spool.
Consider that 3,000# on four 1 foot pads (exaggerated) probably doesn't have half that resistance. The only way that you can pull more weight/resistance than your rig is to anchor it to more weight/resistance. When stretching your rig between two or more points it is easy to tweak the frame if done improperly. More is not always better (if you have it then you will be able to use it).
The real advantage to larger rated winches is spool size. The smaller spools means the less distance it will pull without straps, ropes, cables, or chain. Which means more gear needed.
A slower winch is slow (not that we are impatient, it is just slower), and slow is only what we want when things get critical, until that point faster is always better (right).
A winch is only used or needed when things go wrong (rarely if we are doing a good job of driving, or once a year).
I have a 8,000 HF winch and have used it lots of times. It was used and cheap (cheap is bonus points), and seems a very capable winch for me.
This is installing the first of 5 30'-40' bridges that we couldn't disturb the creek when installing.
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