Check out http://www.4lo.com

There are a few good calculators there that
will answer your questions. I am guessing you will need a 3.90 or something close to that to return it to stock. I just got done with the 4" lift and 315/75/R16 (35x12.5.r16)
on my 98. I kept the "3.55" gears in my rear-end. I have had no problems yet but it has only been about 1K miles.

 

Here is my plan for my truck and I was wondering if anybody had any advice or saw any possible problems before I install it.
97'F150 4.2
installing a 4"-5" superlift suspension
lift
35x14.50x16.5(or possibly 35x12.50x16.5)
tires

Currently I don't plan on changing the gears for at least a little while. If I do what might you recomend to return it to stock 3.55's.
Thanks for any advice. And Merry Christmas.

 

Great thing about gears and tire sizes, you can just use direct ratios.

35/30 = ~1.167
3.55*1.167 = ~4.14

So you looking a 4.10s to get you back to the original final drive ratio. You might want to think about going to 4.30s or 4.56s to compinsate for the heavier, wider tire with greater rolling resistance.

 

When I change mine after the first of the year, I will be going with the 4.56s...I plan on going up in tire size when I wear these out too....so I will still be in business.........Dave

------------------
1998 F-150, SC/Flairside,oxford white 4x2,4.6,auto,3.55s,nerf bars,cls 111 towing,bed liner w/mat,Eagle polished wheels 16x10 w/Yokahama Geolandars 315/75/16s,all plastics guards/bug shields,air raid/k & n filter, superchipped, duals out the back corners, flow master 3 chamber, snug top lid, f-150 online sticker back window-honk if you see me!!! Fabtech 3 1/2 lift,3" spindles, 3" body lift=9 1/2 inches of lift, lift lips.coverking dash cover, Lumi Logo's (front and rear), clear front corner lenses, muth mirrors,dash mounted CB, (TX Chapter requirement,lol),personalized license plates, Superlift traction bars,Image tail light covers (painted).and it still fits in the garage, yeahhhhhh

San Antonio
DWESSELS89@AOL.COM

 

Do you see any problems with rubbing?

 

JW, with the 5" Superlift suspension lift, 35x12.50's will fit fine. But the 35x14.50's are another question. I do know that on Superlift's website, their model truck for the '97-up F-150's is running 36x14.50's with just the 5" susp lift. If you go up to that high, you will need a certain backspacing on a wheel for them to fit ok. Again, check out their website, with the pic of the truck, it lists what wheels it has on it, and their backspacing. www.superlift.com