large single tires instead of duals

uncle ned · June 19, 2006, 08:18:41 AM

Just saw a bunch of new trucks leaving the freightliner plant in cleveland nc. Most all of them had single tires on the rear.Sure did look funny but must be a reason for this.

Uncle ned
"huggy bear"
4104

WEC4104 · June 19, 2006, 09:12:46 AM

The upside includes

- Reduced weight, both in tires and wheels. Since it is spinning weight it is even more important than static weight.

- Reduced rolling resistance, primarily because there are fewer side walls flexing.

- Elimination of problems with dual tire pairs potentially having mis-matched diameters or tire pressures.

Downside includes

- With a flat you have no limp home mode. (Although some designs are "run-flat" types)

- With regular tires up front, and the "super singles" on the rear, what do you carry for a spare?

- Not all tire shops stock these or have the equipment to service them.

Super singles on semis has caught on more in Europe than here in the states.

Busted Knuckle · June 19, 2006, 09:31:12 AM

Yes they've been around in europe for a while, and also here in the US (fuel tankers have been running them for years!) and they are becoming pretty popular here now days! All the major cross-country companies are specing their new trucks with them! BK

TomC · June 19, 2006, 02:05:20 PM

Here's the skinny on the fatty tires. Michelin did the creating of the X-0ne's. While tankers, concrete mixers and others have been using super singles for years, these tires (385/65R22.5, 425/65R-22.5, 445/65R-22.5) are the standard super singles that are aimed at construction and local use. They are not for cross country use (65mph max). The Michelin X-0ne (445/50R-22.5) is a 75 mph tire and is a direct size replacement for the 275/80R-22.5 or 295/75R-22.5. Also is the 455/55R-22.5 which is a direct replacement for the 11R-22.5. If you can't find a replacement single it is approved to run duals-even with three singles still on the truck. As stated, they will save 300lb over 8 drive tires, get 3-5% better fuel mileage-because of less rolling resistance, and it has been proven in fleets that their blow out/flat rate goes down to 20% of duallies!
The only buses that can run these tires are the GMC 4501, Crown and Gillig 40ft'r with tandem axles. THEY ARE NOT YET RATED FOR SINGLE AXLE USAGE-TANDEM ONLY! They do use them on single axle tanker trailers, but are not approved for single axle use on a truck or bus. Good Luck, TomC

Busted Knuckle · June 19, 2006, 03:39:48 PM

Tom thanks for the "Skinny on Fatty tires!" I'm waiting on the day I can get 'm for my Setra! BK

Kristinsgrandpa · June 19, 2006, 05:56:09 PM

About 25 or 30 years ago on the 6 o'clock news in Huntington WV. WSAZ chan 3, it showed a concrete truck that was sitting at a traffic signal and had a blow out on a super single causing the truck to capsize (the concrete drum was rotating) and crush the car sitting at a parking meter beside it.

It also crushed the man that was sittiing in the car.

They should be outlawed for use on concrete trucks.

Ed

TomC · June 21, 2006, 09:08:41 AM

25 to 30 years is a long time to have improvements done on any tire. Super singles are much more reliable than duallies (has been proven in fleet use).Concrete mixers and tankers use them to get more carrrying capacity. Long haul the same, but also better fuel mileage. Good Luck, TomC

Kristinsgrandpa · June 21, 2006, 11:47:48 AM

Does that mean that they wont blow out now?

Ed

Busted Knuckle · June 21, 2006, 12:39:59 PM

Quote from: Kristinsgrandpa on June 21, 2006, 11:47:48 AM
Does that mean that they wont blow out now?
Ed

No not necessarily, but it means improvments have been made! Also how about some particulars on the "bad incident" you saw 25 to 30 yrs ago? Was the tire in bad shape? Did the concrete truck come to a sudden stop? Was the concrete truck actually stopped or try'n to get stopped? Was the truck actually cornering when it rolled? Was the drum overloaded, or out of balance and spinnig to fast for conditions? Was the truck properly maintianed on a regular basis? You see I've been around tow trucks all my life and not always but usually there are more than 1 variable causing accidents and yes sometimes "just plain ol' freak accidents" happen! BK

Burgermeister · June 21, 2006, 02:00:06 PM

Tom,

Can you explain, for those who don't know, what you meant by:

[The only buses that can run these tires are the GMC 4501, Crown and Gillig 40ft'r with tandem axles.] THEY ARE NOT YET RATED FOR SINGLE AXLE USAGE-TANDEM ONLY! They do use them on single axle tanker trailers, but are not approved for single axle use on a truck or bus.

I read you to mean these tires can only be used on those busses with dual drive axles in the rear, not two axle or tag axle equipped busses
C'est Ca? Monseuir?

phil4501 · June 21, 2006, 05:35:39 PM

Quote from: Burgermeister on June 21, 2006, 02:00:06 PM
Tom,

Can you explain, for those who don't know, what you meant by:

[The only buses that can run these tires are the GMC 4501, Crown and Gillig 40ft'r with tandem axles.] THEY ARE NOT YET RATED FOR SINGLE AXLE USAGE-TANDEM ONLY! They do use them on single axle tanker trailers, but are not approved for single axle use on a truck or bus.

I read you to mean these tires can only be used on those busses with dual drive axles in the rear, not two axle or tag axle equipped busses
C'est Ca? Monseuir?

All those buses do not have dual drive axles, I believe they are all tags. I know the 4501 is for sure, I can't swear to the schoolies though.

Does anyone on the board have experience with these tires on a bus?

DrivingMissLazy · June 21, 2006, 06:04:26 PM

They are all dual axle dualies, are they not?
Richard

Quote from: phil4501 on June 21, 2006, 05:35:39 PM
Quote from: Burgermeister on June 21, 2006, 02:00:06 PM
Tom,

Can you explain, for those who don't know, what you meant by:

[The only buses that can run these tires are the GMC 4501, Crown and Gillig 40ft'r with tandem axles.] THEY ARE NOT YET RATED FOR SINGLE AXLE USAGE-TANDEM ONLY! They do use them on single axle tanker trailers, but are not approved for single axle use on a truck or bus.

I read you to mean these tires can only be used on those busses with dual drive axles in the rear, not two axle or tag axle equipped busses
C'est Ca? Monseuir?
All those buses do not have dual drive axles, I believe they are all tags. I know the 4501 is for sure, I can't swear to the schoolies though.

Does anyone on the board have experience with these tires on a bus?

phil4501 · June 21, 2006, 06:14:25 PM

Quote from: DrivingMissLazy on June 21, 2006, 06:04:26 PM
They are all dual axle dualies, are they not?
Richard.

They are.

TomC · June 21, 2006, 10:15:13 PM

What is important is that the 4 X-0nes are replacing the eight tires, whether or not they are 4x4 or 4x2, is not important. It is the load carrying capability that is. I have a call into Michelin asking about running the X-one on a typical drive and single tire tag situation. My guess is no, but I'll relay the exact answer when I get it. Good Luck, TomC

tucsontattoo · June 21, 2006, 10:53:17 PM

Don't belive they are dual axel dualies, the drive axel is a dualie but the tag is singels, isn't it?

Tucson