Ok, I may be a clueless, but tires sizing is getting more complicated.

I put the 2" level kit on and want to go with some bigger tires, ATs.

20" inch tires are so evpensive that I could buy 285/65/17s with some decent rims for the same prices as the 20" tires..

Question is are the 285/65/17s going to be the same height as the same in 20s?? It may seem like a dumb question, but Im not sure??

Also, have any of you guys put on new rims & then lose the TPMS? Is there a way to keep the TPMS operational when awitching wheels?

Thanks for any help...

Karl

 

Nope, they will be three inches shorter.

285: width of the fatest part of the tire from sidewall to sidewall, measure in millimeters.
65: height of the sidewall as a percentage of the width. In this case it would .65*285 or 185.25mm or about 7.25 inches.
17 or 20: the size of the hole in the tire where the wheel goes measured in inches.

so the 20 is three inches in overall height bigger than the 17.

 

A 285/65/20 tire is roughly 34.5" x 11.25" whereas a 285/65/17 is 31.5" by 11.25".

For a 17" tire to have roughly the same height as that 285/65/20 you would need a 295/75/17 which would be about 34.5" x 11.5"...

 

So three inches then hammer? ;o)

 

I just replaced my factory SRA 265/70 R17's for SRA LT265/70 R17's last month. It's not what I started out looking for and when I say looking...I looked for two weeks and drove my tire guy nuts, lol! Both of these tires claim to be 31.5 inches tall according to G/Y specs but the regular SRA 265's I replaced were actually 30.5 inches (1" shorter in height than the LT's). I measured these with a ruler and side by side as well as other tires I originally wanted. The 275/70 R17's were around 33" in height. A set of Cooper 275/60 R17's (which I liked) were a 1/2" shorter than my old tires (30" in height) so I didn't get them and they didn't have any 285/60- R17's but they did have 285/60 R20's which were 33" in height. I was so damn tired and confused with all of these tire measurements that I gave up on my intended tires and just went with the LT's. I would have went with a 32" or 33" but nothing shorter and the LT's are more fitting for me doing construction and trailering anyway. Bottom line is, they don't have much of a selection for 17" rims like they do for 20" rims. I saw some 285/70 R17''s, but I could not find any 285/65 or 285/60's for 17" rims to even see how tall they were.

 

Thanks for the info guys, I want to put some bigger tires on & after talking with ramjam on here , he told me the bfgs 285/65/20s were a good fit w the 2 inch lift, but after looking at the price of the 20s I was looking at getting a tire/wheel package in 17s or 18s. But I guess I may be better off shelling out the big $ for the 20s. Unless anyone has other ideas. But thanks for all the info, cleared things up .

 

Are you sure they where 1" shorter, or just worn down 1"? Did you measure your old tires vs the LT? Or new vs new?

 

The rears were going bald but the fronts had another 10k on them...I don't go fast around turns. And yes I did with a ruler and side by side...I even compared them side by side when they took the old ones off the rims. Even the G/Y tire store couldn't explain it. They had to pick them up from their other store. When they arrived, they didn't look anything like the SRA's I had or the ones in the picture from the G/Y catolog that they told me was coming. I later found out that they are new tires manufactured in Feb/11 and are M+S (light mud and snow) 2,333 lb load range E. I almost didn't accept them but I bought two for the back one day and the other two a couple of days later. They were so firm that it made the softer tires in the front hard to recover from a left or right turn. It would easily over steer as if you had steel belted on the back and polyester on the front, I noticed it right away...not good! So instead of waiting a while like I originally intended, I hurried up and got the second pair for the front. They're not as atractive as the factory ones but I love the firm ride and I'm glad I got em. EDIT: I disscussed the 30.5" height on the forum in early 2009. I had calculated the 30.5" tire and 3.92 gear to have the same ratio as 32.5" and 4.10 gear. Now with the taller tire it probably brings it closer to 32.5" and 4.00 or close and slower holeshot than the RT which btw will pobably raise doubt like it did back then, lol!

 

I have the 285/65R20 BFG ATs on my truck with the 2.5" lift out front, and 1.5" out back. No rubbing at all, they fit awesome.

 

Also, if they are 1" shorter standing side by side, that would mean that they would be worn down 1/2" all the way around. 1/2" on bottom, 1/2" on top. And you will find differences in the same sized tires from different manufacturers.