Ok heres the problem I have. I have a 2005 2wd screw and I am putting 18's wrapped by a 285/75/18 on it. It is stock 3.55 gears I think not sure. With that tire size would I need to regear if so what gears would be best. I do pull a stock car about 2 times a month and my truck is a daily driver. The stock wheels are 255/70/17 with stock 17's. I am adding a 2.5" level to be able to fit the 33" tire in there. just making sure I wont be losing speed or power. Thanks for any help. Also I know i am asking allot here but I may also go with a 3" level and 1" rear block to fit 35' tires. Can anyone help with the gearing for both setups. If it will help the tire i will be running will be the NITTO TERRA GRAPPLERS. Love the look. Thanks again for any help.

 

If your tire size is correct, those are 35" tires. Are you sure you didn't mean 285/65R18? And you will need a lift to do 35" tires.

 

Pluging the numbers into this: http://www.miata.net/garage/tirecalc.html

That's almost a 35" tire you are going to. That's gonna hurt, given you are currently running a 31" tire.

If you are at 3.55 (check doorjamb code for ratio info: http://www.fordf150.net/howto/decode.php), IMHO, I'd go to at least 4:30's - 4:56's, with a lift and towing requirements.



http://www.4lo.com/calc/geartable.htm


MGD

 

Currently I havent done anything I am completely stock right now. Those are 2 options I am thinking of going to. I have also looked at this setup listed below as this seems to be the safest so far. A 2 or 2.5 level kit for the front and running 285/70/17 nitto terra grapplers on moto metal 951's this would keep stock rim size and I was assured by pepboys that a 2 or a 2.5 front level kit would allow the 33" tires to fit no rubbing. Is this setup safer and would I need to swap gears if i run this. I am currently stock right now. I meant 35" I know I put 33" but I did mean 35" I am just seeing what is my safest and best option. Thanks again for all the help also on the chart above not sure what the yellow, black, and blue mean.

 

First - decide upon on the rolling stock.

Then, go ahead and install it, and use yer programmer to adjust appropriately (after confirming yer GR). You will need a programmer to correct the powertrain for this or else shift points, & speedo will be off, and to add a bit of power to offset the rotation mass increases and aero hit from leveling.

Drive the truck use it as you normally would. Then decide if you need a new gearset.

While ANY increase in rolling diameter and wheel weight WILL benefit from a gear swap, a LOT of folks on here do not do it and are happy. especially if they also use a programmer.

It's YOUR SOTP that matters - we ain't you. We can't judge for ya.

My take? Regear to get yer lost torque back - levelling & towing to boot is not optimal on 3.55's with 33's. IMHO....

EDIT - colours reflect the low / high / optimum revs w.r.t TS / GR. The second chart uses Red and Green - it's easier to unnerstand

MGD

 

For 33" yes you need a leveling kit on a 2wd. For 35" though you will need a lift.

 

not sure i agree. yes 33" need a level to fit correctly. currently i fit 35" with a level with no adverse affects. saved me the expense of a lift and the added benefit of 35" tires to play with!

needing a lift, nope. enjoying the fun with 35's, yep.

 

According to your sig, you have 315/70R17 tires. Those are closer to 34" than 35". 34.36" to be exact.

 

my bad, i have 34.36X12.40R17 if you want to be exact. if you ask me, i will call them 35's.

not all 35X12.50R17 are exactly 35". if it would make you feel better i can over-air them to get them to 34.51 and suffice your rating.

point is they fit without a lift. im sure 0.15" will not make a big difference. not saying dont do a lift either. if i had not spent the funds on another project i would have.

 

I've got 35x12.5x20 and I only have a 2" level.

op, I have factory 3.73's and use a programmer to adjust shift points. I've thought about regearing but dont know if the cost is worth it. I didnt feel like I lost alot.

 

You also have a 4x4. The OP has a 2wd. There is a 2" difference in height between the 4wd and 2wd.

 

Ahhh... Didn't catch that... My opinion is still valid as far as re-gearing goes..just not if he can fit 35's...

 

Well I found something that may work. Same as before with the 3" front level and 1" rear block. Tire size would be 285/75/17. That would be a 33.8" tire. Would this setup work with no trimming?

 

So which gear is right?

If I may ask my question in this area as well, if its Ok.

Looking at the chart that was posted, and doing the math I show I would need a gear set of 4.33ish (33" new tire/27" old tire X 3.55) in my two wheel drive. (275/60/20 wheels) I'm thinking I should go ahead and move on up to the 4:56 set. Sound right?

 

They will fit.