I have a 07 JK with a 3.5 rubicon express lift running 35. Can I go up to 37 without doing anything to my axels can I just do tires?

 

Yes, you can leave the axles stock.

But you'd probably be better off reading through a few of the hundreds of threads about strengthening the front.

 

Sure you can...it just won't be very smart! As a bare minimum put some c-gussets on. Depending on the wheeling you do, you may want to add a truss or sleeve as well. Also, you will probably want new gears unless you have already swapped those.

There are numerous threads on running 37s and beefing up axles, search a little bit.

 

I doubt your going to put it through much more than speed bumps- so just do it. If you get ran off the road at some point and actually get them dirty and the axles break- trade it in so the wife can get a cheap JK