Rear tire blowouts

[KEYSJUNK]

I've changed the tire size on my 21ft rear kitchen, 1977 Dodge 440. I put on 8.75X16.5R tires.  Has anyone out there had any problems with this change.  I have had this change now for approximately 10yrs now.  I seem to have rear blowouts on quite a few of my trips.  My tire pressures have been changed to try and resolve this problem, but I still have this problem.  The first time I had the problem was when I put the pressures up the the recomemded 65 lbs.  Blew three tires on that trip. All rear tires.  Dropped the pressure down to 55 lbs and had better luck.  None of the blowouts were side wall failures.  The tread just pelled off of the tire. I have looked under the motorhome and the tires do not seem to be rubbing each other or making contact.  I recall reading about the tire size in one of our back issues.

[susan-y]

KJ that's the size of tires I have on my mine.  No extended trips, max 5 or 6 hundred round trip.  No problems (knock on wood).  Keep mine between 50 and 55 psi.  Sue

[Rodney]

Sounds to me like you have a bad or old set of recaps..
I would replace them all with a set of NEW tires. I would also go to a tire store you trust and have them take a look at your Clipper and see what they have to say. I was lucky to get an entire set of excellent used Toyos and installed them after having them balanced. WOW what a difference in ride and handling.
good luck
Rodney

[KEYSJUNK]

I guess I did not state that these tires where purchased new. At different times after the blowout.  Motorhome tires never stored in the sun either.  I guess that maybe the mechanics on the west coast, maybe mechanics, but the ones here on the east coast are only what we in the profession refere to as R&R people.  The're like deer in headlights.  I have a lot of war stories on this subject.

[Andy Illes]

As we all know.... 800x16.5s are tought to find.  Only Cooper makes 'em, I've beent told.  I wanted to switch to the easier-to-find 8.75s but a couple different tire shops said they'd be too wide.... they'd rub on each other, esp on bumps or heavy load... overheat.... blow out.   Shops around here are pretty familiar with dualie setups.   I've stuck to 800's... done a 3,800 mi round trip to Colo.... couple 1,400 round trips to NY.... no probs, except from a piece of rebar I didn't see onna road.

Dunno if that's the answer.... just know my experience.

[susan-y]

As we all know.... 800x16.5s are tought to find. Only Cooper makes 'em  

So, are those the tires these rigs came with?  That would mean a little less wide tire right?  When I got a new spare Les Schwab in Coos Bay told me that the 8.75X16.5 might not be immediately available in some areas (maybe next day delivery).  That the 16.5 itself was almost a thing of the past.  Might have been just one guys opinion.

[bigray]

I chnaged my tires to 8.75X16.5 about a year ago. I got Michelin which were quite pricey. I got the best deal at Sam's. They coast about $160 a piece.

I run them at about 55 lbs and haven't had any problems (knock on wood).

[Rodney]

Hi All
hope all is doing well.
Thanks for posting this thread It reminded me to crawl under my home and see how the new wheels and tires were fitting on my Clipper.
I changed the wheels and tires when I changed my rear axel to LT 215/85 R16 they are bigger than the one's that came off. height measuring the front is 29 " tall. I had a clearence problem on the right rear inside. when I got back under there I found the tire was still rubbing just a little. I pulled the duals and removed a piece of tin and ground the wood to give some more clearence. Wheew I was looking for trouble there if I hadn't taken care of that. There was also a spacer on the old axle between the brake drum and the inside wheel to space it out 1/4 of an inch I am using that as well.
I like the ride of the larger tires but when I need new ones I will go the next size smaller.
Rodney

[Conrad]

Have a good tire shop measure the rims to make sure that they are fitted to the correct tire diameter.  

I bought mine at Les Schwab several years ago for around $100 each.  8.00 x 16.5 Radials XLT Load rating D.  Made by the TBC Corporation.  I found out later that they are a little on the light side in the sidewall but they have been fine for me.

check link: http://www.hoovers.com/free/co/factsheet.xhtml?COID=14868&cm_ven=PAID&cm_cat=OVR&cm_pla=CO4&cm_ite=tbc_corporation for more info on this tire company.

[bigray]

Mine are the Rib XP load E. I check my air pressure before every trip and those monsters just don't loose air.

[HarryClipper]

After 32 plus years in the tire business ( ran a tire store in the Mojave Desert in the late 70's, early 80's), I can tell you that MOST tire seperations ("coming apart") are because of UNDER inflation, NOT OVER inflation.

Simple to understand really.  Imagine opening your car door at 55MPH, sticking your foot with tennis shoe, etc., out the door on to the pavement, and let see how long you can "drag" your foot without the shoe or your flesh "bursting into flames" (or perceived flames)!

When tires are run to LOW on air with a "load" on them, they build up heat.  Steel belted radials can generate a LOT of heat...because they have..."STEEL" in them!  

Now..."rubber will run away from hot steel" (just like you would if you were rubber).

Most tire store personnel don't have a "clue" on what to inflate a vehicle to, especially any kind of truck tire.  

Look at the sidewall of the TRUCK tire and it tells you the "MAX" AIR PRESSURE UNDER MAX LOAD!!!  It is different wording than a passenger rated tire.  WHAT does a Clipper weigh loaded :?:   Look at the tire information on the side and it tells you the load or "weight" the tire can handle in a "single" or "dual" application.  Figure the load capacity of the six tires, then look at the weight of your Clipper loaded and see if you need to "MAX" inflate the tires to drive safely down the hiway.

Also, improper inflation can affect gas mileage as much as by a 25% loss per gallon! :shock:

If you add the fact that tires only now have a "5 year from date of manufacture" warranty, then imagine just how "DANGEROUS" an old truck tire is that is 7 PLUS years old, weather checked and UNDER inflated and is going down the highway!!! :shock:

BF Goodrich and UNIROYAL are OWNED and MANUFACTURED by MICHELIN TIRE CO. :idea:   BFG has a "Commercial" tire with a hell of a warranty, and UNIROYAL has the same equivalent in their line-up.  Last year they came with a "MILEAGE" warranty, not estimated, but a real mileage warranty!

MICHELIN uses the latest and best technology, Bridgestone is a close second.  GoodYear is, ah...never mind.

Lack of proper alignment will also seperate a tire.

Rotate, align, check air!

By the way, did you know...that for every 30 days you lose a pound or two of air, and...for every 10 degree change down in air temperature, you loose 2 pounds also?  Soooo, do the math for what can happen going from Summer to Fall and NOT checking air in November!!!

Good luck!

Info is out there, if you can find a tire guy that can read!

HarryClipper

"Just drive down that road, until you get blown up"
General George Patton, about reconnaissance troops

[Horst]

Excellent post HarryClipper!

[Shayne]

I just put new tires on the trailer.. yeah, I know it's new.. but it came with junk Chinese tires... anyway..

I replaced them with the BFG Commercial TA that Harry mentioned above.  Nice tire for the money, about $100 per tire.  Decent sidewalls, E load rating.  Made a huge improvement over the other tires.  Not sure if it's available in a 16.5 size though?

But in reading about tires, especially blowouts.  Inflation is key!  And as Harry said, it's better to be a little over than under.  If in doubt, put whatever the max listed on the sidewall is until you can get your rig weighed.

Don't skimp on tires.  If you have a problem, at the very least it can ruin a weekend.  At the worst, it can ruin everything including you.

[Andy Illes]

Harry, that IS a fantastic post... THANK YOU!!  And you're right about finding knowledgable tire guys... even the one I think knows his stuff tells me stuff I wonder about sometimes.  I put lottsa miles on Fred so this is an important issue for me.

Have some questions....

1.  Is it true that 8.75x16s on the Clip could rub and be risky?  That size is common... 8.00s aren't.

2.  Are you saying Michellein (sure agree they'e THE primo brand) and other good brands you mention DO still make 8.00s?  I've been told only Cooper (and several off-brands they make) does, so that's what I got.

3.  Whaddaya think of Cooper?   I'd switch inna heartbeat if I could get Michelleins, or comparable quality.

4.  Pressures.  My sidewalls say max 75, either single or dual.  Is it safe to just leave 'em at 75, even running light (other than rougher ride)?

Thanks again for the GREAT post....
Andy

[HarryClipper]

Thanks "Group" for the replies.  Last year it seemed that 875R16.5 was available from BFG and Uniroyal.  I will contact a wholesaler to see if any exist or ever did.

Meantime, I looked at Michelin's website (www.michelin.com) and found the link below.  Should give a lot of straight up answer to questions we all have from time to time.

As I said originally, they have the best technology available (and they charge for it!), but what is peace of mind and safety worth to the RV'r??? :roll:

Good Year now owns the Dunlop Brand and have mixed emotions on the brand now.  Seems everything Good Year gets involved in goes "weird" somehow, and the Dunlop tire line is no exception!

When I bought my Clipper, it had new tires on it, 5 Firestones (which is made by Bridgestone)and one "Generic" odd ball, still new though.

I have had it a year now, no trips (except to get gas a few blocks), but inflated tires to max pressure and they seem fine!

When I actually get her in a position to "drive" somewhere (next year I am sure), I will either put the 875R16.5 back on, or...convert to a newer sizing in 16 inch.

You may not know it, but the "reason" 16.5 was replaced years back is because the rim and tire have NO SAFETY BEAD to keep tire on rim during a "BLOW OUT"! :shock:

I have "aired up" plenty of new 16.5 tires in my day, and they were always "a pain in the @#*!!! :oops:

The NO SAFETY BEAD makes the tire EXTREMELY hard to inflate in cold weather.  We actually use to put them in the cab of our service truck with the heater on FULL BLAST for 20 minutes and then grab them and run like hell to the machine to mount them and try to inflate them.  

I AM NOT KIDDING!!!

So, with the advent of so many trucks and RV's now, the tire industry had to address the "safety issue" with 16.5 tires and re-engineered the NEW 16 inch tire to be used with a safety bead wheel!

That is why a blow out on a newer vehicle with 16's is a hell of lot easier to negoatiate with, than the old 16.5 "... wobbles all over the place as it goes... "BOOM!!!"

I'll update tire availablity on 875 R 16.5 as I find out more.

Thanks again for listening and have a great evening, or "what ever" you want to have!

HarryClipper

"The inevitable never happens. It is the unexpected, always."
-   Lord Keynes


http://www.michelinrvtires.com/michelinrvtires/pdf/RVTIREGUIDE1.pdf