CRD, tires, and fuel economy

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

My new 05 CRD needs new tires. It is currently running BFG TA KOs (LT 245/75/R16), and my jeep has a 2.5" lift.

I just returned from my first hwy trip after the GDE eco tune. I averaged 29 mps on a 600 mile trip with lots of elevation change (around Flagstaff).

I am wondering if there are tires that would allow me to improve my gas mileage while maintaing moderate off-road ability. I do lots of off-roading S of Moab, UT on rocky roads, but no extreme rock crawling.

The Discount Tire guy said that a P series tire would improve my fuel economy while giving me less sidewall strength. With tire certs they would replace blown tires, but I normally work a LONG way from DT.

The tire guy suggested staying with the BFG TAs or trying Yoko Geolanders. The Yokos come in both a P series and a LT series for that tire. I would really like to improve my fuel economy, but I am nervous about P series tires on rocky, remote roads.

SO, is there any tire that would improve my fuel economy and not lose the ability to do moderate off roading??

My front tires are going fast, and I will be back in civilization in two weeks where I can easily buy tires.

Suggestions are APPRECIATED!

Thanks!!

linewarbr · **Posted:** Tue Sep 22, 2009 12:09 pm

What PSI do you run your tires at?

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

I tend to run them pretty hard. Don't think I always remember to air down for off roading, either. : - )

ATXKJ · **Posted:** Tue Sep 22, 2009 4:26 pm

check tirerack for the tire weight
last time someone did comparisons - I think the Firestone AT's weighted less than comparable tires

and weight is a factor (on economy and on sidewall strength)

dritchie · **Posted:** Tue Sep 22, 2009 5:06 pm

I put a set of BFG Longtrail T/A XL on mine and love them. Not really a AT type of tire, but they are quiet and track true, unlike the OEM Goodyear crap that came on it. I keep mine at 45 lbs., can go to 50 lbs. as they are the XL version.

Dave

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

I had a set of P rated Revo's. I thought they were LT when I bought them (I was in a hurry to get out of town). Needless to say, I drove with them for two years and put them through many tough trails:

http://www.cardomain.com/ride/2662913/4

I am lucky they made it, I would not do it again. Try to find a tire that allows for the greatest PSI while having the lowest weight.

I now have two sets of wheels. The steel wheels have E range MTR's and the stock wheels will soon have new LT rated all terrains. I can say that steel wheels with 235/85/16 MTR's is not the way to go for better mileage...

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

This is turning into a difficult decision--there are just too many choices.

Does anyone have any experience with the Michelin LTX A/Ts?

Thanks!

Bill.Barg · **Posted:** Thu Sep 24, 2009 11:53 pm

The lightest weight LT all terrain tires I could find are the Dunlop RT radial rovers. 40 lbs each compared to the BFG (245-75-16).

Joe Romas · **Posted:** Fri Sep 25, 2009 8:53 am

Trekker

Our CRD's came with the 242 transfer case and as I understand it's important to have the same size tires on all four wheels for longevity of the 242. Now I'm not talking about different size tires, I'm talking about the same sized ones rotated at every oil change as it says in the manual to keep them all the same :shock:

The reason I mention this is because you state "the front ones are going fast"

I rotate all 5 of my original tires and they are all the same wear wise. Our engine adds a lot of weight to the front of the vehicle :shock:

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

Bill: thanks for the info on the Dunlops!

Joe: I just bought this vehicle and have no idea when or if the tires have been rotated.

Finding this tire decision to be a hard one....

Joe Romas · **Posted:** Fri Sep 25, 2009 10:37 am

Trekker wrote:

Bill: thanks for the info on the Dunlops!

Joe: I just bought this vehicle and have no idea when or if the tires have been rotated.

Finding this tire decision to be a hard one....

Bill

I bought Cooper Discoverer H/T for the wife's XJ but both my jeeps are daily drivers.

It's hard to go wrong with Michilin but when my crd needs tires I'll look at cooper's again.

Joe

danoid · **Posted:** Fri Sep 25, 2009 3:13 pm

For mileage I invested in a set of Michelin XPS Rib range E tires - but not for off road, they can be defeated by wet grass. Kind of embarassing.

Joe Dirt · **Posted:** Fri Sep 25, 2009 9:53 pm

I have a set of Michelin LTX a/t2. I love them, they are quiet and very sure footed. I went with the 245/70s. I really like the looks of them because they fill out the fender well better than the stock Goodyears and they are wider. The only downfall is that my mileage dropped around 2mpg.

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

Joe: thanks for the input on the Michelins.

Does anyone know a P rated tire that is any good for off roading?

thanks

CRDMiller · **Posted:** Sat Sep 26, 2009 2:10 am

Ta K/O's are actually, the best tire for your application (imho)

P rating and their load range is significantly less than LT rated radials.
If you had a LT radial and a P radial both rated at 2450 lb the lt radials can actually do a decent percentage over rated, i believe it's 10% standard. That's part of what LT means.

They are pretty much a street tire that does ok around constructions sites and wall mart parking lots. You can beat up on them a bit, and they last forever.

I'm not saying you cant have your cake and eat it but your quest for mpg pretty much stopped when you got a lift.

Your going to experience chunking and elevated sidewall punctures when you even trail lightly with p radials.

I get about 29-30 combined with a IM2. And around 34-36 all highway.

I have km2's in 235/85/16 lr-E they are rated for 80- psi but i get a decent loss of traction on pavement at around 45 psi. I also get massive outer wear at under 35 psi for me front is perfect at 43 psi and rear at 40. At 45 psi the rear would want to slide around a bit. (i consistently drive a decent mountain pass so i have a great basis for comparison)

Don't think of pressure alone as your answer to mpg. Excessive wear is typically what you'll find.

Maby you would be satisfied with a rugged trail (id keep the ko's)
http://www.bfgoodrichtires.com/specs/ru ... /1163.html

or Commercial T/A® Traction
http://www.bfgoodrichtires.com/specs/co ... on/48.html

I dont favor bfg it's just what i'm familiar with, i'm sure Goodyear and others have similar.

The real question is, what do you not like about your ko's? If the answer is mpg, your doing good. They are an excellent tire. (if you don't off-road alot)

if i saw a lifted jeep with less than ko rubber i would wonder wtf the owner was thinking, it's inconsistent with the theme.

Your truck you do what makes you happy, but think about those ko's again.

* re reading your post it almost sounds liek you need to go up in aggressiveness, and not down, you have $$ in a lift, armor, and probably recovery gear, but your using construction site rubber*

ATXKJ · **Posted:** Sat Sep 26, 2009 8:03 am

Trekker, CRDMiller - click on Pablo's link and check out the trail, and some of the earlier ones - he ran those for 2 years.

Yeah he said he wouldn't get P rated again - but look at what he did with P rated Revo's

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

CRDMiller: Some excellent info. Thanks!

My CRD came with this lift-not something I would have done myself. Most of my off roading is moderate and I have used the BFGs for years on the gasser KJ I had before.

I am new to lifted Jeeps. Is the lift costing me significant MPGs?

How hard is it to get rid of a lift? :roll:

Thanks!

nursecosmo · **Posted:** Sat Sep 26, 2009 2:01 pm

What kind of lift is it? I may be interested.

geordi · **Posted:** Sat Sep 26, 2009 4:28 pm

I have the Highway tread version of the BFG Commercial T/A that was posted, and I love them in a Load Range E 215/85-15 size. I'm running STOCK height, and they don't rub at all. Next set of shoes will be the 235/85 size in the same tires, which I have already tried (had one mounted for laughs the day I got the 215s) and the contact is ONLY at the plastic on the pinch weld. I had just bought the truck so I didn't feel like hitting the weld flat then.

I'm getting about 26 highway right now with these, but I also am experiencing a vacuum problem of some sort that is limiting my boost and I think hiding the true potential of my GDE tune. I do the "construction site" level of off-roading, or jumping a curb every once in a while, so off-road isn't my real concern. I wanted mileage, towing capacity, and sidewall strength of a steel sidewall that a P-rated just won't offer. If anyone knows of a physically lighter tire that is available in a 215/85 with a steel sidewall... I'd be all for it.

Trekker · **Joined:** Tue Jul 21, 2009 11:42 am **Posts:** 33

nursecosmo wrote:

What kind of lift is it? I may be interested.

The former owner said it was a Daystar 2.5"
Frankly I know next to nothing about lifts! Don't have a clue how hard it would be to take one off.

Is is standard knowledge (to everyone but me) that lifts cut fuel economy drastically?

Thanks!

CRD, tires, and fuel economy

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