Does anyone have experience with 4.88 gears and 35" tires on an F250 4x4 and V10?
That is what I am about to switch to and I am a little nervous about the 4.88's. Shop tells me it will only be a little lower than it is right now after the tires go on. Probably 2-300 RPM higher at highway speed.
Anyone have any thoughts or experiences?

 

I once had 4.56's on 44's on a blazer.....do you have stock 3.73's now ? I personally wouldn't do 4.88's on just 35"s , just too low on that size of tire. Try the 35"s w/ your current gears first.

 

I have 4.10's right now.

 

Try it w/ the 4.10's, that way you can see how hold up w/ the 35's. I had 4.10's on my 44's at first but it was a big load, thats y i went to 4.56's. but 4.88's on 35's is something i wouldn't do unless the tires were much bigger. 4.88's will kill your gas milage and an extra 2300 rpms at highway speeds is more stress on your motor.

 

I found a final drive calculator somewhere on a tire website, cant find it now. But anyway I am going to 35's and have the 4.30s right now. The calculation if I remember right said I was going to be at around 3.90 after the tire install. If you have 4.10s then 35s would put you in the 3.7x-3.8x range.

 

2300 rpms would be an awful lot. it is more like 200-300 rpms more.

 

your original post looked like 2300, haha...sorry. 200-300 isn't bad then. It's up to you. Let us know what u do.

 

Try the calculator in my sig, it may help you out.

I run 4.56's with 36's and I probably should have gone to 4.88's. 4.56's will be just fine with 35's.

Don't be afraid of a little RPM in the V10, it'll be just fine. 2250 - 2500 RPM is where you want to be at around 70 MPH.

As far as a price goes, look at $300 - 500 per axle in labor, $150 - 200 per gear set, $100 - 200 per install kit (depending on the level of the kit). So anywhere from $1100 - 1800 for the whole deal.

 

4.88s or lowerOne must consider than V10s come with 4.30s stock as well. Add 10% for the tire size increase and you are at 4.73 to get you back to stock. 4.88s won't hurt a thing and will be alot more fun to drive.

 

Damn you guys are good! I will be going with the 4.88's and the 35" tires. Unfortunately I will be out of town for about 2 weeks (earning money to pay for this stuff) and will have to wait until then to get it done.

 

Here's another item for you to ponder......

Whatcha gonna do for differentials?

You gonna stay with the stock open carrier up front and the (I'm assuming) LSD in the rear?

If you are even remotely considering adding a LSD or locker in either axle, DO IT ALL AT THE SAME TIME! Otherwise you will be paying those labor costs again.

I'm assuming this is still gonna be a daily driver for you. If so, seriously look at a Detroit TrueTrac for the rear. It's a much more solid and effective LSD than the OEM LSD. Up front, same thing or drop the bucks and get a selectable.

After having these ARB's in mine, I'M COMPLETELY, 100% sold on these puppies! It is so nice going from open diff's on the road to locked up tight when I need them. I can't believe the hills this thing will climb now without even spinning a tire.

 

I had briefly considered that but have never finished the thought. What do you mean by selectable? Let me rephrase that, what are you selecting? and how do you select it?

Also if you install a truetrac in the rear do you have to do the front or could you leave it OEM? Other than off roading, which I only do occassionaly, (I have 4wd because I have to pull heavy loads in soft dirt and mud or up some pretty steep grades that have dirt roads, I don't really consider that off roading) what advantages would I see by having a locker?

 

Okay, quick differential tech:

Normal / Conventional Differential: Open design, allows one wheel to spin faster than the other, as in turning. But, sends all power to the wheel with the least traction. Good for a street only vehicle.

Limited Slip Differential: Uses clutches, plates, cones or gears to keep both wheels turning (most of the time), but still allows for one wheel to spin at a different speed while still sending power to the one wheel that may have traction. Good for a performance car or tow vehicle, espcially on slick surfaces.

Locker: Makes both wheels spin when ever power is applied. Both tires always receive 100% of the power. Best for off road vehicles or drag type vehicles. Not good for tow vehicles and will increase tire and driveline wear.

Selectable Lockers (Best of all worlds): Open when disengaged / Locked when engaged. Traction when YOU want it. What you are doing when you engage it, is physically locking the axles together, like it was one solid piece of steel. But, these are the most expensive and require the most labor to install.

You're driving a tow vehicle / daily driver, so I'd go Limited Slip (LSD) in the rear. The front you can leave alone. But if you do put one up front, you will really want to consider a selectable, like an ARB, Detroit ElecTrac, Auburn ECTED, etc.

Here is a few links for you to check out.

http://www.detroitlocker.com/ProductsPage.htm
http://www.arbusa.com/air_locker_locking_differentials.htm
http://www.automotive.eaton.com/product/traction_stability/elocker.html
http://www.auburngear.com/oemdifferentials/