New tires for the truck--rolling resistance and mpg savings

[07b2300]

Hi, I'm thinking about trading in my larger, somewhat aggressive LT rated tires for some stock height ones. Costco is having a sale on michelins right now and I want to take advantage of it.

The stock size is 225/70/15 and the best I can find information on is the Michelin LTX M/S. In 2005 Consumer Reports gave them a rolling resistance rating of 57 (but I don't have the information on the size of tire they tested), and said that the tires have good "Rolling resistance; winter grip; Dry braking"

But I have also been reading great things about the Michelin "Radial X" all season. Prius drivers say good thing about the fuel economy and general performance, and Consumer Reports just gave them top ranks on rolling resistance (but give no numbers). They don't come in my size but come in a close size 215/75/15.

So the LTX's would have a shorter sidewall which is supposedly better for rolling resistance and are likely stronger (for a truck), but the Radial X's are narrower, lighter, and less aggressive.

So I'm stuck between them with little real info and need convincing to take the leap to the wimpier but more efficient tire! Anyone have any ideas how much savings in fuel economy the Michelin X would give? BTW, my 07 B2300 truck is a 4x2 has a fuel efficient four banger (rated at 29 mpgs highway).

Thanks!!

[whokilledthejams]

I had a set of the Michelin LTX's on the S10 I used to have. I didn't buy them for FE-related reasons, but they were excellent tires (plenty of grip, not noisy, not over-aggressive tread), and definitely were not a detriment to my FE, as I maintained a consistent 30mpg hwy/25 city. As an added bonus, they were pretty good in snow-- anything that benefits winter traction in a 2WD truck is a big help.

[klrv6]

Just put a set of Michelin Xradial LT tires on our Suburban. They gave slightly better (21) mpgs than the yokohama geolandars (19) that they replaced. Great ride and the price was $23 per set more than somewhat generic brand tires. I wen with the six ply as it has better sidewall support. Sams club has a $60 instant rebate which made them $500 for the set out the door. 235/75/15

[elhigh]

I tried LT tires on my truck several years ago and one of the first things I noticed was that my fuel mileage took a big, big hit. It went down and stayed down. On top of that, the ride was noisier and harsher too, and they didn't wear especially well. I was glad to get rid of them.

Put regular tires on the truck, boom - mileage went back to what I was used to. Never again.

It's just a compact truck - LT tires are kinda overkill for what it can do. Most of the time it only carries me and the wife to work; once in a long while I carry a few loads of firewood and then it's back to light duty commuting. Regular tires are fine for that.

I'm running 195/75 R14 - but that was before 15" was de rigeur for all cars. I'd move up to 15s if I thought there was a significant savings to be had. As for concerns regarding the smaller contact patch, fuggedaboutit. It'll ride like a champ.

[COMP]

i have to have truck tire's on my truck,,,, i use it ,,car tires couldn't take it

[MechEngVT]

For a small light truck I'd go with the narrower/lighter tire, even though it will put your overall tire diameter slightly larger. The combination of taller and narrower should help your highway mileage and anything that reduces your tire/wheel weight helps city mileage.

What you don't mention is the load range rating or the maximum inflation pressure rating. I assume that you will be inflating your tires to their maximum rating to reduce rolling resistance. LT tires come in different load ranges (C, D, E) and each typically have different maximum inflation pressures. If one tire can go a bit higher on inflation than the other and you think you'll be able to tolerate the ride harshness then go with that tire.

I went through the same decision not long ago on whether to get an LT tire or regular tire in my truck's stock 265/70R17. I went with the Hankook DynaPro AS RH03 passenger as opposed to LT because the LT tire was almost 10 lbs heavier EACH. The passenger tire in that size is rated at 44psi vs. the LT tire's 80 psi. I thought the large weight difference would more than handicap the additional air pressure for no net FE gain but large ride punishment. Combine that with the fact that Hankooks in general are hard to find here, and the LTs were completely not available, so I went with the passenger model. Before that I had a stock-size BFGoodrich LongTrail T/A, which was another low-rolling resistance model, and saw no change in FE. I like the ride, grip, and especially the wet handling of the Hankooks better than the BFGs.

BTW checking the Hankook site today they list the DynaPro AS RH03 in a 225/70R15 in passenger, but not LT (they do have the LT215/75R15)

[07b2300]

I hear you elhigh, I put LT tires on this truck and my fuel economy went way down. So even though I have lots of tread left, I don't need the extra load rating and I'm going to swap them out and put the LTs on Craigslist. It makes sense--over the remaining life of the tires even if I just threw these tires away the new tires would pay for themselves.

[07b2300]

Thanks for all your responses. Both tires take the same max inflation--35 psi. For some reason the X radial carries a higher load at 35 psi (150 lbs more). The 215 is .1" higher so almost identical there, and the 215 has a .3" narrower contact (8.7 instead of 9) so very close there too.

Michelin doesn't put the weight of the X on their website so no idea if the X is any lighter, but probably--the treads are a little shorter in the X (10/32 insead of 13/32) so likely a harder rubber and somewhat lighter at the outside circumference where it counts. Also although both are a P rated tire, they consider the LTX suitable for trucks so is likely heavier...

So without knowing weight or RR of each tire makes it hard to know which would get better mileage. While consumer reports gave the X an "excellent" RR rating in their recent test (and #1 overall out of all tires with an excellent RR rating they tested), a previous test had said one of the benefits of the LTX was RR too. But CR gives no hard numbers and both tires weren't on the same test.

With the info I have I should probably go with the LTXs. Lots of great reviews on tire rack for their snow traction, etc and sounds like you had good luck with them whokilledthejams. But if the X would save even 2 mpgs that would be ~$142 per year or $1287 for the life of the tire (at $4 per gallon). Too bad there is so little info or reviews to go on.

[beatr911]

A little late to this but don't worry about the load ratings. My b2300 is used as a truck and have had no problems with the 225/70r14 passenger tires. They are easily within the capacity that they see in use on the truck. LT tires on these little trucks really serve no discernable benefit.

[07b2300]

Yeah, if a 14" P rated can take the load of your truck the 15's should be fine for mine.

The gods have decided--Costco is sold out of the LTXs so I guess I'm going to find out how the Radial X's do on my fuel economy. I'll buy them this Sunday and will post results in a few weeks. thanks again for your responses.