The Super Tire?

[Just Plain Jeff]

About 18 months ago, Prevost Car announced that, as an option, new coaches would be fitted with a single "Super Tire' on the drive axle. This is a Michelin tire which is speed and load rated for a seated coach and motorhome application.

The response to this announcement was less-than stunning. Many over the road tractors and dump trucks have used these tires for millions of miles.

Any thoughts from this group on the benefits/downsides to the Super Tire?

Thanks much in advance.

[dreadnought]

I was tooling down I-20 in Ga. last Thursday, passed a truck & the driver called me on CB. "Hey Stagecoach, you got a tire about to blow." Pulled off on the next ramp & sure enough the side wall was peeling away on a Michelin with 50,000 miles on the tag axle. Limped to the next truck stop and lo & behold there's a mobile service truck changing a tire for a trucker. My lucky day me thinks. Ambled over & told him I needed a 365-70R-22.5 when
he was caught up. He looked at me like I was from Mars & said he'd never heard of that size. It was 5 PM so I spent the night, got up @ 5 AM & limped to Augusta @ 45 MPH w/the flashers on. At the Michelin dealer when he opened his doors. Yeah, he'd heard of the size but never been able to get it! Michelin's distribution center is 125 miles away from this dealer in Greenville SC. I told him I'd rent a pickup truck & run get 2 of them,
figuring to replace both on the tag axle. "Don't work that way. You place an order, they fill it in 2 weeks or so." I bought a used 315 for $150 & came home. Called my tire guy, BIG dealer, yeah that's a weird size, let me make some calls. 2 days later & haven't heard a word. Prevost put 365's on my steer & tag axles & 315's on the drive. 315's are rated for 8200#, 365's will carry 10,500#. I use my bus for business, 8,200 miles last month, & can't afford to sit on the side of the road for 2 days waiting for a tire. I noticed a lot of tour coaches run 315's all around
& I'll bet availability is the reason why. I see more super singles on the road these days but I bet you 90% of truck stops don't have them.

[Jon Wehrenberg]

Getting 12.00 was hard enough. Getting 315 is a little harder. Over the years however I coped in the following way.

If I had a tire fail while on the road and the size on the coach was not available I got the closest size to it that I could and put it on the tag. There is no downside to having an oddball tire on the tag except with the ABS, but if the rolling diameter is as close as possible to the originals you are OK.

In Bill's case which the newer coaches have two sizes I think Prevost did that because of the ever increasing loads on the front axle. The 315 rating for a single is 9000 pounds and that means the tire in some cases is at or in excees of its limits. By beefing up the front end plus going to the larger tire they cured that problem, but they put owners in the difficult position in that every single tire on the coach is hard to buy, and worse, you can't juggle them around in an emergency.

[jack14r]

I understand that Prevost put the 365 on the front and the tag so that in a situation where you could not find a front tire you could use a tag one for the steer.I was not aware that I could use a 315 on that wheel.the knowledge here is overwhelming.Prevost was forced by some converters to come up with a solution to their overweight situation on the front axle of some coaches and this is why the 365 exist,I understand that it is only a motor coach tire.I have read that some front axles on H models have exceeded 20,000 pounds,can anyone document this?

[Jon Wehrenberg]

While substituting for the tag is a viable solution the critical part is that you need to know your tag axle weights so the tire you end up with is adequate, and the rolling diameter is important because if the rotation speeds of your tires vary the ABS sees that as one of the tires locking up and your stopping performance may be impacted adversely.

There really is no perfect emergency solution, so the absolute best answer is to monitor tire pressures dilligently, and change out questionable tires when at home and not hope they last for your trip.

BTW, the tag axle will chew up a questionable tire rapidly. With the sizes Bill has he is really screwed to the extent that the best place to put tires with uneven wear patterns was on the drive axle, an option not available to him with the 365 tires adding further to his tire costs.

Jack, in fairness to Prevost they don't ship buses that exceed axle weight limits. It is the responsibility of the converters to balance and distribute the weights so the limits are not exceeded. Some converters are very good at doing this. Some, not so good. The buyer of a coach needs to be aware of this but I'll bet no buyer checks axle weights before taking the coach. But the coach owner has a responsibility as well. I know of several owners who have carried some very heavy motorcycles in the front bay of an H3 that was likely at or in excess of the limits before the bay was set up to haul the bike.

[lewpopp]

Jeff, you must be out of the loop. No body wants to answer you on the Super Tire. I would like to know a bit about it. I saw them on a customized tractor. Neat looking. I'm sure you would have to dedicate a compartment to carry 2 of them is you installed a pair.

[jack14r]

Jon,I was saying that the converters created an overweight problem,but they required Prevost to solve it with a larger tire.Apparently some converters are still having problems with axle weights and gross weight.I have weighed my Liberty and it weighed 51,880 with a gross weight rating of 54,500 and each axle weight was under.With double slides it only weighs 2,000+ pounds more than jdub's 01 Marathon,I am impressed with Liberty's control of weight and balance.Last year I was at Marathon in Florida and Jeff Gordon"s coach driver told me that the H he was driving weighed 58,000,I was also at Prevost Nashville and was told that their lift would not lift Bill Elliott's coach because it weighed 56,000 lbs.With all the lighter high tech materials being used today I would hope that all the converters have their coaches in weight and balance.

[dreadnought]

Jack, the 315 is real borderline on the 10" 365 wheel. It took 2 cheater tanks and a "full flow" valve on the air line to get the beads to seat. Everyone with this tire setup should be aware of this. If you're stuck on the side of the road with a blowout be sure to tell whoever you call what to bring. Mobile tire trucks don't normally carry all this stuff. You should also be prepared to operate 1 of the "big bang tanks" since they don't send out 2 guys either.

[Jon Wehrenberg]

Michelin lists only the 8.25 and 9.00 wheels for the 315. In an emergency you have to do what is necessary. I can tell you for sure that if you have concerns about seating the bead spend about $35 at Gemplers and buy one of the "O" rings for seating the bead. I have one and it works unbelieveably well.

http://www.gemplers.com/tiressupplies/beadseatingtools/beadseaters/IN225.html

Lew, this discussion goes to the heart of JPJ's original question. If we had the wide singles we would bde more screwed than we are now when we have a tire problem on the road. Now we can get a tire close to what we have to keep us rolling, but with the wide rims required for the singles nothing will fit in the common sizes.

Jack, For as long as I have had coaches the front axles have been overloaded, if not by the converter, then by the owner. The coaches are at or very close to the national axle weight limitations. Some of the coaches will be unable to use certain roads such as the Ohio Turnpike where they have in-ground sensors for weight. Unlike trucks whose front axle weights haven't changed in decades our buses are getting more weight due to slides, materials and features and the end result is what we are now seeing. Liberty stands out as a converter in that they have always taken great pains to limit, distribute and balance the coach weight, something I find remarkable because in my coach for example I have OTR, and auxiliary fuel both of which contribute to the weight.

[Joe Cannarozzi]

A commercial vehicle with the same axle configuration as our buses that has to cross state scales is limited to 54000, 20000 on the steer 34000 on the drives. You can get a little grace on the drives but NEVER on that steer limit. I do not know for sure but if I had to guess I would think that this applies to All vehicles.

If I had a bus that was approaching 20000 on the steer I would definitely want the super singles. If so I would also put them on the tag as well thus keeping the different tire types on the bus to 2. These things are like a dirty little secret that the tire guys do not want you to know about. They are STRONG tires especially the sidewall.

I have them on my dump trlr and when I dump only the back axle remains on the ground. That puts 24 ton of stone plus a portion of the weight of the trailer on the rear axle and those 2 tires. When spreading a load the gate remains latched until the lift cylinder gets up into its last stage making the load shift back to the gate before popping it and then proceeding. When the gate is popped at this point the trlr gives a jerk putting only God knows how much weight and stress on those tires. This process is repeated literally thousands of times during the life of those tires. I have never blown a super single.

What in the heck could you possibly HAVE to have in a camper that would force you over these limits? The more prevalent this issue becomes the better I like ours, 49000 including a 1/2 ton PU in tow. Going down the road with 60000+ of camper and trlr just seems too much like work to me.

What are the cost of these new singles for buses. I run 385's and because most cement trucks run this same size availability is good and I pay a little under 400.

For concerns about availability on the road. This is how I look at it. 99% of tire trouble is from under inflation, previous damage that has occurred in some fashion, they are more than 5 years old or you simply run over something, not paying attention, that is large enough to blow it. Check pressure keep them up to date and keep your eyes pealed.

Thumbs up for the super single but not on the drive axle. In slippery conditions traction will be greatly reduced if used there.

[Jon Wehrenberg]

As the front tires gets wider there are steering geometry problems so I don't think anybody can just go to a wider wheel and mount them.

The answer to the weight on the front axle is simple in concept. Cluster the greatest amount of the coach weight as close to and aft of the rear axles as possbile. It makes no sense to put batteries, the generator or holding tanks any more forward than the bay directly ahead of the drive axle. As soon as that is done the front axle weight approaches the limits. Add in the stuff we normally carry and we are at or beyond the limits.

[garyde]

My 2003 Liberty came with 365's on the front. As I understand it, this was an option as some modification needed to be done.

[jack14r]

Jon,You are right about the effort Liberty has made to insure that their coaches are not overweight on any axle.I was floored when I weighed my 05 with OTR and 2 slides and all my stuff and it was almost 3000 pounds under gross and none of the axles were close to their weight limit,I am still impressed with their engineering.