I'm looking at options for tires. I tow heavy and have a 3.73 rear.

I was wondering how much you notice changes in tire height... eg, going from 31.5" to 32 or 33"? Is this harder on the tranny? Do you notice a loss of power? At some point I guess you might, but when?

 

35's is when you start to feel it a little unless you get a real wide/smaller tire. You'll drop your RPM's on the highway a little. Loaded heavy, they'll take a little more fuel to get them rolling, but these motors are made to work. I'm rollin on 40's.

 

So I'm debating moving from stock (that's 31.x" I think) to 32.x or 33.4" are you saying I won't really notice much? Does that still work towing heavy (14,000#)? I can make up some of the lost HP, but when will the taller tire start to beat on my tranny?

On a practical note - what's the biggest spare I can store under the bed?

 

I tow with mine and I did not like the difference with 315/70 BFGs. They look good and they 4 wheel well, but they made it tow worse. Two things. One was starting out with the auto. 1st is pretty high and noticeably slower with the bigger tires. Next was pulling in OD. I had to drop out of OD a lot more in the hills and watch the EGT.

I then went to 285/70 BFGs. Better for towing.

I then went to 285/75 Toyos. They are a little slower starting out than the stock 265s, but OD works pretty well in the hills. I like the tires so much that I'll stay with them set after set.

The stock 265/70s are the best for towing, but look small and don't 4 wheel well. But if you have 4.11 gears the bigger size should be just fine.

I am running a Smarty and slipped my TC lockup clutch while towing. Be sure to keep the revs up! I won't work it very hard in the lower RPM range and like to see it at about 2000-2200 on grades. This makes a bg difference in the EGT.

A 315/70 fits under the bed just fine and clears the exhaust. But I ran mine out the side recently and love it.

I wish I had a G56.

 

I put the 285/70/17s on my truck at less than 1000 miles. I tow 11,000 and honestly can't say that the 265s would tow any better. I can pretty much pull any pass in the NW and stay in 6th (OD).

There is one that I need 5th on and one I need 4th on. I need 4th basically because its really twisty and I can't safely run any more than about 35-40 over the pass.

My Dad has an identical truck to mine,but he has the 6.7

He still has the stock 265s and even towing 2000 less than me he still runs the same gears at the same times.

So,as far as I can tell,the 285s had no real affect on power.

 

I also have 285/70/17's. Haven't really noticed any difference in towing vs. the stock tires.

MikeyB

 

davelinde - here's a tire size calculator you might find useful: http://www.miata.net/garage/tirecalc.html It'll tell you the height, speedo correction, etc.

I'm looking at either 285/70/17 or 285/75/17 Toyo's when my stockers wear out. I'll probably go with the 75's because a) I have a 6 spd manual, and b) I don't tow heavy. I'd LIKE to tow something heavy (camper/muscle car/boat, etc.), but I'm married and she makes more money than I do.

 

I noticed before the 35's and 4" lift my wife could jump in herself. now I have to push her butt in........LOL

 

Maybe it's when you don't notice it that counts. Like when you don't hit the diffs on rocks. Hah!

Seriously though, I noticed a little hit going to 285 75/17s. Slower starts and I have to use the clutch on 2nd gear starts more than before (not much though). It doesn't bother me though. No mpg drop for sure.

 

my 35" spare fits under the bed, i dont think you could fit anything bigger under there though

 

Went to 305 70 17s and could totaly notice a difference.When not towing it just dont take off at freeway speeds and I used to be able to start out in 3rd with no problem and I can't now.The hills I pulled in 6th I now have to down shift into 5th.Next time I will go a little smaller like a 285 or 295 max.My mileage also went down with the larger tires.I think my mileage would have went up if I would have gotten a narow hiway print.
Towing heavy the taller the tire the worst it will be.

 

tag, this thread looks useful.

 

I hope so...

Right now I'm debating between getting myself some 285's or going to Ricksons.

The a 285/70 is less than an inch taller and the narrow Ricksons are about the same - but to get some real added carrying the wider/taller Ricksons seem to be the ones. It's sounding like people don't really notice 1 or maybe 2 inches higher at all but begin to notice more.