can i use the stock 17x7.5 rims with lt31570r 17 tires? someone just told me the rim is too narrow for the tire. is this true?

 

You can use the OE wheel with that sized tire. If you search "Overlander" you'll find a Jeep prototype vehicle that uses the steel winter/offroad wheels that are the same dimension on their rig. You'll probably need spacers because of the offset of the OE wheel.

 

They are a bit narrow. Need a bit wider to get good wear out of tires and they may be a bit unstable in corners. I had mine on 9 inch wheels neighbor on 10 inch and he got a better ride on same vehicle. Good luck.

 

It is doable, but you have to run the tires at a lower psi to get flat treadwear.

Some tire shops won't do the install.

 

It's usually relatively safe to go 1-Up on the width recommendation by the tire manufacturer. Any larger and you risk breaking the bead when cornering. And improper tread wear.