Taller tire- affect on shift/RPM

Hoping someone can explain this to me. What happens to shift points when moving to a larger tire? I've searched and searched and I can't really find a description of what actually happens. I'd like to move from my current 245-75 MS2's to 265-75's, but i don't want to do it if it's going to feel different driving it. I like the gearing as it is, but I really want a larger tire, if even a 1.2". I know everyone loves their 265-75's. If you've made this jump, can you describe to me the difference in how it shifts? For example, if I step on the gas from a stop now with 245-75's... And it shifts from first to second at 10mph... Will it shift at 8 seconds or 12 seconds with 265-75's? Or will it shift at 10 seconds with a much higher or lower RPM? Same goes for 3, 4, 5? Or will the rpm's be slower to climb from a stop? I'm not even sure how to phrase the question. I know speed is also a variable. Just not sure how this all fits together. If anyone can comment, I'd appreciate it a lot.

 

It's a little different but not very noticeable 4th to 5th is probably the hardest going up a hill at 80mph like to shift in and out but other than that not a lot of change I wouldn't worry you can also refer if you don't like the way it drives but you won't regret it

 

You will feel a very minor power loss but thats about it. The only time shifting points change is when you regear, you don't need to worry about that at all. Only regear if you are going up to 285's or larger, even then you don't have to

 

Of course. Here are a couple of different calculators and a simple chart.
http://www.4lo.com/calc/geartire.php
http://www.ajdesigner.com/phpgear/gear_equation_effective_gear_ratio.php
http://www.southwestpowersports.com/gearchange.html

 

Thanks guys. This is the kind of info I'm looking for.

 

I waited until I bought my 3rd set of tires to make the switch to 265/75/16's. Wish now I'd done it on the 1st set. Under "normal" driving conditions, including pulling 4000-5000 lbs I don't really notice any difference. There are times when driving in city traffic, or on some narrow country roads at 35-45 mph where the transmission tries to shift into OD and it feels sluggish. I've just learned to take it out of OD on those roads and it is fine. Probably should have done the same with the smaller tires, but I never noticed it before.

It may make a difference on different vehicles. I'm driving an 07 double cab 4X4 TRD with 3.73 gears. Higher gears may have different results.

It also changes speedo and odometer readings. According to my GPS my speedo was always reading about 3mph faster than the GPS. With the 265/75/16's they are now in sync.

 

^^Thanks. I've already got some gear "hunting" going on. Seems to happen on the interstate on inclines at ~70-80mph. Also notice it in town around 30mph, as you mentioned. Especially when slowing at an intersection to look for traffic, not coming to a full stop, and then accelerating again. I don't want an exaggeration of what I'm already experiencing. So I'm just trying to get a feel for how it might be with the larger tires.

 

The gear hunting is just inherant to the Tacoma automatic transmissions. My Ex had an FJ and I HATED driving it on the highway for that reason. The tires wont make it any better/worse.

The flip side of that is, I have the 6-speed manual and its a pain in the ass offroad in technical stuff (hill climbs especially). I'm starting to think the 6-speed with a crawlbow is the perfect combination, but I'm completely off topic.

Get the taller tires, you won't notice a negative difference.

 

I have a 4 banger with a manual transmission and I don't notice much of a difference and I'm down about 80 hp or so from the V6. It turns the 265/75 tires with ease. After all they are still only a 31.7" tire so it's not a very big difference in size.

 

^^thanks guys

 

About ready to make the jump. Wondering if anyone else can add comment on my original question.

 

I did that jump and honestly didn't really feel a difference in loss of power. I was still able to keep all my revs below 2k rpm if I really wanted to maximize fuel.. I would definitely go to 265/75 if I were you.

 

The weight, i.e. load range P/C/D/E, of the tires will have as much or more effect on your driving than an inch of diameter. I went from 265/65 to 265/70R17 in a P rating, no noticeable difference.

 

While the above is true on the speedometer, your ODOMETER will now be less accurate due to the change in tire diameter, so measure your dash odometer against GPS or mile marker (ie 50 miles) to see what correction % to adjust your mpg.

 

The difference will be very minimal. For my truck going to 265/75 from 245/75 it actually made it 100% accurate, before it read fast.

 

IF and ONLY IF the odometer was off the same % that the speedometer was off, which may/may not be true. A lot of us believe they are truly independent of each other, not like the old days when both were a single mechanical gauge driven off of a cable, where you could change a gear to correct tire/axle ratio changes and it changed speedometer and odometer by the same amount. When my Tacoma was new, it read 3mph high on the speedometer, but almost perfect (off .5 miles per 100 miles) on the odometer. A change that corrects the speedometer will cause the odometer to change also.

 

Thanks guys. Sure seems like we would know for certain by now if the speedo/odd were tied together or ran independent of each other. I'm familiar with the respective changes associated with tire size change. I'm running about 3mph high so it should be right on with a 265/75. With that change, and assuming the odometer would NOT change, I think I'd honestly be getting a more realistic mpg calculation. I'm consistently in the 17's and I drive with a light foot. I think 18's would be more realistic and more in line with a majority of reports. But... Ha That's another thread.

Looking forward to the bigger tires.