Max Tire Size Advice Needed - please!

[chetwynd]

Hi Guys,

I have a stock 2008 EB 4WD with 20" wheels. I hate the 20" wheel look and am going to get some either 17" or 18" OEM takeoffs as well as new tires. I'd like to put on the largest tire I can without rubbing issues. Can anyone help me sort out the max sizes I can use for each rim size?

Thank you!

 

[Grover6]

I have 20" wheels as well on my '16, and I went up to 285/55/20 from the stock 275 without issue. I want to go up to 305/55/20 and I think that will be the biggest without at least a level kit. I looked at 18" wheels and the 305/65/18 would be equivalent. not sure about the 17's but probably around a 305/70/17?? If you are not looking to change the suspension then the 285 would be as big as you might be able to go.

 

[Iamsam1117]

Put the 3/2 kit on my '15 (pretty simple with a few beers and Jack stands) and upgraded to 275/65/20.... VERY HAPPY!!

 

[GITanker]

I have a 2.5 inch leveling kit on my 2014 Limited 4X4 and put 305/55/20's on mine. Love it.

 

[16plati]

Readylift 3/2 with 35/11.50/20 and 1.25” wheel adapters. She wide now

 

[chetwynd]

I can't lift it at all AND get larger tires or the roof racks won't clear my garage door opening unfortunately.

 

[Adieu]

Stock is around 32", so 33" should be ok im fairly sure?

Tire height (=diameter) formula is:


For ***/yy R zz tires:

*** = tire WIDTH in millimeters
yy = tire sidewall HEIGHT... in PERCENT of width
zz = wheel diameter...in INCHES


So... overall diameter in inches is:

Zz + (2 × *** × 0.yy ÷ 25.4)



....what the hell whoever invented this hybrid inchey-metric-percentey standard was smoking is anybody's guess.


PS a typical stock 18" OEM would be 255/70r18, which makes ~32" total and leaves significant space all around... beware that tired shocks WILL sag under significant overload, though, so don't load up 8 people and a dozen oversize luggages and go travelling over potholes on oversized tires and old shocks

 

[PNWExpy]

Chetwynd do you still need rims? I just took off a set of 18” OEM chrome that I don’t want to keep.

I had 255/70/18s on and those measured about 31” but they were at the end of their life. I went with 275/70/18 on the new set up and these measure 32 1/2”. Rims are 9 inch with 18mm offset. I’ve got a 2007 limited with air suspension in the rear and I don’t rub at all in normal driving conditions. I took it off road and did a quick test. The front seemed to rub a little at full turn and the rear, when flexed, cleared the wheel well but would hit a bracket in there.

 

[Adieu]

Chetwynd do you still need rims? I just took off a set of 18” OEM chrome that I don’t want to keep.

I had 255/70/18s on and those measured about 31” but they were at the end of their life. I went with 275/70/18 on the new set up and these measure 32 1/2”. Rims are 9 inch with 18mm offset. I’ve got a 2007 limited with air suspension in the rear and I don’t rub at all in normal driving conditions. I took it off road and did a quick test. The front seemed to rub a little at full turn and the rear, when flexed, cleared the wheel well but would hit a bracket in there.

You're underinflating or measuring wrong

 

[16plati]

Everyone is failing to realize that tire measurements that companies put online are all at the MAX pressures. So if you have a tire that’s a 35/12.50/20 and it’s MAX allowable pressure is 80psi and you only inflate them to 35-40, you are not on a 35” tire

 

[chetwynd]

Chetwynd do you still need rims? I just took off a set of 18” OEM chrome that I don’t want to keep.

I had 255/70/18s on and those measured about 31” but they were at the end of their life. I went with 275/70/18 on the new set up and these measure 32 1/2”. Rims are 9 inch with 18mm offset. I’ve got a 2007 limited with air suspension in the rear and I don’t rub at all in normal driving conditions. I took it off road and did a quick test. The front seemed to rub a little at full turn and the rear, when flexed, cleared the wheel well but would hit a bracket in there.

I think I'm good for now, thank you though!