Pro's and Con's of increasing tire size

[G.I.G.]

I know certain parts of this topic have been discussed in different threads, but I am torn between increasing tire sizes or just staying with the stock tire size. I need a little help from the folks who have tried both, and what your thoughts are. I keep seeing a '07 4runner SE in the parking lot of my gym with P265/70R17 KO's and it looks great. I am again debating on whether I should up-size tires or stick with the stock size.

First off, I drive 98% of the time on-road. I would probably do a little more off-roading with a good set of AT's on my rig (I still have the OEM Dunlops) but my 4runner is my daily commuter first and foremost. Gas mileage and on-road handling are very important to me as you can probably imagine, and I don't want to give up to much in those categories in order to have a "tougher" looking 4R and a half inch or so additional clearance. Below are the pro's and con's as I see it between the stock tire size and going up to 70 series. For those of you who have experience with both, or currently have 70 series AT tires on your 4R, please chime in.

Pro's to larger tire size:

- Increased ground clearance (albeit minimal, I know)
- More aggressive look
- More tire options in the larger size (i.e. Goodyear Silent Armors, etc.)

Con's to larger tire size:

- Decreased MPG
- Inaccurate spedo and odometer readings
- Potential for tire rubbing when cranking the wheel hard.

Again, I can be way off base on the above assumtions, so any input would be greatly appreciated.

Also, do larger tires increase or decrease your spedo readings and odometer readings?

Thanks!

 

[Falls]

I drive mine as a DD and have no cons at all about upsizing after 46k miles. I am running 265.70/17 Revos at the moment.

Speedo is not off much at all , 2-3 @ 60-65

no rubbing for me .

1 draw back is you should buy an add'l tire for the spare so they are all the same size. You can usually get a good used one since its only a spare.

 

[G.I.G.]

I drive mine as a DD and have no cons at all about upsizing after 46k miles. I am running 265.70/17 Revos at the moment.

Speedo is not off much at all , 2-3 @ 60-65

no rubbing for me .

1 draw back is you should buy an add'l tire for the spare so they are all the same size. You can usually get a good used one since its only a spare.

Cool, couple more questions for ya....

When the speedo is off by 2-3 mph, is it + or - what it would normally be? Any noticable difference in mpg? Does the 70 series spare still fit OK under the car? How is the ride quality of the Revo's vs. the stock Dunlops?

Thanks.

 

[4Runner_96_SR5]

Dont take my word for it, but i think that if you were going 65 your spedo would read lower. It reads the rpm, but doesnt know that the 17 inch tires go further with each rotation.

 

[Falls]

Dont take my word for it, but i think that if you were going 65 your spedo would read lower. It reads the rpm, but doesnt know that the 17 inch tires go further with each rotation.

Correct.

The Revos ride compared to the stock tires is much better . Yes a 265/70/17 spare does fit. I have it in mine , granted it's tighter , but fits.

Don't know what tire you are buying , but I would think any 265/70/17 should fit in there.

I changed my tires out almost instantly so I never noticed a difference in power or milage, all I know is I do get good milage with mine.

I'm getting new tires so I'll have to see if that changes milage.

 

[Thai]

Two things...BFG AT KO only comes in LT. Also, some people have had a tiny bit rubbing with BFG AT KO in the size you listed, but not with other AT tires in the same size...apparently, the square tread on the BFG AT KO is the culprit.

As for the spare, you need to testfit it while getting the bigger tires to be sure.

 

[Kmvreter]

... with P265/70R17 KO's and it looks great. I am again debating on whether I should up-size tires or stick with the stock size.

First off, I drive 98% of the time on-road. I would probably do a little more off-roading with a good set of AT's on my rig (I still have the OEM Dunlops) but my 4runner is my daily commuter first and foremost. Gas mileage and on-road handling are very important to me as you can probably imagine, and I don't want to give up to much in those categories ...

Pro's to larger tire size:

- Increased ground clearance (albeit minimal, I know)
- More aggressive look
- More tire options in the larger size (i.e. Goodyear Silent Armors, etc.)

Con's to larger tire size:

- Decreased MPG
- Inaccurate spedo and odometer readings
- Potential for tire rubbing when cranking the wheel hard.

...

I upsized my 16" to a 75 aspect ratio which is essentially the same as what you want to do with the 17". I upsized when I did replacements with the Mich CT and also with a set of BFG A/Tko I run in the winter. I also keep very good track of mileage and take the odo error into account in the calculations. I agree with your pro's above.
As for the Con's, I only get rubbing at full lock on the wider BFG but it is a non-issue for me. The 4% error in the speedo and odo are also a non-issue (I'm actually recording less mileage on the odo for the actual distance travelled; keep the speedo in mind at higher speeds.) As for MPG, there are some myths about this. My experience shows it is a pro and con. The baseline I compare to is the 3 year history of running the Doneflops. My Mich CT mileage is slightly worse when doing city driving but is actualy better on the highway. Overall it is a wash for me but could be a pro if your on-road if mostly highway. I can't say the same about the BFG because I don't have a good baseline to compare to, I only run them in the winter and they are a true A/T tread. The 4% size difference just doesn't matter in this case becuase I get worse mileage than the CT.
As for the spare, save your money. I kept one of the original regular size Doneflops. I've had to use it on the vehicle (short-term running 3 upsized, 1 regular sized) with no adverse affect to VSC, ABS, etc...

 

[kinchy]

The stock shoes on my Sport (Grand Treks) were dreadful. Noisy, lousy traction and they get terrible scores on all the key varaibles. I put Toyo Proxes on (the same size you referred to in your note). A HUGE difference in handling, noise and wet grip. Beleive it or not my MPG actually increased slightly. I keep em at 35lbs.

They have 10,000 miles on them and look brand new.

 

[Cybercannon]

265/70/17 will be 3.4% off for speed and odo. (Edit: BFG AT/KOs are slightly larger and 4% off) When speedo reads 60 you're really doing 62mph because your new larger tires travel further in the same number of revolutions.

The odometer will record fewer miles than you're actually traveling for the same reason.

The MPG meter will tell you you're getting less than you actually are. That meter isn't that accurate anyway, but with BFG TA/KOs if my mpg says either 15 or 16 I add 0.6 (15*1.04=15.6). For 17, 18 and 19 I add 0.7. For 20 and 21 I add 0.8. Those are rounded, but close.

A better method is to use your trip meter from one fill up to the next. Take that number times 1.034 (or 1.04 for the BFGs) to account for how far you actually traveled on larger tires. Take that answer and divide by how many gallons you filled. Of course, try to overfill or stop fill the same depth as you're previous fill up.


My experiences with these tires have been pretty good. When accounting for difference in size and adjusting MPG I'm doing the same or slightly better than on stock tires. I have the V8, so it's torque may make the little extra weight of the tires irrelevant. As you get larger and larger tires eventually the extra weight and strain definatly will hurt MPG.

So as for your Cons: The MPG at that size is no different for me with my V8. I don't know about V6 owners experiences. The speedo and odo diffrences are minimal and for normal driving I don't even pay attention to it. Even at 100mph on the speedo it would be 103.4 mph in reality (104 with BFGs). Nominal. I have had no problems with tire rubbing on my 05. I did lift it with Daystar before adding the tires though, so without lift or leveling it might rub. I don't know.

The spare tire definatly fits and I have the bulkier weight distributing hitch. Promed got a 275/70/17 Cooper SST spare to fit with the same hitch. The regular hitch gives you more room.
I did get the spare because I do 5 tire rotations to spread the life of the tires.

They're not any louder than the stock tires, but they're also pretty new. We'll see if they get louder as tread wears.

Finally, the BFG TA/KOs are slightly less reactive than a street tire. I don't mind or notice it much, but when turning or other maneuvers the deeper tread gives/flexes more before taking hold. It's hard to describe, but my experience is that street tires are slightly more reactive and tighter in handling. I keep my BFGs at 42 psi on road and it really improved handling compared to 35psi out of the tire shop (C rated tires, so 50psi max cold).

I'm extremely happy with mine and wouldn't go back down in size. I am considering GY silent armors next time I get tires for no other reason than to compare.

 

[BenSD]

I have the same tires you mention on my 04 sport. Your pros and cons are accurate. I do get a tiny bit of rubbing, but it's no big deal. I have not noticed a difference in handling on-road. Offroad, you'll have more confidence because they are tougher tires. Plus, you'll get about an inch more of ground clearance. This means that you'll be able to crawl under the 4runner. I can go from front to back without hitting anything.

I do plan on getting a different suspension that will lift the 4R a bit. that'll take care of the rubbing.

 

[rook]

First off, I drive 98% of the time on-road. I would probably do a little more off-roading with a good set of AT's on my rig

BFG AT KO is not the tire for you. It is one of the more agressive AT's around. Find a tire that fits your usage. For example the BFG Rugged Trail. They also look good from the side because the tread lugs go
down the sidewall slightly, making it look more aggressive. It is also good enough to get you through most trails, just stay away from mud. You will also sacrifice little in the way of fuel econ.

 

[Falls]

Re: Re: Pro's and Con's of increasing tire size

BFG AT KO is not the tire for you. It is one of the more agressive AT's around. Find a tire that fits your usage. For example the BFG Rugged Trail. They also look good from the side because the tread lugs go
down the sidewall slightly, making it look more aggressive. It is also good enough to get you through most trails, just stay away from mud. You will also sacrifice little in the way of fuel econ.

Any AT tire is not good in mud. Depending how deep the mud is and what type of mud.

I've decided that I'm going to stay with a P tire so I'll have a nicer ride , better milage , but still be able to handle off roading. I do go off hiway quite a bit but hey if the Revos go me through then and of the tougher ones like the GY SA should do me . One thing I noticed about the BFG AT ( my all time favorite AT tire ) is that in winter the squared shoulder would seem to catch some of the ruts on the road from other and kinda steered me around , I've not had them on the 4R so I don't know if thats the case. There are a lot of good AT's and all seasons tires out there to pick from. Its overwhelming when shopping for the correct one.

OFF TOPIC:
One story to quick tell. I had an 81 Monte Carlo. It was RWD , just horrible , horrible in snow. When it came to buy new tires a friend that owns a chain of hardware store said he could order me some cheap all season tires called Armstrong's . I did it because cash was an issue , and they were like night and day in the snow. It was like I added AWD to the car. Thats how much difference a good tire can make. Best All season tires in snow I've ever driven on a car. Why I was worried about that snow traction in the car I'll never know since I had an F250 4x4 for my 2nd vehicle. Dumb a$$ kid I guess.

 

[G.I.G.]

Re: Re: Pro's and Con's of increasing tire size

BFG AT KO is not the tire for you. It is one of the more agressive AT's around. Find a tire that fits your usage. For example the BFG Rugged Trail. They also look good from the side because the tread lugs go
down the sidewall slightly, making it look more aggressive. It is also good enough to get you through most trails, just stay away from mud. You will also sacrifice little in the way of fuel econ.

I wasn't considering buying KO's, I just like the look of the 70 series AT on that 4R I keep coming accross. I have it narrowed down to the Revo and the GY SA (now that I am thinking of moving up to a 70 series). I know tire brand is a whole other discussion by itself...

 

[ProMed]

Larger tires made my speedo more accurate due to the factory speedo error.

 

[Thai]

Re: Re: Re: Pro's and Con's of increasing tire size

I've decided that I'm going to stay with a P tire so I'll have a nicer ride , better milage , but still be able to handle off roading. I do go off hiway quite a bit but hey if the Revos go me through then and of the tougher ones like the GY SA should do me . One thing I noticed about the BFG AT ( my all time favorite AT tire ) is that in winter the squared shoulder would seem to catch some of the ruts on the road from other and kinda steered me around , I've not had them on the 4R so I don't know if thats the case. There are a lot of good AT's and all seasons tires out there to pick from. Its overwhelming when shopping for the correct one.

Falls, are you considering LTX A/T-2?? I hear that LTX A/T-2 preserves factory fuel economy, while i have heard many stories of GY SA making fuel economy worst (P and LT rated). I think that it's in the tread design or something. Since you're going with a smooth ride and good fuel economy, i think that you should take a look at LTX A/T-2 again....

 

[Falls]

Yes , I'm going to check them out.

My gas milage and comfort have been good with the Revos , I do not drive conservative and drive a full time 4x4 V8 , so I'm not overly concerned about fuel , just dont want it to drop to 14 or something , otherwise I don't care. A nice ride is important too , but again this already has a pretty truck like ride and I'm happy with it , guess I'm a little misleading with the smooth ride ..... or I would have a Caddy ...lol.

OK back to the topic , I think the 70's are the way to go IMO , they look much better , give you an add'l 1/2" clearance . Its a good thing .