Its time to shoe the buggy. I've looked thru some old posts but can't seem to find an answer to my question. Is there an advantage to increasing the size of the tire from stock? Currently have BFGoodrich...265 R70 17. I am being told that I should not mess with bigger tires as todays vechicles are tuned for best performance and mileage. I don't want to screw up a good deal.
I pull A Cruiser 5th wheel and use it for light hauling. Just the facts men.
What do ya think?
Thanks in advance for your comments.
Later,
Rick

 

It is true larger tires usually hurt fuel economy, but most report no change in mileage with up to a 295/70-17. And with that size tire you shouldn't have any issues pulling your 5th wheel, either. With larger tires your speedometer and odometer will be off, and the ABS may not work perfectly, but none of it is a big deal. You can have the dealer program your new tire size into the ECM to eliminate these issues.

 

There are only three reasons to increase tire size:

1. You want to reduce the final drive ratio (applies to people who are unhappy with the highway cruise RPM of their manual or 4.10 gear trucks)
2. You will be going offroad and need extra clearance or fatter tires to work through mud, sand, or snow
3. You prioritize appearance ahead of performance

If you're in the #3 camp, you'd have to ask yourself if you're willing to pay the price not only at the pump, but also for the increased cost of the new fitment, the increased wear on suspension components and drivetrain, and finally: do you really want your truck to be instantly underpowered compared to how it was right before your visit to the tire shop? If you've ever done a simple mod to gain a few HP, then that small difference matters.

 

many of us with g56 and 3.73's have found that 35's are the cure for high highway rpm's- almost like adding a 7th gear od.

 

Can you fit 35's without a level kit. I've got 285 70 17's which I presume are 33's and don't feel like I could fit bigger tires in the front. Are 35's going to be a 315 70 17 tire?

 

I just went through this myself. With 4.10's like you have I went to 285/70/17. A little less snot off the line but worth it once you're rolling down the highway. Upsize and let your dealer reflash for the new size. As for the automakers putting a certain tire size on, that has more to do with bean counting than vehicle performance, plus production for the masses.

 

4.10 gears, LT315 BFG AT KOs, 2" coil spacers........plenty of power

 

3. You prioritize appearance ahead of performance

If you're in the #3 camp, you'd have to ask yourself if you're willing to pay the price not only at the pump, but also for the increased cost of the new fitment, the increased wear on suspension components and drivetrain, and finally: do you really want your truck to be instantly underpowered compared to how it was right before your visit to the tire shop? If you've ever done a simple mod to gain a few HP, then that small difference matters.[/QUOTE]

Man I have been lumped into the #3 camp Thanks ok I got piggy bank to handle all of the worn parts due to the large lift and tires.

 

i hate my oversized tires. im going with some stock take-offs. cheap and easy

brett

 

The 315 BFG All Terrain's are really nice on the truck. I drive all day for work and can be hauling, towing and start and stop through town all day. The tires are actually rated to be 34.5 on BFG's site. They do rub. But very, very little. The only place I have been able to get them to touch is on the passenger side wheel well. Fully turned right while moving down a pretty steep incline the inside back edge of the tire will just rub enough to put a mark on the plastic. I was nervous about putting them on but I'm really glad that I did. It looks so much better and rides better. Barely hear the tires on the highway. The truck has plenty of power and if the 315's had any effect I can't tell. Okay that isn't exactly true. I don't think you can ever have enough power. I always want more. Just added the Smarty Jr. to help that out just a bit.

 

I did on a set of H2s.

 

Really?
They rub and you're using H2 wheels?
I always though they were okay on the H2's..?

Well so much for my plans then...

 

I think ptgarcia is saying that he ran a set of 315s on h2 wheels with no rubbing...maybe im wrong though. I run 35 x 12.50r 20s on my truck and it improved my mileage on the highway, the more i save the better because I drive 1000 miles a week and that adds up fast!

 

Close, but I ran 325/70-17 Toyo Open Country A/Ts, which measure 35"x13", on H2s with no lift. A little rub on the plastic inner fender but only when turning and hitting a bump.

 

HOV said it best. What "advantage" are you looking for?

It sounds like the stock size is best in your situation. Towing and light hauling. If you are not trying to make the truck look different or change the gearing, the stockers are fine.

Bigger tires for mileage can only help by bringing with them some disadvantage too. For instance, a bigger diameter may help the gearing if it's too low but the power is reduced. And wider does not help with mileage because it brings extra weight, rolling resistance and less precise steering.

With over 120,000 miles I've had the stock size, then 315 BFGs, then 285 BFGs and now 285/75 Toyo ATs. The 315s reduced mileage but were better off road. The power was reduced and the truck did not steer as well after they were worn a bit. The 285s returned some of the mileage loss and were an excellent all around tire, but only D rated. They still got worse mileage than the stock 265s, but not much. The Toyos are a little taller than the 285s and the power feels down a bit when starting out loaded as first gear is too high in the 48RE. But the Toyos are giving excellent mileage. They are a bit narrower and very stiff. Plus E rated.

If you want to try some larger tires or have some for winter season you could get a set of H2 takeoffs with the 315s. Calibrate your speedo and your outa here. Then your 265s could be used for heavy summer towing (with another speedo fix). Also, the smarty will calibrate your speedo, so if you are considering one of those you can factor that in.

The Toyos are my favorite so far. I like the looks and function of bigger tires. Not a wild aftermarket street wheel with 20s, but service in snow and mud and towing. The feeling that the tires can handle anything the truck can. They do look better to me too but not so big that you can't turn without rubbing. As far as I can tell the H2 wheel is the best thing for our trucks with bigger tires.


John