do you NEED to adjust gear ratio after tire upgrade?

How do you get better gas mileage if the engine is turning faster at any given speed?

 

It helps by not giving it more gas on the pedal. if u dont regear u would feel it when u step on the gas that the truck wont go esp at start. and u would feel that u need to step on the gas more for the truck to reach top end speed

 

Sure it helps acceleration, but at a steady speed you are going to be turning a higher engine speed. So maybe it helps city mileage, but I'm not convinced about highway.

 

4 wheel ulimited I believe. It's in Pomona near the 10 and 71

 

So, if you had a 6 lug 4cyl with 245/75/16 and moved up to 265/75/16, That would place my effective gear ratio closer to that of the 5 lug tacos and I should expect better mpgs from what I am hearing?

 

You would effectively have a taller final drive, but you're also increasing your unsprung weight. I haven't personally ever done this but it's something I'm looking into for my 4cyl as well, around town you will probably need more throttle to get around but it seems like on the highway with cruise control going a steady speed you will be turning a lower engine speed and theoretically might see slightly better mpg... I wouldn't expect better mileage though just because of the increase in unsprung weight.

 

ok thanks.

 

hi. do u by chance know how to determine if my gear ratios is correct . had it regeared to 4.56's but im not sure if they really put 4.56's in there. is there a way to test it? hopefully my haunch is wrong that its 4.10's instead. felt that the acceleration is still slow.

thanks fot the help in advance.

 

1 lb of sprung for 10 lbs of unsprung.

You get more torque going to a shorter drive, but you're also turning a higher engine speed. Not really sure you're burning less fuel at a higher engine speed on the highway, though it does take less effort to get moving around town.

 

I don't know if I'm picky, or if the 2.7l has much less power than I expected, but with my 32's that are only 4% bigger than stock, I can't seem to go wheeling without constantly revving the engine past 5k revs in first gear. On the freeway, it barely wants to stay at 70 mph in 5th, and any .5% grade hill will slow it down to 60 unless I shift to 4th.

I want to bring it back down to 31x10.5, the stock size for higher trim tacomas of my generation, I believe.

Or regear it...I think a tire change would be easier.

 

That sounds lame. I wanted to upgrade immediately to 265's but now I am unsure. Did you put on 265's or a 32''? They are close, but from what you are saying every little bit makes a difference.

To compare:


from the online tire size calculator


from the online tire size calculator

 

I have 32x11.5 R15's on.

The door jam says my stock tire size is 225/75R15, but that sounds like the stock size for the base level 2wd's and 32's would be 14% bigger. I'm supposing that my stock size was 265/75R15 (via tirerack.com), seeing as the speedo is only 4mph off when going 60mph.

I'm going to go see what gear ratio I have via http://www.brian894x4.com/Gearratiosanddiffs.html In a few days.

But I can't right now as I have to leave for Montana ^_^.

 

i regeared to 4.56's after getting my 35's...huge difference all around after regearing. for example..going up a long incline on the highway such as the Cajon Pass..with the stock gears the tranny was always back and forth between 4th and 5th gears. with the new gears stays in 5th going up the pass. on the trail is where i feel the gears the most, makes a huge difference crawling over rocks and what not. i barley touch the skinny and i'm easily up and over like i know what i'm doing haha.

 

There are very few circumstances where gearing lower (numerically higher) will improve mileage on the highway. There are many situations when doing the same for lower speed driving, will increase mileage. If you do a mix, you would have to do it for the other benefits, & mileage secondly. If you do a lot of stop and go, or heavy towing, you might one day make your money back....

 

i love my 4.56's..they are the Nitro gears with the thick cut. overall the 4.56's with the 35" tires have balanced everything out very well both streetwise and on the trail. since it's my daily driver i chose the 4.56 over anything lower. if this was my trail rig i'd get 4.88's as that would be more ideal for the trail...make sense? just woke up and havn't had coffee yet

 

Huh. Well I geuss I just might be picky with my truck...because according to http://www.brian894x4.com/Gearratiosanddiffs.html i have 4.10 stock gearing.

What I don't understand is the tire size that was stock with the truck. The door jam says 225/75R15, which - according to that gear reference site - makes sense, but my 32's are 14% bigger than that, and the speedo's only off by about 4.5 mph at 60 mph, which leads me to believe that my stock tire size is 265/75R15, 4% smaller than my 32's.

I want better gas mileage in town, less lugging at second gear on trails/over-revving in first, and less of a need to downshift to fourth gear on the freeway.

Would regearing to 4.56 be overkill for the 32x11.5R15's?