Real skinny tires...

[7milesout]

If I were to do any kind of resistance test, it would be similar to a soap box derby race. Find a hill that levels off, and see which set (installed) coasted the furthest. Both sets of tires would have to be new. This is not something that any of us would do as it would be expensive to have multiple new sets tires available.

I'm in 100% agreement with skinny tires being better for winter traction.

All else being the same except the width, the skinnier tires should win. But someone brought up the fact of load carrying capacity ... and stability. This alone would be a deal breaker, as those skinner tires I mentioned were down 224 pounds per tire. Nearly 900 total pounds. That is quite substantial. I don't think I'd do that even if they were cheap.

[Top_Fuel]

If the goal is low rolling resistance and fuel mileage, then I would find a tire classified as Low Rolling Resistance and not just consider the physical size of the tire.

My own tires are a good example. They were 185-55-15 LRR tires (I'm now running 185-60-15 of the same model tire) but the contact patch of these tires is virtually identical to that of a 165-65-114 Enasave...



I'm guessing that a reduced contact patch is one of the ways they reduce the rolling resistance of a tire (need Basic to confirm that one).

I have changed my opinion on Mirage tires slightly. I do a lot of freeway driving and would advise a 5-speed owner to consider the tallest tires that will fit on the car. 185-60-15s fit with no problem. Metro has 185-65-15 on his car. They are tight up front but they fit and don't rub.

When you have tires this tall, your freeway RPMS will drop by about 200 (or slightly more in Metro's case). My car now behaves like it is a 5.5 speed. I find myself staying in 4th gear a lot longer around town. And I can cruise at 65mph at 3,000 RPMs.

[Fummins]

I have changed my opinion on Mirage tires slightly. I do a lot of freeway driving and would advise a 5-speed owner to consider the tallest tires that will fit on the car. 185-60-15s fit with no problem. Metro has 185-65-15 on his car. They are tight up front but they fit and don't rub.

When you have tires this tall, your freeway RPMS will drop by about 200 (or slightly more in Metro's case). My car now behaves like it is a 5.5 speed. I find myself staying in 4th gear a lot longer around town. And I can cruise at 65mph at 3,000 RPMs.

I had considerably taller 38" tires on my fummins and got pretty similar fuel economy on the highway as what I get in my current stock tired dually. Both truck have the same transmissions and 3.73 gears. The ferd felt like it cruised better at 75mph where my dodge fuel economy starts to dive over 60mph.

There's gotta be a fine line where taller tires start requiring more power/higher load to keep them rolling though.

[Top_Fuel]

There's gotta be a fine line where taller tires start requiring more power/higher load to keep them rolling though.

I agree. I don't want somebody to read my comment an go out and buy some low quality taller tires on heavy wheels and then get pissed when they lose fuel economy. My taller tires are name brand low rolling resistance tires on lightweight wheels. My wheels/tires weigh the same (or possibly less) than the optional 15" wheels that currently come on a new Mirage.

I haven't lost any fuel economy with this setup...but I can't say that I gained any either. I got new tires at the same time the Covid craziness hit...so my driving habits have changed completely. Now I do more city driving than freeway. I do like the way the car feels with the slightly different gearing.

[Basic]

If the goal is low rolling resistance and fuel mileage, then I would find a tire classified as Low Rolling Resistance and not just consider the physical size of the tire.

My own tires are a good example. They were 185-55-15 LRR tires (I'm now running 185-60-15 of the same model tire) but the contact patch of these tires is virtually identical to that of a 165-65-114 Enasave...



I'm guessing that a reduced contact patch is one of the ways they reduce the rolling resistance of a tire (need Basic to confirm that one).

It "can", but it doesn't necessarily pay off the way you think it would. Best example I can give in the contrary is a Super Single Drive tire on a Semi vs Duals. The SSD has a considerably larger contact patch and yet has considerably reduced rolling resistance.

[Fummins]

Who'd a thunk that?

I stole the following big words from here

Reduced cost per mile driven – Super Single tires offer a lower rolling resistance (the energy required to overcome the force resisting tire motion). This is achieved due to the lower overall weight of the tires on the axle, and the number of rotating components per axle is reduced by half. Also, Super Single tires can be retreaded which extends their service life significantly. It is not uncommon for drivers to report a set of Super Singles lasting for 400,000 miles or longer. This translates into greater cost savings over time for the commercial trucking company.

Greater fuel efficiency – Tire manufacturers claim the Super Single offers a fuel efficiency increase of nearly 7%. This is achieved due to the lower rolling resistance of the tires and the lower weight of the components per axle. A 7% increase in fuel efficiency can save over 1000 gallons of diesel fuel annually per truck (assuming the average driver completes 125,000 miles per year at an average of 7mpg). This claim is supported by a study conducted by the Department of Energy. This study demonstrates that fleets implementing fuel saving technology, including Super Single tires, can expect a fuel consumption reduction of 6-10%.

Lower weight per axle – Implementing Super Single tires will result in a total weight savings of 700 to 1300 pounds, while maintaining the equivalent load carrying capacity of the dual wheel setup. This enables a driver to carry more overall cargo per load. Combined with the potential fuel savings the industry makes a strong case for the Super Single tires.

[7milesout]

and yet has considerably reduced rolling resistance.

And less traction. Says real truckers on trucker forums. They agree the SSs get better mpg. But have cited instances of getting stuck on dirt and snow where duals didn't get stuck. They've even made videos demonstrating getting stuck / unstuck. Still, if a truck is going to stay on-road, SSs are the way to go for mpg.

Personally, I wouldn't run them though. My thinking is that when it comes to blowing a tire, I understand SSs are extremely durable and even blowing one is not likely to lead to loss of control. However, if I were the owner of a truck or trucks, the absolute highest goal I would try to achieve, is to not have a truck stranded on the side of the road. Duals will always allow a better chance to AT LEAST make it to a repair center, or off the interstate to civilization.

Those road side strandings are an extremely expensive endeavor for a semi with a load. And combine that with late load penalties ... I'll take duals.

[Mark]

Who'd a thunk that?

I stole the following big words from here

Reduced cost per mile driven – Super Single tires offer a lower rolling resistance (the energy required to overcome the force resisting tire motion). This is achieved due to the lower overall weight of the tires on the axle, and the number of rotating components per axle is reduced by half. Also, Super Single tires can be retreaded which extends their service life significantly. It is not uncommon for drivers to report a set of Super Singles lasting for 400,000 miles or longer. This translates into greater cost savings over time for the commercial trucking company.

Greater fuel efficiency – Tire manufacturers claim the Super Single offers a fuel efficiency increase of nearly 7%. This is achieved due to the lower rolling resistance of the tires and the lower weight of the components per axle. A 7% increase in fuel efficiency can save over 1000 gallons of diesel fuel annually per truck (assuming the average driver completes 125,000 miles per year at an average of 7mpg). This claim is supported by a study conducted by the Department of Energy. This study demonstrates that fleets implementing fuel saving technology, including Super Single tires, can expect a fuel consumption reduction of 6-10%.

Lower weight per axle – Implementing Super Single tires will result in a total weight savings of 700 to 1300 pounds, while maintaining the equivalent load carrying capacity of the dual wheel setup. This enables a driver to carry more overall cargo per load. Combined with the potential fuel savings the industry makes a strong case for the Super Single tires.

See there you go! Adding dual tires to one's Mirage may be a bad move!

I just happened to notice more single tires on semi trailers just recently. Now I know why.

If they reduce "road gators" on the road, I am all for them. Imagine being next to one those tires coming apart while in a Mirage. It would be scary in any vehicle. I realize most of those road gators are from retreaded tires.

From a trucker's perspective - everything about the super single tire seems like a win/win.

[Mark]

And less traction. Says real truckers on trucker forums. They agree the SSs get better mpg. But have cited instances of getting stuck on dirt and snow where dual didn't get stuck. They've even made videos demonstrated. Still, if a truck is going to stay on-road, SSs are the way to go for mpg. Personally, I wouldn't run them though...

I've seen them more on the trailer itself versus the drive axle of the tractor, but I get your/their point. It comes down two skinnier tires will have more traction than one super wide tire.

[Basic]

And less traction. Says real truckers on trucker forums. They agree the SSs get better mpg. But have cited instances of getting stuck on dirt and snow where duals didn't get stuck. They've even made videos demonstrating getting stuck / unstuck. Still, if a truck is going to stay on-road, SSs are the way to go for mpg.

Personally, I wouldn't run them though. My thinking is that when it comes to blowing a tire, I understand SSs are extremely durable and even blowing one is not likely to lead to loss of control. However, if I were the owner of a truck or trucks, the absolute highest goal I would try to achieve, is to not have a truck stranded on the side of the road. Duals will always allow a better chance to AT LEAST make it to a repair center, or off the interstate to civilization.

Those road side strandings are an extremely expensive endeavor for a semi with a load. And combine that with late load penalties ... I'll take duals.

Everything you stated is correct. Especially the downtime part. To the point that really the only fleets that are still committed to SSD are doing so because it allows them to carry those extra couple thousand pounds of payload (i.e. Fuel Haulers, Steel, etc.) and even then many will simply take the hit and run duals because with the shortage of trucks and drivers, downtime is even more of a concern than ever.