Bias Ply or Radial Tires?

[The_Handier_Man1]

Sent: 4/23/2005

I have read all about the use of mixing bias and radials but since my tires will probably rot out before they wear out, how much difference do these things drive with a complete set of bias or radial?    Thanks,   Les

[Cooneytoones]

Sent: 4/24/2005

Well Les....Bias tires have been around for a long time. The are usually engineered for sustained speeds under 60 mph. They get flats more frequently, and are a little rougher riding, especially when parked for a while and cold (they get flat spots in them from the weight of the rig sitting in one spot) Depending on how much, how far and how fast, or what kind of road you drive..Radials are a better & safer in my opinion...

Personally, I just feel better with a radial tire, they are safer at higher speed, which I don't do over 65 too many times....and they seem to not get the little flat spots in them, they still get some, but not as bas as a bias. The ride is smother too. And the rig seems to handle better, Mine had Bias tires on it when I bought it.

But if your just going to drive it a few hundred miles, and a few of week-ends...the bias at the cheaper price would be OK.....Most of my trips this year will be 1000 miles + Interstate driving round trip....And I feel safer on a radial, especially on the Interstate. Like I said, Just My Opinion. Hope this helped...

Timmy

[denisondc]

Sent: 4/24/2005

I would advise getting the tires that had the highest maximum load rating.
I can only discuss the 7.50-17 tire size, so this may be irrelevant for 17.5 tubeless tires. My 72 has the 5 bolt 17 inch split rim wheels, so must use inner tubes, and I only use the bias ply tires. While I have a set of slightly used 7.50-17 radials, they dont have as wide a tread as my bias ply tires, and they dont have the DOT max weight labelling on the sidewall. !!?
In the 14 years and 46k miles I have driven my RV (all with bias ply tires), I have never had a tire problem on the highway. We did wake up one morning to a flat tire in a campground in 1991, which I found out was due to the tube-liner, or boot, having aged and allowed the tube stem to stretch and leak. I have corrected that from re-occurring (on all of my wheels); and in fact am still using the same boots that were on it when I bought the Winny.
The flat spotting is normal with all bias ply tires; and temporary. Its more noticeable with an 8 ply or 10 ply tire, instead of a 2 or 4 ply car tire.
If the RV hasnt moved for more than a week, the flat spotting will be worse, but will go away with a few miles of driving, less than 5 in my case. If you have moved it in the last 36 hours, the flat spotting goes away even sooner. It doesnt bother me.
I bought 4 tires in March 1991 which I used on the back axle until Sept. 2003 when they had worn down to the tread wear indicators - in 42k miles. Cooper Tire doesn’t make that size anymore. Two of the four are now my spares. (I carry 2 spares, since the tire size is seldom in stocked locally anymore). If I hear of Light Truck radial tires which last longer than those, I would be interested.
I also had a pair of tires that I bought in 1993 for the front axle, and discarded them in 1997 because of the Very Noticeable weather checking. They were a different brand than the first four I bought, but I was on vacation, and had to take what they had in stock.
I dont try to run above 60 mph much, but have run at 65 to 70 mph. My normal vacation is 2000 miles in each direction, done in 4 days of driving, in the southern U.S. and northern Mexico in the summer. Towing a car sometimes.

[poppinjohnnies]

Sent: 4/24/2005

I was told by an experienced tire guy to stay away from bias tires simply because of the added safety of radials.  Since I haul my wife and 3 kids in my MH, he didn't have to twist my arm very hard to talk me into the radials.

[Michigan_Don]

Sent: 4/24/2005

I personally would never even THINK about having myself and my loved ones riding around on antiquiated tire technology. Bias ply tires are for numbers-matching, factory chalk mark show cars that never get driven anyplace except onto and off of the trailer!

[biggrock1]

Sent: 4/24/2005

I think I should add that bias ply tires like to follow any little crack in the road and that can frustrate anyone to no end.

[Slantsixness]

Sent: 5/11/2005

ok, here's my two cents:

My winnie ever been run with radials.

Safety? that's a choice, but to say that radial tires do not have problems and are "better technology" is only partially true.

Radials give a more comfortable ride... True.
Radials also give you a false sense of "greater stability" and "handling characteristics"

And to say that no Bias ply tires should ever be driven over 60 (not that it matters much in a winnie...) that's incorrect, totally. Bias ply tires are rated for highway speeds, up to 75mph specifically for truck (LT) tires. And they perform safely at that speed. It's the truck(the winnie) that cannot drive safely at that speed, but the same is true for radials!

Bias ply tires will follow road grooves? yes, but its not hard to control, just annoying.

Bias ply tires cann develop flat spots if stored for more than 3 months. I figure just prop the winnie up on jack stands will solve that. That worked on my old '66 Belvedere...

More flats with bias ply tires? I hear that all the time, but you know, I've never found that to be the case, moreover, I find that radials are prone to develop leaks around the bead seat, or the belts detach or slip (need I say Firestone....)?

Use whatever you like, but I think I'm going with the Bias ply's.

Because I'm cheap.

Tom 

[denisondc]

Sent: 5/11/2005

Im like you slantsixness: thrifty, though thats not the reason I use bias ply tires. I dont find my tires follow road irregularities much, but that might be a function of the roads I am on. The flat spotting is normal, always has been, and the more plies the tire has the more noticeable it would be. Its harmless and goes away in less than ten minutes of driving, at least it does on my winny, with its 7.50-17 tube-type tires, some load range D, some load range E. (4 of the 6 tires on my winny this summer I bought used via ebay, from a Travco owner who had switched to the 19.5 inch wheels with tubeless tires).
The bias ply tires on my motorcycle spent a fair amount of time at 100 mph in the late 60s. I still have the motorcycle too, with over 190k miles on it. The bias ply tires on my Jaguar spent brief periods at 120 mph. So did the radials I replaced them with. The only difference I could tell in the "ride" was the way the car cornered at high speed and in the rain. More predictable and reassuring - until the limit of adhesion was reached - after which a spin was a spin.
But having peace of mind is important too. As long as the tire has at least 10% or 15% more load capacity than you are asking it to carry, any tire is probably all right on an RV.
If I thought radials were really much better, I would buy them for my RV.

[mightybooboo]

Sent: 5/11/2005

"or the belts detach or slip (need I say Firestone....)?"

Mine came with 6 firestone steeltex tires.  I was told that after the second tread seperation that the 16.5" weren't a problem.  WRONG!!!!!!!!!
I replaced the tires asap after the second event.
I still have one as a spare.  I can see the tread is trying to come off just from aging!

Moral is: if its steeltex...BEWARE!

BooBoo

[Slantsixness]

Sent: 5/16/2005

I found the denman Bias ply tires at a 'local to me' tire dealer for just a little more money than Universal Vintage Tire, mounted and balanced and the long stems for the inside rear wheels!. Delivered tomorrow!

Denman 8.00-17.5LT  8Ply. Bias belted.
Funny thing is, I have tires on Smurfy right now that are 15 years old, Delta and Coker brand. They're still not dry rotted and look like new, I just won't trust them! Turns out the 4 "Coker" tires are the exactly the same tire as the new Denman's...
And delta is gone from the Medium truck tire business.

I got tires, and I didn't get tired of trying to find them.

And, by the way, Tire Rack is "estimating" that they'll have the Y785R's back in stock by June 6.... in case you want to spend the extra cash for radial tires, but I like being cheap. I'll take my $85 bias ply's any day over $120+ radials.

well, I will say that if I drive smurfy enough to wear out a set of 6 tires, then I'll go ahead and decide on radials again someday. Heck, by then nobody will make any 17.5's!

Tired-Tom

[Slantsixness]

Sent: 5/17/2005

Got the Denman's sitting all black and pretty in the Garage waiting for me to paint the rims and have them mounted.

$85 each I can get them mounted & Balanced for $10 each. not bad at all

Happy-Tired-Tom

[The_Handier_Man1]

Sent: 5/18/2005

Tom, 

Wilbur got his set of 6 Denman's last week.  I took him for a 40 mile run and evrything seems fine. After setting 10 or more years the old Michelins never seemed to lose their flat spots and I didn't trust them too far from home so the new tires are a big improvement. 

Les

[Rayd]

I know this is an old thread but this topic will never go away. And just like my ex the internets allows me to add or argue with disscusions that were discussed 3.5 years ago. 

All I have ever owned were radials so that is the direction I generally lean.*
As much as I love and respect the Sage we know as Denisondc, I have to disagree with installing  tires that have the highest maximum load rating.

• Rougher ride.

• More weight to balance.

•The bias ply rims are not designed to accept the high pressures you will need to air the tires up to achieve the weight rating.
I have 4 “G” rated tires for my 17.5” duals that can accept 125psi but the max I can subject the rims to is 60 psi (70 psi under the special operating clause thats listed in the owners manual). I run the duals at 55 psi because I believe the rear duals should be about 5 psi below the front tires and the fronts are at 60.

So all that means is I have some rough riding beefy tires that will never be near their weight rating.

*If I had to start all over with tires I would give the Bias-ply a try. The rims, suspension, and steering geometry on these old rigs were made for Bias and when the big switch was made to radials all those items had to be re engineered to accommodate radials.


-Ray

I think we need a poll on this subject...

[Winnebago]

Like others, I'm looking at a new set of tires (8-17.5). Tire shop recommends RT500 Double Coin (http://www.doublecointires.com/files/resources/doublecoin-trailer-rt500-specs.pdf?v=3). Or, I could go with STA Super Transport tires (bias ply) for about the same cost (http://www.stausaonline.com/tires/sta-super-transport/).

Any thoughts? Radials seem to be the better tire--but overkill in terms of max load (concerned about a stiffer riding experience, can the original rims take the higher psi of the radials?). Bias ply tires seem to be old technology. Thanks for any help!

Winnebago GVWR, front: 4910, rear 7280

[DaveVA78Chieftain]

The 17.5 rims where designed for bias ply tires.  You should not use more than 75-80lbs pressure with them

Dave

[Winnebago]

Update: I just went through the "The Chieftain 1976" original manual. For tires, it says 8-19.5. The tires on the Winnebago now say 8-17.5. I'm guessing its just a matter of clearance? Should I be looking for 8-19.5 replacements rather than 17.5? Thanks for any help!

[DaveVA78Chieftain]

D23 would be a M300 chassis that uses 8-17.5" tires/rims.
19.5 rims/tires were only used on the Dodge M500/M600 chassis which I do not believe Winnebago used.

The manual maybe referring to a a Chevy P30 chassis that could use 19.5" rims/tires.  You said you have the Dodge chassis.

Dave

[Winnebago]

Is there any easy way to confirm the chassis size? I was just using the table found in the operators manual to determine tire size (see picture).

[DaveVA78Chieftain]

Locate the Dodge or GM VIN plate then decode it

For Dodge chassis it will either be on the driver area interior wall or the driver side firewall in the front radiator access area.

For GM chassis, on driver area firewall

[Winnebago]

The first three digits of the VIN are M40. Based on information posted on the forum, that designates a M400 chassis. Any thoughts?

[Oz]

Use the Dodge VIN decoder Dave is referring to:

http://www.classicwinnebagos.com/Pages_HTML/DodgeVINdecoder.html#1974


First 2 digits = M4 = M400 chassis so you have an M400 chassis

The 3rd digit = 0 = just means it's a motor home


According to the Dodge Service Manual, section 22-9,  the M400 chassis uses 17.5 x 5.25 flanged rims
same as the M300 Dave mentioned previously.

The M500 uses the 19 x 8 double lock nut rims.  19" tires wouldn't even fit on your rims.


You need 17.5 tires.

It's best to refer to the service manual, it's more definitive and accurate than owner's manuals for the tech info.
If you don't already have it, we have the eManual in the club store:
http://www.classicwinnebagos.com/forum/index.php?action=store;sa=view;id=203

[Winnebago]

Now that I know it is a M400--will that tell me anything about the tire size?

[Oz]

Please re-read my previous post, I was editing it when you replied.


Interesting fact:  Radial tires were referred to as "thumpless" back then since it was just becoming common practice to use them instead of bias tires, which "thumped" when you first start off each drive with them.

[Winnebago]

Thank you Oz! I noticed you didn't post earlier on the bias ply vs. radial debate. Given the information above, what is your two cents worth regarding replacement tires for my bago? Thanks again--I really appreciate the information!

[Oz]

17.5 tires are getting difficult to find and aren't cheap.  Radials ride better and don't have the "thump" when they're cold until warmed up.  As long as you have 1 piece rims and not split ring rims, you can use them.


We have a lot of members with these size tires.  For a lot of good information about them and where people have been getting them, price, etc., go to the sticky topic at the top of this board "FAQs - Frequently Asked Questions" and scroll down to "Tires".  You'll see the topics & links there.