Michelin Defender LTX M/S 235/75-15 109T XL

[SteveSueMac]

Originally Posted by Tireman9

Single or double axle is not the determining factor. It is the type vehicle i.e. not being a standard passenger car.

Station Wagons, SUV, P/U, Trailers all require "P" type tires to be de-rated i.e. Load/1.10 which is considered -10% by many.

Yes my language was awkward there. I meant if single axle - the derated load probably doesn't provide enough capacity and certainly not with another 10% headroom on top of that (unless his trailer is sub 3500# loaded for camping) - where a dual axle with those tires would provide 7900# of capacity. What I wrote sounds like there's a difference in derating P tires if single vs dual axle and that wasn't my intent. Thanks for catching that!

[Bajaexplorer]

Originally Posted by Tireman9

Single or double axle is not the determining factor. It is the type vehicle i.e. not being a standard passenger car.

Station Wagons, SUV, P/U, Trailers all require "P" type tires to be de-rated i.e. Load/1.10 which is considered -10% by many.

I have a serious question, what is the difference from a p car or a station wagon or minivan or a trailer, does the tire knows where is mounted? Lets say the p car is a heavier car than a mini van, an old car you use it as a taxi with lots of people and luggage, then what? do you derated or the tire has a beeeppp beeep to let you know... doesn't make any sense to me at all, the van carries flowers for example..of course it is designed to carry a heavier load... however, the car is carrying a heavier load..then what ..

[CapriRacer]

Originally Posted by Flyingsilver

I have a serious question, what is the difference from a p car or a station wagon or minivan or a trailer, does the tire knows where is mounted? Lets say the p car is a heavier car than a mini van, an old car you use it as a taxi with lots of people and luggage, then what? do you derated or the tire has a beeeppp beeep to let you know... doesn't make any sense to me at all, the van carries flowers for example..of course it is designed to carry a heavier load... however, the car is carrying a heavier load..then what ..

First, in a manner of speaking a tire does know it is on a different vehicle because of the way it is treated.

If you compare a trailer with a car, the first thing you should notice is that the trailer doesn't power itself. No torque is supplied to the tires to make the vehicle move forward - and the tire can sense that.

And other vehicles have different characteristics that distinguish them: Road surface being driven on, suspension stiffness, etc. - all of which affects the load carrying capacity.

And it isn't the vehicle as much as it is HOW those types of vehicles are used that determines what type of tire is used.

So taking your example of a van carrying flowers - I knew a florist once and they used a van because of its interior size, not load carrying capacity. The tires were not strenuously used.

But that same van could be used to haul heavy objects - and the tires would still be expected to perform.

Tires are fairly robust (boy, I hate that word, but nothing else fits as well!) with regards to operating conditions. You don't have to have the inflation pressure exactly right - you don't have to have the same tire in all 4 positions - you don't have to operate only on smooth roads (and the list goes on). In fact, I can use a generic tire in a lot of different types of service - it's just that the tire won't be the best performer.

Tire manufacturers shouldn't design for the best conditions. They should design for the worst! And those adjustments that are made for differing operating conditions take that into account.

So when the standards say to derate a passenger car tire, they are saying that because the operating conditions are typically different and while the tire is the same, the tire is still supposed to be survive those different conditions.

[mojo]

Originally Posted by CapriRacer

First, in a manner of speaking a tire does know it is on a different vehicle because of the way it is treated.

This is starting to get deep...I never knew tires had feelings

I guess that's why they blow...when they feel they are abused not being treated right!

[interstateflyer]

Originally Posted by Tireman9

You can find the answer if you Google


"Interply Shear RV tire)


or

Pro 50 will decrease likelyhood of tread separation and improve fuel economy
Con 50 may increase likelyhood of impact damage but this is not a condition I see very often of tires that are 70, 75, 80 or 85 series aspect ratio

I'm traveling to the Yukon and Alaska in a few months. I normally run the Michelin LTX M/S 2 P2345/75 R15s on my 23D at 50 psi. Given that road conditions can be less than ideal there, do you recommend a pressure lower than 50 psi?

[Rocinante]

Wow - super off topic. Not a bad question, per-se, but it has zero to do with the topic of this thread.

[r carl]

Originally Posted by CapriRacer

If you compare a trailer with a car, the first thing you should notice is that the trailer doesn't power itself. No torque is supplied to the tires to make the vehicle move forward - and the tire can sense that.

When you hit the brakes a tire doesn't know if its accelerating or braking.

[interstateflyer]

Originally Posted by Rocinante

Wow - super off topic. Not a bad question, per-se, but it has zero to do with the topic of this thread.

The Michelin LTX M/S 2 P2345/75 R15s are essentially the same as the new Defender and we were talking about air pressures for typical applications.

[CapriRacer]

Originally Posted by r carl

When you hit the brakes a tire doesn't know if its accelerating or braking.

Yes, it does not know the difference, because to the tire it is merely torque, but if a tire is not on a driven axle, it only feels the braking action, where a tire on a driven axle also feels all the accelerating, as well as all torque needed to keep the vehicle rolling forward.

[Tireman9]

Originally Posted by interstateflyer

I'm traveling to the Yukon and Alaska in a few months. I normally run the Michelin LTX M/S 2 P2345/75 R15s on my 23D at 50 psi. Given that road conditions can be less than ideal there, do you recommend a pressure lower than 50 psi?

Since you are using P type tires the max load in trailer application is the max load molded on tire sidewall x .909


I would
1. Confirm with actual scale measurements that the individual tire loads do not exceed 85% of tire de-rated max load in #1 above when inflated to the 35/36 psi that I believe in on the tire sidewall where it says "Max Load xxxx KG (yyy Lbs) at 35 psi inflation

2. Get & use a TPMS with the Low Pressure warning set to 32 psi so you get early warning.

3. Read the tire "Safety Warning" molded on sidewall and run half way between the Standard load inflation 35/36 and the max pressure found in the safety warning which I thnik is 41/45 psi. This will lower the Interply Shear.

4. Keep speed down to 55 to lower chance of impact damage due to pot hols.

[Tireman9]

Originally Posted by interstateflyer

The Michelin LTX M/S 2 P2345/75 R15s are essentially the same as the new Defender and we were talking about air pressures for typical applications.

I thought the current LTX was a P235/75R15 standard load tire and the Defender was a European design 235/75R15 109T XL.

I agree that this thread has lots of posts about a tire that is not available yet so we really do not know what it actually says on the tire sidewall.

[Bill M.]

The current 15" LTX is a XL tire.

[Phoenix]

Per TireRack.com:

Michelin Defender LTX M/S, 235/75R15, load range XL, service description 109T (109 = 2,271 lbs, T = 118 mph), UTQG 800 A A, maximum inflation pressure = 50 psi, made in U.S.A.

[interstateflyer]

Originally Posted by Tireman9

Since you are using P type tires the max load in trailer application is the max load molded on tire sidewall x .909


I would
1. Confirm with actual scale measurements that the individual tire loads do not exceed 85% of tire de-rated max load in #1 above when inflated to the 35/36 psi that I believe in on the tire sidewall where it says "Max Load xxxx KG (yyy Lbs) at 35 psi inflation

2. Get & use a TPMS with the Low Pressure warning set to 32 psi so you get early warning.

3. Read the tire "Safety Warning" molded on sidewall and run half way between the Standard load inflation 35/36 and the max pressure found in the safety warning which I thnik is 41/45 psi. This will lower the Interply Shear.

4. Keep speed down to 55 to lower chance of impact damage due to pot hols.

The current Michelin sidewall sidewall text reads....LTX M/S2 P235/75 R15 108T XL Extra Load E2....Max Load 2183 at 50 PSI.

The 23D utilizes two 3,000 pound axles. The GVWR is 6,000 pounds. My 23D's CAT scale weight fully load is typically 5250 pounds or 2625 pounds per axle. Using your derated factor of .909 and 85% safety factor, a pair of LTXs are capable of supporting 3373 per axel or 6746 pounds total. That's 1496 more than I would typically need.

I normally air them to 50psi cold at a typical ambient of 60 degrees. I'm not aware of a formula that would accurately determine the least amount of air that I could run and still safely support my load of 1687 pounds per tire on demanding roads.

The new Defender LTX M/S 235/75R15 XL 109T will support 2271 pounds per tire, 88 more than the older M/S 2. That's 68 pounds per tire more when derated and safety margin reduced. That's not a huge improvement. I assume that it would have a minimum inflation for max loading psi that is similar to the M/S2.

I've read that the tread will last 10% longer under harsh conditions and is claimed to be better in snow and ice. That's certainly a positive.
__________________

[Tireman9]

Originally Posted by interstateflyer

The current Michelin sidewall sidewall text reads....LTX M/S2 P235/75 R15 108T XL Extra Load E2....Max Load 2183 at 50 PSI.

The 23D utilizes two 3,000 pound axles. The GVWR is 6,000 pounds. My 23D's CAT scale weight fully load is typically 5250 pounds or 2625 pounds per axle. Using your derated factor of .909 and 85% safety factor, a pair of LTXs are capable of supporting 3373 per axel or 6746 pounds total. That's 1496 more than I would typically need.

I normally air them to 50psi cold at a typical ambient of 60 degrees. I'm not aware of a formula that would accurately determine the least amount of air that I could run and still safely support my load of 1687 pounds per tire on demanding roads.

The new Defender LTX M/S 235/75R15 XL 109T will support 2271 pounds per tire, 88 more than the older M/S 2. That's 68 pounds per tire more when derated and safety margin reduced. That's not a huge improvement. I assume that it would have a minimum inflation for max loading psi that is similar to the M/S2.

I've read that the tread will last 10% longer under harsh conditions and is claimed to be better in snow and ice. That's certainly a positive.
__________________

Looks like you have done proper research and calculations.

The new Defender does not seem to carry the USA "P" prefix but is a European design so the load capacity will be similar but not identical to the P235

[BoldAdventure]

Originally Posted by Rocinante

Wow - super off topic. Not a bad question, per-se, but it has zero to do with the topic of this thread.

Has anyone tried Firehouse subs? They're really yummy.

[slowmover]

It's a horse. No bread or meat. Ask the rider instead.

[interstateflyer]

Originally Posted by BoldAdventure

Has anyone tried Firehouse subs? They're really yummy.

Yes......only in Florida though. Need their iPhone app so we can find them anywhere in North America.

[Lance M]

I had a Firehouse sub a while back. I wasn't too impressed. Maybe it was just the location.

[D Greene]

I've always had a fondness for steamed sandwiches.