Michelin tire inflation charts

[brocki]

I just had my toad (09 Ram 1500) weighed on all 4s as we carry a pretty heavy bike in it and I do want to inflate the tires more accurately than my guess.  The truck has Michelin Defender tires and  I can't find anything on the Michelin web site regarding inflation charts.  Now I think I remember several years ago having the same issue for the same reason (same truck but different bike) and Michelin said in a "chat" that they don't publish them anymore.  Is my memory wrong, or if not, have the lawyers taken over the whole world?  Does anyone out here in our community  have a chart for this tire in a 265/70R17?

[richard5933]

I just read through the owners manual for these tires, and for inflation advise they tell the user to follow the vehicle manufacturer's specifications. Does your truck have a placard which has load & inflation variables? Or perhaps in the owners manual? I was able to find a manual for a 2011 RAM 1500, and best I can tell from the it is that you should look for a Supplemental Tire Pressure Information placard which will contain inflation pressures for various loads. Perhaps yours has something similar.

[brocki]

On 11/30/2020 at 3:11 PM, richard5933 said:

, and best I can tell from the it is that you should look for a Supplemental Tire Pressure Information placard which will contain inflation pressures for various loads. Perhaps yours has something similar.

Yeah Richard, I spent quite a long time with the fellow that weighed the truck going through the Owners manual.  No luck.  I find it rather distasteful that these manufacturers want us to buy their products, and I am NOT knocking any product here, but divorce themselves from helping the user from fear of being held liable.

I did find a Firestone chart through the Escapees/smartweigh program that covered their version of the same tire.  If anyone is interested in this chart, just PM me and I will forward a link.

[richard5933]

I think it's far less common to find such information available for tires used in autos and light trucks. Not because it is not useful, but because it's more likely to cause more trouble than it is to help. What I'm getting at is that most auto and light truck owners/drivers simply don't have the knowledge or awareness of how to properly inflate tires based on load, and manufacturers found it more helpful to just list one (or maybe two) inflation points on the federal placard inside the vehicle. More information was simply adding to confusion and not helpful.

Just look at the confusion many RV owners have, even after weighing their rigs and looking at the load & inflation tables.

I remember as a kid helping my dad do the math trying to figure out how much weight we were carrying in the station wagon so he could set the inflation properly. The placards put in vehicles back then used to have more information for pressure based on the number of passengers, cargo, etc. But even with all that information it would have been rare for a car or light truck owner to know the actual weight of their vehicle to set tire pressures.

[bm02tj]

Chalk the tire and take for a short drive then you can tell if  high or low pressure then adjust 

[brocki]

Good idea..  I hadn't thought of that.  But as said above, I did find a chart for a Firestone comparable tire.  Interestingly enough, I have been inflating to 50psi  loaded with the bike.  Chart says I could be setting at 40 for the load carried, and I did go up to the next load number.  I will re-adjust and monitor.

Richard, I see your point.  But if that was still true, wouldn't you think you could still dig them out somewhere?  Some of really do want to do it right.  Anyway, I solved my problem

[rayin]

brocki for your Ram pickup the Federal Tire Placard on the door pillar identifies the air pressure required for the  rear axle gross weight rating. Are you indicating your bike weighs more than that?

Making a chalk mark across the tread of a bias-ply tire did work to identify the maximum footprint. Since radial-ply tire are designed to maximize the footprint, making a chalk mark across the tread is not an indicator of air pressure  necessary to support the load. That is my understanding, perhaps Tireman9 will join the discussion with his expert advice.

[bm02tj]

I have used chalk on radial tires as long as you do it cold so the pressure goes up with heat not down 

I like to find the pressure then add two PSI  as I can not go by decals with 35 1250 tires on my Jeep 

Also front tires on motorhome  and matched to chart and was within 5 PSI 

Chart says 100 PSI chalk  closer to 105 I run   110 PSI 

 

[tireman9]

I have a page in my tire blog that I try to keep up to date with links to various Load & Inflation tables. I think you will find that almost all tires follow the same numbers with the exception of a handful of Michelin 22.5 items. so if you can't find a chart from your tire brand you can use any of the others except Michelin. If anyone finds a broken link or error please let me know and I will do my best to fix the problem.

RE how to do the calculations:

Here is a worksheet from Bridgestone for doing the calculations if you find a scale that allows one side weighing.

If you can only get the scale readings for your individual axles as you would from CAT scales or at other truck stops, I recommend not simply dividing the scale reading by 2 as very few RVs have their load evenly split 50/50 side to side. I suggest that at a minimum assume one end of an axle is carrying at least 51% of the axle load. If you have a big slide on one side or 2 slides on one side then I suggest you calculate 52 or even 53% of the axle load on one end. Residential refrigerators also can create an unbalance. All of this shows the importance of at least one time getting a scale reading for each tire position (a pair of rear duals counts as one position). Using those numbers calculate your side to side split percentage and use that from then on unless or until you get another "4 corner" scale reading at an FMCA Convention or similar. We have found that some RVs had as much as 1,000# more load on one end of an axle so the unbalance can be consequential. Many times local building supply or sand & gravel or farm feed supply locations have small scales that can give the one side reading so you can use the Bridgestone sheet above.

When consulting the tables ALWAYS use the load on the heavy end of an axle to look up the MINIMUM inflation. ALWAYS go up in inflation to the next 5 psi box. Don't try to split the difference. I also suggest you add 10% to the table number so you can avoid "chasing your tail" with daily temperature induced pressure changes. Finally ALWAYS set all tires on an axle to the same inflation level and use a TPMS.

Here is my blog post on how I program my TPMS.