Tall Tow-Rig Tire Tech

[2xtreme]

I don't suspect that this will directly impact many of you, but I thought that the information might be usefull to some and it may spure other questions when you guys are getting new tires for your vehicles.

I have an Excusion that had 38's and recently put a set of Goodyear MTR 40's on it. In the process of looking into tires for this truck several things were important to me:
1. Size, this is typically the first thing that people look at and many times the ONLY thing that people consider when buying new tires. When you get to 40's you don't have as much choice between manufacturers and wheel sizes so your choices are limited. Keep in mind that the "real" size of the tire may also be significantly different than the "labeled" size of the tire also.

2. Load rating, My 38's were Load rated "E" and since this truck is heavy and tows regularly the load rating and the load weight capability were important to me.

3. Weight, some tires weight significantly more than other tires of the same size and most don't advertise these weights without signficant research.

4. Reviews, how others with the same tire in similar applications felt like the tire performed is of significant value. What many people forget with regard to reviews is that they should be similar applications and that everyone has a different experience level with a particular tire.

5. Price, It is not unusual to find price discrepancies of more than 50% between different tire companies for the same size tires.

For my particular application this was not an easy decision. Since I was purchasing new wheels I had a little more option of tire choices; BFGoodrich KM2's, Goodyear MTR's, IROK, and Toyo MT.

Here is how I narrowed down my choices.
1. The Toyo's were both exceptionally heavy and expensive, plus everyone has these on their lifted SD's already.
2. The BFG KM2's in this size are significantly more money than the others and weighed more than the MTR's.
3. The IROK has a SIGNIFICANTLY higher weight rating (load rated "E") and were less money than the MTR, and many people say they are an acceptable road tire on tow rig's. My concern was their weight and road maners and how they perform on snow/ice.
4. The MTR was reasonably priced, less weight than the others but was a load rated "C" tire which considering my experience towing with big tires did concern me.

In the end I decided on the MTR. The sales guys convinced me that the tire load was adaquate for what I was doing with the tires (it is within a couple hundred pounds of the 38's "E" that I was replacing).

When I installed them and aired them up I was in shock. Something I had never even thought to consider was the tire pressure that they are recommended to run at for max load capability. In the case of my previouse 38's it was 65psi and the MTR's it is 35psi!! Which means that I am getting "almost" the same load capability of the old tires at just over 1/2 of the tire pressure.

The first drive in these tires was incredible!!
1. The lower tire pressure is a very "soft" ride.
2. The tires track much nicer (this is probably just due to new tires instead of old tires).
3. These tires are much quieter than the old tires.

I now have about 2000 miles of towing on these tires and I must say that so far I am impressed and very happy with the decision. I still have two significant areas that I am interested to see how they perform; snow/ice performance (which I won't be able to see till winter), and how they hold up over time (tread wear and inner carcas strength) and obviously this will take a long time to understand better.

I just thought that I would pass on the info, some of you might find this usefull for your tires selections in the future.

Michael

[redneckboarder]

so how big of a drop hitch do you have?

[2xtreme]

so how big of a drop hitch do you have?

I have a 12" drop hitch for my 20ft car hauler but I am only useing 10" of it currently.

I use a 8" Drop receiver and adjustable 8" drop hitch for my smaller trailers.

both are rated at 10K

Michael

[Ba-Riedo]

I assume you have the new MT/R?

-Alex

[2xtreme]

I assume you have the new MT/R?

-Alex

Yes.

[JBweld]

Where's the pictures?

[NW-ZJ-SCOTT]

good to read. i will be picking up an excursion at the beginning of the year and plan to start out with a small lift and possibly some 35"s. i plan to use if for towing and i was always under the impression that if you tow, always use E rated tires.

[2xtreme]

good to read. i will be picking up an excursion at the beginning of the year and plan to start out with a small lift and possibly some 35"s. i plan to use if for towing and i was always under the impression that if you tow, always use E rated tires.

At that size of tire you might have to, depending on the weight of the truck, load, and trailer.

Keep in mind that as a tire get's larger in size it usually has more weight capacity than a smaller tire, or higher weight capacity at a lower psi. So you will want to check that specifically for a 35 when you get ready to look at tires.

Michael

I will load some pics soon.

[XJ_ranger]

I'd like to throw a few thoughts on air pressure in here:

When towing, make sure the rear tires are AT the manufacturers recommended pressure.

Geico wrote up $3900 in damages to my tow rig from a blown rear tire.... :tears:

[5.9cummins]

Michael where are the pics??

[Motornoggin]

Good info on the tires.
I gotta say, I have never understood the reasoning behind lifting a tow rig. There are so many disadvantages to doing that and I think they far outweigh the advantages. Do you actually like towing with 40's or do you just tolerate it?

[2xtreme]

I'll get pic's up soon, it really doesn't look much different on 40's than it did on 38's in a photo.

I agree that there really are not very many practical reasons for lifting most vehicles (even strickly off road vehicles). Most of the disadvantages of towing with a lifted rig are pretty minor to deal with (I am more cautious on down hill winding passes than I would be if it was not lifted) most of the disadvantages are pretty easy to overcome with a little bit of experience with the rig. On the other hand this rig was originally built as a tow rig (that was it's original purpose, and it may perform significnatly better at it than other lifted rig's, I honestly have not driven that many of them to compare).

For me, the benefit of personal expression outweights the disadvantages of it being lifted. ;)

Michael

[2xtreme]

I'd like to throw a few thoughts on air pressure in here:

When towing, make sure the rear tires are AT the manufacturers recommended pressure.

Geico wrote up $3900 in damages to my tow rig from a blown rear tire.... :tears:

Good point Opie, It should be common sense to run tires at max tire pressure when they need it, and it should also be common sense to check the tire pressure regularly. Having said that, many people don't.

I check both the tow rig and trailer tires before "almost" every use, and I always run the tires at max cold pressure.

Tires can do A LOT of damage when they come apart!!

Michael

[dellstopjeep]

i have seen some pretty bad looking accidents because of real real big lifted rigs towing. Ya it looks cool but not exactly real safe. On the other hand a excursion on 40's with the 7.3 is my dream tow rig!

[2xtreme]

i have seen some pretty bad looking accidents because of real real big lifted rigs towing. Ya it looks cool but not exactly real safe. On the other hand a excursion on 40's with the 7.3 is my dream tow rig!

Thats funny. ALL of the accidents I have seen have been with stock vehicles (towing and not towing). Does that mean that stock vehicles are not as safe as lifted trucks ;)

So out of curiosity what would be unsafe about towing with a lifted rig anyway?

Michael

[WaXJ_Skier]

So out of curiosity what would be unsafe about towing with a lifted rig anyway?

Michael

1. Higher center of gravity ( sane driving pretty much removes this as a major risk)

2. The higher you are the longer you have to fall in the event something fails (proper maintenance greatly cuts the risk.)

[IXNAYXJ]

So out of curiosity what would be unsafe about towing with a lifted rig anyway?
:rolleyes:

-----Matt-----

[fubar XJ]

:D

I hope Michael's being facetious. The higher center of gravity is the biggest factor. Steering corrections at highway speed lead to more sway on a lifted rig. This is usually fine as long as things like anti-sway bars and tire pressure are all good to go, but it is a factor regardless. A longer, wider rig will be more stable whether it's lifted or not, but lifting anything decreases it's stability as the COG is higher and will factor into how it reacts to sudden steering corrections at speed. Similar to a sky-high lifted rig on the trail, it will lean more and be more prone to flopping or even going over end to end on steep ascents and descents.

[88manche]

I still wanna see pics.

[mud1059]

Torque.... The longer the drop hitch, the more multiplied the torque onto receiver. I know a guy that had a problem with this....his Jeep cartwheeled down Main Street in Puyallup, IIRC. ;)

[2xtreme]

Yes, My question was facetious, but not entirely. I am well aware of what I believe the issues are with lifted trucks (both towing and not towing). On the other hand I believe there are MANY other issues with vehicles as a whole that are probably much more significant. I will list a few of the more diverse issues just to provide an opinion:

1. Vehicles driving on the street with loads not contained (including speakers, groceries, etc).
2. Vehicles driving with children, dogs, birds, newspapers, make-up in the drivers lap.
3. Drivers drinking coffee, talking on the cell phone, putting on make-up all at the same time.
4. Vehicles that weight less than the trailer they are towing.
5. Vehicles that are towing more than the recommended amount alowed by the vehicle.
6. Towing with no brake controler.
7. Unsecured or inadaquate secured loads on trailers.
8. Driving on donut spare tires or with bald tires.
9. re-tread tires on large trucks.
10. Drivers who simply are not paying attention to driving.

While I agree that driving a lifted (or any modified) vehicle could be considered more dangerous than a stock vehicle, I would argue that there is a much longer list of other items that should be considered far more dangerous that towing with a lifted truck. My vehicles are equiped well to tow, I never tow more than they are rated for (including tires), they are well maintained, and I drive in a manor appropriate for the vehicle I am driving. Accidents can always happen, and I am not perfect, but I see things on the road all the time that scare me to death and lifted tow rigs is not at the top of that list.

Sorry it isnt the highest quality pic, I will take some more later.
http://i32.photobucket.com/albums/d19/2xtremexj/Excursion/P1020559.jpg

Michael

[2xtreme]

Torque.... The longer the drop hitch, the more multiplied the torque onto receiver. I know a guy that had a problem with this....his Jeep cartwheeled down Main Street in Puyallup, IIRC. ;)

Yes, I have made it a point to inspect all of my receivers on a routine basis since that insident. I have also doubled up the tow straps and locations that hold the Jeep on the trailer, and continue to check tire pressure in both vehicles. :peace:

Michael

[oldskooldubbin]

So out of curiosity what would be unsafe about towing with a lifted rig anyway?

Michael
How about brakes? Big wheels and tires are much more heavy and you factory brakes just were not meant to handle all that extra weight.

[2xtreme]

How about brakes? Big wheels and tires are much more heavy and you factory brakes just were not meant to handle all that extra weight.

As a general rule, this would be my major concern with most lifted vehicles also.

I have not yet had the breaks apart on this truck and so I don't know if they are stock or not. However, SD brakes are designed for towing from the factory and in comparison to MANY other vehicles that I have driven with stock sized tires, this thing stops on a dime with or without the trailer (with trailer brakes). In fact, the stopping distance with my Ex on 38's compared to my Older Suburban on 31's is about 1/2 the distance!! (this was a hard but not emergency stop in an uncontrolled test).

Michael

[bmfm64]

i tow all the time in my 4 door long bed superduty with 12 inches and 39.5 boggers.... no problems and i tow a 10k dune hauler and a bobcat 325 on a 5k trailer on a regular basis... like you said it's about setting the truck up right and not being an idiot behind the wheel.

[Avanteone]

i tow all the time in my 4 door long bed superduty with 12 inches and 39.5 boggers.... no problems and i tow a 10k dune hauler and a bobcat 325 on a 5k trailer on a regular basis... like you said it's about setting the truck up right and not being an idiot behind the wheel.

Yeah, but you are a jackass. :D

[bmfm64]

Yeah, but you are a jackass. :D
and good at it! :wave1:

[Avanteone]

and good at it! :wave1:

You coming to our Meet and Greet?

[bmfm64]

ya we be up there saturday mornin just for the day though.

[Motornoggin]

I don't necessarily believe that a lifted tow rig is really any more dangerous than a stock rig, I just don't see any advantage to doing it, but I see many disadvantages. First, it's expensive for no or little performance gain on a street rig, but your COG goes up, and more is better, right? Secondly most of the time, people retain the stock gearing yet put on oversize tires. Now, I know diesels make lots of torque etc. and can generally handle it, but it still, it makes the engine and trans work harder, and is harder on bearings etc. Third, the oversize tires have a taller sidewall which allows for more deflection and distortion and general overall squirrelyness. Fourth, the vehicle is now punching a larger hole through the air, running larger diameter tires and has more weight and rolling resistance which = poor fuel mileage, but you aren't really sure about that because your speedometer is probably off. Finally, you need a longer drop hitch, which has more flex and probably a smaller towing capacity. To counter that, you can do an axle flip on the trailer, but now we are back at that pesky COG thing again.
Don't get me wrong, i like the looks of a lifted CC as much as the next guy, but my tow rig mods are all about comfort and towing performance. A lift and large tires doesn't fit the bill.

[Phil]

I like how the one in front of the trailer is on 40s, and the one on top of the trailer is on 33s.

My only question is, did Superlift spend as much time designing the suspension for towing as Ford did?

[chpmnsws6]

Reasons not to tow with a lifted truck-

-CG is way off
-Brakes not designed for the added load the tires add
-Drop hitch is just a leverage point to toss your truck around
-Even with your massive drop hitch, from the picture it still looks like your trailer is riding on the back tires
-In most sates, the height you are at is illegal..... and for a reason

We owned a horse trailer sale/rental business and saw this kind of thing all too often.


Now that I'm getting off my stump...

Good looking 7.3! You wouldn't happen to be on Diesel Bombers would you?

[mr_wallace]

Yeah your tires could have a good load rating. But what about your rims? And load ratings on tires usually gets higher as the rim gets larger, not just the tires alone. In your picture it looks as if you should drop your ball mount one more notch, your trailer should sit level unloaded, not slightly higher to make up for tongue weight. But its true, it all boils down to the driver.

[2xtreme]

The photos are not taken on level ground. It sits level on level ground.
Yes, the wheels have a higher load rating than the tires. I have never compared the load rating of different size wheels, I didn't know they changed significantly with size. I do know that they change with different brands, and manufacturing processes.

Michael

[noutlawjeeper]

Have you ever meet Michael? If you did you wouldn't be questioning him like he's an idiot.