QuestionQUESTION: I have a 2006 Chevy Express 3500 passenger van. I don't tow or haul anything but my kids. I bought a set of 4 tires last winter and the sidewall says max psi 44. My door panel however says I should have 80 in the back and 50 in the front.
What pressure should I use?
Thanks
ANSWER: Dear Ron,
Thank you for using AllExperts.
I'm somewhat distressed at the information you have provided as it seems that 'P' (designates (Passenger) type tires have been mounted on your 3500 series van. Your van requires 'LT' type tires and my records show that the original tire size was LT245/75R16 load range 'E' (10 ply). Yes, the door placard pressure calls for 55 psi front and 80 psi in the rear.
Did you specify the passenger ('P') type tires, or did the tire installer "sell" this to you? I would like to know what size they are to check if the load capacity is anywhere near safe for your van.
There's another "difficulty" when applying passenger tires to light trucks (your van is categorized as a light truck) that were originally
fitted with 'LT' type tires. The load rating of the passenger type tires is "discounted" to only 91% of the tire's load rating. All this may seem somewhat confusing, but here is one explanation for this (link). It is simply not a good idea to replace 'LT' type tires with 'P' (passenger) type tires.
I'll be waiting for any follow-up questions that you may have
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=70
---------- FOLLOW-UP ----------
QUESTION: Thank you for your quick response but it is a little distressing to me also. I did not specify any type of tire. I do remember him asking me what I do with it(ie transport people)but that is it. The tires are Goodyear Fortera P245/75 R16. Temp B treadwear 600; load capacity is 2271 pounds. It looks like it is a 5 ply(2+2+1). I'm not sure what to do now. I took the pressure down to 50 in each tire but then I am concerned they will be under-inflated and risk a blow out. What do you think?
Thanks again
AnswerDear Ron,
I believe that your tire installer acted irresponsibly. A replacement tire fitment should never be based on the tire installer's 'guesstimate' of what loads you may or may not carry# Clearly, your tire installer has never heard of the P-metric tire rule for discounting its load capacity when installed on light trucks and has not acted professionally. Let's compare the load capacity of the two tires:
LT245/75R16 @ 55 psi = 2,335 lbs per tire
LT245/75R16 @ 80 psi = 3,042 lbs per tire
P245/75R16 (load index 112) = 2,469 lbs per tire @ 41 psi (max load)
However, as I mentioned, the passenger tire's load capacity has to be "discounted" when mounted on a 'light truck', therefore the effective load capacity of the P245/75R16 is:
2,469 lbs. X 0.91 = 2,247 lbs. per tire. A significant reduction. This means that your rear axle has a "load carrying capacity" deficiency (according to what GM specified for your vehicle) of more than 1,590 lbs.!
I think you have only several options:
1. Go back to the tire installer and demand a full refund towards the correct tire size (any tire failure leading to an accident would put significant liability on them).
2. If you receive no satisfaction from the retail dealer, contact Goodyear corporate consumer relations. They'll understand this huge mistake and the potential liability. You may very well get a quick "policy concession" from them.
3. Somehow, find a place to WEIGH your vehicle in its HEAVIEST loaded condition (all passengers and max. expected cargo full of fuel)...by EACH axle...and then let me know what the weight is per axle. Probably a difficult solution.
In the meantime, make sure you have 41 psi in each tire (max. allowable).
DT
