larger tires power lost

1roy · **Joined:** Wed Jul 13, 2005 9:59 pm **Posts:** 38

my 04 liberty has the 235/70 tires i am going to up grade to 245/75 revos how much power will i lose off the line and will over drive still work

benmar2000 · **Posted:** Sat Dec 24, 2005 12:46 am

I can't answer that on the Libby.. Yet..

But when I went from 215/75R15 to 30x9.50R15s on my YJ 2.5L.. I did notice a small power lose.. But nothing major... By looking at the specs.. I don't think you will notice anything...

HTH

Ben

KJRenny · **Joined:** Wed Oct 19, 2005 10:52 pm **Posts:** 72

I have to disagree... I went to a 245/75 and there is a noticable loss in go power. Highway driving(60mph-70mph) the truck has to constantly downshift to get over small overpasses.

Taz · **Posted:** Sat Dec 24, 2005 11:47 am

The truck still has the same power. The engine is in a different (lower) RPM range with the larger tires, and it needs to downshift to get into the power band in the RPM range.

hillcountrykj · **Posted:** Sat Dec 24, 2005 1:16 pm

You will see a lost of fuel milage too. But in my opinion it is worth the trade off. It will depend on what type of tires you buy too. some are heavier than others, and a all season tire will roll better than a mudd terrian or an all terrian tire.

Taz · **Posted:** Sat Dec 24, 2005 2:32 pm

Remember that if you do not recalibrate your spedometer your fuel milage will show a drop even if it does not really change. The tire sizes you are looking at will have a difference of about 5% in the odometer and spedometer readings. If your Leep gets 20 mpg without a spedo recalibration it will show about 1 MPG loss after the tire swap. My last rig I actually saw a milage increase on the highway going to bigger tires since the engine was running at lower RPM's, I also saw a slight milage decrease in the city from the extra rolling resistance of the larger tires.

krazz1e · **Posted:** Sat Dec 24, 2005 5:19 pm

very minor. you can notice a difference at first but that quickly fads. Still has plenty of pickup. If the diff could handle a bigger tire up to 33's would probably be ok.

No worries, get the 245/75's!

Bakerkj · **Posted:** Sat Dec 24, 2005 10:42 pm

Just push down on the skinny pedal a little harder and you'll be fine..

warblade666 · **Posted:** Sat Dec 24, 2005 11:00 pm

Just remember that LT245/75R16 tires with an E-load are about twice the weight of the stock P215/75R16 or P235/70R16 load-b tires.
They are also 2" larger , which changes the gear ratio too.

zeero · **Posted:** Mon Dec 26, 2005 1:58 am

Whats the speed-o difference with 245/75/16's on? :wink:

ManicMechanicJoe · **Posted:** Mon Dec 26, 2005 7:16 am

It's gonna feel like you regeared a little higher. I gained a couple of miles per gallon because the engine runs 200 rpms lower at 60. Over drive still works, it just likes to "hunt" between gears more (i have the 45rfe) kinda like an old TH700R4 (chevy's first 4 speed overdrive). In town, my fuel mileage decreased, but since my driving is split 50/50 between city and highway the difference is made up and i get the same mileage if that makes sense. I run an all terrain tire which helps. A 245 is a skinnier tire so your fuel mileage may actually be better then mine. If it bugs you too much, find a wrecked 4 cylinder and get the front diff of it, then put it and a new set of rear gears in and you will have enough power to turn 33's with ease. Man, I want 4.10's

Taz · **Posted:** Mon Dec 26, 2005 5:48 pm

zeero wrote:

Whats the speed-o difference with 245/75/16's on? :wink:

About 5%

larger tires power lost

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