On my Ford van I have a decal in the door jam listing the proper size of tire and recommended air pressure.(235*75*15) I run that tire size and have always kept the pressure at the recommended 41psi. I recently had the tires rotated and the shop changed the pressure to 32psi. I noticed the softer ride but was curious what the lower pressure would do to tire wear and longevity? The title shows the weight to be 5400lbs so I don't require the max load capacity of the tires. I value whatever mpg gains I can get. What would you do?
A matter of reduced pressure.
- Thread starter Piston_slap
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Well the tire shop is just helping you to your next shopping experience in their store. I always check my tire pressure right after I leave from having my tires rotated.
Lower pressure will result in slightly lower mpg as the rolling resistance increases.
I've got some experience with tire pressure changes, and instead of even wear, you will likely see the outside of the front tires begin to wear more rapidly than the center. This is more noticeable in heavier vehicles.
The bulk of my experience is from 2000 and 2004 Jeep Grand Cherokees of around 4000 pounds. I bought one with 72k and the other with 18k; both had badly worn outer edges on the front tires, and were inflated to the factory specified 30psi. I immediately went to max rated pressure (35) and kept those tires awhile, until they started washing out in the wet. Upon replacement my new tires were rated for 44psi max; after some experimentation I found that 40-42psi was a pressure that gave even wear as well as noticeably crisper handling.
The ride was not a cushy as it had been before, but for me it was worth it to have tires that kept their wet handling capabilities their entire life and lasted 60k rather than 35k.
You're going to get a lot of opinions on this one, many of which will preach to use the placarded pressure.....so
Ultimately test different pressures and decide for yourself.
Originally Posted By: JohnnyJohnson
Well the tire shop is just helping you to your next shopping experience in their store. I always check my tire pressure right after I leave from having my tires rotated.
Agreed!
I've got some experience with tire pressure changes, and instead of even wear, you will likely see the outside of the front tires begin to wear more rapidly than the center. This is more noticeable in heavier vehicles.
The bulk of my experience is from 2000 and 2004 Jeep Grand Cherokees of around 4000 pounds. I bought one with 72k and the other with 18k; both had badly worn outer edges on the front tires, and were inflated to the factory specified 30psi. I immediately went to max rated pressure (35) and kept those tires awhile, until they started washing out in the wet. Upon replacement my new tires were rated for 44psi max; after some experimentation I found that 40-42psi was a pressure that gave even wear as well as noticeably crisper handling.
The ride was not a cushy as it had been before, but for me it was worth it to have tires that kept their wet handling capabilities their entire life and lasted 60k rather than 35k.
You're going to get a lot of opinions on this one, many of which will preach to use the placarded pressure.....so
Originally Posted By: JohnnyJohnson
Well the tire shop is just helping you to your next shopping experience in their store. I always check my tire pressure right after I leave from having my tires rotated.
Agreed!
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Your door jamb decal may state that 41psi is the max recommended pressure for the vehicle's max load, or it may simply be a "recommended pressure". If the former, less pressure for less-than-maximum loads may be fine for the longest/most even tire wear. If the latter, pump them back up to Ford's recommended pressure. My local Discount Tire routinely over-fills my tires at rotations on the assumption that I, like most, will pay no attention to their handiwork, and they assume that there will be enough seepage through the alloy wheels over time to bring the pressure down, something 98% of their customers never check between rotations. Most folks don't read the decals on their vehicles.
The tech working on the vehicle is just lazy. Probably sets ALL tires to 32#. We have techs here at the dealer that do the same thing. Drives me mad.
True, tire neglect is a problem out there.
Your 41 psi is made for maximum loads with max speeds on that van.
Going down to 32 psi is a bit excessive though. The tire shop was lazy.
I'd allow maybe as low as 35 psi IF you can be sure you aren't using that van to max capacity, and keeping your speeds down to 75 mph max at the lower 35 psi.
If you are loading the van up to max capacity, do use the 41 psi standard.
Your 41 psi is made for maximum loads with max speeds on that van.
Going down to 32 psi is a bit excessive though. The tire shop was lazy.
I'd allow maybe as low as 35 psi IF you can be sure you aren't using that van to max capacity, and keeping your speeds down to 75 mph max at the lower 35 psi.
If you are loading the van up to max capacity, do use the 41 psi standard.
Tire stores techs are not super trained. They just bang on tires and move on to next car.
Are these LT tires? If so you need to run them a bit higher than 32 psi. For P rated tires I find you can up a bit to 35-36 psi without affected NVH too much, so give that a try.
What I was about to say light truck tires are a different ball of wax than P-metric. Whats the sidewall max pressure of the new ties? 55lbs/sqin gauge?
What tonnage is the van and what do you carry?
Shaggin wagon or work truck?
What tonnage is the van and what do you carry?
Shaggin wagon or work truck?
Nick1994
$100 site donor 2024
Inflate to 41 psi. You don't want your van to imitate the Explorers of the 90s and roll over from a blowout.
Your Econoline came with P235/75R15/XL 108S tires and a recommended Cold Tire Inflation Pressure of 41psi Front/Rear.
For best overall performance, and safety, you should run them at the specified 41psi.
The tire store folks you dealt with do not have a clue ...
Of course, if they put a P-Rated tire that was not XL on, then you are really in trouble - there is no way to inflate a non-XL P-Metric tire to sufficient pressure to meet the minimum load requirements for your Econoline.
HTH
For best overall performance, and safety, you should run them at the specified 41psi.
The tire store folks you dealt with do not have a clue ...
Of course, if they put a P-Rated tire that was not XL on, then you are really in trouble - there is no way to inflate a non-XL P-Metric tire to sufficient pressure to meet the minimum load requirements for your Econoline.
HTH
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