Hey All,
Still been searching different tires to upgrade my JKU. Anyone have experience with 315/70r17s? How well does everything hold up to the larger tires? Any shakes? Wobbles?
Besides needing a couple inches of lift, is anything else required to run these? Thanks for your input.

 

315/70-17's/35x12.50-17's are probably the most popular sized tires for JK's. The question is what specific tire are you considering and what engine, transmission and gearing does your Jeep have?

 

2018 jku , 3.6, auto 3:73.

 

If you are keeping the stock wheels then you will need 1.5" spacers to avoid rubbing. SpiderTrax, Bora, among others are good quality.

 

Upon the inspection of our new Quadratec Hardrock wheels I noticed that these wheels look just like the Mopar hard rock wheels but with a difference of 30mm within the offset (et) because of the wheel width, we're opting for a 285/70/17 as these would be a slight less wide tire that the 315's. Checking the specs the less wide tire would be better in the snow and other rough terrain. I was also given a chance to see our wheels with 315's on them while picking up the wheels from Quadratec as the counter person showed us a jeep in the parking lot with the 315's and the 10mm wheels. I didn't like the looks.. the wheels stuck out farther then I would like them to be. Thus we'll be going with the 285's. It's not about height or width, it's about traction and control.

 

With your powertrain, you will be ok with 35's. If you had taller gears you would probably have to install lower gears.

 

So I could run these okay on stock wheels if I stick with those with a couple inch lift and set of 1.5 inch spacers?

 

SIRed

It ready depends on the tires used as not all tires measure equally even though they maybe listed as the same IE 33's etc the tires could actually measure more or less than 33'' if you follow. Like select a tire you're interested in, head over to their site and locate the specs page. If the tire you've selected has an allowance of wheel sized that includes the 7.5 stock wheel then you're good to go. I mean in your case the tire would have a budge because the wheel is holding them in around the rim line.

 

FAQ's and Thoughts On Lifts are stuck right to the top of this Modified area. Probably would not be a waste of time to browse through them.

By 'couple inches of lift', how high are you actually thinking of going? That could get into a bigger discussion of budget and specific components.

Do you plan to chop the flares or go to flats?

Have you considered new rims with an appropriate backspace? (take a look at the specs for the tire you want. It will list a recommended rim width range. You stock rims will be narrower than that range, so make sure the shop will mount them!)

 

What nthinuf said.

315/70/R17s are likely the most popular size many go with when moving to a larger tire, 2nd most popular is the 35x12.5R17, which are essentially the same size tires, just different units of measurements stamped on the side of them.

You will need a lift for some additional fender clearance, and you will need proper back spacing to provide steering clearance. For the steering clearance there are 2 most common ways to address that problem.

1. Purchase new wheels with 4.5 to 5.3" of back spacing (This is the better way)
2. Purchase 1.25 to 2in" spacers (1.5" is most commonly used). There's a couple items of concern with the back spacer method. The width of the stock wheels are narrower than manufacturer recommended wheel width for a 315/70/R17. For a 315/70/R17 an 8-11in wheel width is recommended. Due to the stock wheels being below 8in of wheel width, many (ie not all) tire installers won't mount them for you on the stock wheels. Adding spacers adds some complexity to the setup. You need to ensure the spacers are properly installed, and check to make sure the lugs holding them on have not loosened over time, where you need to pull the wheels off to do a check.

Both methods are often used with good results, where #2 is the lower cost option. I've used both methods, and highly prefer the 1st method. Which reminds me, I have a set of lightly used Spidertrax 1.5in spacers I should probably sell because I realize I'll likely never use them again now that I have wheels with proper back spacing.