I've been reading the posts about gears and tires and I would like to clairify a few things

-Can the stock rims be replaced with having to get a different size tire (will the rims be the same size?)

-how do I know what size gears I have?

-There was a site posted that had info about matching the gears with poper size tires and how crucial that can be, does anyone know what that site is?


-How do I know if a shop is worth the money? (what do I ASK?)

01 F350 CC Longbed V10

 

AKTruck

SuperDuty truck tires and rims...

Typically the factory rims are 16/17/18 inch diameter by 8 inches wide and accept a wide range of tire sizes safely. I think many of the larger tires that are popular up to 33X12.5 will live OK on 8 inch wide rims...much bigger tires will need to move up to 8.5/9/or 10 inch wide rims

If your truck is a 05 or later then the smallest rim diameter is 17 inches because Ford increased the disk brake rotor diameter and 16" rims no longer fit

The tallest tire that safely clears all the way around at max rebound and compression on a 4X4 TRUCK is the 33X12.5... if you go to 35s or 33x13.5 wide you need a lift and change of rim offset for full clearance

Also you need to know that the factory rims are HUB centric... they use shouldered lug nuts to pinch the rim to the axle flange and the center hole is supporting the up and down weight and obviously keeping it centered... Many of the cheap aftermarket rims that are popular like the Mickey Thompson Classic IIs are LUG centric and they use cone shaped lug nuts and the up and down weight is on the axle studs and the centering is by all 8 of the lug nuts... None of these designs has the same weight carrying capacity as the HUB centric design does...hint...that is why they are $250 dollars cheaper apiece!

Your truck 01 F350 CC Longbed V10 most likely has 3.73:1 gears in it and this is a very good ratio for most medium duty tow and haul and running empty... 4.10:1 and 4.30:1 are a little better at acceleration from a standing stop and do real good in hilly or mountain terrain with a serious load on the back. For a real tall lift and tires in the 36 and up range then 4.56 or 4.88 are usually needed to keep cruise RPMs in the power band... you can get crazy and go to 5.12:1 or 5.27:1 and a set of 40 inch tires but I don't recommend it unless you have gobs of money for complete drive line reconstruction and bulletproofing of the trans

On the drivers door jam is a label with the axle codes and we have a table on this site that can translate it.. you can have 3.73:1 typical stock ratio for 2000-2004 or the optional 4.10:1 or 4.30:1 and there is also a optional Limited Slip (LS) for all three of these ratios

We also have a link in this forum for a gear and tire diameter calculator that will give you RPMs at different speeds....

When selecting new gears or new tires it is wise to adjust them so the the V10 runs around 2100-2250 RPM at 70 mph... typically this range has best throttle response and MPG

Sorry I don't have the links on this computer... someone will post them after they read this

 

Fred - I am pretty sure that all the 16 inch wheels on the 1999 thru 2004 SD's were 16 x 7 from the factory. At least all the ones that I have seen (including mine) have been. Just wanted to clarify.

 

AKtruck --

Check your VIN door sticker under axle code. Hope this helps...

biz

 

I think the 7 inch wide for the 16" rims is correct and I forgot to add that in as I was typing furiously on my info piece above... This limits saft tire fitment to most of the 11.5 wide designs... I know folks who have put very wide tires on the 7" wide rims but I think it is not safe for towing heavy this way.... too much side wall flex and tire roll off in a tight turn is possible on the front end

 

17" wheels are 7.5" wide if memory serves

 

I pull a gooseneck trailer (about 16K-17K) every once in a while so my question is how tall can my tires be? I have heard 285's are to tall, anybody know?

 

ON what truck?

SRW, DRW, 4x4, 3.73:1 or lower

My SRW F350 4x4 with 4.30:1 is running factory 33inch (275x70x18) tall tire

285s depending on aspect ratio (45, 50, 55, 60 , 65...etc) are not much taller

That all said the 285/295 series is used all the time on these trucks... just be sure to get a set with a high enough load rating for your truck with trailer hitched...HINT...NOT all Load "E" tires have the same load capacity.... they can be as low as 1900 pounds "E' rated at 60 psi up to 3640 pounds at 80 psi and a lot of them are in between these extreemes... on dual wheel axles they are slightly de-rated but you still get to multiply the de-rated capacity by 4... so 4, 2100 pound max weigh tires have more capacity (8400 ponds) then my two 3640 tires (7280 pounds)

I think the 285s work fine on most all the 99 and up SuperDuty trucks but may have issues on the rear duals...sorry been a while since I looked up what the max width can be fitted to dually rims but I seem to recall that 245 is stock and up to 265 can be fitted

 

I find these two sites to be a helpful site for that.

One for getting the right tire diameter. http://www.miata.net/garage/tirecalc.html

And the other to help you with determining RPMs at a given speed. http://www.angelfire.com/space/slr/RPMCalculator.htm

As much as I love FTE, I find the calculators here a bit limiting for those calculations.