Stumbled across some FE-related links...
 

I was watching How It's Made and they did a segment on remolded tires. I had never heard of remolded* tires (not recapped tires, that's different), but it reminded me to google for regroovable tires, a designation I've often seen, mainly on the side of school bus tires.

While reading an article on regrooving, I saw links to some other interesting tire questions. The links led to a Q&A column written by a commercial tire expert who represents Goodyear. I was interested, so I kept reading.

I read a couple responses to questions about sidewall irregularities -- when you see the one straight bubble-like thing going from rim to tread, that one is okay, it's just a joint that wasn't manufactured smoothly. I read lots of responses about tire age; the expert representing Goodyear repeatedly says that they're fine as long as there are no visible cords/belts and no cracks deeper than 2/32 of an inch.

I stumbled across this:
I wondered what an SAE fuel economy test is. So, back to google. The answer, or at least as much of it as the SAE is willing to give away for free, is here. Later, I found the SAE summary of another test, due to another response.

I found one company's description of how they do the tests. They also had some other interesting links.

I found this blog entry from Consumer Reports about how they test for FE. One thing they wrote that caught my eye:
I'd like to know more about that.

I also found lots of links about a snake oil product that claims to have produced FE results with SAE testing. It looks fishy to me. The same site had an article about Ford using nanotech materials to help improve FE.

*Remolded tires: They grind off any remaining tread and grind the sidewall smooth, patch any holes, add new rubber, mold the new tread and sidewall, and vulcanize the whole thing. This differs from recapped or retreaded tires, which have the old tread removed and then new tread glued on, depending on who you ask -- the Tire Retread & Repair Information Bureau says that they are vulcanized and the only difference is if the sidewall gets new rubber or not.

That same industry association strongly advocates never running underinflated.

Edit: I keep finding more in that tire column...shouldn't I be doing something more useful with my time?
Yes, it's okay to use tubes in tubeless tires

On my 74 Chevy p/u when I put new tires on it, one wheel had a tube in it. I figured it was an easy way to fix a leaking tire, so I opted to not put a tube back in that wheel. That was a mistake. That tire went flat every 7-10 days. I ended up going back to the tire dealer and had them put a tube back in that wheel. There must have been something wrong with that wheel. Anyway I never had any further problems with that tire.

-Jay

I had a couple tires on a 1997 F350 dually 12' stake body dump (which, BTW, is for sale) that wouldn't hold air so we put tubes in them. Later, when we replaced them, we found that there seemed to have been abrasion between the tube and tire, leaving marks as if they had rubbed off some of the tire's rubber. I'm not sure how to reconcile that experience with the advice in that column, except that those tires were pretty badly beat up regardless of tube usage.

Now remoulded tires sound okay, provided the carcass hasn't seen excessive wear and fatigue, the belts could be splitting up if someone ran it round half flat all the time for instance. The other problem with them would be you'd get 4 tires with the same tread, but possibly different internal construction, more or less belts, plies in different directions etc, meaning they might behave different... so if you could get your own tires remoulded that you knew you'd treated right, it might be a good thing, but otherwise, it's something you'd only wanna do to a car you deliver pizzas in round the city all the time or something, not one you take on long trips.

Yeah, I think remoulded tires, like recaps/retreads and such, are mainly used on big commercial trucks and most popular in big fleets where you can have your own tires redone and returned to you. I have bought anonymous LT-series recaps for the dumptruck that preceded the one I mention above, though.