Tires: bouncing tires, tire placard, 2004 dodge 2500

Question
QUESTION: I have a 2004 dodge 2500 that has a bad bounce at speeds between 45 and 50 miles per hour had them balanced twice rotated once smooth ride before 45 and after 50
thanks

ANSWER: James,

Let's start with the basics:

On every vehicle sold in the US – and I am told this is worldwide, but I have not been able to verify this - there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.

One word of caution:  Some trucks use tires with the letters "LT" in front of the tire size - and some trucks use tires with the letter "P" in front of the tire size - and some trucks use tires with the letter "C" after the tire size.  You should not use "P"'s in place of "LT"'s and vice versa.

Go find the vehicle tire placard and verify that you are using the same tire size as listed there.  If true, then verify that the pressure listed on the placard is what is actually being used in the tires.  By that I mean you need to check it yourself, as many folks at tire shops think they know what is supposed to be used and don't always use the placard for reference.

If the tire size is different than the placard, post a followup telling me what the placard says about the tire size and the pressure and what size is actually on there.

If the tire size is per the placard and the pressure is different, then adjust the pressure to the placard and let me know what happens in a followup.

If the tire size and the pressure are per the placard, then there is a somewhat complicated procedure to follow that starts with a whole list of questions.  It's too long to post in this response, so post a followup.

---------- FOLLOW-UP ----------

QUESTION: the sticker on the truck says Lt 265/70 R17E cold 60 psi
the ones on it are p 265/70R 17 max 45psi
put correct pressure in the ones on it problem seems worse

Answer
James,

As you can see, the reason I always ask folks to compare the vehicle tire placard to the tires currently on your vehicle is because those have to be correct before we go further.

According to Tire Guides, a publication that summarizes vehicle tire placards, in 2004 there were a variety of versions of Dodge 2500's and some of them came with LT265/70R17's, but none of them specified 60 psi front and rear.  They all had a staggered pressure of some sort.

As background, you should be aware that LT265/70R17's can be inflated up to 80 psi.

But you have P metric tires in the size P265/70R17 and they are normally used at 35 psi, even though the sidewall may something different for a maximum pressure.  You need to replace those tires immediately as they do not have enough load carrying capacity for your truck. These tires may fail due to overload and if you remember the Ford/Firestone situation some years back, this can have tragic results.

But I do not think the bouncing problem is caused by the tires.  More likely it is a failed shock.

Shocks can fail in either 2 ways:  They can fail "soft" - that is they lose their damping ability and the result is a bouncing effect - or they can fail "hard" - and the result is no suspension travel, which would also result in bouncing.

So have someone look at the shocks.

But for safety's sake, replace those tires with Load Range E LT265/70R17's.  Do this now, not tomorrow.