Optimized Tire Pressure

I just purchased new tires (Michelin LTX M/S 245/75R16) for a 2016 144 Sprinter. It has been recommended to me to get the front and rear axis weights of my Sprinter, and then, use the suggested Michelin inflation table for my new tires (shown below). This would mean ignoring the 49psi/70psi (front/rear aisle) inflation amounts post on the driver’s door. Is this a good idea?
My vehicle weighs 3620 front/3460 rear (pds). According to Michelin’s inflation table my optimized inflations could be approximately set to 40psi/35psi (front/rear). These tire pressures are significantly less (especially for the rear tires) than what MB has posted on the driver’s door (49/70).

Michelin LTX M/S2 (LI=120) chart:
Axle
weight
3400 @ 35 psi
3730 @ 40psi
4060 @ 45 psi
4410 @ 50 psi
4670 @ 55 psi
4960 @ 60 psi
5250 @ 65 psi
5530 @ 70 psi
5800 @ 75 psi
6084 @ 80psi

Interesting data, especially from the manufacturer.

My Michelins have run at 40 psi on all four corners for the last 150k miles. GVW is about 6500 lbs.

glasseye.... sounds like you ignore MB’s posted tire pressure values and you have 150,000 miles on a set of Michelins?

I run 45F/50Rear on my BFG KO2s and I noticed that after driving through dirt, that the rear tires only contact the ground in the middle 80% of the tire or so. There's not enough weight to even flatten out the tire. So, I wouldn't be surprised if I could drop those down even lower to the numbers you posted.

I'm surprised that your rear axle weight is so high - do you have a lot of weight in your conversion? I think you are about 2,000 lbs over the stock curb weight.

gordo019,
Can you post a link to the Michelin Load and Inflation Table you used to get the tire pressure vs axle weight values in your original post?
Also, is your Sprinter a Cargo van, passenger van, or crew van, and have you up fit the interior.
Do you have the OM-651 4 cylinder 2.143 liter engine and 7 speed transmission or the OM-642 V6 3.0 liter engine and 5 speed transmission?
The tire pressure values on the door post ("B" pillar) and the LH side if the driver's seat box are the maximums, if you load your van to the GAVWR.
If you are running much lighter, then you can bring the tire pressures down some, but from 70 PSI rear to 35 PSI rear is probably too much a reduction. You would need to keep track of heat build up to see if that pressure would work.
I run 55 PSI (per the door sticker and seat box) in all 7 tires on my 2014 516/3500 USA NCV3 170" wheelbase, high roof, short back that weighs 7,000 lbs. most of the time, and I get > 100 k miles from a set of Michelin Defender LTX MS2 tires, rotated every 15K miles.
Hope this helps,
Roger

ENMeyer and sailquik..... 2016 Cargo van, 4x4, 6 cylinder, high roof. I think the rear half of our conversion is very light, as we only have a basic platform bed, no tanks, no batteries, or heavy appliances. Here is the link to the Michelin inflation table (pdf, page 22):
https://www.michelintruck.com/assets/pdf/Truck_Tire_Data_Book_Sept2011.pdf

The door plate numbers are at rated load. Using the tire load and inflation tables is preferred and safe.

gordo019 said:

glasseye.... sounds like you ignore MB’s posted tire pressure values and you have 150,000 miles on a set of Michelins?

Click to expand...

I wish!

I'm on my fifth set, I believe. Those are the M+S type, too. Noticeably less mileage than summer tires due to the softer compound. Stability and handling are excellent.

The previous post shows that my pressures are in line with Michelin's recommendations.

I am getting a recommendation to go from 49/70psi (front/rear) per door MB label spec to maybe 47/47psi?

If that is what you van weighs, yes. If you check the owners manual, it should list reduced tire pressures for your laden weight. The "recommended" pressure on the placard is the worst case pressure.

glasseye said:

I wish!

I'm on my fifth set, I believe. Those are the M+S type, too. Noticeably less mileage than summer tires due to the softer compound. Stability and handling are excellent.

The previous post shows that my pressures are in line with Michelin's recommendations.

Click to expand...

Another data point have had multiple pickup trucks with LTX MS and consistently got 80000-90000 miles per set. Weight 4800 pounds 35 psi

If I run my tires at anything below 45 psi the TPMS lights up on the dash and I get the message indicator. So... I'm a 47/70 psi front/rear guy. My oem tires (can't remember the brand) lasted 45000 mi. Seemed like they wore pretty evenly. Got a new set of LTX MS Michelins 5000 miles ago. Really like the ride. 2015 Roadtrek SS Agile on a 2.1 I4 7 speed.

skier, I believe you can "re-set" the TPMS to reflect your preferred pressures... can't remember right now, but there've been posted instructions on how to do this on this forum. I had to adjust mine as the TPMS light started coming on. Since going through the re-set, no more dash warning light. 2015 SS Agile w/3-liter V6.

I haven't had my individual axles weighed yet, but I know I'm running close to GVWR. In spite of that, I've found reducing pressure a bit improves the ride. I'll have to see how that affects the tires -- last spring we replaced OEM Kumhos with Michelin Defenders. (OEM tires were shot at 36K miles.)

Incorrect. The ABS etc only cares that the rolling diameters of the tires are within a certain range. There is no magic voodoo going on. Using the load/inflation tables basically guarantees that the rolling diameters will match. That is because the load/inflation table is based on sidewall flex remaining uniform despite load variance.

If you read the owners manual it specifically (for most years) has a load/inflation table. Running higher than the load table specifies is generally safe, but may result in odd tire wear or a harsher ride.

Adjusting the TPMS thresholds is generally a reasonable procedure, and is a common change when tire sizes are not stock.

The vehicle MFG may adjust tire pressures for comfort etc, but the load and pressure relationship is part of the tires design. The tire consortium creates the specification range for each metric tire type, and all tires sold in that size/type will roughly conform to it.

For liability reasons the tire pressure on the door placard is almost always specified for max laden weight. For the attentive and knowledgeable owner, reducing from these numbers based on axle weights is completely acceptable and safe. Just know that if you add significant weight above that current inflation pressures, you will need to air up the tires accordingly.

great/timely discussion here!
i've been running 55/70 all this time (likely explains why my prev set of snows is so worn in the center of the tread)
typical weights: 3260 front / 3500 rear (conversion van with minimal furniture+eqpt)
seems like i could take the rears (new LTXs) down to 50 and the fronts to 40?

(and maybe make the dang truck ride a little smoother/quieter)

Update..... I reduced my tire pressure to 49/54psi. Now the Sprinter’s tire warning light is on. The Sprinter control console has an alert message stating to check the tires. The rear tires are highlighted. Anybody know what is going on?

Midwestdrifter said:

...
If you read the owners manual it specifically (for most years) has a load/inflation table. Running higher than the load table specifies is generally safe, but may result in odd tire wear or a harsher ride. ...

... For liability reasons the tire pressure on the door placard is almost always specified for max laden weight. For the attentive and knowledgeable owner, reducing from these numbers based on axle weights is completely acceptable and safe. Just know that if you add significant weight above that current inflation pressures, you will need to air up the tires accordingly.

Click to expand...

There are no variable load/inflation tables in the NCV3 owners manuals. There is only a table of recommended pressure for maximum axle loads, much like the door placards.

gordo019 said:

Update..... I reduced my tire pressure to 49/54psi. Now the Sprinter’s tire warning light is on. The Sprinter control console has an alert message stating to check the tires. The rear tires are highlighted. Anybody know what is going on?

Click to expand...

Your rear axle tire pressures are below the stored value in the TPMS. You need to reset/restart the TPMS in your Sprinter. The procedure is in the owners manual. Example page attached.

Sharing my experience in case anyone finds it helpful:

1. I had ABS activation at slow speeds for a while and finally got Joel at MMS to check it out. Turns out the front passenger Tone Ring was bent - I had my Ball Joints replaced approx 6k miles ago and believe that's when the Tone Ring could have been bent). Joel was able to straighten the Tone Ring back into place. I then drove 900 miles with no issues. Right after returning home to GA, I started having ABS activation at slow speeds again.

2. After chatting with Joel, he mentioned checking tire pressure as I recently got new tires. I also used pressurized electronic cleaner and sprayed out the front ABS wheel sensors as I did not have an air compressor handy.

3. I checked tire pressure and had 80psi in rear and 63 in front. I proceeded to read just about every thread related to tire pressure on this forum and found this current one to be the most useful for me. I reduced PSI to 60 in front and 65 in rear and have not had ABS activation since. If it does return, I will probably try reducing tire pressure more and might even do this just for the handling change alone - soooo much better at 60/65 than 63/80.

4. I got my vehicle weighed as per rec from forum - Download Cat Scale Locator and Weigh My Truck and then go to your nearest CAT Scale. Super easy and $12.50.
Steer Axle (Front Axle)=3040lb
Drive Axle (Rear Axle)=3720lb
GVW (Gross Vehicle Weight)=6760lb

5. Reviewed link below for Michelin Load information (see pic below).

outbound said:

great/timely discussion here!
i've been running 55/70 all this time (likely explains why my prev set of snows is so worn in the center of the tread)
typical weights: 3260 front / 3500 rear (conversion van with minimal furniture+eqpt)
seems like i could take the rears (new LTXs) down to 50 and the fronts to 40?

(and maybe make the dang truck ride a little smoother/quieter)

Click to expand...