I have 35X12.5 Installed and a 4.5 Lift with these new tire hauling large loads seems gutless out of the whole I have 3.73 stock gears and it hauled way better when I had the stock tires because it was obiously geared lower. My question is what would my gearing roughly be right now with 35's?? And what gears would I need to have to get back to roughly 3.73's??? And also would that just ruin my fuel economy?? Because with going bigger tires and raising my gear ratio I still get worse fuel economy is that cause of the extra drag of the big tires?? All help would be appreciated as I do tow 10,000 Lbs occasionly and it sucks right now, even with the chip, exhaust and intake.

 

i think 3.30 somethings

 

Anyone with a little more input??

 

If you had 265/70-17's and now have a 35" tire you've effectively lowered the gear ratio to 3.37:1. To get back to stock you need 4.13:1 gear ratio. So dropping in a set of 4.10's will bring you back to stock. Keep in mind, however, performance will still be a little off because of the much heavier tire and it's rolling resistance, so mileage will suffer a bit no matter what. If they were available I'd recommend a set of 4:30's. Good luck!

 

As stated above your gearing is the range of 3.30-3.35, can't find that darn algorithm for exact number.

And as stated above replaceing 3.73 with 4.10 gears will get you very close the stock ratio.

 

just do more bombs and leave the stock ratio in

 

Its a simple ratio. The 265/70-17 equates to a 31.6" tire. Effective gear ratio=(old gear ratio)x(old tire diameter)/(new tire diameter).

E.G.R.= 3.73 x 31.6/35 = 3.368

 

Thanks for the reminder. It is so much easier now on the Internet, I know that somebody out there knows the right answer. I probably did a while back, but the short term memory is toast and I never could remember the 70s or 80s .

 

Thanks guys that makes perfect sense, do you think if I went to 4.10's that my milage would be better than with the stock gearing and the big tires?? Or would it just get worse because now I'm turning more RPM again and also the drag of the big tires. I would think it would get slightly better if not about the same. Thanks in advance guys!!

 

Still not going to be great with that large rotating mass...
Wont lag as much, but higher rpms than you have now, cruising...
My problem is I see 75-85% city, and little highway, 315s would probably kill my mileage in stop and go...

I still cant decide myself, 285s, 305s, or 315s...
Just hit or miss with people having the death wobble and fuel mileage turning to complete crud...

Did you have any hint of the DW with your 35s? uneven wear?

 

I think at best it may get slightly better, and and worst it will stay the say, assuming you don't get on it more with that new found power...

 

With my 325's and 3.73's I bet I get 12 mpg in the city. But that's what I've been getting for the past 15 yrs. I've had hot-rod trucks or lifted trucks since I was 17, and they all got crappy mileage. Of course gas was a bit cheaper at that time...

 

I have had no sign of the death wobble at all my truck runs very nice with the lift the only thing is the ride is a little tighter with the extra leaf I added and the wonder is worse because of the wide tires but otherwise I'm very happy with the ride quality of the truck for the size of the tires. My milage isn't the greatest though, but mid you the milage on my truck hasn't been the greatest even since new when it was stock but I'm comparing to my buddies 5.9 Cummins 2nd gen and he gets amazing milage compared to the 3rd gen motor.

 

I had the same problem with the toyo mt's In my opinion they are the best looking tire and the worst riding tire. The wider tire and side lugs kill your mileage. I went to the bfg 315s and increased my mileage 4mpg. Run the tires as hard as you can that will help as well. I run them @ 60 all though they are only rated to go to 50. The only draw back is if you have 8" rims you will wear the middles out on the rears faster! If you are regimented in your tire rotation its not much of a problem. I got 50k out of the last set i had. As for power with 3.73's your gonna loose some turning big tires! Just find the happy place in your rpm's (mine is 1800-2000) and you will let the massive amonts of torque do it's job.

Just my opinion

 

I saw this in catalog the other day and it just popped into my head that it may help you out.

http://www.motivegear.com/pages/charts/CHART.pdf

The chart pretty much says that I have the wrong gears also (since I run 285's that are 32.9" dia by spec). I'd love to have 4:10's but can't afford them for both axles. Maybe someday someone will trade me straight across.