Tow Vehicle Tires

[mojo]

Gee, Moosetags started this thread 7 years ago and here we are still bickering about it. I wonder what he bought and if he still remembers how well they lasted....?

[CapriRacer]

Originally Posted by TG Twinkie

The tires are P275/65R18 114T M+S Max load 2601 @ 44psi
What pressure to use in your truck?When the truck is empty and not towing I run 30psi in the front and 33psi in the rear.
What does the vehicle tire placard say? (If the tire size is the same as what is written there, then the pressure is appropriate as well.)Door placard is 30psi front; 33psi rear. Tires are the same as the placard.
And why weren't you discussing the front tires? The rear axle is where the load is, not considering the WD hitch. When the box is loaded (not towing) you can't use a WD hitch. When towing, I run 33psi front and 40psi rear.
The front axle rating is 3900#. The rear is 4100#. GVWR is 6900#.

The 114T number is higher than the 104T mentioned above on these tires.
An LT235/75R15 Load Range C has a Load Index of 104/101 (Single/Dual), while a Load Range E in the same size has a Load Index of 116/113.
First, what I am saying is those tires are not Load Range D tires. They are Standard Load P type tires
My tires fall in between the 104 for "C" range and 116 for "E" range. So they are in the "D" range. So I guess they are not "P" rated metric.

Allow me to try to state this a different way:

If you have a P type tire (the letter "P" in front of the tire size), then they are either "Standard Load" or "Extra Load". Look at the sidewall of the tire for those words.

If a tire has a "Load Range", it is an LT or an ST or some other kind of tire. not a P type tire.

"Load Range" is NOT a range of loads. It's a way of expressing the maximum load for the particular tire size - and the fact that one could build a tire with a higher load carrying capacity in a given size by increasing the inflation pressure. For example, a very small LT tire like an LT205/75R15 Load Range D has a load carrying capacity of 1765# (single), while an LT255/85R16 Load Range D has a load carrying capacity of 3000#(single)

http://www.trucktires.com/bridgeston...loadTables.pdf

See pages 98 & 99.

Now let's look at what is on your vehicle now. P275/65R18 114T - that's a Standard Load tire. (It doesn't come in an XL!)

The load carrying capacity on your tires at the inflation pressure stated (30/33) are 2202#/2305#.

The GAWR's on your vehicle are 3900# and 4100#. Note that the GAWR's are less than the load carrying capacity of the 2 tires on each axle (4404#/4610#). That means the inflation pressure listed on the vehicle tire placard is adequate for the fully loaded vehicle.


OK, that's the first step. I'll let that sink in before I move on.

[crispyboy]

Capri Racer,
You should contact the Alumpalooza folks about putting on a tire seminar at a trailer rally or maybe writing an article for the Blue Beret. It would provide a lot of help to us obsessed tire geeks.

[DKB_SATX]

Originally Posted by slowmover

Or, a quality gauge in the first place. Given the expense of [10] best quality tires in use at any time (service + spares' perhaps $2000 or more), a LONGACRE tire gauge or other might be considered realistic in price ($100 under/over).

You are just WRONG for giving me one more bit of tool porn to want. Now I "need" one of these.

[switz]

Longacre has refurb/blems of the 0-100psi digital gage under $100 instead of over $135.

I have one on order.

[Gene]

Cheap gauges are fairly accurate—between the compressor gauge, hand held one and and TPMS monitor, they are all within 3 lbs. of each other. That's about 4%. I go with the higher number of the 3 and figure that works best.

After buying a top of the line miter saw as my Xmas present to myself, I have to avoid tool porn for a while (I do like to look).

Gene

[slowmover]

Originally Posted by Gene

Cheap gauges are fairly accurate—between the compressor gauge, hand held one and and TPMS monitor, they are all within 3 lbs. of each other. That's about 4%. I go with the higher number of the 3 and figure that works best.

After buying a top of the line miter saw as my Xmas present to myself, I have to avoid tool porn for a while (I do like to look).

Gene

Gene, I feel certain that you'll need it around the new house when it comes air-powered paint sprayers, etc. Proper line pressure, you know . . . .

[rodsterinfl]

Update to posting on an old post!

Ok, we finished testing the tire situation. Here is the run down. I have a 2009 F150 and a 25' Safari. I had D Rated General Tires on the tow vehicle and bought new Michelin E rated M/S 2 tires for it (same size) and suddenly have a problem with sway. Before the tire replacement, the truck and trailer moved as one on the highway with a solid feel.

I earlier mentioned that it may have been caused by under inflation. That was corrected and it made no difference. Secondly, we readjusted the WD hitch using different chain settings - no difference. We are convinced now that it is the tires and that they have a softer give as they also ride softer overall and are quieter. I am in the process of purchasing a used pro pride 3P hitch as a result.

BTW, I have the Longacre 0-125 digital gauge red face. Thanks for the advice though on air pressure.

[Gene]

We have the Load Range E Michelin M+S AT2, a slightly different tire, but I think it is more in the tread than the sidewalls. We keep the pressure in the mid 40's. On our Tundra, we have never had any sway.

You have an '09 truck—can it be the suspension? How is it wearing? Have you tried to upgrade shocks—ours came with Bilsteins and they are a good upgrade. That would be the simpler thing to do next. It looks like you can get a set of 4 for $300-400.

Michelins do ride well and somehow the combination does not work as well with your Ford as you want and need. The original tires may have masked a problem with the Ford suspension.

Gene

[SteveH]

I had a similar, but different problem a while back....I replaced some Michelin LRE's with some Pirelli LRE's, same size, same truck, same trailer, same hitch and adjustment, and with the Pirelli's I had "instability", but not sway.

Aired the rears up to 80 psi( up from 75 , and the fronts at 60 (down from 65) and it was better, but never was as good as the Michelins.

[TouringDan]

I needed to replace the tires on my 2008 Toyota Tundra and I stumbled across this thread; the information provided by Switz and CapriRacer has been particularly helpful. Thanks to the both of you.

I was happy with the original equipment P Michlin tires (P255/70R18) and got 47k miles out of them, so I went ahead and replaced them with LTX (P) 255/70R18 112T tires rated at 2469 lbs. The LTX tires provide more tire load reserve- 2469 lbs vs. 2245 lbs.

I thought about going with a higher rated tire (LT), but felt that I did not need it since I was under the max rear axle rating, not by much though, and did not want to take a chance on affecting the ride, stability or handling of the vehicle.

I will report back on the performance of these tires.

Dan

[Phoenix]

We have a 2008 Tundra CrewMax TRD; and the tires we run are Michelin LTX M/S2 LT, load range E, 275/65x18 (standard for TRD).

In this size, the maximum load spec for the LR-E tire is 3,415 pounds @ 80 psi, while the max load for the "P" tire is 2,601 pounds @ 44 psi.

For the $9 difference in price, the LR-E tire is 8 pounds heavier due to an additional steel radial belt, and it has the Michelin "Green X", low rolling resistance rating.

We run 55/65 psi (F/R) when towing and 55/45 empty. And, while the LR-E LT tire rides a little firmer and less "squishy" than the OEM BFG Rugged Trails (same size) at 44/44 psi, the ride is not harsh or truck-like compared to HAL, our old 1978 Chevy crew cab, 3/4 ton, long bed pickup with 454 V8. However, I should note that HAL's truck-like ride was undoubtedly attributable to the suspension, since it had Michelin LTX M/S LT, LR-E tires on it, too (the previous generation of the tire on our Tundra).

For $9 extra per tire, the extra confidence, safety margin and load capacity (when inflated to 80 psi) is a bargain, without sacrificing ride comfort.

Just another opinion...

[TouringDan]

Phoenix

I considered the LTX M/S2 LT tires also. I guess that I mainly went with the P tires as they were available in the stock size and I have not had any experience with the LTX M/S or S2 tires. I probably would have made the same decision as you had I been in your shoes.

Time will tell for me.

Dan

[LI Pets]

Just put on a set of Toyo's open country II, great reviews.

I'll follow up soon Friday 250 mile trip

[No. 13]

When you guys refer to your LTX tires in Load range E it confuses me. When I go to the Michelin website they don't use the D or E designation but rather 114S, etc. Doesn't only a true LT tire use the D or E code exclusively? I have P275/65R18 tires on my Tundra with 114S load/speed rating which is 2601 lbs. @ 44 psi. What would this be; a D or an E? Thanks.

[Gene]

Load Range was invented to get away from 6 ply, 8 ply, etc., since ply did not determine the strength of the tire anymore. But now they are coming up with numbers to replace LR. You can back into it by looking into the maximum pressure. LR C = 45 psi, LR D = 65 psi, LR E = 80 psi. But I think they may only be using those numbers for P tires, not LT tires. Tire mavins may correct me on some of this (or all of it).

Your Tundra, like ours, came with P (passenger) tires, not LT tires. They were cheapo Goodrich tires which were wearing fast and at 18,000 miles I figure they might get to 25,000 before they had to go. Since we were planning a long trip, I figured it was better to have better tires that I wouldn't have to replace on the trip. I got LTX A/T2 LR E tires and after 65,000 miles, much of it towing, they are still going, though I think this fall is the time to replace them. They ride better than the OEM tires and certainly have lasted longer. They're expensive, but in the long run, cheaper.

Gene

[No. 13]

Thanks Gene...I am a little less confused now.

Gene

[CapriRacer]

Yes, P type tires come in "Standard Load" (SL) and "Extra Load" (XL), but it is common for the Load Index (eg 114S) to be used.

LT type tires come in Load Ranges (C, D, E, etc) and it is also common to use the load Index, but usually LT tires have dualed rating which are lower, so the Load Index comes out looking differently: (120/116S)

[switz]

The Longacre tire gage (that was recommended earlier in this thread) turned the annoying TPMS warnings on the GoldWing motorcycle into past history. The home air compressor's air chuck with gage was actually 6 psi low at 41 psi and that lower pressure triggered the TPMS warning. The other tire gages were also inaccurate. I now verify tire pressure on all my vehicles with this new gage.

Longacre has factory refurbished units for around $100 versus $135 for new and they come with the same warranty. I returned the unit to check calibration because of the error mentioned above, I thought the error was in the Longacre. It was spot on.

My Dodge door label suggests 45 psi in the rear tires when there is little or no cargo in the bed and 70 psi fully loaded. Even with the full air suspension system, the difference in ride is substantial, especially for full figured folks.

Fortunately, my truck came with Michelin tires as I would have exchanged non Michelins immediately after driving off the dealership lot. The LT265/70R17E tires are rated 3,005 pounds at 70 psi and the rear axle is rated 6,010 pounds. Inflating these tires to the maximum of 80 psi would allow them a load of 3,195 pounds each, but the axle rating would still be the number for load capacity.

Initially, I used around 55 psi in the rear tires as the axle load was under 5,000 pounds. Maybe the Hensley masked any handling issues.

On the next trip in September, the truck and trailer may be nearly loaded to GVW capacity carrying the steel and cast iron camping cooking gear, tables, coolers with water and ice, cooking tent etc we will use to make meals for 20 some family members, so I will run the tire pressure on the rear tires to 70psi.

Since the Kelderman air suspension system included an air compressor and air storage tank and I have an air coupler by the license plate, I can inflate the tires at any time.

I keep the truck in a climate controlled garage where the temperature does not exceed 80 degrees. Thus heat damage to the truck tires is reduced. Unfortunately, our Airstream is parked outside under a roof, so while no sunlight directly hits the tires, the warming 119 degree summer days will negatively impact the life of the trailer tires.

There is a simple but expensive solution to the tire heat issue in Arizona, travel the northern states all summer.

[dkottum]

"There is a simple but expensive solution to the tire heat issue in Arizona, travel the northern states all summer."

We do it the other way, her Arizona in winter and my Minnesota in summer, taking the long way around to get back and forth.

doug k