I read a lot about the wear and tear that 35s 37s cause to bearings and axle components but I don't understand why. I also don't understand why an axle can bend for the same reason.

 

Leverage and torque. It's the same physics that make a pry bar work.

 

For just dd it has more to do with back spacing of the wheels and where the center of the tire is in comparison. Farther your tires stick out the more deflection on the bearings, joints, axle tubes. A good way to show it is by using a Popsicle stick between two books, closer the space the stronger the stick, wider the weaker it is.

Wheeling takes into other considerations like weight of the vehicle, tires etc... And how you drive it.

 

Ok, I bought my jeep with 35s, so I'm not privy to the process. Are all 35 and larger tires spaced for clearance?

 

The rims, not the tires.

As the tires get taller and/or wider, you need to make room for them. That involves either rims with less backspace or wheel spacers (pushing the rim/tire further out of the wheel wells), and may involve adding a lift or taller bumpstops or flat flares to keep the tires from moving up and contacting the flares.

Your 35's are not contacting anywhere, correct? So it is likely that you are not using the stock rims, or that you wheel spacers attached behind them.

 

They are most likely heavier as well. I think our 35" Toyos are nearly twice the weight of the stock tires. Double the weight on the end of your popsicle stick and things start to go bad in short order.

 

It rubs a little in reverse only.

 

I just felt compelled to respond to this thread and the Popsicle stick comparison. If a JK axle is approximately 60 inches wide and a popsicle stick is approximately 4 inches in length let us compare the change in perspective. If you add a 1.5 inch difference on each end of the axle this is approximately a 5% increase in length. The relation of length of the axle and the popsicle stick is a 15 to 1 ratio. If you were to increase the length of the popsicle stick in direct relation it would be about .1 inch on each end. If you do this you would find very little difference in the actual stress put on the end of the axle or stick. I find it hard to believe that adding 5% to the length of the axles has that much of an effect. I think that the stock axle is just weak from the beginning and could and does get bent even with stock wheels. As for the weight of the tires, they would only change the rotating mass. If you were jumping a lot and they were hanging on the axles then the weight would matter. I think that the amount of weight added to the JK, bumpers, winches, body armor etc, has a bigger effect on the ends of the axles.

 

Its mostly about the weight. I heard that every 10 more pounds of rotating weight(tires) is equivalent to 100 pounds of dead weight on your jeep. Heavier tires are harder they are to turn, so more stress on components that have to turn them.

 

This makes sense. However, the extra rotational mass doesn't have to be flying through the air as in jumping. Potholes, speedbumps, curbs, the ruts in my driveway, etc. all affect the lengthened popsicle stick.