The great tire search of 2008

[kitcar]

That and Firefox is turning into a POS. I get almost done with this post and Firefox decides to update and freeze. Twice. Sweet. I even had a nice update about my last experiment which has gotten my truck, Stinkerbutt, up to a repeatable 25.6 mpg going to and back from the shack (252.6 miles). The next goal is 30 mpg, the hardest of all to get to. I'm going to use a combination of the new tires and further aero modifications to the body.

For the THIRD attempt at posting, the tires on my truck are worn out and I'm using my handy federal rebate check for new ones (free money, free tires, how can I go wrong?). The current tires the Kelly brand and I am replacing them with Hankook RH03 tires that have an "above" average rolling resistance rating under the SAE J1269 tests, according to Consumer Reports (be prepared to dig for the results: Search for "rolling resistance", then "Blog: roll out the rolling resistance" THEN the link at the bottom of the blog entry, NOT the top one.). CR buys the J1269 results from (according to their blog) NERL (National Energy Research Laboratory). I've been doing the research since February and even called UMTRI (University of Michigan Transportation Research Institute) for some pointers. Now, the current worn out tires are very wide, over 9 inches of tread patch. The new tires have a tread patch of around 6.75 inches (same edge tread design - I'm told ribbed edges are the best for mileage by UMTRI)

My first attempt at ordering the RH03s met a dead end. I was also looking at the more expensive Michelin Cross Terrains and the Bridgestone D684, both with "above" average rolling resistance. Locally, the price is over $150 and no body can get them. Online at tirerack.com, the price is $81 + $20 shipping and they called me the next day to tell me that they can't even get a backorder on them; apparently, a manufacturer has bought the entire run from Hankook for a hybrid SUV. Four pages deep into Google, I found saveontires.com who actually, physically have them at $62 each, FREE shipping. I'll have them in hand next week.

Yeah, I know, 2% tops. 25.6 mpg + 2% = 26.1

[opelgt73]

Hey I noticed that you have three 0 MPG readings in your gas log that are taking your average down. You should delete those.

[kitcar]

"Warning: mysql_result() [function.mysql-result]: Unable to jump to row 0 on MySQL result index 15 in /includes/functions_garage.php on line 159"

And there's a division by zero error on line 136 when trying to delete the entries. It appears to be a module error that crops up in the coding. A tip for the admins: see bug #5929. It's actually not a bug but a limitation in MySQL, according to Konstantin Osipov. It's a "to be fixed later" bug/limitation. I should just delete the garage.

And so ends the great entry deletion marathon. Again.

[theholycow]

Great job on the research!

Here's the direct link to rolling resistance ratings that Consumer Reports has from NERL:
http://www.consumerreports.org/cro/cars/tires/index.htm

You'll need a CR membership to go further than that, unfortunately.

I'm not sure that narrower tires yield better rolling resistance. There are a few theories that say wider tires should be better; some of them make sense but are difficult to observe/measure, and others aren't really obvious but are measurable. There's two links in my sig about tire width and pressure, both of which cover both issues to some extent, if you have too much time and patience on your hand and need to spend some.

Spending more on LRR tires is generally not going to pay off, but in your case it sounds like you didn't pay much anyway!

[Jay2TheRescue]

Originally Posted by theholycow

Great job on the research!

Here's the direct link to rolling resistance ratings that Consumer Reports has from NERL:
http://www.consumerreports.org/cro/cars/tires/index.htm

You'll need a CR membership to go further than that, unfortunately.

I'm not sure that narrower tires yield better rolling resistance. There are a few theories that say wider tires should be better; some of them make sense but are difficult to observe/measure, and others aren't really obvious but are measurable. There's two links in my sig about tire width and pressure, both of which cover both issues to some extent, if you have too much time and patience on your hand and need to spend some.

Spending more on LRR tires is generally not going to pay off, but in your case it sounds like you didn't pay much anyway!

I don't have a CR membership, and probably most here don't. Would you be able to recommend a few tire brands/models that CR reports as having low RR? Maybe list say the top 2 passenger tires, truck tires, and performance tires? I'm tire shopping too. I've been looking at the either the Michelin XC LT4, or the Michelin LTX A/T2 for my truck next go round for tires.

Thanks, Jay

[theholycow]

That's a good point. I don't have a CR membership either. kitcar, can you also recommend some of the top scorers that have Load Range 'E', if possible?

[Jay2TheRescue]

Wikipedia has a short list that the gov't rated in 2003...

http://en.wikipedia.org/wiki/Low-rol...sistance_tires

[Jay2TheRescue]

I have another good read from what I can see skimming through it. The state of California did a report on tire design and rolling resistance. If you can wade through the bureaucratic technobabble there are some good nuggets of info buried inside.

http://www.energy.ca.gov/2006publica...0-2006-001.PDF

[kitcar]

Thanks for the compliments. I can get around the "issues" with copyright by writing a little review of their article. The ratings I paid attention to are the ones for light trucks/SUVs, but I'll take a gander at the passenger car tires. Gimmie a few hours and some beers and baseball while I write it.

The reason for my additional research is this quote, "The entire spectrum of tire technology has changed in the past 3 years" when I talked to UMTRI so (in my opinion) the 2003 data is too outdated to be of serious use. That said, as far as the truck/SUV ratings go, we see three brands with lower rolling resistance: Hankook, Michelin and Bridgestone but only some models and sizes. That is important but does it mean that only some sizes are tested or those are the ones that netted the best gains? That said, I see that the snow/ice/dry braking suffer with the lower resistance of some tires. Not an issue in my case since I have the limited slip option and 4 wheel anti-locks on Stinkerbutt.

I'll go write the review and post it as a reply to this thread.

[Jay2TheRescue]

Thanks... we shall await your review...

Jay