No hesitation at all.

RacerZX wrote:No hesitation at all.

Thanks. Sure makes it that much easier for me to decide. What are the odds that the dealer can re-program the computer to compensate for the tire change? Has anyone tried this? I can live with the mileage being off, as I've had to do that in almost every vehicle I've ever owned. But, it would be nice if it could be corrected.

NVSteve wrote:I know the on-board computer won't be reflecting the correct totals, but you should be able to get it dead-on using any of the tire size calculators online & a bit of math.

I did some corrected numbers and was able to pull off 20.5mpg in my 06 LE over a 200+ mile, 65mph (for the most part) run with 285/70R17's. That was very little in town driving with a few slow downs for tolls and exit ramps tossed in.

20.5??? when I went up to the 31.6" my fuel eco became even more dismal. I got 370 miles on a tank once... ah those were the days...

My experience is a little different I came from the 245/75 16 (same overall diameter as the stock SE and LE tires) which according to my GPS was showing the speedo being 2mph fast at around 65mph, but when I went to the 265/75 16's the speedo was true . So I suppose I am getting 19-18mpg at 62-65mpg in ideal conditions (downhill with a tailwind).

Carl, what load rating are the new tires? I went with Toyo Open Country A/T which are only C rated, But I found that I needed to air the tires up to around 47psi for them to not track and follow ruts and being bullied by. I've noticed the suspension has really taking a beating for it in return. I'm 500 miles away from 36k and I'm starting to think it may be time to upgrade to the OME setup like Blink and the others installed

Fofiddy wrote:20.5??? when I went up to the 31.6" my fuel eco became even more dismal. I got 370 miles on a tank once... ah those were the days...

Yea man, but I was Mr OldMan driver to pull that off. Absolutely no goosing it, departing from a stop at very light/leasurely pace. Just cruising. I spent a majority of my time in the slow lane. I didn't mind too much because it only got me to my destination in CT about 15 minutes later than normal but it felt like I was going soooo slow. I also went up 95 for this trip as opposed to the Merritt Parkway. Too many hills on that road.

Here's the TireRack.com specs:
285/75 RR16
122/119R D
3305 lbs.
65 psi
17/32"
55 lbs.
7.5-9"
8"
11.4"
NA
32.8"
634

I'm running them at 40psi now, and they are a bit sqooshy but not badly so. I'll try 50 some time soon to compare.

I thought this may be helpful to you guys http://www.dakota-truck.net/TIRECALC/tirecalc.html

phantom2 wrote:I thought this may be helpful to you guys http://www.dakota-truck.net/TIRECALC/tirecalc.html

Or this one, which supplies more info: http://www.discounttire.com/dtcs/infoTireMath.dos

I happen to like this one because of the graphical representation of the tires also. But the layout on the DiscountTire site is more at-a-glance comparable.
http://www.miata.net/garage/tirecalc.html

So with heatgun and dremel in hand I attacked the fender liners yesterday to encourage them to stay out of the way of my 33" BFGs. The first pic here highlights the issue:

Obviously the rub mark on the frame rail is unfixable, but it's also extremely minor and doesn't make any noise when touched. The fender liners though, while also not any serious problem, do make annoying noise whenever the wheel is about 3/4ths the way to lock.

First up the forward areas.

Just nail it with the heatgun until the black plastic has a slight wet look to it and then push it in and hold in place until it cools with the heavy gardening gloves I hope you're wearing (light mechanics gloves won't cut it, gets tooooasty). For those tough corners, use a large philips screwdriver to pop the corner in and then continue to hold all the rest with your gloves until it cools off and stays in place.


Now for the rearward one, it's a little more complex, the contact area is much larger and involves the mud flap. Here's the detail of the problem:


Now with the mud flap taken off (4 screws, easy as pie):


Again heat-gun the sucka extensively. Can be kinda hard to get the whole area hot enough and hold it all in at once, and if you try to do it in two parts then the area you've already tweaked starts going back to it's original shape as you heat up the adjacent area =P, but keep at it and it'll work out.


Then I cut out the section of the mud flap that was rubbing, here's the pic of it reinstalled:


And in the end it all worked perfectly, no more rubbing at all that I've been able to hear in a couple test drives so far. Here's what the clearance looks like now:

Carl,

Thanks so much for the pictures and step-by-step. That really clarifies things.

that's great, thanks! i may have to give that a whirl this weekend.. I only have an issue with the front one (as far as I know..havent looked down there in awhile) but its pretty annoying..

NVSteve wrote:

RacerZX wrote:No hesitation at all.

Thanks. Sure makes it that much easier for me to decide. What are the odds that the dealer can re-program the computer to compensate for the tire change? Has anyone tried this? I can live with the mileage being off, as I've had to do that in almost every vehicle I've ever owned. But, it would be nice if it could be corrected.

To answer my own question, the service department I visited today said that they can't reprogram the speedo. It was quite a team effort in finding that answer, with the conversation ending up with talk of the vaporware 5" Calmini lift & larger tires. Wonder how they'll react when I bring it in with the modest OME lift installed.

One minor downside with these bigger tires is the hit on straight line performance. Sure it's a bit slower due to the gearing change (taller tires = taller effective gearing), but I was surprised to find how much the added weight and rotational inertia effected things. I just had the truck on the Dyno this last Saturday before installing a Gibson exhaust and found only 300HP at the wheels instead of the previous 320.

Now a different dyno on a different day will show some differences, but 20 is beyond the margin of error, and that was only spinning two of these monster tires.

Gibson write-up to come soon as I can get back to the dyno to do a follow-up test...

RacerZX wrote:One minor downside with these bigger tires is the hit on straight line performance. Sure it's a bit slower due to the gearing change (taller tires = taller effective gearing), but I was surprised to find how much the added weight and rotational inertia effected things. I just had the truck on the Dyno this last Saturday before installing a Gibson exhaust and found only 300HP at the wheels instead of the previous 320.

Now a different dyno on a different day will show some differences, but 20 is beyond the margin of error, and that was only spinning two of these monster tires.

Gibson write-up to come soon as I can get back to the dyno to do a follow-up test...

Man, do you have your old wheels? Or could borrow a set from someone else, so you can get the true results. Or you going to have to redo all the other tests, with the 33s..