Advice On Replacement Tires

[stikine]

The BFG AT T/A KO (315/70/R17D) that came on my van have chunks of tread missing from the outside of the treads (from hitting rocks) and lots of small, shallow cracks in the middle of the tread and I'm trying to figure out what to replace them with. They only have 28,000 miles on them, but maybe that is par for the course on these 10,000 lb rigs.

I have read plenty of other posts and there does seem to be a persuasive argument made for going with E rated tires for the heavier build up that allows higher PSI and/or max load per tire as compared to D rated tires, which in turn gives a greater safety margin for these heavy rigs.

I was looking at the BFG MT T/A KM2 (305/65/R17E) which is about 1.5" smaller in diameter, is E rated, but has the same max load, 3195 lbs as my AT's but does allow 65 PSI as compared to 50 PSI for my old tires. I realize there will be more noise on the highway, not very good on ice but they do get very good reviews on rocky dirt roads, where I often find myself. I also realize the speedometer will be off a bit, as it was flashed for the BFG AT's.

The other options are to replace with the same tires, or I do see where the Nitto Terra Grapplers (305/70R17E) at 3640 lbs max load seem well liked on this forum, though they don't have a very aggressive tread, they would seem to be a very good all around tire.

Any thoughts appreciated.

[Roonie]

I currently have the terra grapplers 315's and they are not that aggressive at all. I have spun the tires very easily in a little mud and they struggle in off road conditions when they shouldn't. I would not get them again if your doing any off roading at all. They do great on the road.

I have been doing the research as well and I am going to get the 305 Toyo Open Country MT in E rating for all the reasons you listed above. The reviews rate them with good road manners and a quiet ride. They do well in most conditions. And yes I only got 29k (current mileage) out of the terra grapplers.

Check out tire reviews on sites like this....

http://www.offroaders.com/tech/AT-MT...en-Country.htm

[stikine]

The Toyo MT's do look good - think you will be happy with them - lots of good reviews. They are really quite limited in 17" though, you must have 16" wheels?

Just noticed that BFG AT T/A KO in a 305/65R17 is E rated with maximum inflation pressure of 65 psi, so now I'm seriously looking at these as I really liked my old BFG AT's, but would really like to get a load range E tire, so these might do the trick, even though my clearance drops almost 2".

I think the BFG MT T/A KM2 are a heck of tire, but I bet they would give me less miles in the long run and not so good on snow unless you sipe the center of them, but they sure get good reviews.

[tomesd]

I've got the Nitto Trail grapplers- a cross between a MT and an AT tire. The tread is more aggressive but not too loud on the road. It's also E rated, very happy with then.

[SierraHawk]

I need a set of 285/75/16 R Load range E tires and am looking for any recommendations.
I did a quick/simple review of the comments about tires on sportsmobileforum.com
(+) is good (-) is bad

A few have a price.

Most members using E rated tires for off road use found that they don't seem to do well in the snow.

Michelin LTX M/S (+) $200 Sears

Goodyear Wrangler MT/R with Kevlar (- +)

$216 @ Sears

Goodyear Silent Armors +

BFG All-Terrain T/A® KO (+ - -) One member cited 2 tread seperations on one set.
$1030 for 4 @ Costco

BFG mud KM2 $233 @ Discount Tire

255/85/16 = 33 Narrow/aggressive (+)

295/75R16 BFG (+)


Nitto Terra Grappler (+ - - + -) One comment: spun out in shallow mud.

Nito Trail Grappler (+ +)

http://www.discount-tires-2go.com/Nitto ... appler.cfm
$195

Toyo Open Country M/T is E (+ + +)
$223

The link: http://www.offroaders.com/tech/AT-MT-Ti ... ountry.htm Approx 20% of reviews were not favorable.

One comment: Nitto and Toyo are the same company

[SierraHawk]

Need another opinion related to tires: I am now running 285/75/16 tires (33" dia). A 275/70R16 is 31" high and has a 10.60" footprint. If I put these on, I would loose 2" in radius (1" in clearance). If I use a 275/70R16, would I notice any less strain on the engine while towing a 7000# trailer over steep mountain passes?

[lactic]

I just replaced my aging 285/75/16 E rated BFG ATs with Toyo Open Country MTs in the E rated 305/75/16.

LOVE THEM!!!

These tires beat the crap out of my previous AT's in every way other than road noise at highway speed and that's not even that noticable.

Seriously, this was the best thing I have done to my van since I bought it 2 years ago.

Can you tell I'm happy with my ridiculously expensive investment?

[Viejo]

Need another opinion related to tires: I am now running 285/75/16 tires (33" dia). A 275/70R16 is 31" high and has a 10.60" footprint. If I put these on, I would loose 2" in radius (1" in clearance). If I use a 275/70R16, would I notice any less strain on the engine while towing a 7000# trailer over steep mountain passes?

Going from 33" to 31" is a reduction of about 6% in diameter so about 6% reduction in circumference and about 6% lower speed for a given RPM and gear and so about 6% less load on the engine. Whether or not you will notice the 6% difference is another matter.

[Roonie]

Originally Posted by SierraHawk

Need another opinion related to tires: I am now running 285/75/16 tires (33" dia). A 275/70R16 is 31" high and has a 10.60" footprint. If I put these on, I would loose 2" in radius (1" in clearance). If I use a 275/70R16, would I notice any less strain on the engine while towing a 7000# trailer over steep mountain passes?

It all depends on weight as well. For example I am going from 315/70/16 Nitto terra grapplers to 305/75/16 Toyo MT's and the Toyo MT's even though they are smaller actually weigh a little more since they have more tread. The rolling weight matters.

[Silver350]

Originally Posted by SierraHawk

Need another opinion related to tires: I am now running 285/75/16 tires (33" dia). A 275/70R16 is 31" high and has a 10.60" footprint. If I put these on, I would loose 2" in radius (1" in clearance). If I use a 275/70R16, would I notice any less strain on the engine while towing a 7000# trailer over steep mountain passes?

Smaller tires will help .
I assume from other posts that you have a 5.4 L and most likely the 4R75 transmission. Based on that, you will want to keep it above 2500 RPM when working it because that is where the peak torque is and maximum HP is reached at 4500 RPM. So if you drive below 2500 RPM climbing a big hill you will be wondering why your engine is struggling.

Stock tires and gearing with O/D shut off would put your RPM at 60 MPH @ 2527 with a 3.7 rear end and 2800 RPM with 4.1's. You don't have to drive that fast but notice how high the RPM is. The factory designed it that way for a reason.

With 31" tires, O/D shut off at 60 MPH the RPM is 2483 with 3.7's and 2750 with 4.1's. Close to stock.

With 33" tires, O/D shut off at 60 MPH the RPM is 2332 with 3.7's and 2584 with 4.1's.



Notice what the smaller tires do to your overall gearing, they lower it, rasing your RPM at a given speed. That is why the smaller tires will help you pull the big load. Higher RPM = power, it has nothing to do with the weight of the tires.

A 9000# SMB pulling a 7000# trailer is asking a lot from a 5.4L with 33" tires unless you have 4.56 rears. Maybe you could put it on stock tires when you tow and leave your gearing alone. Carry your big tires with you and put them on once you drop your trailer. Don't make the mistake that keeping engine RPM low is somehow taking it easy on the drivetrain. It isn't. Drive slow, keep the RPM up even if you have to drop another gear. Oh and don't forget to use your four way flashers going up hill.