Finally...i Understand

rws262 · February 18, 2011

So after nearly two days of looking at metric tire sizes, i finally have grasped what they are trying to tell me.

Now on to the question of what to get. I am getting Cooper Zeon LTZ's on 20x9 rims. The tires i have now are stock 275/55/R20 and i figured i would get the same size, unless i can get away with a 275/60/R20 without a level/lift kit. What do you think, can i get 275/60/R20's without a lift kit? Its a tire that is 1.12 inches taller (if im doing this right) but the rims are now going to be 1/2 inch wider. and where does rim offset figure into this?

Now on to the lift question. I like the rake in my truck as i pull a lot of heavy stuff, mainly racecars. What kind of lift (if i need it) will get me up to fit the tires but keep the rake? And how much bigger lift would i have to go to get something, say, 305/55/R20?

Next question, if i hook up to the race trailer and it sags down a little bit but still fairly level, will the rear tires rub at all?

Last question: if i go with 275/60/R20, is there anything that has to be calibrated in speedo or anything else?

Thanks for all the help guys. I have learned a lot from this site.

blackout07 · February 19, 2011

You will need a 2" leveling kit in order to fit a 275/60/20, and they will still likely rub some.

What is the offset of the wheels you will be running?

If you want to run 305/55/20's, you need a minimum of 4" of lift. 5-6" is best. I ran a 2" leveling kit/3" body lift with those tires.

Rear tires shouldn't rub at all.

Your speedo will likely be off a little..not sure how much.

Knowklew · February 19, 2011

275/60-20 = 32.99'' basically a 33.

You need a level kit for a 33

rws262 · February 23, 2011

Would 305/50/20's work on a 20x9.5" wheel, +35mm backspace, and a 2" RC leveling kit? its a 32" tall tire, thats 12" wide. Not sure how the extra inch wide rim will work.

jimbrown1 · February 23, 2011

If you run a 275/60/20 instead of OEM 275/55/20 your speedo will be off a little over 2 mph unless you get a BB tune to compensate.

I'd like to get the Cooper Zeon in 275/60/20 when these crappy Goodyear Eagle LS2 wear out but not sure if the RC 2" level kit will allow me to run those tires or if I need the Bilstein pre-load level unit I see at offroadwarehouse.com or shockwarehouse.com.

Put up some pics when you decide and get everything installed.

beave84 · February 23, 2011

You will need a 2" leveling kit in order to fit a 275/60/20, and they will still likely rub some.

What is the offset of the wheels you will be running?

If you want to run 305/55/20's, you need a minimum of 4" of lift. 5-6" is best. I ran a 2" leveling kit/3" body lift with those tires.

Rear tires shouldn't rub at all.

Your speedo will likely be off a little..not sure how much.

That one bad ass rig you have

chakis24 · February 24, 2011

If you run a 275/60/20 instead of OEM 275/55/20 your speedo will be off a little over 2 mph unless you get a BB tune to compensate.
I'd like to get the Cooper Zeon in 275/60/20 when these crappy Goodyear Eagle LS2 wear out but not sure if the RC 2" level kit will allow me to run those tires or if I need the Bilstein pre-load level unit I see at offroadwarehouse.com or shockwarehouse.com.

Put up some pics when you decide and get everything installed.

depending on how nice your dealer is they can do it for you too. if its a common size that they already have programmed they may do it for free- otherwise you'll have to pay substantially more if its an off size. the dealer i used to go to reflashed for me when i went from the stock 265s to the 285s (33s). even if they dont have your exact size you can get something close.