I've heard one of the biggest things to help fuel mileage is to lower how much 'rolling resistance' you have on the truck/trailer. Do super singles actually help with that?
I used to drive for a company that runs super singles.They swore they increased mpg.I found two problems with them.1) If you have tandems on your drives,like so many trucks do,they create a rut in the asphalt which leaves a ridge in the middle.A super single runs on top of the ridge making it hard to control at times.It keeps wanting to drop off the ridge into the rut.2) If you by chance blow one out,you are stuck.Can't limp in to a truck stop for repair.One upside to them is the company was getting about 80,000-90,000 miles out of a set of them.Some trucks even went to 100,000 miles.They aren't cheap either. They don't work on split tandem trailers either.
I used to drive for CFI (now Conway Truckload), who equip all their tractors and most of their trailers with Michelin super singles. The ride quality is great, they lower the net weight of your truck by approximately 100 pounds per position (replacing two tires with steel rims with one super single with the aluminum rim) and they last a long time. The truck I was driving had 292,000 miles when I left with two of the original tires still in service.
Now I lease a rig from Hill Bros and the very first change I made when I ordered it was to exchange my duals for singles. As of today my truck has 282,500 miles on it and I'm nearing the end of useful life of my first set. The driver posting before about 80-90-100,000 miles from a set was way off base there (perhaps he was talking about some sort of specialized trucking like logging?).
A few weeks ago I ran across an article in one of the digest-sized magazines the truckstops give away where Michelin tested a set of its super singles against the best from Goodyear and some other manufacturer and beat them by 7% in fuel economy. I expect they have posted the results online if you care to google for them.
I have posted all of my settlement numbers for the past two years on my blog in spreadsheet form (linked below). In my first year I purchased approximately $59,000 in fuel at the pump and received approximately $42,000 in FSC, resulting in a fuel bill of $17,000 for the year. This was enough fuel to run my truck for 133,303 dispatched miles (approximately 145,000 including OOR). My second year numbers were $47,600 (pump price), $32,000 (FSC), $15,600 (adjusted fuel bill) for 122,900 paid miles.
You can view all my numbers, weekly, quarterly and yearly via the spreadsheet.
I would also point out that since I mostly haul refrigerated freight, most of the loads are heavy. I estimate 75% of my loads are 40,000 pounds or more and I drive a truck with a modest engine (2007 Volvo 780 with the 2006 Volvo D12 and a 13-speed).
In a month or so I'm going to have my truck in the shop for its 300,000 mile maintenance and to have a new set of Michelin super singles installed. I wouldn't want to drive without them.
They don't work on split tandem trailers either.
1) Why is this? Too much scrubbing of tire rubber if front tandem airbag can't be dumped.
2) Why do some companies use them on spread axle trailers? Don't care, deep pockets.
I HATE them. It's not my truck, so not my choice, but having again blown a tire, sitting on the side of the road waiting, because you can't go anywhere I have had enough.
They suck in rain, bobtailing in the rain is like riding a bronc, no matter how much I slow down, you slip and slide everywhere, no better in the snow.
Big whoop, you save a few percent on fuel mileage. I know it makes a difference if you own 1000 trucks, but for just one, who cares.
If I ever have a truck of my own again, I would not have them, I really hate them.
I hear these stories about traction problems all the time and, quite frankly, I haven't seen it. I stayed behind to keep an eye on things after Jim there left CFI, so I've been rolling on super singles for around half a million miles. Rain and snow are not a problem for me and never have been.
A few years back I had a blowout and I sat on the road for hours as I waited for someone to bring me a new tire from several hundred miles away. That's probably the biggest knock that I would have with regard to the single tires. This situation has improved significantly though, as even T/A and Petro keep super singles in stock now.
TL;DR - Yes, they most definitely help fuel mileage. Traction issues are overrated. Blowouts are a problem when they happen, but they don't happen much.
I have driven 8 years on duals and 2 on super singles. I don't believe I am "overrating" the traction issues. I started to jackknife a year ago in Wyoming, doing 15 mph in the slow lane, going after a truck in the ditch, while I was being passed at about 30 or so miles an hour.
I am scared of getting in a wreck because of losing traction. I have hydroplaned empty, bobtailing and loaded light more often than I can count. Slipping and sliding with the least bit of snow on the ground. And that is with new tires, don't get me started on how bad it was before I got a new set.
As for the fuel mileage savings. My 65mph truck gets a whopping 5.8 or 5.9 mpg. With a Detroit 60 series motor.
My last truck had the new DD15 and I got a whole mile to the gallon more.
Anyhow, I consider myself a fairly experienced driver, and I stand by my evaluation of the super singles. They suck.
