Worth going from 3.73s to 4.10s? | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Worth going from 3.73s to 4.10s?

358R

Well-Known Member
Joined
September 2, 2012
Messages
113
Reaction score
8
City, State
Clemson/Aiken, SC
Year, Model & Trim Level
99 Mounty 5.0
So, truck is a 99 Mounty 5.0 2wd. Will be lowering it 2" this week and hopefully installing my TM headers soon after (and full exhaust after that). The end game is to improve MPGs, but looking to add some "fun" to the truck (ability to pass a little easier without having to drop out of O/D and then drop a gear). Will either be going with 255/55R18s or 275/40R18s for my 18x9s.

Question is: Will going to 4.10s completely negate everything I'm doing MPG-wise or no? I understand that it's only a "step" up from the 3.73s...so my thought process is that it won't be but a few hundred RPMs higher...but would also rev up a little quicker. I've gone from 3.27s to 3.73s in a mustang before and saw little to no loss in MPGs...but it also doesn't weight 4600 lbs.

Thoughts? Opinions?
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





The 4.10's would be about best if those tires end up being more than 60lbs per wheel/tire. The tire and wheel weight will hurt mileage more than a minor gear change.

I had 72.5lbs tire/wheel on my first 98(pictured in my Avatar). Those hurt fuel mileage a ton. I had Cobra 17's before that, weighing 58lbs per wheel/tire. The heavy wheels I had were cheap 18's, with 265/60's. I slowly changed tires as I wore them out, down to a 255/55/18, and those were still around 64lbs together. I have some used 17's not to use, they are forged and only weigh 22lbs per wheel. The tires I have for them are 275/55's, and together will net me 58lbs per wheel/tire. That will return my mileage to near stock.

Have you thought of the 275/55/18 tires, which are only 30" tall, the stock diameter for best speedometer readings. The 255/55's are 29" tall, I liked those but wanted wider also.
 






The 4.10's would be about best if those tires end up being more than 60lbs per wheel/tire. The tire and wheel weight will hurt mileage more than a minor gear change.

I had 72.5lbs tire/wheel on my first 98(pictured in my Avatar). Those hurt fuel mileage a ton. I had Cobra 17's before that, weighing 58lbs per wheel/tire. The heavy wheels I had were cheap 18's, with 265/60's. I slowly changed tires as I wore them out, down to a 255/55/18, and those were still around 64lbs together. I have some used 17's not to use, they are forged and only weigh 22lbs per wheel. The tires I have for them are 275/55's, and together will net me 58lbs per wheel/tire. That will return my mileage to near stock.

Have you thought of the 275/55/18 tires, which are only 30" tall, the stock diameter for best speedometer readings. The 255/55's are 29" tall, I liked those but wanted wider also.

Do you have pictures of 275/55s on yours? And the wheels in question are 18" replica 03/04 Cobra wheels. Can't find the spec on the 18s, but I know the 17s weigh 23lbs/each. Also, did you have any rubbing/scrubbing issues with the 275s if you indeed have them?
 






Or would a 4.33 or 4.56 be more what I'm looking for (and me keeping in mind that weight reduction is more the key than the actual gearing...within reason of course)?
 






The 94-04 Mustang wheels are generally about 32mm offset wheels. Those are the closest of stock type that come closest to being right. I had to use 1/4" spacers with my 18's(35mm offset(made them 29mm offset). With those I had no rubbing except the sway bar end to end, and the inner fender(top when I hit a bump hard(slow and hard)). The ball joint clearance is the biggest thing to watch for.

I don't have the 275/55/17's mounted yet, the wheels are away being refinished. These I have are 16mm offset, so they will easily clear the inside(17x9's like those 03 Cobra wheels). I think you will likely need a spacer in front, and tie back the parking brake cable at the left rear. Those 9" wheels with 30 or 32mm offset, will be inboard about a 1/4" more than my old 18x8.5" wheels. Here below is a picture of those with 265/60/18's.

These are effectively an 18x8.5" wheel with 29mm offset.

Moven 18x8.5 72lbs.JPG
 






Or would a 4.33 or 4.56 be more what I'm looking for (and me keeping in mind that weight reduction is more the key than the actual gearing...within reason of course)?
There are several members here with 4.10's in their 302 trucks, and they love them. I have a V6 truck with 4.10's, and that's a great gear for the SOHC V6. For performance you will like the 4.10's better, but with near stock tire heights, 4.30 may be pushing what you want for highway rpm's. If you are a type of person who doesn't mind the extra rpm's, then going two steps won't bother you.

For my 99 V6 truck, I'll eventually swap a 306 into it. When I do that I'll leave the 4.10's alone, but build the transmission with close ratios. That will move the 1st and 2nd gears closer to 3rd/4th, which don't change. It will be like having 3.55's for 1st and 2nd gear, and 4.10's for 3rd/4th. That will work for me, because the 306 will make a lot more torque, enough to negate the gear deficiency at the start. If I don't like it after that's done, then I can do the diff's later.
 






The 94-04 Mustang wheels are generally about 32mm offset wheels. Those are the closest of stock type that come closest to being right. I had to use 1/4" spacers with my 18's(35mm offset(made them 29mm offset). With those I had no rubbing except the sway bar end to end, and the inner fender(top when I hit a bump hard(slow and hard)). The ball joint clearance is the biggest thing to watch for.

I don't have the 275/55/17's mounted yet, the wheels are away being refinished. These I have are 16mm offset, so they will easily clear the inside(17x9's like those 03 Cobra wheels). I think you will likely need a spacer in front, and tie back the parking brake cable at the left rear. Those 9" wheels with 30 or 32mm offset, will be inboard about a 1/4" more than my old 18x8.5" wheels. Here below is a picture of those with 265/60/18's.

These are effectively an 18x8.5" wheel with 29mm offset.

View attachment 152194

These 18x9s are 26mm offset, 6.11 backspacing. I'm still learning about wheels, offsets, etc on one of the other posts that's all about that stuff. (No, I'm not asking for help with the math, just posting for future readers in the event this comes up again) I'll have to work out my math and spacing issues later. I've seen 18x10s on the back of some so I'm thinking I'll be ok.
 






The front is the hard part with wide tires and wheels. I had little trouble with 17x8" Cobra wheels, but those being 1" narrower are easier.

That 18x9" wheel with 26mm offset will be inboard by about 3mm, more than my 18's were, plus the 1/2" wider wheel(1/4" inboard and outboard), so the gap to the BJ will be about 3/8" closer than I had. I think you will need a spacer, maybe 1/4" will do it, maybe. The tire you choose will affect it, I began with 265mm and came down to 255's. I still have the 255/55/18's, but they are going on my 99 to wear them out and get rid of the wheels(too heavy).

If you could get a tire to test fit with, that would be best to make sure it fits in the front, Can you you get a single 18" tire somewhere in that 255-275mm range?
 






I think so. May be some red tape involved though to get it home from work. I'll investigate tomorrow.
 






ok, i'm getting side tracked, but am i correct in reading that my stock wheel is 15x7, -19mm offset, and 3.25" backspacing?
 






That 19mm offset sounds about right, and the stock wheels were all 7" wide, 15x7 or 16x7. The stock clearance though is more than what people end up with on the inside though, so the stock figures don't really help when you change the wheel by 2" etc. The lower profile tires mean less sidewall movement, so they can have slightly less clearance. The tire must never touch the ball joints, being steel they will eat a tire.

Other members have also put tires near what you are aiming towards. The Saleen XP8 Explorers came with 18x9" wheels, and those were around 20mm offset. But most of the XP8's were 99-01's with the wide fender flares, so the tire didn't seem to be out too much on those. The most recent member to put those XP8 wheels on his truck used a 255/55/18 tires, which fit easily, on his white Limited, 2000 model I think.
 






My stock Terminator wheels fit about perfect with a 1" bolt on spacer all around. If I didn't have the big flares they would have stuck out though
 






That is a good description also. The space is not ideal for a 9" wheel or a 275mm tire, but located perfectly they can fit. With narrow wheels and tires, they can be in or out a lot and still clear fine.

I bought the thin fender flares from a 98ish Sport, to better cover the big tires I'm planning. These flares are about half the width of the big ones, and have a small corner piece at the bottom made for the non running board trim. Those I'll have to trim, cut up to mate to my 98 running boards.
 






Back
Top