15" to 16" Wheels/Tires on 2007 Safari

[boondockdad]

I've noticed some pretty good camber on the wheels when backing into tight spots... so much so, it appears abnormal... since the wheels tuck up into the well, could this be the reason?

[Gene]

Originally Posted by Rollertoaster

We changed our wheels and tires today from the OEM Marathons to 225/75R16
Michelin LTX A/S load range E tires.
Terry

Terry, are those LTX M/S (mud and snow) or LTX A/T2 or something else? I have been checking out all the Michelins that would fit and I haven't seen an LTX A/S.

Were you able to use the OEM hubcabs? I like those wheels and they seem easier to clean.

The references to "offset" are a mystery to me. I never had to know anything about wheels. What does it mean?

Glad to see they fit well. I did some measuring the other day and LTX would have about 5/8" clearance and LTX A/T2 would have about 3/4" according to what I figured out.

Gene

[boondockdad]

Originally Posted by CrawfordGene

The references to "offset" are a mystery to me. I never had to know anything about wheels. What does it mean?

Gene

Gene,

here's a good article-
Wheel Tech - Offset

it's where the wheels hub-mating surface is in relation to the wheels centerline.

[Bluto]

Anyone using the Michelin XPS Rib tire on their trailer? It's a highway tread design instead of a mud and snow. I have used them on my last 2 trucks with no problems. They have steel belts behind the tread and the side walls. I found it surprising but they ride real smooth too!

[RossFam05BH]

Bluto wrote

Originally Posted by Bluto

Anyone using the Michelin XPS Rib tire on their trailer?

We have run XPS ribs for a couple of years. We feel our choice has been a wise change. See our thread for a more in depth discussion.

Bye,
Paul

[boondockdad]

Originally Posted by RossFam05BH

Bluto wrote We have run XPS ribs for a couple of years. We feel our choice has been a wise change. See our thread for a more in depth discussion.

Bye,
Paul

I can't believe I've never come across that thread... thanks.

As much as I want Michelin's, not crazy about the larger wheel- from an aesthetic as well as performance standpoint.

Maybe use a lower aspect ratio... 65 or 55? From searches so far, it looks like lower aspect ratio tires have lower load ratings... which is problematic since my trailer CAT's around 10,000lbs for CC trips

[2airishuman]

Originally Posted by finalcutjoe

...Maybe use a lower aspect ratio... 65 or 55? From searches so far, it looks like lower aspect ratio tires have lower load ratings... which is problematic since my trailer CAT's around 10,000lbs for CC trips

hi fc'

folks do this, but there are issues...

-lower aspect ratio=LESS VOLUME of air, as much as 50% less.

-which makes potholes and curbs and camping lumps more likely to damage the tires/wheels.

-lower aspect ratio leaves LESS margin for error on the tire pressure issue. 3-5 psi loss is BIG DEAL with shorter tires.

on multi axle trailers parking, backing up and turning put a LOT of stress on the sidewalls as the tires ROLL or squirm away from the pivot point.

ST tires are designed to handle that issue, P and LT tires are not.

this might not be a problem for single axle trailers OR basic towing on the open road,

but i back into a lot of TIGHT spaces and can watch the tires roll over and leave rubber in an arc or plow the gravel...

another point 4 confusion (finding proper LOAD tires in NON st format )...

here is a tiny snip from this thread... http://www.airforums.com/forums/f438...s-e-56442.html

Originally Posted by 2airishuman

...on a RELATED issue,

there is a difference between tires with an st tire LOAD RATING and a P/LT tire LOAD INDEX...

this is ONE of reasons why trying to select and use LT tires for towing is tricky,

because the LOAD INDEX of LT tires doesn't EQUAL the LOAD RATING of ST tires...

folks confuse this issue regularly which is understandable...

LT tires are not load rated for the ISSUES st tires must tolerate.

and even LT tires fail...

http://www.airforums.com/forums/f438...art-25929.html

i enjoy reading and learning from those who have made the LT hop and appreciate their efforts.

clearly it has been successful for some, but i'm not going there anytime soon.

there are E rated st tires with several brand names, that fit your trailer weight.

cheers
2air'

[Gene]

Very interesting threads 2air, and I have some thoughts/questions.

Some people use Michelin XPS Ribs because they have a steel cord in the sidewall, thus they believe that sidewall is equivalent to the stronger sidewalls ST tires have. I doubt there's a definitive answer to this.

Perhaps an very good tire not exactly engineered for the purpose intended is better than a not so good tire engineered for the purpose intended—i.e., is any Michelin LT tire better than a Marathon? "Better" for what? Sidewall strength, UV, speed, load seem to be the components most talked about, but traction and tire life are important too.

I know about the lateral pressure on tires when backing, but I haven't seen any posts: "My LT tires came off the rims while backing into a tight space". Maybe this is not a problem. The posts I haven't seen are about both LTX and XPS Ribs (I suppose the possibly nonexistent posts I haven't seen are also about wooden buckboard wheels too).

There's a difference between Load Range (letters life D and E) and Load Index (numbers like 94, 115, etc.) and that they measure different things. Load Index measure vertical stress and generally applies to car tires and some light trucks. Load Range measures horizontal stress and has been usually the tire of choice for trucks and trailers. Some tires are rated both ways—thus the Michelin 225/75/16 LTX and XPS are 115 and E. So if the Marathons, Maxxis and Michelins are all Load Range E, shouldn't all their sidewalls have the same strength?

UV problem: If I keep my tires covered when home, why is there a problem with LT's?

Gene

[2airishuman]

Originally Posted by CrawfordGene

... thus they believe that sidewall is equivalent to the stronger sidewalls ST tires have...

Perhaps an very good tire not exactly engineered for the purpose intended is better than a not so good tire engineered for the purpose intended...

gene

i'm not a tire engineer or expert from the RMA so i can't answer your questions and won't try.

but these two clips get to the core of MUCH of the problem and random UNtested solutions...

1. "thus they believe..."

unfortunately what folks believe may not be accurate. false beliefs CAN drive marketing or product changes.

and repeating 'beliefs' over and over don't make them any more true.

i can point out 100s of examples of this, but wont'.

2. "stronger sidewall"

my post doesn't suggest the sidewalls are STRONGER on st tires, but are designed to handle the stress of side rolling and squirm on the rims.

it might be because of the shape, suppleness, GIVE in the carcass, materials used, BEAD or some other issue that is NOT strength related.

3. "a not so good tire"

again repeated OVER and OVER it's just an opinion.

usa and CANADIAN made gyms had a bunch of failure reports YEARS ago...

chinese made tires were NEVER part of this blip of activity, but NOW seem to get ALL of the blame.

most 'bad tires' were canadian made and PRE 2004. this is well documented and beyond dispute, really.

have there been failures on tires made AFTER 05 ? sure.

but there are also carlise failures, greenball failures, towmax failures, maxxis failures, mich' failures, st/LT/p failures and so on...

and none of those are connected to the canadian made st tire failures from 2001-2004.
_______________

a LOT of harmful INfcorrect misleading and incomplete reports have been posted here.

often ONE single tire or set of RELATED tires gets reported and REposted over and over.

just like tire threads start again and again with the SAME people posting into them.

i've read a bunch of posts recently that go like this...

"my trailer has gyms and for 2-3 years of towing they've been fine, no troubles, no issues, no failures. BUT i don't trust them now because of reading here..."

so apparently intelligent people are REJECTING there own experience, based on UNCONFIRMED or incomplete reports by strangers...

and MANY who leave a tire UNDER inflated for years, ONLY report problems when the tire fails, WITHOUT declaring the past abuse.

many folks don't KNOW that they are mistreating a trailer tire. these tires get regularly abused and ignored in ways the tires on a car do NOT.

we'll never know how many tires ROLL of the wheel or bead. zep didn't have to report this LT tire failure, but did.

photos and accurate reports take TIME AND EFFORT to post, satisfied gyms uses SELDOM report their trouble free experiences.
____________________

do i whole heartedly trust gy or ANY tire make? no of course not.

does a/s offerring a few other options AT the service center (not on the production line) mean NEW EVIDENCE supports these offerings ?

no, it is just a vendor response to customer requests.

and i can point to MANY industries with product offering driven by customer request...

people want what they want EVEN if the want is unrealistic or a better solution already exists.


cheers
2air'

[Gene]

2air,

Neither of us are tire engineers, though I'm not sure that would qualify us if we were.

Of course what people believe can and all too often is wrong. Humans are experts at rationalizing and justifying. But…

Opinions are what we have to go on and some are well thought out and some are not. That is a major challenge of Forums—sorting out noise from good stuff. Sort we must and my admittedly subjective belief is that Marathons seem to get more bad reports. It has been posted that the Maxxis is built better than the Goodyear and how it is built, so that may be a fact. Yes, some of the reports are repeated over and over on myriad tire threads. Hopefully I've mentally sorted well, maybe not.

It may or may not be that is the sidewall that is stronger or some other factor, but the question remains the same. The Load Range indicates how the tire responds to horizontal stresses (that would include sidewall strength, bead, lettering, etc.), thus isn't an E tire the same regardless of whether it's an ST or an LT?

Other than Zep's LT tire failure, I don't recall other LT failure reports though I'm sure there's some somewhere. Zep's tire was a Firestone produced in 2005 or so. I have a vague memory of one or two Maxxis failures, no Michelins.

None of this is a objective, double blind study. I wish there were one.

Airstream's selling of 16" wheel and Goodyear LT tires may or may not be a response to customer requests. The tires are Goodyear because that's what their wheel supplier sells if my information is correct. The Marathons do not come in 225/75R16, the Goodyear LT's do.

Here's something else I wonder about: If psi has a direct relationship to load bearing (vertical), shouldn't LR E tires be inflated to 65 psi to be equal to a D tire?

Gene

[2airishuman]

Originally Posted by CrawfordGene

...thus isn't an E tire the same regardless of whether it's an ST or an LT?...

basically no they aren't the same. you can explore for the distinctions.

we don't need double blind studies but folks do need to understand statistics and risk analysis.

millions of gyms, a few 1000 maxxis and a few 100 LT tires...

so IF there had been 1000s of gym failures, we would expect to see only 3-10 maxxis and MINUS ZERO LT failures...

if the RATE/risk of failure is similar across the brands.

we read about a shark attack and translate that to fear of swimming in a mountain lake.

IF folks understood the statistics there would be almost NO one using casinos even with the glitzy ads featuring winners.

the gym thing is this process in reverse.

for example, the MOST common tire failure ALL of us towing on the highways observe is...

18 wheeler tires, and the bones are ALL along the roadways to prove it.

does that mean the big tires have a higher failure rate

OR does it just reflect the % of tires rolling on highways OR the miles PUT on these tires or the issue of retreading?

gyms DO have nylon perimeter bands (now) that function in the same way as the nylon caps on maxxis,

and gy does make ST tires in 16s. who knows what sizes MAY become available now that production is domestic again.

as for failures i've had 2 maxxis sidewall blow outs, both while traveling less than 30 mph. i've covered this is other threads.

we've also covered inflation tables and load related issues, so no need to repeat that info.

there isn't much new on ANY of this, since it is NOT the original thread theme.

i'm all for improvements but the idea that a different choice IS an improvement doesn't automatically follow.

cheers
2air'

[boondockdad]

Air, Gene-- seriously, I could register your posts for college credits... but with no ACTUAL data, EVERYBODY is making decisions with anecdotal evidence.

For me, it's 8+ years of my Dad's A/S on Michelins (not ST), with never a blowout... and 3 BO's on my 1 year old, ST-rated GYM's

[2airishuman]

hi fc'

WICKED looking!

and the collateral damage, expense of travel 4 repairs and 'time out' for this only add to the pain and cost.

a 30 slide is the heaviest thing on 2 axles that a/s builds.

imo it should wear E rated st tires at birth, with PROPERLY rated rims.

a/s has switched to higher rated rims on these, now they need to uprate the tires or stop building them.
__________________

the following may NOT apply in your situation, this is a generalized statement...

here's how i envision the dominos falling on many 2 axle rigs...

1. a low pressure event happens on ONE tire while towing or in storage.
2. without tpm the owner will be UNaware of this until manually checking pressures, or only after the tire is VISIBLY low.
3. so the under inflated tire may be in service for a day or 2 (couple of 100 miles) at a MINIMUM and often longer.
4. the owner now INFLATES or corrects the low pressure tire, OR mounts the spare and goes back to towing.

the PROBLEM is BOTH of the tires in this scenario SHOULD be REPLACED as soon as possible, not used.

because BOTH tires on that side should be considered OVER loaded, OVER stressed and pushed beyond the service description.

and it's possible the OPPOSITE side tires may be OVERloaded on some trailers or stressed beyond service design.
________________

most of us who check pressures and find a low tire simply top it off and watch it for a few days.

IF the pressure holds, it's back to normal operations and that might be OK for lighter trailers or 3 axles or LT and P tires...

but with ST tires and a trailer at the TOP of the weight chart,

that choice is gambling on the hope no internal damage was done to the low tire OR other tire...

and the odds favor the house. in this game we will lose.
________________

jack went to 15 inch E rated maxxis st tires on the 30 slide, AFTER a chunk of tread block was lost on a 3-4 year old gym.

i think that was a good choice for that model stream and the D rated tires survived so long because of very very careful monitoring.

i've camped with a lot of folks and seen a few dozen nasty looking tires like your pictures,

on ALL decades of trailers and from all tires makers.

many of those trailers had collateral damage involving wheel wells, skin, plumbing, belly pans and so on...

so it is NOT uncommon, can be traced to many issues from old tires to road hazards, to neglect, and to OVER loading...

and it also happens when everything is maintained PERFECTLY and within load parameters.

but HIGHER load rated tires should improve the odds for the heavier trailers...

and adopting the proactive attitude that one tire issue OFTEN means replacing both might prevent some tire disasters.

cheers
2air'

[Gene]

Originally Posted by finalcutjoe

Air, Gene-- seriously, I could register your posts for college credits... but with no ACTUAL data, EVERYBODY is making decisions with anecdotal evidence.

finalcutjoe, credits in what? At least a BS from the Technical Institute of Retread Elucidations.

I agree anecdotal evidence is a large part of this ongoing series of threads. Unfortunately it is most of what we got.

As to why isn't an LR E tire the same across the board, "basically no they aren't the same. you can explore for the distinctions", does not contain the usual links so I could explore on the Forum or elsewhere. So the information must not be on the Forum, Wikepedia, or somewhere else in the usual syllabus.

There's more to these ratings than I understand and I keep hoping a real tire engineer shows up. Until then I hope to get knowledgeable answers from fellow students.

"Millions" of Marathons? Certainly a lot of Marathons, but this is a Forum with hundreds of very active members and maybe a thousand or so less active. The analysis (if I dare call it that) could be restricted to what we see here. It seems to me there are a "lot" of Marathons and a bunch of other tires, a fair amount of Maxxis and LT's. I wish I had an intern or a graduate assistant who go over all the tire threads and count all the reports and see how many are repeated. Some people do report they have had no problems so that could be included. Not a very good study, but slightly better than impressions.

We are going over this again and again. I keep hoping something new will come up and sometimes it does. Is it frustrating to see the same stuff? Yes. Inflation of E's? I was hoping for a simple answer so I wouldn't have to try to find it, alas.

Gene

[redstart]

Hello! Grad student in statistics here... i know nothing about tires.... but joe is right, without actual data we got nothin.

the problem with using the information posted on this site is VOLUNTEER BIAS. Anyone who posts here does so voluntarily, and volunteers have more of an interest in the subject matter, possibly because they have had problems... or they work for goodyear...or something...they don't represent the true population and so making inferences from this data can be misleading...

Do I get an A?

[rluhr]

Good posts here lately. 2air's opinions echo many of my own opinions on this subject. In particular, we agree that there is a serious dearth of statistically valid evidence. But there is good industry knowledge of the many causes of tire failures. We can do well just by heeding what the real authorities (Rubber Manufacturer's Assoc among them) tell us from their research.

I feel the pain of those who have had repeated tire failures, because I have too. Fortunately, we've never had a blowout, only numerous flats and tread separations (over about 80,000 miles of towing). There is a good reason for that: we've always caught tire problems before they led to a complete failure.

There are many causes of tire failures, but the big ones seem to be underinflation, excess stress, and improper patch technique. I don't buy into the theories that Goodyears are inherently bad, because statistically valid evidence is just not there. My own experience has been very good with Goodyears compared to other brands, and that means exactly nothing.

So what to do? I wouldn't run out and swap a whole set of tires and wheels that are perfectly good. First, get a tire pressure monitor. Everyone who is towing a trailer should use one, in my opinion. Nothing else will let you know when one trailer suddenly goes low while towing. Remember, loss of air pressure can happen because of road debris and rotten tire stems, and no brand or load rating is immune to those problems.

Second, if you have a flat repaired, be sure to always get a patch plug, which both fills the hole and seals the tire from the inside. Otherwise, you've created a ticking bomb.

Third, inspect your tires at every fuel stop. It's easy and takes just a few seconds while you are waiting for the pump. A broken belt problem will manifest itself suddenly and without prior warning. It looks like a bulge or an irregularly worn patch. In just a couple hundred miles, a tire with a bad belt can wear bald in one spot -- and the next step is a blowout.

Fourth, replace the tires following industry recommendations for time and treadwear. If a tire is severely stressed, as described by 2air above, or damaged, get rid of it. Don't try to make a tire last longer than it should, just because "it looks okay".

Fifth, weigh your trailer and make sure you aren't overloading your tires. Most people never weigh their trailers and that's a big mistake. It costs just $9 at a CAT Scale. Check the load inflation table to ensure you are inflating to the proper pressure.

Take those simple five steps and you may find you are replacing tires more often than you did before, but you'll also lower your chances for an expensive blowout with the collateral body damage that almost always occurs.

Finally, if your tires are wearing oddly (at one edge or another), and you've been running proper inflation pressure, have your axle alignment corrected. The mothership can do it (about $250 for a tandem) and some Airstream dealers can do it too.

[Gene]

Originally Posted by redstart

Hello! Grad student in statistics here... i know nothing about tires.... but joe is right, without actual data we got nothin.

the problem with using the information posted on this site is VOLUNTEER BIAS. Anyone who posts here does so voluntarily, and volunteers have more of an interest in the subject matter, possibly because they have had problems... or they work for goodyear...or something...they don't represent the true population and so making inferences from this data can be misleading...

Do I get an A?

We got no professors here, so no grades.

Statistics aren't always available, so we have to use thinking instead.

Gene

[Gene]

Rich, all of those are good suggestions.

I used to use plugs years ago when I repaired some tires myself, but then tire repair shops started using the internal patches claiming the plugs could pop out. I still carry plugs for emergencies. I've never had problems either way.

Thanks for inflation tables. I was looking for them yesterday and couldn't find them in the time I had. The ratings for LT's are close, but not the same as ST's. The numbers that interest me are both for 225/75 tires at 65 psi. The ST 15" is 2,540 lbs. and and LT 16" is 2,335 lbs. Either is much more than my trailer weighs. If you go up to 80 psi in an LT LR E tire, it will be rated at 2,680 lbs. I see Terry says (Post #1) he inflates the 16" LT, LR E tires to 45-50 psi and that would mean each tire was rated at 1,790-1,940 lbs.

When we are told to not run underinflated tires, I often wonder what is "underinflated". For ex., a trailer weighing 7,000 lbs. with tandem wheels, would only need to have ST 15" tires inflated to 35 psi according to the tables (total 7,040 lbs.). But no one would do that even though the tables seem to say it's ok.

Lots of questions, few answers.

Gene

[redstart]

Originally Posted by CrawfordGene

We got no professors here, so no grades.

Statistics aren't always available, so we have to use thinking instead.

Gene

You know, you sound just like my supervisor!


.....me scurrying away from this thread....

[Gene]

Originally Posted by redstart

You know, you sound just like my supervisor!


.....me scurrying away from this thread....

He must be very, very smart.

Gene