New Truck with old Trailer, Sway issues

[RRS2670]

Has anyone used these General tires in the link below for towing? The aren't "LT" tires, but they have the XL (extra load) rating for my size, 275/55R20. I've used General tires on my Silverado (not sure what model) in the past with good luck.

https://generaltire.com/tires/light-.../grabber-hts60

[JohnB]

Hi Russ,

Thanks for reporting back. No worries on the timing, understand the net not cooperating.

I myself have not used the General tire for towing. In looking it up, the General Grabber 275/55R20 has load index of 117 at 51 psi. This is higher than your Dueler at a load index of 113 at 44 psi. That trend for the General is helpful I would think as you gained some more stiffness air pressure if you need to use it. It for sure is rated higher than your current tires, so load carrying should not be an issue.

Something that did catch my eye on the General site, was this 45 day satisfaction trail they are mentioning. I wonder what that is all about and what they would do if your towing does not improve?

You can at try the side wall pulling test against on the General against your Dueler before they mount the General. If the dealer does not have a new Dueler to compare it with, then when they unmount yours, you can try the side wall pull test to at least see if the stiffness is going in the right direction.

I did reach out to our tire engineer we have here on the forum to see if he can add some good info to this issue. Finding new tires that will perform well in sidewall stiffness for towing, is an issue we all have. Also would like to know if he has anything more to know when a tire needs a breaking period before towing. I'll report back anything I can find out. He may even post directly.

John

[Tireman9]

OK, JohnB asked me to jump in on this topic by one of your members. My prime area of expertise is on tires, but I have also done extensive long-distance towing with a C3500 (454 gas) Dually with an 8' slide-in camper in the bed and pulling a 26' enclosed trailer with an 88 Camaro race car, tools, etc inside. I have towed from OH to FL and Calif and even made a trip on the Blue Ridge Pkwy while towing the race car trailer.

Some observations on info in this thread.

"P" type tires on the TV should be an indication that the TV should be limited to single axle "pop-up" or small boat trailers. Multi-axle trailers almost always indicate the need for a real truck (not just something that looks like one) This would mean LT type tires and 3/4 or 1-ton vehicle rating.
HERE is a good post on how to match Truck & Trailer. It is much better to do a little work and learn the ratings than relying on the salesperson telling you that you can pull a 5-ton trailer with a Ford Ranger just to make the sale.

P vs LT type tires. No, they do not make tires "between" these two types. If there is no P or LT before the numbers in the size then it is what is known as a "Euro-Metric" type tire and with an inflation of 36, it is definitely a P-type tire.
The P and LT and ST designations are found in tires designed and intended for highways in America. The inflation level molded on the tire sidewall is the give-away.

35 or 36 is standard Passenger type tire
50, 65, or 80 or higher is an LT type tire or a trailer only ST type.
In Europe, they use a "C" after the size to identify "Commercial" use i.e. LT. Don't confuse this with Load Range C which is the US Light Truck Load Range (old ply rating)

XL or Extra Load type are Passenger type tires that aren't quite LR-C Light Truck tires. This type was originally intended for "Station Wagons" which have been replaced by SUV.

Vehicle "Sway" is a function of the tire inflation and the suspension design and vehicle loading. When inflated to the sidewall pressure there can be different sidewall stiffness but they should not be significant in the same Type tire and Same Load Range (Passenger are really LR-B except for the XL passenger tires, but none say that)

Weights. Empty weights are really on little value in determining what will run down the highway safely. Fully loaded and hooked up individual axle loads are what is needed. With trailers (and motorhomes) it is even better to know the scale weight on each individual tire position as many RVs have been found to be 500 to 1,000# out of balance side to side.

Stability.
Increased tire inflation will almost always result in improved stability.

New Tire "squirm". When you apply any new tire to any vehicle you may notice for the initial 100 to 200 miles less stability than on the tires you just took off. This happens for a few different reasons.
1. All tires have a "release agent" that allows them to be removed from the curing mold. This is a slippery substance that will wear off in a few miles.
2. When you buy new tires you are not making a clean, apples to apples comparison. You, as the driver, are comparing a worn older tire with a new full tread tire. Even if the tires were identical in construction and rubber compound you will get crisper and more solid handling with a worn tire (less tread) than a new (more tread) tire. In car racing, our tires may only have 2/32 or 3/32 tread depth while new tires come with 8/32 to 12/32 or more tread depth. In some classes of racing that require the use of "street" tires new tires have most of their tread "shaved" off with the express purpose of improving handling.

Getting scale weights. While you may not want to make a special trip to a truck scale or gravel pit or feed supply to get your individual tire loads you can at least stop at a truck stop on the Interstate on your next trip to get a reference number for each axle.
HERE is a worksheet to allow you to calculate individual position weights.
and HERE is a Youtube video on how to weigh on a truck scale.

Trailer tire inflation:
To lower the Interply Shear (force trying to create a tread separation) You should run AS A MINIMUM the inflation required to support 110% of the MEASURED load on the most loaded tire. Better yet run the tire sidewall inflation number. You can learn more from THIS Google search or go to my blog and read up more than you ever really want to know about the tire mechanics involved in the tire construction.


Hope this helps.

[henryj]

Grabber HTS-60

Grabber A/TX

Henry

[JohnB]

Originally Posted by henryj

Grabber HTS-60

Grabber A/TX

Henry

Good charts. Wish they would add 2 columns. Travel trailer towing and tire sidewall stiffness.

[JohnB]

Originally Posted by Tireman9

Stability.
Increased tire inflation will almost always result in improved stability.

New Tire "squirm". When you apply any new tire to any vehicle you may notice for the initial 100 to 200 miles less stability than on the tires you just took off. This happens for a few different reasons.
1. All tires have a "release agent" that allows them to be removed from the curing mold. This is a slippery substance that will wear off in a few miles.
2. When you buy new tires you are not making a clean, apples to apples comparison. You, as the driver, are comparing a worn older tire with a new full tread tire. Even if the tires were identical in construction and rubber compound you will get crisper and more solid handling with a worn tire (less tread) than a new (more tread) tire. In car racing, our tires may only have 2/32 or 3/32 tread depth while new tires come with 8/32 to 12/32 or more tread depth. In some classes of racing that require the use of "street" tires new tires have most of their tread "shaved" off with the express purpose of improving handling.

Thank you Roger for your comments.

On the new tire squirm, it seems the 100 to 200 miles now can approach 3,000 to 4,000 miles as I have found with the last set (2 years ago) nof Continental Contrac TA's. The prior set, now approx 6 to 7 years ago, I would say did fit in the 100 to 200 mile range. I never tracked it back then as I may have had 300 to miles on the tires before the first tow. But this last set 2 years ago, was an issue taking so long.

Has the tire industry changed the mold release compounds in recent years making this issue worse? It does not yet appear to be brand specific as other campers folks have reported this too on 3/4 and 1 ton trucks.

Thanks

John

[dtcaswell]

Thanks John,

Dave

----------------------------------------

Originally Posted by JohnB

Hi Dave,

I have a good friend, who tows his 27' Coachman and 34' Cougar camper with 2012 1500 Ram, Crew cab, short bed, rear coil springs, no air suspension. He has the 5.7 Hemi. He is using Cooper Discover 275-60-R20. I helped him with his hitch and I even road around the block in it. He has not reported any towing issues with the Cooper tires.

On LT tires, Henry J had some suggestions on brands. And I agree on a 1500 truck, see if load range D is available. Jumping all the way to LR E can be a hard ride jump in some cases.

In my search and by close towing friends & family using 3/4 ton trucks, these brands have been shown to have side walls that work well towing.

Cooper Discover HTP
Mastercraft Courser HXT (also part of the Cooper tire co)

Firestone Transforce.

Continental Conti trac. (but the new ones need approx 4K miles break in)

When I went to NTB for my last Continental Conti trac, I was worried they may have been discontinued. I also has a flat on one of them. They had a very well seasoned manager and we were talking tires as I needed 5 of them. He started talking about the Michelin LTX and I quickly dismissed this as the side walls for me, were too soft.

He agreed, the Michelin were the softest side walls of all the tires he has. He said we can go feel the tire sidewall and tell. So with my flat off the rim, we pulled on the sidewall/bead and felt an unmounted tire sidewall flex.

Then went into his storeroom and started pulling on LT tire sidewall/beads for stiffness. For sure, the Michelin hands down was the softest by a long run. Since I knew the Continental Conti trac feel and it works on my truck, which was very stiff, we tried many brands which felt the same stiffness. Some lots stiffer, almost solid, some softer.

We ended up with BFG Goodrich Commercial TA All Season 2 having the closet side wall stiffness. Just BFG does not make my size.

What I learned is, a way with an unmounted tire that works for towing stability, to gain a feel for sidewall stiffness in finding a replacement. Never had that before. Then you can compare brands for other attributes as all season, tread pattern etc. For towing, you need a stiff enough tire with a ride you can live with and the tire life and cost hopefully align.

You may be able to do the side wall feel test on yours to help sort this out. Talk to the tire dealer manager and explain your problem. Ask them if he has a new tire of your existing brand/style that has issues, get a feel of it and then see if in his store room you can find then stiffer. You still do not know if it tows well or has the tire break in squirm, but you know more than you did before.

Hope this helps and let us know what you come up with and how it works.

John

[RRS2670]

Hi Roger ( I assumed this from the RVSafety.net website),
FYI, it seems that some of the "here" links to your website in your post don't work, message says "URL Invalid".

So I assume that you probably didn't go through all of the post. Many of the things you've talked about have been covered. I have weights on my axles with loaded truck and trailer (I keep most stuff stored in trailer), minus maybe 200-300 lbs, my wife, food and cloths not included. So my truck, trailer and axles are nowhere near the GWR's. My tires had well over 4k miles so the release agent should have been worn off. So the question comes down to, is the tread or the side wall causing the Squirm that I'm experiencing. I really wasn't aware of the Euro-Metric rating until I looked at Discount Tires (one of my post on P.1 has 3 links to this info) explanations of this and the load range vs load index ratings, because I didn't see the P or LT in front of the size. So after talking to John B and hearing of other peoples issue's with tires, I'm trying to find more appropriate tires.

I found that the Bridgestone Dueler H/L Alenza's (275/55R20 113T, 44psi max inflation) aren't the best tire for heavy towing. I found this article on Tire Deets.com, that specifically states: "If you don’t need the towing capacity of highway tires, a set of Bridgestone Dueler H/L Alenza Plus tires will do an excellent job. These tires can be still used for towing of smaller trailers and most hauling jobs you need – you just won’t have the ability to tow the biggest of trailers." They are calling these Touring Tires.

I am having a hard time finding All-seasons Highway tires for my size that are offered in LT tires. If I go to All-Terrain, it is much easier to find the LT designation with D & E load ratings. In the same article I mentioned above (https://tiredeets.com/best-tires-for...ilverado-1500/, they mention the General Grabber HTS60 in my size as being a good trailering tire. This tire is the XL , has a has a higher load index of 117 and a higher max pressure tire inflation at 51 psi. When you look at the link https://www.discounttire.com/learn/l...nge-load-index for XL rating, it looks like it has a higher Max pressure rating then stated on the chart. This max pressure is equivalent to the LT C1 load range shown in chart. Do you think this would make much of a difference on the squirminess of my truck and trailer? By your explanation of the air pressure supporting the load, it seems that the sidewalls would have to be stiffer (thicker) as the max pressure goes up on tires. Can you provide some more insight on this and let me know if I'm interpreting something wrong.

Thank you for your input, Russ

[Tireman9]

Originally Posted by JohnB

Good charts. Wish they would add 2 columns. Travel trailer towing and tire sidewall stiffness.

John, Not sure what the features would be for TT towing? Since most LT tires could end up on pick-up or SUV what would be the test or measure? many of the tires might only have just one or two owners and few people have any experience if scientific comparisons of tires. Any tire evaluation must be made using complete sets of new tires to be valid. Who is going to buy 8 or 12 tires just to do an evaluation?


Sidewall stiffness. Now "Lateral Stiffness" can be measured using an expensive test machine where a tire is loaded against a plate and the force to move the plate sideways is measured. You end up with something like 200 Lbs per inch but this is not a dynamic measurement which is what we, as drivers feel.

[Tireman9]

Originally Posted by JohnB

Thank you Roger for your comments.

On the new tire squirm, it seems the 100 to 200 miles now can approach 3,000 to 4,000 miles as I have found with the last set (2 years ago) nof Continental Contrac TA's. The prior set, now approx 6 to 7 years ago, I would say did fit in the 100 to 200 mile range. I never tracked it back then as I may have had 300 to miles on the tires before the first tow. But this last set 2 years ago, was an issue taking so long.

Has the tire industry changed the mold release compounds in recent years making this issue worse? It does not yet appear to be brand specific as other campers folks have reported this too on 3/4 and 1 ton trucks.

Thanks

John

It may be that it is taking a few thousand miles of different tire handling for you to becone"used to" the new feel. I doubt the mold release can last that long.
Now different tread compounds (improved fuel economy or improved wear or other performance changes Snow, Wet, Dry traction would require a different tread rubber and possibly diferent belt stiffnes which would yield different "feeling".
Example: I would expect the Grabber HTS-60 and A/TX to have significantly different Traction, wear, Ride, Handling or noise "feeling" so how would you go about evaluating which tire is "better" for towing with?

[Tireman9]

Originally Posted by RRS2670

Hi Roger ( I assumed this from the RVSafety.net website),
FYI, it seems that some of the "here" links to your website in your post don't work, message says "URL Invalid".

So I assume that you probably didn't go through all of the post. Many of the things you've talked about have been covered. I have weights on my axles with loaded truck and trailer (I keep most stuff stored in trailer), minus maybe 200-300 lbs, my wife, food and cloths not included. So my truck, trailer and axles are nowhere near the GWR's. My tires had well over 4k miles so the release agent should have been worn off. So the question comes down to, is the tread or the side wall causing the Squirm that I'm experiencing. I really wasn't aware of the Euro-Metric rating until I looked at Discount Tires (one of my post on P.1 has 3 links to this info) explanations of this and the load range vs load index ratings, because I didn't see the P or LT in front of the size. So after talking to John B and hearing of other peoples issue's with tires, I'm trying to find more appropriate tires.

I found that the Bridgestone Dueler H/L Alenza's (275/55R20 113T, 44psi max inflation) aren't the best tire for heavy towing. I found this article on Tire Deets.com, that specifically states: "If you don’t need the towing capacity of highway tires, a set of Bridgestone Dueler H/L Alenza Plus tires will do an excellent job. These tires can be still used for towing of smaller trailers and most hauling jobs you need – you just won’t have the ability to tow the biggest of trailers." They are calling these Touring Tires.

I am having a hard time finding All-seasons Highway tires for my size that are offered in LT tires. If I go to All-Terrain, it is much easier to find the LT designation with D & E load ratings. In the same article I mentioned above (https://tiredeets.com/best-tires-for...ilverado-1500/, they mention the General Grabber HTS60 in my size as being a good trailering tire. This tire is the XL , has a has a higher load index of 117 and a higher max pressure tire inflation at 51 psi. When you look at the link https://www.discounttire.com/learn/l...nge-load-index for XL rating, it looks like it has a higher Max pressure rating then stated on the chart. This max pressure is equivalent to the LT C1 load range shown in chart. Do you think this would make much of a difference on the squirminess of my truck and trailer? By your explanation of the air pressure supporting the load, it seems that the sidewalls would have to be stiffer (thicker) as the max pressure goes up on tires. Can you provide some more insight on this and let me know if I'm interpreting something wrong.

Thank you for your input, Russ

The link to Truck Trailer matching is HERE
https://rvsafety.com/rveducation/tow...ks-and-trailer


The two on weights and weighing toward the end worked for me.
https://fifthwheelst.com/documents/B...eWeighForm.pdf

[JohnB]

Originally Posted by Tireman9

John, Not sure what the features would be for TT towing? Since most LT tires could end up on pick-up or SUV what would be the test or measure? many of the tires might only have just one or two owners and few people have any experience if scientific comparisons of tires. Any tire evaluation must be made using complete sets of new tires to be valid. Who is going to buy 8 or 12 tires just to do an evaluation?

Hi Roger,

Getting back to you on this. I know you are the "tire guy" and have lived and breathed tires all your career. I am, and we are, genuinely grateful for you helping us with your background. My career before I retired comes from a machine design and mechanical failure analysis background. I enjoy going deep and entrenched in mechanical problems and trying to make them simpler for folks to understand and help them troubleshoot their camper/truck towing problems.

I will try and explain the big-picture issues at hand when tires become a problem and can add to instability in the truck when towing a travel trailer. I'm not the tire guy here to know what is inside the tire causing the tire to react the way it does, but tires can make or break a stable towing camper setup from what I have learned. I can elaborate more on that if needed. Tires have to carry the weight, which is reasonably straight forward, but they also need to create a stable towing platform on the truck to resist the left to right forces acting on the truck from towing in many types of conditions.

For this discussion, I am going to focus on towing a travel trailer (TT) as opposed to towing a boat, flatbed trailer, 5th wheel, etc. The TT is many times connected with a ball-type hitch several feet behind the tow vehicle (TV) rear axle. The TT has a large frontal area exposed to the wind, and they can be as long or longer than the tow vehicle (TV). Many campers use and need a weight distribution (WD) hitch to connect their TV and the TT. These WD hitches also should have an anti-sway feature for when adverse towing conditions present themselves.

Many factors need to be in place to help create a stable towing truck and camper combination. These factors are mainly mechanical things, some which are; proper loaded TT tongue weight, suitable sizing of the TV for the TT, an effective WD hitch with anti-sway controls adjusted correctly, towing speed, and tire pressure, to name a few. I will not go into great detail on them right now, but to sum this up, tires are factor by themselves in creating a stable tow rig.

There are WD hitch systems on the market that use high friction to help keep the TV and the TT connection stiff while heading straight ahead when sway forces act on the camper and the truck. Other hitch systems change the pivot point behind the rear axle to lower the effect of sway forces on the vehicle. Both of those TT connection hitch type systems need the truck tires to withstand and resist lateral side forces imposed on the sidewalls of the tires to ward off instability in truck and camper.

I’ll explain this with a direct example on the WD hitch system used on RRS2670 (Russ’s) truck and camper so we can talk to what the tires needs are. When a sway force hits the side of the truck, camper, or both, the hitch connection resists to its ability not to allow the TV and the TT to pivot on the tow ball while towing straight ahead. I’m assuming we can all imagine this, if not ask, and I will elaborate.

While the anti-sway systems can do its part in trying to hold the TT and TV straight, the truck has to be stable to the road, or if not, the TV will start to pivot on the rear tires as it is the next pivot point past the tow ball. The truck front tires also work to prevent the rear tires from having that pivot action occur. If the tires where rigid with no flexing in the sidewall, the only movement of the front or rear of the truck would be by sliding friction of the rubber on the pavement. We know rigid tires are not practical, but it does help show the issue I want to talk to next.

The tire tread is riding on the road surface and creates a high friction force to the road. Unless the sway forces acting on the TT and TV are so high they break that high friction loose, the tire's tread is stable going straight ahead.

The tire bead is engaged to the metal rim. The wheel and rim are very stiff, and for this situation, more rigid then whatever comes at the tire in a lateral force. The tire tread would break free from the road easier then flexing the wheel.

Now let’s look at the tire sidewall, which by design, is a flexible part of the tire. It is supposed to flex. I made some assumptions there that they are flexible; if I misspoke please correct me. If the sidewall is soft (less ability to resist) compared to the lateral side forces acting on the TV, the front of the TV will shift to the left or right in the tire sidewall. You can see this on soft sidewall tires by rocking the back of the truck back and forth by hand and looking at the wheel rim and tire sidewall. You can see the front of the TV moving left to right flexing in the sidewall. The wheel is rigid, the tread is stiff to the ground and the flex is in the sidewall, thus the front of the truck moves.

An unknown now is, for this truck, camper and WD hitch system, how much does the tire sidewall need to resist sidewall flexure that is it does creates an instability in the truck handling? That is not an easy question to answer. And a very difficult to know when you are buying tires for a TT towing setup, as tire sidewall flex is not something that advertised as a performance characteristic of the tire. As I’m sure you can explain better, tires are made to deliver all types of features such as; long tread wear, cold weather traction, on and off-road traction, weight carrying ability, smooth ride, quiet, fuel-efficient and the list goes on. The tire manufacturer alters the design to optimize certain features, possible the smooth ride, tire tread life, etc. while sacrificing lower optimization of other features. But, lateral sidewall stiffness is not yet on the list; however it is an essential feature to camper folks towing TT’s.

If you want tires with “features” for a stable towing TT, the tires need the ability to handle the heavy loads while resisting enough sidewall flex not to allow the truck to have instability. Also required are traction in all types of on-road conditions, off the road can be a different tire type: tolerable tread wear, with a practical level of smooth ride, low noise, and acceptable cost are also wanted. I may have missed a few, but that is a good start. If there were a sidewall rating of sorts that the truck was deemed to need by the manufacture and the tires where rated to adhere to the standard, then selecting TV tires for towing TT’s would be a lot easier.

Towing with a pickup, SUV or van has similar issues. I use to be a SUV tower, and tires on my 1500 Tahoe or 2500 Suburban had the same effect as my F350. Just the weights and trailer sizes were very different.

Since in today’s current marketing of tires, where truck manufacturers spec. of sidewall stiffness is not a rating, we are sort of left to try and sort through this ourselves and hope we pick the right tire to do the job. Some long tenure tire dealers who have experience with TT towing may be able to help. And then there are camper folks who talk about their towing experiences and what size truck, brand, camper size and what tires did they run and did they work out OK. Sorting that out is not simple, but it does work. You just need a lot of towing friends to create your own little database of what works and does not.

Originally Posted by Tireman9

Sidewall stiffness. Now "Lateral Stiffness" can be measured using an expensive test machine where a tire is loaded against a plate and the force to move the plate sideways is measured. You end up with something like 200 Lbs per inch but this is not a dynamic measurement which is what we, as drivers feel

Yes, I have seen a video of that testing machine a while ago which is I recall was linked on your blog. Today we have no rating to the consumer or the tire dealer on sidewall stiffness. My tire dealer understood the problem I was describing and he took me to his backroom and we pulled on the sidewalls of the tire to compare brands and type of tires, all rated for towing heavy loads. While a crude test, it was amazing the difference amongst the brands. Yet all were rated for handling heavy loads. We were comparing them to my current truck tires when I have a spare unmounted.

Any ideas you can give us in sorting this out is welcomed.

Thanks

John

[JohnB]

Originally Posted by Tireman9

It may be that it is taking a few thousand miles of different tire handling for you to becone"used to" the new feel. I doubt the mold release can last that long.


Now different tread compounds (improved fuel economy or improved wear or other performance changes Snow, Wet, Dry traction would require a different tread rubber and possibly diferent belt stiffnes which would yield different "feeling".
Example: I would expect the Grabber HTS-60 and A/TX to have significantly different Traction, wear, Ride, Handling or noise "feeling" so how would you go about evaluating which tire is "better" for towing with?

The handling of the tire squirm, or whatever it was, did not reset my feeling for what is considered acceptable or a new feel. I am anal about having towing stability in my rig or anyone I help. It is either a solid and stable setup or it gets fixed. I am very sensitive to changes in truck handling. I could even feel the instability effect fading gradually away. 500- 1,000 miles was the worst, then 1,000 to 1,500 was notable better, and so on until around 3,500 to 4,000 it dissipated. Something in the tire changed. What exactly I’m not sure. I questioned myself and even reset the WD hitch and anti-sway system twice, which had no effect on the problem. My wife also felt something in the truck that was not the same.

The feeling in the truck, I will try and describe was like driving on ice, and you “felt” the truck start to slightly shift enough that it was about ready to start skidding. There were also times when high winds just barely started to affect me that never did before. But, with either of those two feelings, I did not have to do any steering corrections. I just felt it. Thinking back on this, with the high winds issue, do tire sidewalls stiffen slightly since new and take a set once broke in? It may be a combo of tread friction and sidewall stiffness.

As I said, the same tires brand and type 6 years ago never had this issue. If the problem would not have gone away, I was looking at changing tires, which on that size tire is costly. They cost enough for the first time and not sure what I would have exactly changed too.

[Tireman9]

Originally Posted by JohnB

Hi Roger,

Getting back to you on this. I know you are the "tire guy" and have lived and breathed tires all your career. I am, and we are, genuinely grateful for you helping us with your background. My career before I retired comes from a machine design and mechanical failure analysis background. I enjoy going deep and entrenched in mechanical problems and trying to make them simpler for folks to understand and help them troubleshoot their camper/truck towing problems.


snip


I will try and explain the big-picture issues at hand when tires become a towing heavy loads. While a crude test, it was amazing the difference amongst the brands. Yet all were rated for handling heavy loads. We were comparing them to my current truck tires when I have a spare unmounted.

Any ideas you can give us in sorting this out is welcomed.
Thanks
John

You are correct that the lateral "sway" is complex. In all probability, even with identical tires on two different TV TT combinations, the sideways stability could range from fine to un-acceptable due to the numerous combinations of features and performance you covered.


In theory, it might be possible to learn the "lateral stiffness" measured a pounds per inch of sideways deflection, of a group of tires but the ranking would probably change as we move away from 100% rated load and 100% rated inflation.


While your comments on lateral stiffness are generally correct as stated it is also true that tread depth plays a larger portion of the "feel" and response than most understand.
An "aggressive" tread pattern (off-road) will be better if forward motion but I believe it would most likely be worse in side to side motion just as a deep tread tire is definitely worse than a shallow tread depth.


There are some standard tests run during the tire development process that MIGHT reflect the "feel" people are talking about and that would be cornering force at low "slip angle" but without extensive testing and on-vehicle testing ($$$) this is an unknown.


You mentioned the hitch system. I am wondering who has done a solid comparison of sway vs hitch weight distribution systems. I am thinking that this could be done for only a few $Thousand in a week or so, if someone would donate the use of a few different TV and a few different TT as well as the use of a test track or very large empty parking lot.

[Tireman9]

Originally Posted by JohnB

The handling of the tire squirm, or whatever it was, did not reset my feeling for what is considered acceptable or a new feel. I am anal about having towing stability in my rig or anyone I help. It is either a solid and stable setup or it gets fixed. I am very sensitive to changes in truck handling. I could even feel the instability effect fading gradually away. 500- 1,000 miles was the worst, then 1,000 to 1,500 was notable better, and so on until around 3,500 to 4,000 it dissipated. Something in the tire changed. What exactly I’m not sure. I questioned myself and even reset the WD hitch and anti-sway system twice, which had no effect on the problem. My wife also felt something in the truck that was not the same.

The feeling in the truck, I will try and describe was like driving on ice, and you “felt” the truck start to slightly shift enough that it was about ready to start skidding. There were also times when high winds just barely started to affect me that never did before. But, with either of those two feelings, I did not have to do any steering corrections. I just felt it. Thinking back on this, with the high winds issue, do tire sidewalls stiffen slightly since new and take a set once broke in? It may be a combo of tread friction and sidewall stiffness.

As I said, the same tires brand and type 6 years ago never had this issue. If the problem would not have gone away, I was looking at changing tires, which on that size tire is costly. They cost enough for the first time and not sure what I would have exactly changed too.

I don't know what would change so significantly in a tire sidewall between mile 200 and 1,000. When you change tires even of the same brand/size and design when production dates are many years apart there are numerous detail construction changes that you might feel but one thing you haven't done is doing a direct "blind" evaluation back to back on the same road within an hour of each other.


I can give you an example from my personal experience. At a car company test track in FL I was given the opportunity of evaluating the ride harshness of two different design cast-aluminum wheels. We drove on one set then returned to the garage. The tires were dismounted from "set-A" wheels and mounted on Set B wheels and placed back on the vehicle so the tires were in the same position in the 2nd evaluation. This eliminated any possible interference from changing individual tires which we know can deliver minor differences in ride comfort. I was amazed to feel the difference in less than 1 mile. Note these tests are done with no radio playing, windows closed and A/C off so there is no extraneous noise input. Ride and handling evaluations need extreme control to limit all extraneous variations

[JohnB]

Originally Posted by Tireman9

I don't know what would change so significantly in a tire sidewall between mile 200 and 1,000. When you change tires even of the same brand/size and design when production dates are many years apart there are numerous detail construction changes that you might feel but one thing you haven't done is doing a direct "blind" evaluation back to back on the same road within an hour of each other.

Thanks and understood about manufacturing techniques changing. Continuous improvement mandates face every industry to increase profitability while maintaining quality. It's the name of the game.

A direct blind test, your right, I have not done that. But I can, if this ever comes up again. What attributes in the tires change that I should be looking for? and should this test be after the tire temp rise stabilizes?

I know tire rolling warm up increases the air pressure in the tires, which has the ability to stiffen the tire. I see the warm up pressure rise on my TPM. That said, when the problem was occurring, we were on a 1,500 mile trip. I did not feel a shift in stability across a 250 mile daily segment of the trip, which occurred frequently. Some days 150 miles, other days 100 and some 200. I even reset the Reese DC in a truck parking lot and checked the WD settings trying to see if it would improve on that same trip. Again, resetting the anti sway did not change the truck effect. The WD was checked, but not moved, it was where I keep in on this truck.

To note, trying to keep an open mind that the truck front end may have changed causing the issue, I did change the steering stabilizer (original OEM) to a new Bilstein. Ford 4 x 4 Super Dutys with a solid front axle can have an issue of wiggle when the stabilizer goes bad. I must admit, the new stabilizer was well worth the change and upgrade to a better stabilizer. Unfortunately it did not shift the tire feeling. I am just noting this to not lose track of the details occuring at the time. I also tested each tie rod ball joint for excess play. None noted.

Thanks

John

[JohnB]

Originally Posted by Tireman9

You mentioned the hitch system. I am wondering who has done a solid comparison of sway vs hitch weight distribution systems. I am thinking that this could be done for only a few $Thousand in a week or so, if someone would donate the use of a few different TV and a few different TT as well as the use of a test track or very large empty parking lot.

This topic may be a complex as which tire do I buy?

There are many WD and anti sway hitches for sale today. More than ever as the RV industry is booming now and most need a WD hitch. Many of these hitches cloan of some of the older WD hitches for anti-sway methods since patents have run out. The WD on most of these hitches use similar principles to shift weight, differences come in the anti-sway controls and how to adjust the WD. Anti sway systems come in 2 general types.

Type 1. These hitches employ friction as the principal to resist resist sway at the tow ball connection as the anti-sway feature. Some create higher friction than others, and as such have different degrees of how much anti-sway forces they can resist. Trailer size and length enters into how much friction you need. Price point seems to be a large driver in this market. More effective high friction sway controls cost more then the less effective ones. Reese, EAZ lift, Curt, Equal-I-zer, Fast-way, Andersen, Husky, Draw-tite are some of the ones in this type. There are many more.

Type 1A. This is a subset of type 1. This WD hitch creates WD on the TV using the same principle as type 1. The anti-sway on their newest design hitch, use a castering effect between the hitch head and spring bars to, pull/snap the TT back in line with the truck at the tow ball pivot connection in place of friction. The older design of this hitch did use friction. There is only 1 brand I know of using this concept, Blue Ox.

Type 2. These hitches work to change pivot point between the TV and the TT. By reducing the distance of the pivot point behind the rear axle, sway forces cannot create as large a force (leverage) against the side of the TV/TT. The concept of these types are similar to a 5th wheel hitch which has the pivot point very close the rear axle and no large rear overhang like in type 1. Hensley, Pro-Pride and Pull-Rite are the only 3 hitches I'm aware of that shift the pivot point. These types of hitches are very effective in eliminating sway as they change the pivot point where sway starts acting on the TV. These systems cost the most as there is more machining and fabrication involved opposed to Type 1/1A hitches.

I am not aware of an industry wide test with an objective outlook on this to test and rate all the hitch manufacturers. This is like testing pickup trucks, who is the best? If you follow the WD hitch, anti-sway market, I suspect if you call any of the type 1 or 1A manufacturers they will not guarantee their product will solve all your towing sway issues if you press them to put that in writing. I posed this to Reese years ago, there are too many variables involved to guarantee it. Consider the type 1, 1A hitches as a tool in the tool box of hitch systems. They all help do the job, just some are better than others pending what TV and TT you have.

If you call the Type 2 manufacturers, there are more than likely 2 of them that will tell you that their hitch will solve all your sway issues. They are competitive rivals. However, all 3 of these high end hitches have drawbacks pending your situation. And soft side walls tires on the front of the TV can still cause TV stability issues when making turns with a heavy trailer pushing you on these systems.

There is no perfect hitch system where one size fits all. An industry wide WD anti sway system test I'm sure would stir up the towing world. We really need the truck manufacturers to get on board with this too and the tire manufactures to support it.

Owner education on how to use and adjust their hitch is a another topic. As well is, how to know which hitch system to buy for your TT and TV.

We would really need someone high up in the industry to do this test. SAE maybe. I would like to be part of it if it ever came to be. Or at least see it.

[JohnB]

Originally Posted by Tireman9

You are correct that the lateral "sway" is complex. In all probability, even with identical tires on two different TV TT combinations, the sideways stability could range from fine to un-acceptable due to the numerous combinations of features and performance you covered.

In theory, it might be possible to learn the "lateral stiffness" measured a pounds per inch of sideways deflection, of a group of tires but the ranking would probably change as we move away from 100% rated load and 100% rated inflation.

While your comments on lateral stiffness are generally correct as stated it is also true that tread depth plays a larger portion of the "feel" and response than most understand.

An "aggressive" tread pattern (off-road) will be better if forward motion but I believe it would most likely be worse in side to side motion just as a deep tread tire is definitely worse than a shallow tread depth.

There are some standard tests run during the tire development process that MIGHT reflect the "feel" people are talking about and that would be cornering force at low "slip angle" but without extensive testing and on-vehicle testing ($$$) this is an unknown.

You are correct, different TV’s, TT’s and WD/anti-sway hitches combinations affect towing stability. Tires are also in the factor set, but let’s hold the tires until last for a moment. Between my own towing experiences and helping others over the years, the TV, TT and the WD anti-sway systems by far have more variables to sort out then just the tires. However, those non tire variables are very mechanical in nature and there are more adjustments to help align the situation to a stable towing system. There is also much more known and written about how to pick the right TV, WD hitch/anti-sway system and TT to be a good towing combination. And in most cases, it all works out “after” optimizing each of those variables.

To help sum up the factors associated with TV, TT and WD/hitch system, IMO you have to optimize “all” the known towing factors (variables) of the TT, TV and hitch system by adjusting them “first”, before pointing to the TV tires as the problem. That said, the tires (both TV & TT) must be aired up correctly for towing at the start of all adjustments. If you made it through the list of TT and TV setup and you are still having issues, you should first question yourself and recheck to make sure nothing was missed. If you made it again to the same place, then TV tires enter the equation. The TV, hitch and TT setup can in some cases, produce similar issues to what soft walled tires feel like.

On tire sidewall stiffness, I’ll offer a “thought” that there is somewhat of a large range of lateral stiffness that can be tolerated in creating a stable towing combination. And in some cases, increasing the tire air pressure 10 psi or more above door sticker rating can help solve the problem. But, you cannot go above max sidewall pressure, so the range of air pressure adjustment can sometimes be limited. I “think” the sidewall issue starts when the tire construction has “very’ soft walls, which often aligns with very smooth non towing tire performance. I do not know where that limit lies, yet anyway, but it seems once you cross the limit there is no getting away from it short of changing to a different tire.

[JohnB]

I’ll have a personal experience on soft walled tires to share. I had a 2003 K2500 Suburban towing one of our prior Sunline T2499 campers. I used the Reese DC hitch system. The truck came with 16” Firestone Steeltex LT LR E tires as OEM. The door sticker stated 50psi front axle and 80 psi rear axle. After optimizing the TT, TV and hitch system, that TV & TT combo was very stable. There was no high wind or semis passing that ever phased the system in the 20K miles we towed with it.

The truck reached approx. 55K miles and I needed new tires. SteelTex was discontinued so the research started for a LT replacement. I was after the best tires for the job, and I was willing to pay the cost. The search at the time (2007) came back with Michelin LTX tires (the first generation LTX). There were rated to be able to carry the heavy loads needed for towing. I had a friend towing with his older F250 with the 7.3 diesel in it and a larger TT and he swore they were the best tires he ever had. I also used the LTX P tires on our other vehicles, non-towing and they gave good service. So I bought 5 of them for the Suburban. The day I left the tire shop, the truck drove the smoothest it ever had compared to the SteelTex.

After about 500 miles on them we headed our first trip camping with the new tires. TV tires were at 50psi front and 80 psi rear as I did on the SteelTex and door sticker stated. All was good until we made it onto the interstate and started towing above 50mph. We had mild to high (30mph) cross wind gusts that day. Semi’s flew by and no issues, but when a wind gusts hit the side of the truck, the whole rig went unstable. The wife screamed, what’s that, as the instability shook the rig so much. The next several campouts had the same issues, just they were not as high a wind gusts.

Troubleshooting started going through the WD hitch, anti-sway, twice no less. No change in the handling. Then I came upon tire pressure experiments on the LTX. The rear was already at 80psi so not adjustment there. I took the front from 50 to 60psi and there was a global shift in being better in stability in the truck. Next trips I kept upping 5psi at a time. I found at 70psi the tire was too stiff if I hit a bump, the whole front end of the truck would shift in the bounce. So I backed down to 65psi. The front end bounce was tolerable, and the truck stability back to about 85% of what I had before. At the time, we were changing campers and the F350 soon come to full loaded weights of the new camper. If I was going to keep the Suburban, I would have changed tires with only 15K miles on them.

After talking with my friend with the LTX on his F250 diesel, his diesels truck needs a minimum of 70psi on the front for the same 16” tire I had. He towed at 75psi on the front. The front end was heavier and it all worked for him. He never had any issues as never towed in the 50psi range. He was swearing by them and I was swearing at them.

Is there a way to sort out the sidewall stiffness difference between 50psi and 70psi on a certain tire? The Steeltex was rigid enough that 50psi worked well, ride was stiffer expected on a 3/4 ton truck. The LTX never aligned with that stiffness, possibly short of going to 70 psi and above. My son’s 2500 Avalanche has 16” LT Cooper Discovery tires sized the same as what was on my Suburban towing a larger camper then I did with the same WD anti-sway hitch with no issues at 50psi. The Suburban and the Avalanche share the same GM frame, wheelbase, suspension & GVWR specs for those model years, just a different body style. The Cooper/Mastercraft tire was a tip from one of my friends using them on his older Chevy 2500HD pickup which has a similar front axle to the GM 2500 SUV towing a similar TT size and weight with the same Reese DC hitch. There may be hope in sorting this out if we can figure out where range of too soft a sidewall exists.

It seems you have to give up some level of smooth ride in order to gain lateral sidewall stiffness.

[henryj]

One aspect of tire stability not mentioned yet is the role of wheel width compared to tire section and tread widths.

My previous '15 Silverado included 18x8.5 wheels and P265 tires as part of NHT max tow package. I immediately replaced the factory tires with Michelin LTX M/S2 also in P265. These Michelins had a 10.7" section and 8.3" tread. I had excellent results with these tires and even bought a second set. IMO the 8.5" wheel and 8.3" tread was a key part of the stability and satisfaction I felt with these tires.

My current '19F150 has 18x7.5" wheels even though it is also the max tow package. I was planning on replacing the factory P275/65 tires with LTX, but missed some parts of my homework. The LTX P275 has a whopping 9" tread width and 11" section width. Far too much tire for a 7.5" rim on a truck meant for towing. I believe this Michelin could well have given me the same kind of instability John is talking about.

While redoing my replacement tire search I found myself fishing in a very small pool. I needed at least 116 Load Index and the same OD as the factory tires to avoid speedometer errors and I didn't want to buy new wider wheels. 255/70 was the ideal tire size, but it was not readily available across brands and didn't have 116 LI. I finally settled on BFG All/Terrain 255/70 LRD. It has a wider tread at 8.4" than I'd like on a 7.5" wheel, but at least the section width of 10.2" is a much better fit for the 7.5" wheels.

I completely missed looking at wheel size on the door stickers of the the inventory trucks before ordering mine. In hindsight, I would have seriously considered the 20x9.5 wheel option. In the end I paid a couple hundred more for LRD tires than I would have paid for the 20" wheels. Am I further ahead? I don't know?

Anyway, when buying trucks, new or used, always look at the wheel width and contemplate what kind of replacement tires are available/better suited for towing.

Henry