Super singles

[SHARP327]

Something to consider when thinking of putting full size tires on a pusher axle.

When trying to exit a loading dock with a well and especially one that has a sharp crest at ground
level you'll find that the lift axle with full size tires may prevent you from exiting the ramp, I've even had the axle up with the smaller tires and actually spun my drive tires getting over the crest due to the lift axles tires coming in contact with ground.

Just something to consider.

 

[usafk9]

My understanding is that there's only 2- a zero offset, and a 2" offset. I'd bet money that yours would be the zero.

Incorrect offsets, loaded heavy would more than likely cause bearing failure. Let's ask Doggie Daddy how many bearings his wife's truck has eaten.

DD?

 

[BigCat]

Got a link to any or all of these "reports"?

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Here is one link speaking of wheel bearing load shifts causing wheel end damage. Google wide base tires or super single tires axle bearing failure.

Document Display | NSCEP | US EPA

 

[Doggie Daddy]

Incorrect offsets, loaded heavy would more than likely cause bearing failure. Let's ask Doggie Daddy how many bearings his wife's truck has eaten.

DD?

The correct answer would be zero.



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[Doggie Daddy]

Here is one link speaking of wheel bearing load shifts causing wheel end damage. Google wide base tires or super single tires axle bearing failure.

]

Well I did Google super single axle bearing failure, and I did click on your link. The article you posted stated that it COULD be a problem, but I have found nothing that says that it actually IS a problem.

Another myth debunked.



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[Ragman]

Another myth debunked.

 

[layoutshooter]

Interesting read on the subject.


17. Can I convert from dual wheels to a super-single (wide-base) wheel?

Yes, but there are several considerations:


1) The required stud length may be different.

For hub-piloted applications using 22mm 2-piece flange nuts, a minimum length is required for proper thread engagement to the nut. All ConMet trailer and drive axle hubs designed for dual wheel applications can be used with wide-base wheels. This assumes a 1/2" brake drum thickness, 1.13" wheel disc thickness and a 1.19" nut height, giving a minimum required stud standout of 2.94 inches from the hub flange. A longer stud, while affecting appearance and socket fit, is also acceptable. Some available nuts include: Metform 39627 (1.06" height) and Hayes Lemmerz 90846 (1.19" height).

For stud-piloted applications on drive and trailer hubs: All ConMet trailer and drive axle hubs designed for dual wheel applications can be used with wide-base wheels. Standard ball seat cap nuts for single or outer dual applications can be used for steel wheels. The thread size is ¾"-16. For aluminum wide-base wheels, ConMet recommends Alcoa 5995R/L cap nuts, or equivalents, which have been engineered to fit wide-base wheels.


2) For super-single (wide-base) wheels on drive and trailer hubs the hub will be derated for load for wheels over 1" offset. See ConMet Technology Bulletin 1009934"Wheel End Load Ratings for Hubs Used in Single Tire Applications" for further details.

IMPORTANT: Outset wheel may decrease the load rating for other components such as axles and bearings. Manufacturers of those components should be consulted for approved load ratings. Many manufacturers of axles wheel end components recommend that the P type spindle be used in conjunction with outset wheels.back to top

Welcome To Consolidated Metco

 

[zorry]

Sounds like no problem with Zero offset.
Within a month of converting my last COE to super singles I pulled a 96,000# load from Miami to Cleveland.
I put acouple hundred thousand miles without a bearing failure.
I DID tighten the bearings at some point as routine maint. I found that most mechs do not now how to check wheel bearings.
I challanged a good mechanic. He checked the bearings and said they were good.
I showed him my way and he said **** !
There was just a little free play and we adjusted them.

 

[roadeyes]

More info on page 36 here:

Today's Trucking: The truck news website and magazine publishing information on trucking regulations, trucking industry, fleet management, owner/operators and the latest in trucking products, truck statistics and trucking services.

As has been mentioned, it appears bearing issues are more likely with conversions due to improper installation.

I think I would consider specing a new truck with Factory super singles but I do not think I would take the risk of converting.

As well,that just had me thinking that it might be something to look out for if purchasing a used truck with super singles.

Are they factory or converted?

 

[Refer Hauler]

I've ran these on a previous tractor, I have seen some uneven outside edge wear and was told by KW that it was most likely axle flex. Tractor came from factory with the wide base Michelin tires, did this in an effort to decrease weight, saw minimal fuel milage increase. On a lightly loaded TT or straight truck they are a good investment. But running in the 78 to 80K range most of the time they were not for me. Biggest problem that I had is ruining the rim before you can get stoppped after a blowout, Average road service bill $1250.00 ($900 tire and $350 rim). Availability was never an issue. Present tractor has standard dual set up and a pre-emission engine, between EGR,DPF and $1250 tire/rim repair bills I was going broke at high speed so I traded down. present down time is <10% of the previous truck

 

[zorry]

How can someone buy one tractor with Super Singles and say there is no fuel gain ? Compared to what ?
My first SSs were from the factory. Ran heavy with no problems . Air pressure fanatic. No blowouts or uneven wear.
Next set were a conversion. Done properly. Ran overweight loads (permited) occaisionally. Same great results.
When you see tankers dropping fuel look at their tires. They should be at gross almost every load.
I see nothing to fear.

 

[usafk9]

I say your KW dealer just got a promotion from the Yugo dealer. If there's 'axle flex with wide singles, then there is with duals, as well. Did he feel comfortable telling you his product was a POS?

Outer edge wear is either an inflation or alignment issue.

FWIW, our fuel mileage gains are both when the lift axle is deployed or not. We lose almost 1 MPG when down, bug's better than when we had duals on the drives.

Lastly, I'm curious what tires are on your drives now?

 

[BobWolf]

Sounds like no problem with Zero offset.
Within a month of converting my last COE to super singles I pulled a 96,000# load from Miami to Cleveland.
I put acouple hundred thousand miles without a bearing failure.
I DID tighten the bearings at some point as routine maint. I found that most mechs do not now how to check wheel bearings.
I challanged a good mechanic. He checked the bearings and said they were good.
I showed him my way and he said **** !
There was just a little free play and we adjusted them.

How do you check and adjust drive axle bearings? is it the same as steers or different.
I think a how to would make a good post.

 

[zorry]

Bob,sent pm. Running hard,too tired to retype now.