What pressure do you use 16" Michelin?

[TinTin]

For reference, could someone post links to the load/pressure tables for the Michelin LTX tires that many Airstreamers are switching to:

for those who have upsized from 15 to 16 inch:
LTX MS2 225/75R16E

for those who have upsized from 14 to 15 inch:
LTX MS2 235/75R15E

[Ag&Au]

Originally Posted by TinTin

For reference, could someone post links to the load/pressure tables for the Michelin LTX tires that many Airstreamers are switching to:

for those who have upsized from 15 to 16 inch:
LTX MS2 225/75R16E

for those who have upsized from 14 to 15 inch:
LTX MS2 235/75R15E

Here's a start. There is also a note that says if the tire you have is not listed, contact a dealer.

Load & Inflation Tables | Michelin Truck

Ken

[TinTin]

Ken: I've seen those tables before, the LTX tires aren't listed.

[Ag&Au]

Originally Posted by TinTin

Ken: I've seen those tables before, the LTX tires aren't listed.

When I searched "michelin truck tire load pressure tables" using Google
I got a whole mess of links. If you don't want to wade through all that, I guess the fallback is contact a dealer, or perhaps when someone else here see's this, they will know more than I.

Try Page 22 in this document:

http://www.michelintruck.com/assets/...k_Sept2011.pdf

Ken

[TinTin]

The link you provided is helpful re: the 16 inch Michelins. Thanks.

Too bad they don't list the 15 inch LTXs. Though they are still available, I guess their days are numbered.

[Ag&Au]

Here is the latest issue:

Michelin Truck Tire Data Book

On the blue menu bar at the top of the document, there is a pdf symbol that will let you download a page or the entire menu.

I downloaded it for my own use, but it is too large of a file to upload here. It is 13.4MB.

I wonder, if you searched for earlier versions you could find one that has the 15 inch tires.

Ken

[TinTin]

I pick up my tires tomorrow. Another member let me know by PM that maximum inflation on the 15 inch LT23575R15 is 50 psi (1985 lbs). A much simpler inflatory decision than that of the 16 inch version.

[Ag&Au]

Originally Posted by TinTin

I pick up my tires tomorrow. Another member let me know by PM that maximum inflation on the 15 inch LT23575R15 is 50 psi (1985 lbs). A much simpler inflatory decision than that of the 16 inch version.

I apologize for not posting that. I thought you knew that and just wanted to see a load/pressure table. I ran across that 50 Psi figure by searching for LT23575R15 . One of the the results was the specs.

Anyway, I'm sure you will be pleased with the tires.

Ken

[TinTin]

I like my numbers simple, 50 psi and 110 ft lbs torque for the 15 inch Michy setup. Same numbers used for the 14 inch GYMs.

[dkottum]

Thanks TinTin, good report on a 15" "Michy" setup. We need more of this, what works for you on your Airstream.

[switz]

When we installed the 15" Michelins on the factory 15" rims on the 2013 25FB International Serenity that had a GVW of 7,300 pounds, the scales reported that the trailer axles were loaded sub 6,000 pounds camping ready.

The 15" LTX (P) 235/75R15 XL Michelins have a side wall rating of 2,183 pounds but must be derated to a capacity for trailer use of 1,985 pounds (see 49 CFR 571.110 below) at 50 psi which is the maximum air pressure per the tire sidewall. That means the four tires can support a total load of 7,940 pounds. That is at least a 25% load safety margin with better and wider tread for improved braking and the bonus of softer ride for the trailer.

If I remember correctly, Andy at CanAm suggested 44 psi for our trailer. I did not see any issues, but carried 44 to 46 psi as the analog tire pressure gage had 2 psi increments. When I started using a racing quality digital gage, the I set the pressure to the 45 psi and knew it was plus or minus 0.5 psi of that number.

The last trip with the Classic, I set the 16" LT225/75R16/E LTX M/S2 Michelin tires at 75 psi and had lower pressure rise and temperature rise than at 80 psi. Some are using 72 psi and I will try that the next time to see if the numbers improve.

************************************************
49 CFR 571.110

Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.


S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

[CapriRacer]

Originally Posted by r carl

Are you defending st tires?

No, I am pointing out that there has more to these changes than just a change from ST to LT - or from Goodyear to Michelin. There are multiple changes being made and i think everyone selects one as the one that made the difference - and they forget about the others.

[dkottum]

Switz, thanks for the excellent user's report on both 15" and 16" Michelin upgrades and your reasoning for the tire pressures you have chosen.

[TinTin]

Originally Posted by switz

49 CFR 571.110

Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.


S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

This is the key information, of value to anyone switching ST to LT!! Thanks Switz. Do you have the original link to these regs?

[crispyboy]

Another possible tire for those looking for a 15" tire is the General Grabber HTS P235/75/r15 XL with a weight rating of #2271 (derated #2043) - a few more than the Michelin and less money.
I had these put on my brothers box utility trailer which was just taken to Saskatchewan on a trip. He paid ~$120 each plus there was a $70 rebate for 4 tires.
With the weight ratings this 15" tire and the info that Switz published i could probably squeek by with my 8400 gvw trailer. My weight tickets for the airstream axle load is #7400.
Grabber HTS

[switz]

As the load on the axles get closer to the tire maximum rating, there is less lee way for a heavy corner. Both our 25FB and Classic were/are 200 pounds heavier on the street side rear wheel. Thus the need for some wiggle room.

The 25 models with 7,300 pound GVW and the 27/28 models with 7,600 pound GVW will work with the 15" Michelins as wood most tri-axle models.

[switz]

Here is a link:

http://www.gpo.gov/fdsys/pkg/CFR-201...sec571-110.pdf

[TinTin]

Originally Posted by switz

Here is a link:

http://www.gpo.gov/fdsys/pkg/CFR-201...sec571-110.pdf

Many thanks, switz!

[switz]

That US regulation might not apply in Canada.

[TinTin]

No problem. I'm more interested in thoughtful guidelines than regulations.