Probably the single most often asked question on any truck forum starts with "What size tire......".

So here is a breakdown of how much lift you need to clear various tire heights. Keep in mind this is simply just to fit without trimming. Good performance, especially off-road will undoubtedly require additional lift or trimming. Aftermarket wheels with a deeper backspacing, or wheel spacers may be necessary in many cases. This data is 3rd Gen Ram 1500 Specific, 2500 data to follow.


For up to 33" tires, there is no lift required.

For 35" tires, a minimum of 2" of lift is required.

For 36" tires, a minimum of 4" of lift is required.

For 37" tires, a minimum of 6" of lift is required.

For 38" tires, a minimum of 7" of lift is required.

For 39" tires, a minimum of 9" of lift is required.

For 40" tires, a minimum of 10" of lift is required.

 

35/12.50/17 with a 3" body lift

 

I voted stock but their a little biger 275/65 R20 whitch is a little over 34".

 

6" lift, 35" Pro-comp X-terrain. although diameter is one major factor in fitment, its not the only factor. just as important is the backspacing with the wheels. the incorrect backspacing can cause the tire to rub the frame rail at full turn. Make sure to also do some research and figure out the correct backspacing/tire width you'll need.

 

6" Fabtech with BFG AT's that came on it. 17x10 wheels. I'll be the first to admit that they would probably fit better with a little more backspacing (not sure what it is now), but I dont want the tires sticking out any further either. diameter measures out to about 34" as they are now, with a little wear on them.

 

285/75r/17 just shy of 34" . fit with a 2.5" level on a 2500

 

redone heres what back spacing is :
How to Measure Wheel BackSpace


Items required to measure wheel backspace: Tape measure Straight edge Wheel w/o tire (preferred)

The easiest way to measure backspace is to lay the wheel face down onto the ground so the backside of the wheel is facing up. Take a straight edge and lay it diagonally across the inboard flange of the wheel. Take a tape measure and measure the distance from where the straight edge contacts the inboard flange to the hub mounting pad of the wheel. This measurement is backspace. The above photo shows three wheels with 2",3", & 4" backspace.

 

Is there a chart somewhere that shows tire size conversion charts? This may be a silly question, but I'd like to know all the tire sizes that come out to be 33" to 35" tall. For example... If I'm looking for a 34" tire I can't just say "34x12x20"... I need to know 285/70/20 (which is probably way off )

So I need a chart. If this is obvious and overdone, forgive me.

 

Ask and you shall receive:

http://www.redrock4x4.com/tech/tire_calc.php

 

Well that chart tells me I have 34.1x10.8x20. So can I run 17" rims with 315/70/17 BF tires with no lift, and calibrating my speed sensors with no issues? What offset would I need? I have a 05 ram 1500 5.7 Thunder Road 4x4 qcswb with 275/65/20 tires now. If not what would work in 17" without lifting, and what would work with lifting 2"s? Does it have to be a suspension lift, torsion keys? What about 35x12.5x17 tires?

Thank you